# Help me get out of neutral: Coupler Challenge!



## ga2500ev (Apr 20, 2008)

I'm going to start this thread with an apology. There are dozens of coupler threads on the forum, and tons more blogs about EV couplers. I honestly think that I've read them all.

I have a very specific set of requirements that I'm trying to achieve. My apology is for cutting off all the reasonable ideas that folks will invariably post because they won't meet the requirements.

Some background. Like most of you I want an EV. My two primary requirements are that I want to get it done cheap and that I want to accomplish as much as possible DIY. The reason for both is that I really do want to do more than one. But often posts asking for how to get stuff done on the cheap is met with resistance. One example I saw in this forum to a really modest EV request (5 mile range, 25 MPH max speed):

http://www.diyelectriccar.com/forums/showpost.php?p=131536&postcount=18



> If you're goint to invest some time and money to build an EV.... invest $8k, 150 hours and end up with a 'real' functional vehicle, not just a golf cart.


Not helpful. So that's my apology.

Now on to the challenge! The setup:

1992 Geo Metro 5 speed
8" series motor pulled from an airport tug. Splined shaft
Matching female shaft coupler (will try to get a pic up soon)

The objective: design a inexpensive, non machined, clutchless motor coupler that can be put together using hand tools DIY.

The restrictions:

1) The coupler can be temporary. Just looking to get the EV grin. Any design that can be reasonably expected to move the vehicle 50 miles at 40 MPH meets the definition of temporary. Lovejoys in particular are acceptable even if they are made with sintered metal. I know they will break.

2) No machine shops. Any operation must be able to be performed in a house garage or backyard.

3) As inexpensive as possible. The $50 coupler is a better design than the $500 coupler.

4) Uses off the shelf parts that are not made of unobtainium. If it helps, I do have access to Grainger for example. Online resources that are not auctions are acceptable.

5) A tools budget is allowable as long as the tools can be reused to make more couplers. To keep purchases from getting outlandish, let's set the tool budget at $300. Again tools need to be off the shelf from places such as Northern Tools or Harbor Freight. Online resources that are not auctions are acceptable.

6) No modifications to the splined shaft allowed. The coupler needs to work with either the existing splined shaft or with the female coupler. So no turning the shaft (which would require a machine shop) or filling the shaft in allowed.

That's all I can think of right this second. The restrictions rule out couplers like the Electric Lemon coupler for example.

My hope is this challenge spurs some ideas to get more hobbyist into the EV game. If we can show that with a $200 shell, a salvage motor, and a bit of backyard ingenuity (and home hand tools) that they can get on the road, maybe we'll see some progress.

Thanks for reading and good luck. I am looking forward to hearing your ideas.

TIA for getting my EV project out of neutral.

ga2500ev


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## Woodsmith (Jun 5, 2008)

What does the female part of the splined coupler look like? Does it have a drive flange on it to mate/bolt onto an other component?

You could remove the centre from the clutch plate, the part with the splined hole and the springs around it. That could then be drilled and bolted to a flange on the motor shaft part if it has a drive flange on it.

The difficulty if getting it properly located so that it is both axially and radially aligned.

Have a look at jackbauer's thread, post 24 onwards I think, and it will show how he connected his clutch centre to his adaptor using bolts.

It would help if you had a good pillar drill that doesn't have play in the chuck bearings as you could use it to manually rotate parts to align them. A dial gauge is a must but are also fairly cheap on Ebay.

Sometimes avoiding machining is a false economy. I spent £180 on a small old lathe, £10 on a selection of dial gauges and £8 on a book on how to turn. It will pay for itself many times over in terms of DIY and accuracy of work.


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## DONEAL (Sep 10, 2008)

“Any operation must be able to be performed in a house garage or backyard.”
This is doable.

“The coupler needs to work with either the existing splined shaft or with the female coupler.”
Need a picture of the female coupler, in order to offer help.
From woodsmith‘s post >“The difficulty if getting it properly located so that it is both axially and radially aligned.”<
Agreed! This is a very important step.


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## DIYguy (Sep 18, 2008)

I think mine cost me less than $100 and $50 of that was to high speed balance it..... I did have a turned/keyed motor shaft....but maybe u could find a splined hub from Princess Auto or TSC that would fit ur spline...??


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## ga2500ev (Apr 20, 2008)

DONEAL said:


> “Any operation must be able to be performed in a house garage or backyard.”
> This is doable.
> 
> “The coupler needs to work with either the existing splined shaft or with the female coupler.”
> Need a picture of the female coupler, in order to offer help.


It looks like the involute splined coupler in this image:










It was used to connect the splined shaft of the motor to the splined end of the wheel axle on the tug it came from.



> From woodsmith‘s post >“The difficulty if getting it properly located so that it is both axially and radially aligned.”<
> Agreed! This is a very important step.


