BloodClod's Belt-Drive Yokomo 834B

[Mr. ED]

I wouldn't worry about braking. Breaking though...

[BloodClod]

Just about every part is rare , I've seen a few rear drive pulleys for the slipper type pulley come up on eBay but not a front one for about a year and I check virtually daily for 834 parts , good luck , I ration driving mine because of the down time if I brake anything.

sigh... thanks for the advice.

Modding and running these old treasures are really a special experience. lol!

Maybe it's time to explore a belt drive... have some ideas but will go do some research to see if they are feasible.

[BloodClod]

I wouldn't worry about braking. Breaking though...

Just realized in my absence I've lost access to the BST forum to look for stuff. But I'm guessing parts are just as rare there as they are on ebay?

[BloodClod]

The body looks good and I really like the turnbuckles , they do fill that space as well as being a functional support to the roll hoop , do they add any torsional rigidity to the chassis ?

Yes the turnbuckles do reduce torsional flex which I think is good as the kydex chassis is so soft and flexible. Once the turnbuckles are bolted on, the rear suspension works better.

[Dadio]

Cool

[tiger1]

Cool stuff!!!!!!

[BloodClod]

Cool stuff!!!!!!

Good to see you man!

How's everything going?

[BloodClod]

Okay... it's a tad crazy but the journey that started with a search for sprockets... led to ideas about a belt conversion... which led to a search for pulleys and parts... which ultimately resulted in me buying a 3D printer over the weekend and watching many hours of youtube videos on 3D design and printing. lol!

Mocked up some new pulleys in CAD...



Front Pulley.



Rear Pulley.

I've done some test prints and the pulley fit looks pretty good. Need to fit them to the car and try to do some testing.

Fingers crossed this crazy idea will somehow work. lol!

I'll post some pics later.

[Mr. ED]

Ooh! I'm jealous now: I'm still waiting for the parts I designed and ordered prints of about 2 months ago.
Did you draw the teeth profile or is there a module for that in your cad software?

[BloodClod]

Ooh! I'm jealous now: I'm still waiting for the parts I designed and ordered prints of about 2 months ago.
Did you draw the teeth profile or is there a module for that in your cad software?

2 months? Wow... why is it taking so long?

You might consider buying a printer and doing it yourself. I've been interested to pick up 3D printing for quite some time now but the start up cost was just too high - but I did some research recently and it seems the tech has reached a point where you can get a decent machine for quite a low price provided you're willing to do some assembly and set up.

I have been using my very old version of AutoCAD for my CNC but have always pretty much worked in 2D - so I had some learning to do to get these pulleys designed. I actually did it with Tinkercad which isn't the most powerful tool but is actually amazingly easy to get started with and surprisingly versatile with some imagination.

There's actually a gear designer there which I was very impressed with and will try sometime but for these first pulleys I drew them myself based off measurements from a touring car pulley. I did some testing with just the teeth to ensure good alignment with the belt before printing out the entire pulley.

The beauty of the 3D printer - I was able to make some changes and also design a larger 18T pulley during lunch and printed them all out when I got home!

I don't think the basic PLA has the strength to work as a gear but so far I am reasonably confident it will work as pulley. If it doesn't I can always try a different material or send it away to be printed professionally in some exotic plastic blend. lol.

Any pics of your pulley design?

[BloodClod]

Okay so I made some progress last night.

First off, a picture of the very first pulleys I pulled off my 3D printer. They aren't perfect, but better than I expected for a first print and they fit fine. These are 16T pulleys.




I tested them in the car with the belts that I had and I realized that the 453mm belts that others have referred to in their builds is too short for me as I would like to retain the battery in the existing position and will need a longer belt to go over the battery.

Since I was going to a longer belt, I decided to try bigger pulleys instead which should take the load better. So I printed up some 18T pulleys instead and mounted them onto the 834B.

Here's the V2 18T pulley in the front. It fit very well!




Here's the rear pulley mounted.




With the pulleys in and the belt tested I found that I would need a belt tensioner to take up the extra length of the belt as well as to route the belt over the battery. Some quick measurements, some time on CAD and then the 3D printer spit this out!




Here's how everything mocked up in the car.




Of course I could not resist powering it up and I'm happy to say that bench testing went very well. I'll post a vid up soon for those who might be interested.

However, this quick mock-up and test allowed me to refine my designs a bit more and tweak the measurements of everything. I'll be printing up a new set of pulleys and tensioner with these incorporated. I also have a new idea which I am going to try with regard to the way the belt runs.

[BloodClod]

Nothing exciting... just a very quick vid of the first test of the belt-drive system on the 834B. The old wheels are somewhat unbalanced and causing the vibration. The belt-drive itself is quite smooth.

The only thing I realized is that front pulley is actually not in line with the rear - i.e. the belt doesn't parallel to the centerline of the chassis. I think this was not a big deal with the chain... and it's actually working fine with the belt, but my next set of parts will do something about this.

[a01butal]

I posted this a while ago. FYI

http://www.rc10talk.com/viewtopic.php?f=29&t=36513

[BloodClod]

I posted this a while ago. FYI

http://www.rc10talk.com/viewtopic.php?f=29&t=36513

Hey a01butal, thanks for the link. Your thread was one of the many that I referenced when working out how I wanted to do the belt conversion. The set you have certainly is interesting to me, mainly because it still uses the stock chain guide. I think it works because of the large pitch of the teeth on the belt. I was curious how it your setup would perform but I think you mentioned it was only going to be a shelf queen.

Yours is the only commercial conversion set I've seen - what a rare find!

[a01butal]

[/quote]

Hey a01butal, thanks for the link. Your thread was one of the many that I referenced when working out how I wanted to do the belt conversion. The set you have certainly is interesting to me, mainly because it still uses the stock chain guide. I think it works because of the large pitch of the teeth on the belt. I was curious how it your setup would perform but I think you mentioned it was only going to be a shelf queen.

Yours is the only commercial conversion set I've seen - what a rare find!
[/quote]

Yes, I'm very impressed with your conversion, I was lucky to find mine (conversion) kind of hidden in an eBay auction buried behind some other items and luckily it wasn't bid on and I got it pretty cheap. I never did get much info about it anywhere even the Delta guy Dave Campbell couldn't find anything on it. Good luck and I will be watching to see how this works out for you.