Turquoise Energy Ltd. News #113
covering October 2017 (posted November 3rd 2017)
Lawnhill BC Canada
by Craig Carmichael


www.TurquoiseEnergy.com = www.ElectricCaik.com = www.ElectricHubcap.com = www.ElectricWeel.com

Feature: Finally!!!: A Simple, Practical Plan for an Add-On Wheel Drive Motor! (See: Month in Brief, Electric Transport)

Month In Brief (Project Summaries etc.)
  Note on Motor Controller Repair/Power Transistor Replacement - Chevy Sprint Electric Conversion with Improved Transmission? (thought of and then abandoned... because -->) - Finally! A practical plan for an add-on wheel drive motor!

In Passing (Miscellaneous topics, editorial comments & opinionated rants)
 - English Alphabet: Like a Number System Without a Zero - British Columbia Place Names (Where does the cat wipe its feet? Kitimat)


- In Depth Project Reports -

Electric Transport - Electric Hubcap Motor Systems
* Chevy Sprint somewhat variable transmission
* Wheel Drive Motor Revived: Hybridize a gas car, the 2001 Toyota Echo *** The Simplest Plan Ever! ***
* The Unique Feature: Single Variable Pulley on Pivoting Shaft... best choice?: automatic centrifugal pulley
* Then there's the Slipping Clutch with Flywheel idea(again?)... or a centrifugal Clutch?

Other "Green" Electric Equipment Projects
* Plan for a portable "Bandsaw Alaska Mill" for cutting lumber?

Electricity Generation (no reports)

Electricity Storage - Turquoise Battery Project (NiMn, NiNi, O2-Ni), etc. (no reports)



October in Brief

   "Immediate needs" seemed to trump "most valuable overall projects", and I worked mainly on how to efficiently electrify a car. Gasoline costs a lot around here, and in my new rural location I find I am spending hundred of dollars per month on it instead of tens, which I can ill afford, while electric car components and enough batteries for two electric cars sit idle in containers and in the shop.
   This month I sold the Dodge Caravan minivan (now running fine) that gave me all the trouble in the move up. I loaned Tom the pickup truck when he also sold his Caravan. The truck is also for sale - I figure I can haul pretty much anything it could haul in a trailer behind the more economical Toyota Echo, which is now all I have to get around in. I just hope I don't need to level-haul any vehicles behind such a small car.
   Tom is buying a used Nissan Leaf. He still hopes to bring them up and sell them on Haida Gwaii. He almost had a financial backer who lives here convinced to bring in five immediately, but the man's wife (who herself drives the only Nissan Leaf presently on the island!) vetoed the project.
   But I don't want a Leaf now. In October my protracted efforts to figure out a good way to do an add-on electric drive seem to have finally, after so many years, paid off. I came up with what looks like a pretty simple and practical way to put an add-on motor in the trunk of a car to drive a rear wheel directly. There are even several variations of the design in case the first doesn't work as well as hoped, and I have the components for any of them.
   For now I'll use the reliable electrical components salvaged from the Suzuki Swift: the Curtis AC motor and controller and the lithium ion batteries, and I'll install it all in the trunk of the Toyota Echo. The efficient mechanical drive to the wheel is the new and key thing. It will be interesting to compare the performance with the Swift with the very same electric drive system but without the reputedly lossy regular automotive transmission, to see how much extra speed and range it gets. If it draws 80-90 amps in highway cruising instead of 100-120, and gets 50 Km range instead of 35 with 50% battery reserve, it will definitely have achieved what is hoped. In fact, considering the Echo still having its gas engine and transmission will be substantially heavier than the Swift, achieving even the same performance would have to be counted as a significant improvement.
   Later I may try my own motors and controllers again. And ideally get the nickel-air batteries going. Potentially, producing complete economical "add-on hybridizing" kits, or even doing complete hybridizing jobs, has a lot of appeal. with others to do the actual work, of course.

   Even now, when I want to do most anything, I find that I usually can't find all the parts that I want. Probably they're there in a box somewhere. somewhere. A whole slate of mechanical parts seemed to have vanished until most of them turned up all in one inconspicuous, unlabelled square plastic bucket when I finally took its lid off. The rest were in an odd shaped box I had found one large item in and then forgotten about.

   But it's been difficult to find time for even the most exciting electric transport and green energy projects. I've spent more time chopping up spruce branches, and now the fourth huge spruce tree has been cut down and is lying on the lawn.

   I got a large chainsaw and borrowed an Alaska mill attachment, and have cut part of another tree into cants sized for cutting into 2" x 6" and 1" x 6" boards with the electric sawmill later. There's lots more to go, and now another huge tree.
   That's assuming I get my electric mill fixed... and also that I can't get, borrow or rent some bigger mill. (Say! Why would one not make a suitable "hand-held" bandsaw that one could use as an Alaska mill instead of using a noisy, big kerf gas chainsaw? Oh, no, not another cool project idea! One for the "wish list", I guess!)


   My lab power supply, finally retrieved from Victoria, soon started to buzz loudly and malfunction. When I opened the case it worked fine, but when my back was turned it quit with a burned smell. I spent time on two days fixing it, replacing a transistor and a quad opamp. It worked great again for a few hours except it would only put out 2 amps max instead of 10 (charging the box of 7.2 volt Honda hybrid NiMH cells, which by then badly needed it). Then it went back to buzzing loudly. I turned it off. (I guess I'll have to charge the rest of the Honda cells with solar panels in the rain, since 7.2 or 14.4 volts is wrong for any charger I have.) Perhaps it needs a new main capacitor and I'll order one along with a gradually accumulated list of other electronic parts I want. If that doesn't work, I guess I'll need to buy a new one - ugh! (I wonder what the Coast Guard electronics shop did with the two I designed and made for them in 1978? I heard a few years later they were still using them. I still have the schematics, but I can't see spending the time to make another one.)

   The grand structure that we (mostly Tom Sawyer) erected over the summer to cover my travel trailer also progressed. The metal roofing finally arrived on the 24th and we finally had it covered by the evening of the 27th. Drip caps at the edges and gutters and downspouts are yet to go. The Sawyers have moved to Skidegate Landing "for the winter" but I suspect probably won't be back to turn it into a dwelling per the original plan - Lawnhill isn't a very convenient location for them as things are working out. If not, what will it be? A lumber shed? An electric car conversion shop? A garage/hanger for a ground effect vehicle?