I know this will be a significant part of the challenge. Right now I'm just trying to envision what components can be fitted together to make the coupling.

ga2500ev


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## icec0o1 (Sep 3, 2009)

Woodsmith said:


> Have a look at jackbauer's thread, post 24 onwards ...


Hehe, I'm sorry I just found this funny


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## DONEAL (Sep 10, 2008)

Do you think the splinted coupling is the same spines that’s on the transmission pilot shaft?
>It was used to connect the splined shaft of the motor to the splined end of the wheel axle on the tug it came from.<

If it was long enough to couple splined end of the wheel axle it may be long enough to couple the splined of the transmission shaft.


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## DavidDymaxion (Dec 1, 2008)

Many would recommend against this approach, but it does meet your requirements:

http://www.poormansev.com/id21.html


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## ga2500ev (Apr 20, 2008)

DavidDymaxion said:


> Many would recommend against this approach, but it does meet your requirements:
> 
> http://www.poormansev.com/id21.html


Well almost....



> *Find a good local machine shop and get to know them*


*

ga2500ev

*


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## ga2500ev (Apr 20, 2008)

DONEAL said:


> Do you think the splinted coupling is the same spines that’s on the transmission pilot shaft?
> >It was used to connect the splined shaft of the motor to the splined end of the wheel axle on the tug it came from.<
> 
> If it was long enough to couple splined end of the wheel axle it may be long enough to couple the splined of the transmission shaft.


Now that's certainly something to think about. The traditional thinking is always to adapt the center of the clutch disk with its perfectly matched splines to the transmission input shaft. Never thought of a female to female spline coupling that mates the motor directly to the input shaft for the trans.

I don't have the trans pulled from the car yet. I may see about either doing that or getting quick access to a transmission to see if such a coupling is possible.

ga2500ev


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## DONEAL (Sep 10, 2008)

Just checked out DavidDymaxion web site, He has already done what I suggested. 
If the involute splined coupler doesn’t match the splines on your transmission shaft then you could look at having a professional welder weld it to a flange that can be drilled. Then you could bolt the flanged end to the old clutch disk as woodsmith suggested. I’m sure you can get it welded for less than the $50.00 you mentioned. 
My coupler is attached to my old clutch disk.


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## vpoppv (Jul 27, 2009)

Well, I suggested that you don't use my coupler idea because I didn't believe it would be strong enough. It's strong enough to go 50 miles at least, so maybe it could work for you. Measure the outside diameter of your female splined adapter: if it's exactly 1 3/16", you are set! That happens to be the exact diameter of a Metro clutch center and a hub will be able to connect the two. It will cost you $5.29 though, so I hope that's not out of your budget. I imagine that it will be bigger though....


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## ga2500ev (Apr 20, 2008)

DONEAL said:


> Just checked out DavidDymaxion web site, He has already done what I suggested.
> If the involute splined coupler doesn’t match the splines on your transmission shaft then you could look at having a professional welder weld it to a flange that can be drilled. Then you could bolt the flanged end to the old clutch disk as woodsmith suggested. I’m sure you can get it welded for less than the $50.00 you mentioned.
> My coupler is attached to my old clutch disk.


Could I weld it myself? This plan is starting to make some sense. Take the current involuted spline coupling I have, weld a flange to it. Then take the inner clutch disk (with springs), get it properly aligned, and bolt to the flange.

I can see doing this. What are the pitfalls?

ga2500ev


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## ga2500ev (Apr 20, 2008)

vpoppv said:


> Well, I suggested that you don't use my coupler idea because I didn't believe it would be strong enough. It's strong enough to go 50 miles at least, so maybe it could work for you. Measure the outside diameter of your female splined adapter: if it's exactly 1 3/16", you are set! That happens to be the exact diameter of a Metro clutch center and a hub will be able to connect the two. It will cost you $5.29 though, so I hope that's not out of your budget. I imagine that it will be bigger though....


I see in your video that you simply set screwed the clutch center to the hub? Do you still have that arrangement, or did you move to a stronger connection?

And what do you do if they are not the same size?

Does anyone sell keyed inserts to change the inner diameter of a hub end? It seems like the perfect arrangement for non matched ends. Get a hub that's big enough to accomodate the larger end, then put a reducing insert into the smaller end to get a inner diameter that matches.

I really wish that such an adapter system existed off the shelf. I think that's one of the reasons that everyone likes Lovejoys so much, because you can get two different jaw couplings for the two different ends.

What about a splined insert so that a splined shaft can be converted to a keyed one?

I'll keep looking. Thanks for the suggestions so far.

ga2500ev


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## Thaniel (May 25, 2008)

ga2500ev said:


> 2) No machine shops. Any operation must be able to be performed in a house garage or backyard.
> 
> My hope is this challenge spurs some ideas to get more hobbyist into the EV game. If we can show that with a $200 shell, a salvage motor, and a bit of backyard ingenuity (and home hand tools) that they can get on the road, maybe we'll see some progress





ga2500ev said:


> Could I weld it myself?


Welding?? Kind of deviating from the basic handtools here. Perhpas we can find a home lath that fits in the $300 budget 

Seems funny to me that dropping something off at a machine shop and picking it up a day later is taboo but welding is on your list of OK. I'm still trying to wrap my head around the fear of machine shops.

Doing a simple changing the clutch job on my car has the flywheel being dropped to a machinist. Oh and turning brake rotors. Oh and milling heads and surfacing exhaust manifolds. Grinding and seating valves. All typical automotive machining that is done all the time. 

For something spinning at many thousand RPM's precision is needed. It doesn't have to cost a lot of money to have it done right.

Thainel.


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## ga2500ev (Apr 20, 2008)

Thaniel said:


> Welding?? Kind of deviating from the basic handtools here. Perhpas we can find a home lath that fits in the $300 budget
> 
> Seems funny to me that dropping something off at a machine shop and picking it up a day later is taboo but welding is on your list of OK. I'm still trying to wrap my head around the fear of machine shops.


Simple. I don't know any machine shops. So my expectation is that they will be just like every other type contractor that I've ever met. Specifically:

1) They will charge too much.

2) They are arrogant. Always have the attitude that they know everything, and you as the customer knows nothing.

3) They can never get done what you want to get done when you want to get it done.

4) The job won't be done right the first time.

5) Getting in contact with them is a pain.

Ask me about the new roof I just got put on.

Finally there is the point that I will need to get more than one of these done.

So if at all possible I would like to do it DIY. If that requires buying a tool that doesn't cost $1500, then that is a route that I would rather pursue.

Working with contractors always requires a measure of trust. But that trust is elusive because all contractors are doing the work for money, so the money is what's important to them, not the relationship with the customer now customer satisfaction.

There are real reasons that folks want to do things DIY. It's a hobby. They love to do it. They are enthusiasts.

Contractors of all types (mechanics, HVAC people, roofers, yard mantenance, machinists, etc.) never ever do the work because they love to do it.

So I avoid them at all costs. I gave the job to the roofer on a personal recommendation. I'm still not happy.

Does that help clarify?


> Doing a simple changing the clutch job on my car has the flywheel being dropped to a machinist. Oh and turning brake rotors. Oh and milling heads and surfacing exhaust manifolds. Grinding and seating valves. All typical automotive machining that is done all the time.
> 
> For something spinning at many thousand RPM's precision is needed. It doesn't have to cost a lot of money to have it done right.
> 
> Thainel.


I've never found one I could trust. My son is my mechanic. I trust him. I don't have a son that's a machinist. So there's no trust there.

ga2500ev


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## EV-propulsion.com (Jun 1, 2009)

I do have to disagree on your view of the worlds workers.... but anyhow over the years working with machine shops, I have had couplers made from 150 for a basic one to 425 for a very difficult one. I think that something spinning near your body at 5000 rpm should not be taken lightly (ask Don Garlits the drag racing legend). This is probably the one part that you really want to spend the effort (and money?) on precision. 5000 rpm failures are not pretty. 
I realize this is not in your original design requirements, but you may want to reconsider..........
Oh, surely your son would know of a machinist being in the mechanic field?
Mike
www.EV-propulsion.com


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## TheSGC (Nov 15, 2007)

I designed my coupler myself then hunted down a local machine shop to build it. I actually went to three until I found one I liked. 

I was originally going to use E-Machineshop.com, but I thought the pricing was too high. Turns out it was dead on, and probably less of a lead time than what the local shop did, but I am happy with it. Next coupling will be from E-Machineshop.com just for simplicity. 

My coupling is a taper locking setup that connects to the flex plate on my torque converter. Been working great for over 1,000 miles and only cost $300 for the coupling and $220 for the plates.


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## vpoppv (Jul 27, 2009)

ga2500ev said:


> I see in your video that you simply set screwed the clutch center to the hub? Do you still have that arrangement, or did you move to a stronger connection?
> 
> And what do you do if they are not the same size?
> 
> ...


 Yes, I have it setscrewed, but I think what is really holding it is the "key". I used a standard key, which fits in all the hubs around that size. Hubs are made to be welded, so you should be able to weld two hubs of a different size together {one size would fit your female splined piece, the other would fit your clutch center} and that "may" be strong enough. So far, mine has held withoud any welding, but if it does fail, I can then weld it.....


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## Woodsmith (Jun 5, 2008)

Without making this into a gripe I will have to disagree with your view of contractors. Some are really good and honest and work well and don't over charge.