   Then, somewhere my last year's personal income tax (almost finished just before the move) has disappeared and will have to be redone, and so have most of my corporate tax and SR & ED papers, which were not in a box titled "SR & ED 2016" when I finally opened it to do the paperwork. It's going to be a royal pain doing the SR & ED application for 2016 without a previous year's version to use as a template, and I'll be working on it well into November. Not that it doesn't take weeks anyway. I'd have sworn I was very careful with all of these vital papers when I was packing for the move!

   Okay, so much for excuses. On to an electronics thought and finally the one grand project on the list from the very beginning: putting a motor on a car wheel to turn an ordinary gas car into a pulg-in hybrid.


Note on Motor Controller Repair/Power Transistor Replacement

   When I went to repair the Kelly BLDC motor controller, I had a terrible time unsoldering the power transistors from the circuit board - more trouble than I've ever had before unsoldering damaged components. I may have ruined the controller, which I still haven't tried to reassemble. Even if it works, I spent far too much time on what I thought would be a simple job.
   A better plan now very belatedly occurs to me. Instead of trying to unsolder the burned TO-220 package transistors, I could have used small side cutters and snipped off their pins, right at the base of the transistor, leaving as much pin sticking up from the circuit board as possible. Then I would have snipped off the excess pins of the replacements, tinned them, and soldered them against the pins left in the circuit board.
   Too late for me for this board, but I suggest anyone who has to unsolder blown TO-220 (etc) power transistors from a multi-layer board consider it as a potential technique.


Chevy Sprint Electric Conversion with Improved Transmission? (thought of and then abandoned)

  Ways to use an existing transmission to run the Sprint in a more efficient way seemed to blur and become elusive the more closely the details were examined. So I thought again about trying a "made from scratch" transmission with belts. The resulting design seemed reasonable, but I worried there might be too much tension and belts would slip instead of moving the car.

   Suddenly it was all eclipsed by a better design for an add-on wheel drive motor that looked very workable, practical and efficient.



Finally!: A Simple, Practical Add-On Wheel Drive

   After all the frustrations with considering the Sprint transmissions and their elusive possibilities I had a new thought: a simpler way to electrify a car or to turn a gas car into a hybrid. It has an excellent chance of being successful and practical, and it has a small number of pulleys and shafts to introduce few inefficiencies. The Toyota Echo looked like my best candidate. The plan would be:

1. Put a very large chain sprocket onto the outside of a vehicle rear wheel - preferably the right side as before. It will hardly stick out past the car body, if at all. The bigger the sprocket is, the less tension there is on the chain to move the car, and the larger the reduction ratio that can be attained in a single step. I recently ordered a 120 tooth #40 chain sprocket for the Miles truck from rebelgears.com, but decided to use it for this instead. (It arrived on the 28th. I could do the truck this way instead of the car? - or later, in addition to the car?)

Giant 120 tooth, #40 chain sprocket on car wheel.
(Just say "NO!" to any rear-right flat tires! - ouch!)

2. Tie a small chain sprocket to a shaft behind the wheel, to connect to the wheel with a chain. This would be done per previous issues (TE News #91 & 86) where I considered how to mount a motor behind a wheel and connect it with a chain or belt, except that this is a new, intermediate ('mid') shaft, not the motor shaft itself. A 12 tooth sprocket with the 120 tooth one would provide a 10 to 1 speed reduction. Also 200 foot-pounds of torque at the wheels would be only 20 foot-pounds at this mid shaft, much reducing the chance of a belt from the motor being prone to slipping.

3. Put the motor in the trunk, above the mid shaft, with a pulley on it, directly in line with a pulley to be installed on the mid shaft. A slot is cut into the trunk floor for the belt to go down through. The size and type of belt pulleys depends on the linking method, next.

4. Here are three ways to link the motor to the mid shaft in such a way as to have a lower reduction ratio for high speed driving (estimating about 6:1 for the Echo with 14" wheels), while still getting enough torque to start the car moving:

    (a) Connect a 4.5" V-belt pulley on the motor in the trunk to a spring loaded variable pulley on the mid shaft underneath it with a V-belt. With the variable pulley relaxed at 4.6" effective diameter, the 10 to 1 reduction of the chain will apply during startup and lower speed travel. When the pulley is tensioned for higher speed travel to 2.6" (by the driver pulling a shift lever back), the increased speed of the mid shaft will provide an overall reduction of 6.25:1, so the motor doesn't have to go too fast to move the car fast.

   A late thought (Nov. 1): A custom variable pulley on the motor could be centrifugally operated, and thus the car would be fully automatic. It would would relax to the open, minimum diameter position. A spring between the motor and the mid shaft mountings would tension the belt. As the motor speeded up, weighted arms spinning on the shaft would press the outer end of the pulley inward against this spring tension, increasing its operating diameter and thus reducing the speed reduction, eg from 10:1 down to 6:1. I think this would be the best system, but I'll have to make the centrifugal pulley.

Final(?) version of variable pulley system - Centrifugal variable pulley to be made.
Visualize the motor and its variable pulley being above the mid shaft (in the trunk) instead of to its right.
Mid shaft (left), 1" shaft 9" long with 20 tooth sprocket (6:1) and 5" V-belt pulley, needle bearings.
Standing in for the chain and the giant wheel sprocket, some chain and a disk (right).
Standing in for the (unmade) centrifugal variable pulley, a variable pulley with spring (central).
Standing in for the motor... weighing in at 85 pounds... is the Curtis 96 volt motor.
(with fitting still to be removed from shaft where pulley is to go.)
(I must remark there's not much shaft on the motor to attach to. They could have made it an inch longer, at least!)

    (b) In this method the link is a slipping belt clutch, with a flywheel on the motor. In this case, the lower desired reduction ratio desired for higher speed driving is used, eg, a 20 tooth chain sprocket drives the 120 tooth one for 6:1. The belt could be a V-belt or flat belt. To start the car moving, the motor is revved up with the driver pressing a clutch pedal. As the clutch is engaged (releasing the pedal), the flywheel on the motor slows. Its stored kinetic energy combined with the torque of the motor boosts the car into motion in spite of an insufficient reduction ratio for the motor torque alone. (To be honest I had forgotten about this technique. I re-discovered it in TE News #98 when I started looking through to review what projects I had undertaken in 2016 for the SR & ED application. So I've already demonstrated experimentally that it works.) The 10 or 12 pound cast 12" V-belt pulley is probably about the minimum desirable flywheel, and it could be the V-belt pulley on the motor if used with an appropriate sized other pulley and chain drive sprocket to get the right ratio.