I am one. I do my work (carpentry) because I love it. I charge the least I can afford to and even if I have to do a difficult or out of hours job to get someone out of trouble I won't hit them with a big bill unless they have agreed a premium price before hand.
I have done small bits of work for free just because I could and it didn't stop me earning on another job.
If I have a saving on a job it is passed onto the client.

I am honest and reliable and most of my work is by word of mouth due to my integrity and trustworthiness.

I have even done work for cakes and return of labour (I draw the line at personal services though).

Anyway, my lathe cost £180 and it means I can make some parts and also model parts for a machine shop to make properly.

It may be worth you checking the local business directory for a local machine shop and then stopping by to have a chat. You might find someone who will do what you need them to do for a reasonable price. The effort may be worth while for a high speed spinny bit next to your ankles.


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## DONEAL (Sep 10, 2008)

I don’t know if you could weld it yourself (DIY). I don’t recall reading any post from you about your expertise in welding. This is a great forum, but sometimes people “jump the gun” post before they know all the facts. For all we know you very well may be an expert in welding.
But remember, what other members have already posted. about The alignment of the motor, coupler , adapter plate, transmission and the tolerances of them. If you get the motor out of alignment with the transmission The coupler could fail or the Front bearing and seal of the transmission would prematurely fail. 
You did have some good points about contractors, But at the same time you cant put them all in the same boat. And yes it does pay to know the person that is doing work for you, Naturally if your good friends ,then that individual will go the extra step for you.


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## ga2500ev (Apr 20, 2008)

DONEAL said:


> I don’t know if you could weld it yourself (DIY). I don’t recall reading any post from you about your expertise in welding. This is a great forum, but sometimes people “jump the gun” post before they know all the facts. For all we know you very well may be an expert in welding.


I am not. But I am certainly willing to learn.
There are welding tools that are within the tool budget. There is also considerable debate as to the utility of low end welding equipment. That's a debate for another day.



> But remember, what other members have already posted. about The alignment of the motor, coupler , adapter plate, transmission and the tolerances of them. If you get the motor out of alignment with the transmission The coupler could fail or the Front bearing and seal of the transmission would prematurely fail.


I'm aware of this. It's one of the reasons that it's a shame couplers cannot be made reliably with Lovejoys which can tolerate at least a little bit of misalignment.

The structural stability between the motor and the tranny is kept in place by the adapter plate. There are a ton of sites (including multiple threads here) that describe how to put together workable adapter plates.



> You did have some good points about contractors, But at the same time you cant put them all in the same boat. And yes it does pay to know the person that is doing work for you, Naturally if your good friends ,then that individual will go the extra step for you.


I was asked to explain my fear of machine shops. I did so. I'm well aware that not all contractors fall into this boat. The problem is that enough of them do that finding a good one is like finding a needle in a haystack, paying for each opportunity in both time and money. I'd rather spend my time learning how to do something new myself, and money on tools to do that.

BTW I put the tool budget contraint in because someone was going to wander into the thread and point out that machining a precision adapter is easy to do if you spend $2500 on machining equipment. But it isn't cost effective unless you amortize such equipment over a ton of projects. The box of DIY with limited tools is in place for a reason.

As for my son knowing someone, he's into ordinary car repairs, not tweaking. The other problem is that his crowd is by definition a generation younger than me. That brings up a whole 'nother set of personality quirks to deal with.

The bottom line is that if I do it DIY, then all I have to trust is my brain, which I've lived with all my life, and the tools. It also gives me an opportunity to gain some valuable resuable expertise.

We've wandered off the track. I started this thread looking for some ingenuity. A teachable moment or three. Can this be done within the constraints given?

DONEAL, you stated in your initial post that his may be doable. Care to explain?

ga2500ev


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## DavidDymaxion (Dec 1, 2008)

http://www.grassrootsev.com has a great video on making an adapter cheap.

I calculated that only about 0.007" of imbalance on your flywheel can cause 100 lbs of imbalance force! It helps if you are going clutchless (less mass to vibrate), but even there you can get vibration.

Expanding on the grassroots thing, here is an idea I had for mega cheap DIY: Buy a taperlock coupler for a pulley. Put in on the electric motor. Cover holes in the motor with tape, so metal chips don't go in. Spin the coupler with the electric motor. Slowly and carefully flatten the face and radius the part with a hand grinder, taking measurements frequently.

The fact that you are "machining" it on the motor shaft guarantees it is concentric with the rotation of the motor.

Note, I have not tried this! I actually bolted on my taperlock and then machined the coupler square to the axis of rotation by hoisting my motor onto my machine, like in the grassrootsev videos.

I used a $600 Harbor Freight lathe/mill machine, worked great and paid for itself on just the adapter.



ga2500ev said:


> I am not. But I am certainly willing to learn.
> There are welding tools that are within the tool budget. There is also considerable debate as to the utility of low end welding equipment. That's a debate for another day.
> 
> I'm aware of this. It's one of the reasons that it's a shame couplers cannot be made reliably with Lovejoys which can tolerate at least a little bit of misalignment.
> ...


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## Woodsmith (Jun 5, 2008)

Step by step guide?

Go buy a good, old lathe for a few hundred dollars.
Go buy a dial gauge for a few dollars.
Go to a scrap metal yard and buy some off cuts of round steel bar in a variety if diameters.
Buy a book on how to use a small lathe for model making and read it while trying out the lathe on the scrap bits of round bar.
When you know what you are doing with the lathe you will have a useful tool that you can keep and use or sell to recoup your money afterwards.

Buy a budget welder, MIG will be good but MMA (stick) will do.
Buy a DVD on how to weld.
Go back to the scrap metal yard and buy some steel plate and some round tube
Learn everything you can about welding and practice with scrap from the scrap metal yard.
You want to be able to weld tube to plate accurately to make flanges and understand the stresses involved.

Dismantel your clutch centre so that you have just the part with the splines in it.
Saw off any excess bits of metal so that you have a splined tube with 'ears' on it.
Place it in the lathe and make sure it is centred using the dial gauge and then machine it so that the 'ears' become parts of a disc and it is circular.
Then machine the tubular part of the clutch centre so that the 'ears' form a shoulder on the centre to locate the clutch centre into a hole. When located in a hole the 'ears' must be flat on the surface.

Go back to the scrap yard and find a thick disc of steel, preferably an off cut of a round bar with a diameter at least as big as the diameter across the 'ears' on the clutch centre.
Place your splined coupler tube in the lathe and centre it with the dial gauge.
Machine a shoulder on the end.
Place the steel disc in the lathe and machine a hole in the centre that will tightly locate the splined tube on the shoulder you machined earlier.
All being well, press in the splined tube so the shoulder is tight and square.
Tack weld together.
Place the assembly in the lathe and check again with the dial gauge and adjust until it is square and true.
Remove from the lathe.
Fully weld the disc to the splined tube both inside and outside of the joint.

Place the splined tube into the lathe and centre it using the dial gauge.
Machine the disc so it is flat, true and round.
Machine all the welds so that they form a continuous smooth junction to the joint. This will help balance and reduce stress. Don't remove so much weld that the joint is weak.
Machine the hole to tightly fit the machined part of the clutch centre.

Press the clutch centre into the steel disc so the shoulder is tight and square.
Place in the lathe and rotate by hand to check it is true using the dial gauge.
When it is true remove it from the lathe and then drill tight fitting holes through the 'ears' on the clutch centre right through the disc.
Bolt together with M8/M10 high tensile allen headed bolts. Make sure the unthreaded section of the bolts are a tight fit and bridge the joint between the two parts. This ensures that there is no shearing stresses across the bolt threads. Use high tensile locking nuts.
Put the assembly back on the lathe to check it is still true and adjust if necessary.

That is the minimum you should be looking at to make a coupler.
Ideally the assembly should be balanced afterwards but you could just machine away any lumps of weld so the joints is still strong but smooth and even.

Note: When forming shoulders in the parts allow a radiused inside corner and relieve outside corners to accomodate. This will reduce stress risers.

ETA: all the above is guidance only on how things might be done and may be riddled with errors and other such mistakes, and of course, my own ignorance. Use your own judgment and seek professional advice before contemplating folllowing any of the above. If it all goes wrong then it is your own fault for blindly following the scribblings of some unknown person, probably unqualified and inexperienced person on the internet.


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## DONEAL (Sep 10, 2008)

“Any operation must be able to be performed in a house garage or backyard.”
This is doable. In other words, you don’t have to have a fully equipped mechanic’s garage, or a machine shop.
I was referring to the above, and I agree, “We've wandered off the track.”
“ I started this thread looking for some ingenuity. A teachable moment or three.”
Yes, I think, there has been some teachable moments in this thread. (your thread.)
“ Can this be done within the constraints given?”
And yes, I believe This is doable.


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## DIYguy (Sep 18, 2008)

step by step guide....

#1. plant feet firmly shoulder width apart.

#2. place palms of hands flat on surface outside or in front of feet.

#3. pull hard until cranium breaks through the sand it is buried in... 

heheh, sorry man, couldn't resist. (hey, I apologized, just like you!) lol


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## DC Braveheart (Oct 12, 2008)

ga2500ev said:


> Simple. I don't know any machine shops. So my expectation is that they will be just like every other type contractor that I've ever met. Specifically:


Sorry you have such a hard time with contractors. I've never used a machine shop until this past week when I needed to get my flywheel shaved so it would fit my motor adaptor. Here's my experience wrt your comments.