With V-Belt, slipped as a clutch


or Flat Belt

    (c) Use a centrifugal clutch to drive the chain, again with a flywheel (on the motor or on the mid shaft). Where the other two methods require operator control - and the controls and linkages that make them controllable, this one is automatic and makes the link between the motor and the mid shaft fixed instead of having to be adjustable while driving. This simplifies the design (as does the newest idea for a centrifugal variable pulley).
   As I seem to already have an "ideal" centrifugal clutch for the job (www.HilliardExtremeDuty.com, purchased at Princess Auto, with a 10 tooth #40 chain sprocket output), I was favoring trying out this last and simpler method first. With this 10 tooth sprocket driving the 120 tooth the reduction is 12:1. Since 6:1 is desired, and a flywheel, the motor would get the heavy 12" cast double V-belt pulley, and the mid shaft a 6" one to double the speed. This double speed of the mid shaft happens to be desirable as the higher RPM would engage the centrifugal clutch better, with half the torque required at the clutch owing to the 12:1 chain drive ratio.
   There is however one potential problem with this design, and it depends on the characteristics of the clutch. If the drop out RPM isn't much lower than the engagement RPM, the flywheel will be disengaged too soon and can't impart much of its energy to car motion. So if I did try this technique, I'd just have to see how it works with the clutch I have. If it's not satisfactory, I don't think I'll try making another centrifugal clutch, so I'll have to try one of the other methods. (The centrifugal variable pulley now looks like the best to me as of newsletter time.)

With Centrifugal Clutch

   The wheel can move owing to its suspension, moving the mid shaft back and forth a bit since they are fixed together in distance by a horizontal bar to keep the chain always at the same length and tension. The mid shaft also moves up and down, tied to the motor by the shift mechanism used to vary the pulley distance (for the first two methods). The mid shaft is thus "floating", but it links the motor (moves with the car body) flexibly to the chain sprocket on the bouncing, vibrating wheel. The pulley shift or clutch engagement mechanism will have to be quite strong, as the torque of the wheel drive will be pushing the mid shaft down - or up when driving in reverse. An advantage to the centrifugal clutch is that the drive belt is a fixed length/tension adjustment, so the mountings will intrinsically be more robust.
   By the 24th I finally realized that the mid shaft mounting and the motor mounting should ideally be all one unit (no matter how big a hole, or how many small holes, need to be made in the floor of the trunk). Both ends of the mid shaft mounting, inner and outer, should be equally tied to the car frame/body to hold it horizontal, and to the motor mounting to hold that in line. But it needs to move a bit as the wheel springs, and vibration from the wheel and motor should be dampened so they don't transmit to the car body. I can think of several ways to accomplish these things. If the belt needs to move to tighten and loosen (variable pulley & slipping belt designs), the motor could be mounted to pivot against this frame to move its pulley up and down - which suggests relatively simple ways to create the clutch or variable pulley shift mechanism.

   Final notes: a chain in air isn't ideal since chains need lubrication. One could of course try a toothed belt or a flat belt that needs no lubrication. But the chain and chain sprockets is the easy type to find and install. My thought for keeping the chain lubricated is to have a small reservoir of oil somewhere with a wick sticking out and brushing against the chain. I think if it's set up right, it should always keep a bit of oil coming when the chain is turning, without having it continue running out oil when the vehicle is stopped.
   It can't be denied the having the motor (and motor controller) in the trunk uses up trunk space. But the biggest space hog of an electric motor system is the batteries. The Echo has a large trunk and I plan to put everything - the charger(s) and the battery box as well as the motor and controller - in it, so everything to do with the add-on drive is there except the operator controls (hopefully none) and meters. It can all have a removable cover over the top to leave a shallow trunk space above. And I can always put the back seat down for more room. It's a worthwhile loss of space that is not often needed!



In Passing
(Miscellaneous topics, editorial comments & opinionated rants)


English Alphabet: Like A Number System Without a Zero

   In the English/Roman alphabet, only 5 letters (A,E,I,O,U) represent vowel sounds. However, there are in fact nine vowel phonemes, that is, 9 unique single vowel sounds. To make matters worse, the most basic vowel sound, the basic "grunt" (as the French pronounce the letter "E"), from which all the other vowels are variants, is missing. This is like having a number system with no zero. Thus one is forced to choose some inappropriate vowel. Consider the final vowel sound (for convenience) in each of these words:

word
faucet
scissor
puzzle
former
fabulous
future
rider
fashion
merit
alpha

(or, say, the first vowel sound in "consider" or "require", etc.)

   It is seen that it is (most commonly) pronounced the same in each case, regardless of spelling. What has happened is that, with the required base vowel being missing from the alphabet, any and all other vowels are employed to spell the word. Let's see... is it closest to "a", "e", "i", "o" or "u"? Well, really it's none of them. Maybe use two vowels like "io" or "ou"?... or leave the vowel out completely and add an "e" to the end of the word? If one could have one's way just a little bit (fat chance in this case!), I would make a new letter, perhaps "i" with no dot, to represent the base vowel sound. Or maybe the upside-down "e" used in dictionaries. If I really had my way, there'd be letters for all nine vowels and single letters for consonants "th" and "sh" (voiced and unvoiced) and the stopped glide "ng".
   Of course, then it might start to look more like Cyrillic, and we in the west might not think eastern Europeans and Russians were some sort of bizarre alien life forms for the more phonetic alphabets they use.


British Columbia, Canada Place Names

   A while back (~1971) one of my high school classmates brought around a photocopy of the original sheet of paper describing the new "Murphy's Law" to our electronics class. There were a number of examples given, of which I roughly remember just one: "Figures will be given in the most impractical possible units. For example, a velocity might be recorded in furlongs per fortnight." The remaining examples may have been lost to history (at least to my knowledge - or they may still be out there somewhere), but the basic "law" is remembered to this day, mostly in electronics and computing design circles: "Anything that can go wrong will go wrong, and at the worst possible time."
   Much later (but still before the internet), someone had a sheet of "Alberta Place Names", wherein Camrose was described as "Engine Flower" and "Pharmaceutical Cap" meant Medicine Hat. (which is a plenty strange name as it is, now that I think about it!)
   Ever since, I've thought off and on of doing one of BC places. But I didn't think of more than a couple. At thanksgiving dinner this year I finally set out and between us my punster brother Stuart and I came up with a few good alternative names for places in BC. (Stuart is the one who calls the Cunningham building at the University of Victoria the "Clever Pork" building.) Alas, thinking there were other copies and then deciding not to include it in TE News #112, and with the tablet I wrote them down on later deciding to turn itself off in the middle of some work and restart without remembering my recent files, somehow every copy or the only copy got deleted, as an illustration of Murphy's law.
   Here are the ones I can remember, plus some more I added later. Most of them are towns. Those marked with an asterisk "*" are features, generally a lake, a river or a mountain. Those not hailing from BC may likely expect to "get" few of them. Those from BC, and especially the coast and Vancouver Island may "get" ... well, a couple, anyway. Maybe I'll think of a few more later for another issue.