> 1) They will charge too much.


Mine quoted me c. $120 for the work ... ended up coming in at $58



> 2) They are arrogant. Always have the attitude that they know everything, and you as the customer knows nothing.


Mine was far from it. He was very interested in what I was doing with my car and spend 10 minutes listening to me talk about it. Then he went on to tell me about a friend of his who, in the early '80s converted an ICE to run on pure compressed air. He wanted me to bring my car back so he could see it when complete.



> 3) They can never get done what you want to get done when you want to get it done.


I dropped my flywheel off off at noon on a Friday. Despite snow over the weekend I got a call on Monday at 11am to tell me it was ready to pick up.



> 4) The job won't be done right the first time.


Well I haven't run the motor with it yet ... but what he did has certainly resolved the clearance issue I had.



> 5) Getting in contact with them is a pain.


Mine answered the phone when I first called, was there as promised when I turned up to drop it off and called me to tell me he was done (no chasing for days to get status).

Sorry you've had bad experiences ... but as you can tell from the above, it doesn't have to be that way.


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## ga2500ev (Apr 20, 2008)

Would anyone care to explain why this operation can only be custom built without the use of any off the shelf parts?

Here's an example with a keyed shaft motor using OTS parts by one of our own, M. Paul Holmes:

http://www.youtube.com/watch?v=9BI0292l71o

Does the fact that my motor has a splined shaft make something similar impossible to do? If so, why?

Thanks for all the contributions so far. It's been a learning experience.

ga2500ev


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## ga2500ev (Apr 20, 2008)

Snippage...



DC Braveheart said:


> Sorry you have such a hard time with contractors.
> 
> Sorry you've had bad experiences ... but as you can tell from the above, it doesn't have to be that way.


My contractor experiences really isn't the point. The real point is the explore ways to design completely DIY, with tools that don't cost a mint, using off the shelf parts, which are both available and precisely machined.

A machine shop isn't going to manufacture a splined shaft coupler. They would buy one off the shelf. Same with hubs.

There are tons and tons of off the shelf parts. What I'm trying to figure out is how can they be utilized, with a bit of home cooking, to develop something usable.

ga2500ev


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## Woodsmith (Jun 5, 2008)

Off the shelf partys would be great where they are available.

Ideally you would get an off the shelf taper lock coupler with a keyway or splined drive flange to suit your motor shaft and the coupler would have standard bolt holes to match it to a splined coupler that fitted the transmission shaft.

However, in reality the transmission side is the unknown. You could take your transmission to a shop and ask for a female spline to fit. But you already have one in the clutch plate that you can modify to fit.

Someone on here did find that their clutch splines were the same as tractor splines and so bought a tractor PTO coupler.

I have no idea what else would have splines that match my transmission, or yours.

For those who are keeping the flywheel there is the added problem is that the motor coupler has to be tight to prevent wobble at speed. That means that generally sliding fit splines are not suitable unless there is a way to make it tight and fixed.
Also there is unlikely to be a standard off the shelf coupler, splined or taper lock, that will have a crankshaft end to fit the flywheel.

Also in many cases the demand for such complete 'odd ball' coupling solutions would not create sufficent market to bring prices down.

So, yes it would be great to be able to get all off the shelf parts but it isn't always possible or practical or affordable.
This is the main reason, I think, why we end up making, or commissioning someone to make, the couplings for our conversions.


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## ga2500ev (Apr 20, 2008)

Woodsmith,

Thanks for the insight.

Clutchless seems like a requirement. Direct coupling and less spinning mass means less headaches. That's a reasonable compromise considering the restrictive environment of the challenge.



> Ideally you would get an off the shelf taper lock coupler with a keyway or splined drive flange to suit your motor shaft and the coupler would have standard bolt holes to match it to a splined coupler that fitted the transmission shaft.


Since there's no market for the transmission end, I wouldn't expect that item to exist off the shelf. But as we well know we have the clutch disk.










The inner disk with the springs can be bolted onto a flange something along the lines of this:

http://video.google.com/videoplay?docid=4146487354510920974

Of course the sprocket used in the video is a keyed shaft.

So the objective is to piece together a flange on one end of the coupler to bolt the clutch disk to and ends up with the female spline coupling I already have on the other end.



> However, in reality the transmission side is the unknown.


It's well known because of the clutch disk. That's the starting point.

ga2500ev


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## Woodsmith (Jun 5, 2008)

ga2500ev said:


> Woodsmith,
> 
> It's well known because of the clutch disk. That's the starting point.
> 
> ga2500ev


I mean unknown as in it would be more difficult to go to a mechanical component supplier to ask for a spline to match a 1976 Ford Cortina 2 litre ghia gearbox as the supplier wouldn't know what the spline would be on it.


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## grayballs (Aug 27, 2008)

ga2500ev said:


> Here's an example with a keyed shaft motor using OTS parts by one of our own, M. Paul Holmes:
> http://www.youtube.com/watch?v=9BI0292l71o
> Does the fact that my motor has a splined shaft make something similar impossible to do? If so, why?
> 
> ga2500ev


"A machine shop isn't going to manufacture a splined shaft coupler. They would buy one off the shelf. Same with hubs."

That it can't be done at home, or with OTS parts is not the point, at least, in my opinion. It certainly can be done with OTS parts and at home. My guess is that you, and many of the rest of us have been less than sucessful in our searches for OTS parts to match our projects. 
I'm not a fan of Lovejoy couplings for these type of applications, in fact I think those that are using them are asking them to do something that they just weren't desingned for,,, designing for failure? My $.02

Saying that a machine shop is not going to manufacture a splined hub is also a bit of a stretch. I'm capable of doing just that in my own 'backyard shop', but it is a lot of work. I'm guessing anyone with a decent lathe and a bit of thought can accomplish this task. In my case, I chose to use correct hubs for my application, machine them to size, and weld them into a hub that fit my needs,,,,,, a lot less work! I guess time will tell whether or not it was worth it.


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## ga2500ev (Apr 20, 2008)

grayballs said:


> "A machine shop isn't going to manufacture a splined shaft coupler. They would buy one off the shelf. Same with hubs."
> 
> That it can't be done at home, or with OTS parts is not the point, at least, in my opinion. It certainly can be done with OTS parts and at home. My guess is that you, and many of the rest of us have been less than sucessful in our searches for OTS parts to match our projects.


I agree. But is that because we are searching in the wrong places? Or because the parts really don't exist OTS?


> I'm not a fan of Lovejoy couplings for these type of applications, in fact I think those that are using them are asking them to do something that they just weren't desingned for,,, designing for failure? My $.02


But it's one of the reasons that for this challenge I specified a limited functional duration for the coupler. I'm well aware that it's a jerry rigged setup destined for failure. Right now I'd just be happy with the ability to move the car around the yard without having to push it. Or a test drive around the neighborhood.

It's a proof of concept. Can a functional coupler be built with OTS parts without having to completely commit?



> Saying that a machine shop is not going to manufacture a splined hub is also a bit of a stretch. I'm capable of doing just that in my own 'backyard shop', but it is a lot of work. I'm guessing anyone with a decent lathe and a bit of thought can accomplish this task. In my case, I chose to use correct hubs for my application, machine them to size, and weld them into a hub that fit my needs,,,,,, a lot less work! I guess time will tell whether or not it was worth it.


I've gotten the feeling that folks on this thread are annoyed with my slavish fear of committment. I just want to clarify that for most of us doing our first EV, that it's a massive leap of faith. While there are some that have in house shops, loads of time, and tons of money, there are others like myself that are functioning on a shoestring budget and the hope of getting something workable without having to throw a wheelbarrow full of money and frustration into it.

It's a temporary coupler. A test piece.

Can it be done without buying a lathe, drill press, and mid level welder?

Can you test with lovejoys and set screws?

That's all I'm asking.

ga2500ev


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## SimonRafferty (Apr 13, 2009)

A couple more options for you.

You can make a female spline by drilling a ring of holes such that the spaces between the holes engage with the recesses in the splined shaft. Then drill the centre out of the ring of holes.

It's tricky to get right - but can be done. I used this method to make a PTO hydraulic pump for my Land Rover.

I did it using a bench drill and a set of dividers for marking out.

Another option is to use a grinder to cut a very thin slice off the end of the spline shaft. You can then take this to a laser cutting company and ask them to cut several out of sheet. The sheets are then stacked to give you a female spline of the required depth.

If they cannot work from the slice of spline, scan it with a flat-bed scanner then draw round it using a CAD program leaving a small gap all the way round. They will normally be able to work from the CAD.

Have a ring of holes cut into each sheets that match whatever you want to drive - a universal joint for example. Use these to bolt the laminations together.

Si


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## ga2500ev (Apr 20, 2008)

Simon,

Thanks for the reply. No problem with the female spline. I have the matching coupler for it. See attached pics.

The problem is getting it attached to the spline of the clutch disk. And to do so without as little machining as necessary.

For the sake of argument let's say we're working with a Lovejoy so that some misalignment is tolerable. With one half of the Lovejoy you insert the female spline coupling. I'm trying to figure out how a keyway can be cut into the female spline. I found a post here that gives some ideas:

http://www.minibuggy.net/forum/shop-talk/10775-cutting-keyways.html#post162343



> Do you have an angle grinder and some new discs? I've built a jig before out of a piece of angle iron on its edge (a "V" shape). Then I took my angle grinder with a new disc and clamped it on a work bench vertically above the angle iron.
> 
> I think you see where im going with this.
> 
> ...