BC Place Names (Answers below)

Fish Limb (by Stuart, long ago)
Where the cat wipes its feet (from CBC Radio, long ago)
Fish fortress
Tired of eating wild game for dinner
A Royal that's always burning the meat
Naval Victor
Inky Flow
* Arithmetic Offspring Pond
Abbreviated Litigation
Good place for a long walk?
Big Utensils
* Famous name for such a small waterfall
* A flow of yellow metal
* A tall fabricator of primitive missiles
A harbor in inclement weather
Grassy Knoll (Hint - see top of newsletter)
A meritorious town
Witch Hazel
Tons of small nuts, stale or fresh
Space flights are not directed from here
Tarp for a VW Bus
Torch a wasp

Salmon Arm - Kitimat - Castlegar - Sikamous (sp?) - Queen Charlotte - Nelson - Black Creek - Matheson Lake - Lytton - Trail - Grand Forks - Niagara (Creek) Falls - Goldstream - Mount Arrowsmith - Port Clements - Lawnhill - Merritt - Hazelton or New Hazelton - See previous answer (Disclaimer: The clue is not an intended slight to the inhabitants of either town.) - Houston - Vancouver - Burnaby


- Why does it feel like a 50-50 chance when plugging in a polarized 120 VAC plug is more like 1 chance in 50?*

- A watched pot never boils. An unwatched pot boils dry.


* (Applies to North American plugs where one pin is just a tiny bit wider than the other, so it's hard to tell which is which.)



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- Electric Hubcap Family Motors - Turquoise Motor Controllers
- Preliminary Ni-Mn, Ni-Ni Battery Making book

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   The rest of the newsletter is the "detailed reports". These are not for general reading, but for anyone who wants to get into the fine nitty-gritty of a project to glean ideas for how something might be done, as well as things that might have been tried or thought of... and often, of how not to do something - why it didn't work or proved impractical. Sometimes they set out thoughts more or less as they occur and are the actual organization into writing of those thoughts. They are something of a diary and are not as extensively proof-read for literary perfection and consistency before publication. I hope they add to the body of wisdom for other researchers and developers to help them find more productive paths and avoid potential pitfalls.




Electric Transport

New Chevy Sprint Conversion(?)


New Plan for All Belts Variable Transmission

   My later thought trend (by October 12th) has been that electric motors are more flexible as to RPM ranges than gas, and don't really need the sophisticated differential variable transmission. It's nice that I conceived it, and it would be great for petroleum based cars and perhaps has other valuable uses, but electric cars can use something simpler. They really still are best with two gear ranges, eg, around 10 to 1 reduction for starting up, and 5 to 1 for high speed travel depending on the motor, wheels and vehicle. Variable between those ranges is even better. A single variable pulley can provide that 2 to 1 difference of reductions.

 After running through the manual and automatic Sprint transmissions and being unsatisified with the possibilities for making any sort of really satisfactory unit, I went back to thinking about a "transmission from scratch" again, this one with belts.
   I think much of my problem with belts slipping in tests a year or so ago was because the pulleys I was using had a glossy smooth enamel finish, and that I'd have got better results if I had taken some sandpaper to them. Now someone at the auto parts store sold me some "tack" spray, and said that would fix any slipping belts. If I'd known about that stuff when I was trying belts before, it just might have made a lot of difference. And I still haven't given the flat or poly-V belts idea a fair trial.

   So why wouldn't I give it one more try?: redo my own transmission box and have just belts and pulleys, including one variable pulley to get the variable ratios between about 10 to 1 and 5 to 1? At least with my own chassis made of flat plate metal, I can attach things and configure things to my heart's desire as required to fit everything - preferably starting with a plan with all details worked out in the first place so if all goes well I'd only have to do it once. With all belts there'd be no use for oil immersion and I'd just enclose it to keep dust out. (Grease the bearings well!)
   To help me lay things out, I could make plates of thin plywood and cut holes as required. It would be easy to do and strong enough to hold the shafts in place and let me put belts on them (loosely) and see how it turned, of course by hand with no load. If something didn't fit right, or if the assembly didn't fit properly into the car, I could easily drill more holes, add wood to cover holes, or start over with the desired changes. Once everything seemed to fit together and was in line and turned as expected, I could replace the plywood with metal plates and bearing holders.

   I would take the 10" drum and mount it on the differential as a flat pulley, and the two 2.5" poly-V pulleys and put them on a fixed shaft, so the two poly-V belts in parallel can provide a final 4 to 1 reduction, hopefully with sufficient traction and strength. (That 99% efficiency figure for flat belts greatly appeals.)
   The motor would simply drive a small V-belt pulley. There would be two intermediate V-belt axles, one of which would be mobile to shift the variable pulley, and the other a further fixed reduction. The last V-belt would drive the axle with the poly-V belts to the differential. The need for two intermediate shafts instead of one is a bit vexing: The shaft with the variable pulley has to pivot on an axis parallel to another shaft so its fixed pulley always stays at the same distance to that shaft, to keep the belt tight. Neither the motor shaft nor the differential shaft is accessible to put bearings on, which would hold a two stiff arms assembly to the pivoting shaft for that purpose.




Two views of the planned transmission.
It would need much larger plate metal sides to hold the extra shafts.
Motor would be at top left pulley in 2nd image

Caveats - Force on Belts?

   Because all the belts and pulleys except the last drum will be running at least 4 times faster than the wheels, they will have 1/4 or less as much torque on them and so less chance they'll slip. Both drive shafts would be connected to the front wheels. If any of the belts (except the one on the variable pulley) tended to slip or to overheat, and it couldn't be fixed, that one could be replaced by a chain, which would need an oil drip or something for lubrication. Hopefully that won't happen, but it is my main and serious concern as a possible failing of the design. I can use decent sized pulleys at the motor.
  The 10" (textured surface) drum with two 'flat' (really poly-V) belts on the differential should have a pretty good grip, but it has a lot of force on it. I could wish for a larger drum, but it would be hard or impossible to fit it into the space available. Either it would hit the firewall or the drive shafts would have to be moved out and operate at a substantially greater angle from 'straight' than originally. And then also the only 'flat' belts I have would be too short.
   I could also wish for a larger diameter variable pulley, but I don't know where I would get one or if it's possible make them larger for regular V belts and still get 2 to 1 speed variation. I had bought a special variable pulley belt with one near-vertical side and one angled, which should allow larger variable pulleys, but a fairly exhaustive search of my shop etc, still cluttered with half full packing boxes, hadn't uncovered it. (I finally found the box of belts and pulleys near the end of the month.) And I don't have that larger pulley (or any pulley) for it anyway.


Using the Auto Transmission Unit as a 4:1 Transfer Case with Clutch?

Following thoughts of slipping belts for a wheel drive motor system (below), I did think of a fair possibility for using the Sprint's automatic transmission unit (Oct. 18th). One of the internal rotating parts had some sort of clutch that could be engaged by pressing something against one end. It didn't take much pressure on any one spot to engage it at least to the extent that it couldn't be turned by hand. It looked like one spinning part still installed in the case had a ring that would do the pressing all around the clutch's rim. (An engagement ring?) Perhaps it is this clutch that slips in forward and engages in reverse? If it could be connected as required and made to act as a sensitive input clutch to get the transmission to slip or to grab when and as desired in either direction, it might be the piece needed to use the transmission as a 4 to 1 transfer case, with the clutch to get the car moving from a stop. There are some unknowns in this, like how is this spinning clutch activated anyway, and can it be controlled from outside the case? (...or perhaps by centrifugal force?)
   IF the mechanism could be coaxed into working as desired, the most objectionable part would be that 3.9:1 may not be a high enough reduction ratio, and there's no effective way to alter it if it isn't. Then again, the Sprint is lightweight and the Curtis motors have a lot of torque.

   But once thought of, the wheel drive idea below looked so promising that it quickly became the focus, and all the other ideas were dropped.


Wheel Drive Motor Revived: Hybridize a gas car, the 2001 Toyota Echo
* The Simplest Plan Ever *

   After all the frustrations with considering the Sprint transmissions and their elusive possibilities, and still being somewhat leery of the possibility that the belts in the custom Sprint transmission plan would be too prone to slipping because of the relatively high torques on them, I had a new thought: what seemed like a simple and practical way to electrify a wheel for an electric drive, which could turn a gas car into a plug-in hybrid. This was, after all, my original intent in 2008. It's been a long time coming!
   With the right parts, the numbers give it much less torque on the belts and hence the best chance of working well. And it has the smallest number of pulleys and shafts to introduce the fewest inefficiencies. The Toyota Echo looked like the best candidate, with the Miles mini cargo van as an alternate. In fact, as the days passed, I thought of 3 or 4 ways to do very similar wheel drives in the same basic configuration.
   The key component would be a very large chain sprocket mounted on the outside of the car wheel (right rear). The 120 tooth, #40 chain sprocket that I had already ordered would make for minimum tension on the chain with maximum torque to the wheel. It also would make it possible to have any reasonable desired speed reduction in a single stage of chain. Ratio for the other sprocket having (eg): 12 teeth = 10:1 ; 20 teeth = 6:1 ; 24 teeth = 5:1.


Giant 120 tooth, #40 chain sprocket on car wheel.
(Just say "NO!" to any rear-right flat tires!)


The sprocket is held on the wheel by 7/16" "coupling nuts".
One end was tapered, and drilled out and re-threaded (12 mm x 1.5 mm thread pitch), to fit the wheel.
The outer ends were left as 7/16" with flat ends.
(Yes, I do wish the O.D. was larger!)


The cut down (on a lathe) trailer hub goes on the inside,
with the axle sticking out.
(Four of the mounting holes in the sprocket were superfluous.)
 


Another view.
The thickness of the trailer hub, together with the coupling nuts,
set the sprocket almost an ideal distance out from the tire.
The axle sticking out doesn't turn with the wheel.
It will hold the bar that attaches the mid shaft mountings.
(It will be cut much shorter once everything is fitted.)
(Amazingly the nut on the inside end of the axle doesn't quite touch the wheel.)

   The small drive sprocket would attach per previous issues (TE News #91 & 86) where I considered how to mount a motor behind a wheel and connect it with a chain or belt, except that this sprocket is mounted on an intermediate shaft, not on the motor shaft itself. (I'll refer to this as the "MID shaft".)
   The motor is in the trunk, behind the wheel and above the mid shaft. The connection between the motor and the mid shaft is via a belt and pulleys. This link is the part that differs in the various options that I thought of.
   In the first way a variable pulley changes the overall reduction ratio between around 10:1 and 5:1 or so, with 10:1 being used to start up and (as low as) 5:1 during driving. In the next type, the belt is slipped to act as a clutch. At the lowest speeds this clutch is slipped to get the vehicle going, and then the ratio is fixed at 5:1 or whatever. A flywheel is used on the motor to provide momentum to get the car to move as the clutch engages, instead of stalling the motor. In the last idea, a centrifugal clutch is used instead of slipping the belts, to provide the same effect.

   The basic layout has various advantages. Any and all the variations can be tried out by making pretty small changes. And it should be pretty simple to try out different motors. And we can't forget the maximized efficiency of having just one belt and one chain between the motor and the wheel, providing the furthest driving range for any given battery storage. (Town and back without recharging, here I come!)

   Plus, as noted before, there are the advantages of any layout in "hybridizing" a gasoline car, over an electric only vehicle. If the batteries run low on juice one can start the engine and continue on gasoline. (and perhaps recharge while driving?) Ditto for any trouble with the electric drive system, which is especially valuable in a prototype. And of course likewise if one runs out of gas or has engine trouble, one can drive to a service station on electric power.
   Then, in a typical installation one can use a lesser mass of batteries, enough for a "typical" drive with a good reserve instead of going for the maximum possible range. And one can perhaps use a smaller motor (or a lower maximum reduction ratio), counting on the gas engine to provide starting torque in really tough situations with a heavy load on board.
   Plus there's the major artificial consideration fabricated by "the powers that be": one doesn't have to license a second vehicle at double the cost to drive no further while reducing pollution and consumption of non-renewable petroleum fuel. (Perhaps this silliness should be eliminated by insuring the drivers instead of the vehicles. If I'm insured for liability, I should be able to drive any licensed vehicle with my own coverage that I've paid for. And then any licensed and insured driver could drive a vehicle of mine without worrying about my coverage and what it covers. Vehicle damage coverage could perhaps still be on each vehicle, but its cost would be minor compared to compulsory liability insurance cost. But I haven't thought out all the possible implications of this idea.)