This is the type of ingenuity I've been looking for in this thread.

So after keying that coupler, use some part of the clutch disk for the other side. Key it in a similar manner.

A die grinder or a Dremel with a cutting disk along with some jigs would be the toolset.

It won't be perfect. It won't be permanent. But that's not what I'm looking for. Just some type of test setup to get the car moving.

Keep the ideas coming.

ga2500ev


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## Woodsmith (Jun 5, 2008)

ga2500ev said:


> It's a temporary coupler. A test piece.
> 
> Can it be done without buying a lathe, drill press, and mid level welder?
> 
> ...


If your shafts are about the same diameter and you can get tools to them while the motor is mated to the transmission you could try this.

Get a piece of pipe that is a good fit over the shafts and the right length to join the shafts.
Saw a cut right through the length of the pipe so it is split.
Then saw the inside of the pipe diametrically opposite the first cut.
Fit 4 or 6 hefty hose clamps over the pipe and assemble the motor to the transmission.
Then tighten the hose clamps, 2 or 3 over each shaft making sure the worm drives are equally spaced.

That would work as a low speed, low torque coupler. It won't last too long though and you risk a little surface wear to the splines if you are not careful and spin the coupler.


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## ga2500ev (Apr 20, 2008)

Woodsmith,

I agree it's temporary. But I think it's too low tech a target considering that female splined shaft couplers are available for both the motor and transmission shafts.

A lot of the parts needed for this are already machined. I'm just looking for ideas for attachment, such as cutting keys without having to buy a lathe or a mill.

ga2500ev


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## Woodsmith (Jun 5, 2008)

Well, keyways can be cut with a hacksaw and a file.


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## ga2500ev (Apr 20, 2008)

Woodsmith said:


> Well, keyways can be cut with a hacksaw and a file.


Home users have access to power tools. A die grinder would seems to be a better fit here. Even better, I do have an air compressor to drive an air die grinder.

I'm trying to work through the next issue with a new understanding of how a clutch disk is actually mounted. The original vehicle the motor came from used the coupler to attach the motor shaft to a fixed splined axel as a direct coupling. Similar to an EV, the motor bolted to a plate that kept the motor fixed to the axel.

Up until the weekend I had a flawed perception of the order of mounting of the flywheel, pressure place, and clutch disk. I always thought that the pressure place was fixed between the flywheel and the clutch disk and that the clutch disk was the closest item to the trans.

But my son gave me some schooling on how it actually works. The clutch disk is sandwiched INBETWEEN! the flywheel and the pressure plate. The throwout bearing pushes the movable part of the pressure plate into the clutch disk from the transmission side. Huge revalation for me.

The upshot of this is that in a normal config, the clutch disk is not lock mounted to the trans input shaft.

So this gives rise to another issue. The female spline coupler above is not secured to the motor shaft. No set screw or taper bushing or anything. It just floats. With the clutch spline doing the same, that means that a couple made with these two female splines are not fixed to either shaft. So all the split coupler designs (like lovejoys) which operates on the premise that that the halfs are securely fixed to the shafts are going to have problems.

ga2500ev


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## DONEAL (Sep 10, 2008)

"The female spline coupler above is not secured to the motor shaft."
So, drill a hole and tap it and add a set screw, the other half, (transmision shaft) doesnt need to be.


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## Coley (Jul 26, 2007)

All that you need from the clutch disc is the very center.

The rest with the springs and all are not needed.

The springs were to help smooth out the crankshaft pulses and is NOT needed on an EV.


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## ga2500ev (Apr 20, 2008)

Coley said:


> All that you need from the clutch disc is the very center.
> 
> The rest with the springs and all are not needed.
> 
> The springs were to help smooth out the crankshaft pulses and is NOT needed on an EV.


Good to know. That's what Ben Nelson did for his second coupler in his Electro Metro project. Video here:

http://www.instructables.com/id/S950N66FNFPVGZI

The first mated a Lovejoy connector.

Since I last posted I did get an opportunity to visit Grainger and do some test fitting of the splined female coupling. It was too big to the 1-1/8" Lovejoy and rattled in the 1-1/4" one. So it looks like we're looking at a 1-3/16".

Also took some measurements and it looks like I have a 7/8" in spline with 13T. The Surplus Center actually has couplings in those dimensions. The three parts would come in under $100 and would require minimal machining.

I haven't pulled the clutch from the Metro yet. I know that the disk has an 18 tooth 3/4" inner diameter. I haven't found a hub in those dimensions. But I plan to pull the clutch, drill out the inner disk and see what I can fit it to.

ga2500ev


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