With a Variable Pulley

   This was the first idea (and the last: with a different variable pulley, centrifugally closed instead of opening against a spring). The plan would be:

1. Put a large chain sprocket onto the outside of a vehicle rear wheel - preferably the right side as before. It won't stick out very far. I recently ordered a 120 tooth #40 chain sprocket for the Miles truck, but perhaps I'll use it for this instead. (I could do the truck this way instead of the car. Or perhaps I'll get another sprocket for the truck later.) This is a key part. The large size allows a large reduction ratio in a single step. And at about 19" diameter this sprocket wouldn't fit easily anywhere but directly on a wheel.

2. Tie a small chain sprocket to a shaft (the "MID shaft") behind the wheel to connect to the wheel with a chain. (again see TE News #91 for the mounting plan.) A 12 tooth sprocket with the 120 tooth one would provide a 10 to 1 speed reduction.

3. Put a variable pulley on the other end of this same shaft, which should be underneath the trunk. Because of the speed reduction, 200 foot-pounds at the wheels (my target torque) would be only 20 foot-pounds at this shaft, much reducing the chance of the belt being prone to slipping. (Again the variable pulley I have goes from 4" to 2.5" effective belt diameter - pretty small for high torque.)

4. Put the motor in the trunk above the shaft, with a 4" V-belt pulley on it in line with the variable pulley. A slot is cut into the trunk floor for the V-belt to go down through. With the variable pulley relaxed at 4" effective diameter, the 10 to 1 reduction of the chain will apply. When the pulley is tensioned for higher speed travel to 2.5", the increased speed of the mid shaft will provide an overall reduction of 6.25 to 1, so the motor doesn't have to go so fast to move the car fast.

   An interesting point is that the wheel can move owing to its suspension, moving the mid shaft back and forth a bit since they are fixed together in distance by a horizontal bar to keep the chain always at the same length and tension. The mid shaft also moves up and down, tied to the motor by the shift mechanism used to vary the pulley distance. The mid shaft is thus "floating", but it links the motor (moves with the car body) flexibly to the drive sprocket on the wheel. The shift mechanism will have to be quite robust, as the torque of the wheel drive will be pushing the mid shaft down - or up when driving in reverse.

   Actual construction will await arrival of the 120 tooth chain sprocket. I could conceivably start on the motor mounting et al and the mid shaft, but I'd rather start from the wheel, because it's the part that I can't alter, and work back to be sure the rest fits to that. Or I could start on the electrical parts - a battery box for the trunk, and all the wiring and controls. Hmm!

   A late thought was that a variable "V" pulley on the motor could be centrifugally operated, making the operation automatic. (More below.)

The Unique Feature: Single Variable Pulley on Pivoting Shaft

   A perhaps unique feature of most of my more recent variable transmission ideas is in using a single variable pulley on an offset shaft that pivots to change the distance between that pulley and a fixed pulley, in order to tighten and loosen the belt and cause the pulley diameter to change.
   This is less complicated than systems where the shafts are fixed, and one pulley must shrink as another expands in order to keep the belt tension the same. With a spring loaded variable pulley shifting is simply a matter of pulling on the shaft to tighten the pulley toward its smaller diameter, or ceasing to pull to let it spring out to its larger size. It is also more practical for an EV because electric motors run well over a wide range of RPM.s and so don't require such a wide range of reductions as gas engines.

   Of course available variable pulleys and belts made for mopeds or snowmobiles may wear out faster than is desirable. But one could make specifically automotive belts and pulleys that are better than common V-belts. Honda Insight, for one, has or at one time had a variable pulley transmission system with metal link "V belts". A variable pulley is more complex than a fixed ratio, but still looks pretty simple to implement. And for an EV even less than 2 to 1 change in ratios gives the flexibility to make a lot of difference.

   A final thought: On November 1st it occurred to me that with a custom pulley, the variable pulley could be centrifugally operated, and thus would be fully automatic. It would be on the motor, and would relax to the open, minimum diameter position. A spring between the motor and the mid shaft mountings would tension the belt. (This eliminates the need for a spring spinning on the output pulley, which is instead a regular V-belt pulley.) As the motor speeded up, weighted arms spinning on the shaft would press the outer end of the pulley inward against the spring tension, increasing its operating diameter and thus reducing the speed reduction, eg from 10:1 dropping to 6:1 depending on driving speed and conditions.
   There are very small centrifugal variable pulleys on mo-ped or snowmobile type variable pulley systems with little ball bearings in them for centrifugal weights, but from what I was shown at Victoria Motorcycle these wear out in short order. Thus I would start with a fresh design, of larger diameter, eg, perhaps the same 2.5" to 4.5" size of the mo-ped output pulley, which would be the input motor pulley, driving a larger fixed pulley, eg, 4", 6", 8" or 10" depending on ratios. (A flywheel is unnecessary with the variable pulley type.)

   (I just might go for designing this pulley in preference to using the centrifugal clutch, which I had been leaning toward.)


Four V-belts:
1. (rear) The one-side-vertical (actually 87.5 degrees, the other is 18 degrees) variable pulley belt, "Comet" brand.
It is wider than the rest as well as having different angles, and so won't fit on a regular V-belt pulley.
With the 'vertical' side, its alignment won't shift as the variable pulley diameter changes.
This is probably the best belt for a heavy load like a car (even with 10:1 speed reduction),
but this one is too short for the larger pulleys which are also wanted for a heavy load...
and it's the only one I've seen so far.

2. "V" variable pulley belt. They're wider than regular V-belts, but have the same angles
(13 degrees each side), and those up to about 16 or 16.5 mm wide will fit regular V-belt pulleys.
The notches in these belts doubtless improve their efficiency for going around a small pulley.

3, 4. Regular V-belts. These are the most commonly available, but note the different widths,
over which you seem to have little or no control when purchasing one in a store.


Then there's the Slipping Clutch Idea [Again? Oct. 14th or 15th]

   The variable pulley replaces the idea of having a slipping clutch of some sort just to get the vehicle moving in order to have a lower drive ratio for higher speeds.
   But I think the clutch idea still has merit, perhaps especially with a flat belt and pulleys, and especially compared to a V-belt with a small variable pulley made for mopeds. The one using a rope in a planetary gear did get the Sprint moving with pretty low power driving it in fall 2012 (at about 7 to 1 reduction(?) ...egads was it really FIVE years ago?) It could be done pretty much the same way as the variable pulley, so trying out one doesn't preclude the other.

   A way to do the above wheel drive might then be to use chain sprockets to get the desired lower reduction ratio (ie, for higher speeds), so for example, a 24 tooth sprocket on the mid shaft with the 120 tooth wheel sprocket for 5 to 1. (...Make that 20 tooth for 6 to 1, as the Echo has 14 inch wheels where the Sprint has 12"!) Then use (the previously made) 7" flat belt pulleys on the motor and on the mid shaft. While the pressure on the belt and pulleys is (almost) doubled over the variable unit, they are larger pulleys. The 7" flat pulley compares favorably with the 2.5" smaller diameter of the variable pulley. Plus, the 99% efficiency of a flat belt is bound to be higher than that of a V-belt.
   However, for the sake of increasing the flexibility and reducing the number of potential problems getting it going, I'd try it first with a slipping V-belt. I presently only have one size of 'flat' belt, while V-belts are commonly available in a wide range of lengths. Selecting the belt length and adjusting the spacing of the pulleys on the mid shaft, the motor position can be easily adjusted to its best position at the right end of the trunk. One can select larger pulleys than the variable one and a match for it, and I have some very scucum commercially made cast V-belt pulleys of a good size, eg 5" to 8". The reduction ratio can also be optimized here by pulley selection without changing the drive sprocket and chain length.
   The clutch mechanism might be (for better mechanical fitness and to eliminate a heavy spring, at least for the prototype) a lever that pushes or pulls the pulleys apart to tighten the belt, rather than a pedal that loosens them. The pull/push down should most ideally be on the pulley end of the mid shaft or even inboard of the pulley, partly to somewhat counteract the push down on the outer end from the torque of the chain tension, which will act as twisting forces on the mid shaft. Again, all the mountings have to to be strongly built to withstand the several strong forces that will be acting on them despite the limited possibilities for attaching them.

   Note that it would also be possible to do this arrangement without a mid shaft, with a belt to be slipped directly between the wheel and the motor directly behind it. Again the pulley on the wheel would be as large as possible, and the small one sized for (eg) a 5:1 speed reduction. This arrangement would put the full torque of the wheel on the belt, so it assumes that the belt can be made not to slip when it's not supposed to, and also that it can never come off the wheel when loosened, which it seems to me would be a bigger challenge than with smaller pulleys. It might be well worth a try at some future time, but I don't plan to attempt it now.

Or a Centrifugal Clutch

   On the 16th yet another idea occurred to me. In a similar vein to a manual clutch, one could use a centrifugal clutch. This has the advantages of being easiest to make and being easiest to drive - automatic. I went to my shop and dug out one of the ready-made centrifugal clutches that I bought some years back to study or use. (Where did the other one go? hmm.)
   This one had a 10 tooth, #40 chain sprocket as its output. At first glance, the reduction seemed too high - 12 to 1 with the 120 tooth wheel sprocket. But on further consideration, that would in fact be pretty much perfect. One of the problems with the stock centrifugal clutches is that the RPM of activation is higher than is desirable for an electric motor system. The motor revs up too high in order to engage the clutch. But the present configuration could run a 2 to 1 speed increase to the mid shaft, with (eg) 8" and 4" pulleys, so that it spins twice as fast as the motor. The overall speed reduction to the wheel is then the desired 6 to 1. Now the shaft spins fast enough to engage the centrifugal clutch, and the overall reduction is the desired amount. No mechanism for engaging the clutch is required and the arm linking the motor and the mid shaft is simpler.

   I think I'll try this out first, owing to the simplicity of construction and installation. At first didn't like the bronze bushing on the output drum instead of roller bearings. I thought this would wear out quickly. Then I realized that it only turned until the clutch engaged. After that it was locked to the shaft rotation.

   An interesting point to this one is that the car wheel turning doesn't couple back to the motor. The centrifugal clutch won't engage no matter how fast the hub spins, when the input side with the centrifugal weights isn't turning. So the motor would probably just sit still while driving on gas. This also reduces the potential for regenerative braking (which would drop out at low speeds), and it precludes charging via the motor-as-generator while driving. But that bronze bushing would really be spinning - ooh!

   This plan told me where I might start before the big sprocket arrives: The clutch is sized for a 3/4" shaft and I didn't have any. Turning down one end of a 7/8" shaft would be ideal. For that I had to set up the machine lathe, which hadn't been done since the move. After locating its motor I accomplished this on the evening of the 19th (even eliminating a couple of nuisances like a pulley that used to rub on a guard with a scraping noise).

   Next, just how was that floating mid shaft and its two components to be mounted, anyway, to be tied to the wheel and to the motor? The bar from the wheel has to be outside the big sprocket, so it makes sense that it's also outside the small sprocket of the centrifugal clutch. There's no particular need for the shaft to extend past the sprocket, except that would be the place for a bearing, and it will provide an end stop so the clutch drum with the sprocket can't fly off the end. Then the arm only provides a shaft bearing at the outer end. It might twist, and there's nothing to keep the shaft and the arm from sliding away from each other. Keeping the shaft and chain aligned would seem to suggest the arm from the wheel needs either to fork into two end points ("y"), or to turn a "U" at the end, with the arms of the "U" on each end of the mid shaft:

 |
 |
U.

(Well, that's probably as clear as mud!)


The Chain Sprocket Arrives!

   The giant 120 tooth sprocket arrived on the 28th. The mounting holes lined up with the wheel studs, but I thought it would take some doing to mount it. Probably I'd have to make wheel nuts that were a couple of inches long and tapered at both ends, to hold the wheel on and also to hold the sprocket far enough out that the chain clears the tire. I've never been able to find much 12mm x 1.5mm hardware except the exact stud bolts and short tapered nuts that are usual on cars. I thought the trailer hub would have to be cut (or drilled) out where the wheel-nut bolts go through the sprocket to hold it on, as it overlapped with them.
   But it turned out to be simpler. I found 7/16" coupling nuts and on Halloween (31st) - one year to the day since I first landed on Haida Gwaii - I turned just one end of each conical on the lathe, and drilled out and re-threaded that end that end for the metric wheel bolts' size. (The dealer actually pulled the 12mm x 1.5mm tap out of a full tap & die set and sold it to me separately!) The other end I left with its original 7/16" thread, for bolts I can easily get around here, and I left the end flat to butt up against the face of the sprocket. Then, I put the cut down trailer hub on the inside where there was just enough room for it, and its thickness, added to the length of the coupling nuts, set the sprocket away from the tire just the right amount. Having the hub on the inside meant the axle stuck out just far enough, to give the lowest possible profile for the bar across to the mid shaft. Although the trailer hub was 4" diameter (101.6mm) 4 bolt pattern instead of 100mm, with its lug bolts removed its larger holes accommodated 100mm with little slack using the 7/16" bolts (which BTW needed to be about 1.75" to 2" long and were purchased that day). And I had picked 2.5 inches "out of a hat" as the size for the sprocket's center hole, and that turned out to be just slightly larger than the flange round the trailer hub center (2.47"), so that too was pretty close to perfect.
   With 2 of the nuts prepared I trial mounted the sprocket on the car wheel while there was still some light to look and to take a picture. I could hardly ask for things mostly not made to fit together to fit together better, except that I wished the rather thin coupling nuts had a wider outside diameter - more like a regular wheel nut diameter - to provide more support for the torque from the sprocket to the wheel. But they'll do for now! Perhaps I can find some better ones on line later.



Other "Green" Electric Equipment Projects

Plan for a Portable Bandsaw "Alaska Mill" for cutting lumber?

   A chainsaw with an Alaska Mill attached can cut logs into straight pieces of wood. They have a great advantage for the small operator of being able to cut the log where it lies - no need to transport a tree trunk that can weigh tons. However, they are noisy and slow, they use a lot of fuel and they waste a lot of wood in a thick (3/8") kerf.
   To make the first cuts in the rough shaped log, one places a long flat board such as a 2" x 8" on top, sitting on nails or screws that have been pounded or screwed into the wood so that the board is supported on the heads of all of them. (I prefer deck screws, put in with a cordless drill, because it's easy to twist them up or down until all are in alignment. A string is helpful.) 2 or 3 longer nails/screws are put through the board into the log to hold the board in place. The depth setting of the cut has to be greater than the length of the nails plus the thickness of the board. The saw, sliding along the board, makes a horizontal cut through the entire width of the log at height of the cut. (usually near the top of the log) The mill and chainsaw bar have to be long enough to fit over the log at that depth. After two such cuts have been made at 90 degrees (use a square!), the log has two flat sides to slide the mill along and the board and screws are put away for the rest of the cuts.
   On the evening of the 28th a new idea came to me: to use a "hand held" bandsaw mill in place of the chainsaw mill. Here is the basic outline, which is as far as I'm taking it for the present.
   Most bandsaws are made with a sort of "C" shaped frame well out to the side to allow a maximum cutting width. The trick here is that for the mill, that width becomes the cutting depth, so it doesn't need to be anything like so wide. The design of the saw then can be fundamentally changed.
   Two straight steel bars (or even just one - "unistrut"?) run from the left wheel to the right wheel to hold the wheels in place. This will be inherently a lot more sturdy than the typical "C" shaped offset bandsaw frame, and it uses minimal material. This will bring the weight and size of a bandsaw way down. For 14" bandsaw wheels, then, the maximum possible depth of cut will be 7.5" less the amount of frame sticking out below. If it's a 2" frame with no other impediments, then the maximum depth of cut will be 6", which I would consider adequate for most purposes. 12" wheels with a 4.5" cut depth might be considered adequate by many, and even 9" wheels (if a wide cutting band will readily bend to that diameter) could make 3" thick boards. (However, these small sizes might need to make more than one cut to square off the top of the log.) A motor sitting on the top of the bars, less than 6" in diameter to fit under the band, would be ideal to keep the weight centered and low down. If a larger diameter motor is required, it will have to be mounted to the front or rear with only its pulley in line with the driver wheel pulley. (Where there is no power I would run a generator to power the saw motor rather than mount a gasoline engine on the saw, keeping the noise and exhaust away from the miller. I would break the log into movable slabs or cants, then do the rest of the cutting where there's a plug in.)
   Below the bar would be a flat "Alaska Mill" type of frame that can be adjusted up or down to set the depth of the cut. Somewhere a small jet of water will wet the band to keep it cool. Carefully situated handholds and safety guards taking potential band breakage as well as flying chips into consideration would of course be part of the layout.

   It would have a very thin kerf and use much less power than a chainsaw mill. It will still probably be pretty slow cutting. Is it worth building? Might an "Alaska Bandsaw Mill" replace most small "push saw along tracks" sawmills? I have a need for one if I'm going to sell lumber, but at this point I have no plans for interrupting other projects to start on this one. For now, I'm going out for my daily (or less often) dose of trying to start a huge ornery chainsaw, noise from which hearing protectors are inadequate, and hot gasoline exhaust fumes spewing in my my face, to get covered with sawdust and do my daily Alaska mill single cut on one of the big logs lying in my yard, intending to eventually break them all down until I can move the pieces and get them under cover. ... ... ... So much for that! I couldn't start the chainsaw and I'm tired out from trying. My typical results with pull-rope-to-start gasoline appliances! An electric bandsaw mill might have finished the cut by now, or at least would be well into it.

   I wondered what I might use for a motor for such a hypothetical saw. Electric induction motors are pretty heavy - my 7.5 HP on the pivoting blade mill is about 50 pounds, and that's a light one. The chainsaw with mill attached is about 40 pounds. Could a bandsaw Alaska mill match that, or even be lighter? One could do a gas motor, I suppose. Then in the shop I saw the Ryobi skill saw with a broken blade guard. Assuming it would be easier to buy a new saw than a blade guard, I had planned to cut off the cord and throw it out. Here was another idea. It said it was 13 amps. In theory that would make it over 2 horsepower. (13 A * 120 V = 1560 W) High RPM: more power in a small size with light weight... and it would plug in anywhere. Okay, that's not much power for a mill, even a bandsaw mill. But in the "Alaska" mill, the saw can be swiveled back and forth to cut first at the right, then at the left, then the center. Unlike a mill on a track, it doesn't have to cut all the way across at once. It would be slower, but it would probably work! As long as the friction from the section of blade that isn't cutting at any given time isn't too high.

   Someone said he'd seen such a mill on youtube. But his description sounded odd: stand the log on end and cut down vertically?!? I found a chainsaw mill that cut down, but no bandsaw Alaska mills of any sort. The clerk at the chainsaw store, who had done plenty of Alaska milling himself, had never heard of such a thing. (I went there because I couldn't start the chainsaw, but it fired on his first pull!, and started a few pulls later. I figured it would! Somehow it had been flooded, and leaving it for two days hadn't helped. I've never heard of such a thing!) I cut my slab the next day, and with my ears still ringing hours later, I determined I'm going to build that bandsaw Alaska mill! Or maybe I'll call it a "BC Mill". Diversions, diversions! Car first. Lambda ray energy second. Then the mill. No, the ground effect craft! No, the mill! No, SR & ED tax report for 2016!... Hmm.



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Haida Gwaii, BC Canada