Dave's 80:1 RC mid drive kit build log

[Ecyclist]

@tangentdave did you use GearTrax for the cycloidal gears or hardcoded equations?

Just so you know, any software including GearTrax will only design theoretical shape. Practical shape require some adjustments.

 

[Azalin]

Just so you know, any software including GearTrax will only design theoretical shape. Practical shape require some adjustments.

Yes. Mine doesn't work well. It needed some tolerences or I'll have to remove some material from the disks manually.

 

[Ecyclist]

This is a very thick disc / gear.
Are you running one or two?

 

[Azalin]

2 discs 12mm each because the thickness of the needle roller bearing is 12mm. This gearbox is going to be into the 4th axis of my CNC. I may slightly reduce thickness to 10mm.

 

[Ecyclist]

Two discs is a way to go, but 12 mm is a lot to ask.
I imagine you are getting deflection on your cutter. Your shape will be off.
Are you machining out of chrome moly? Are you using a four flute stub carbide end mill?
You might be able to alleviate some problems by removing about 0.1 mm from the bottom of each curve.
You can even take out more like 0.2 - 0.3 mm by plunging. The bottoms of curves are not working surfaces.

 

[richj8990]

Not unheard of for the bearing to fail. Pretty sure it's off the shelf size... should be written on it somewhere. If not then someone here will know which it is or take calipers to it for internal and external diameters and race width....

Dave hasn't been responsive on here for some time. I hope he is OK.

Website is down. Not a good sign lol.

 

[Azalin]

Two discs is a way to go, but 12 mm is a lot to ask.
I imagine you are getting deflection on your cutter. Your shape will be off.
Are you machining out of chrome moly? Are you using a four flute stub carbide end mill?
You might be able to alleviate some problems by removing about 0.1 mm from the bottom of each curve.
You can even take out more like 0.2 - 0.3 mm by plunging. The bottoms of curves are not working surfaces.

I made a special jig to place the disc to the table of the mill perfectly aligned. Then I cut some about 0.1mm material from the bottoms. Feels much better however I still need to cut the double eccentric shaft. This will be my first time with eccentric on a lathe so I'm not quite sure how to do it.

Best

 

[Ecyclist]

I used a milling machine for the double eccentric shaft as well.

 

[Azalin]

Did you make the eccentrics separately then joined them together?

 

[Ecyclist]

No, I made it as one.

 

[Azalin]

OK that's interesting. I assume you've used a rotary table.

 

[Ecyclist]

No, I used a CNC mill. I made a fixture with a keyway. I machined one side, flipped over and machined a second side. Easy.

 

[richj8990]

Does anyone know where this motor mounting bracket is for sale. Is it custom or did he get it from some other manufacturer. The thing I like about it is that it's long enough that more narrow pedal cranks will clear the sprocket since it's mounted higher up the downtube. I can't do that right now with a different setup because the Hailong battery mount is taking up the space to properly attach an extended motor mount. I have to zip tie the front mount in order to clear the battery mount since they are in the way of each other, not exactly ideal but it more or less works. Later after this battery dies I would be interested in getting a motor like this or at least the mount, and play around with combining it to more narrow cranks.

 

[Ecyclist]

Does anyone know where this motor mounting bracket is for sale. Is it custom or did he get it from some other manufacturer. The thing I like about it is that it's long enough that more narrow pedal cranks will clear the sprocket since it's mounted higher up the downtube. I can't do that right now with a different setup because the Hailong battery mount is taking up the space to properly attach an extended motor mount. I have to zip tie the front mount in order to clear the battery mount since they are in the way of each other, not exactly ideal but it more or less works. Later after this battery dies I would be interested in getting a motor like this or at least the mount, and play around with combining it to more narrow cranks.

Tangent and mine Avian are all custom made.

 

[juanjo]

¿Alguien puede ayudar a construir un kit de estos?

 

[Ecyclist]

¿Alguien puede ayudar a construir un kit de estos?

Can you post in English?
Can you program CNC mill?
Can you machine parts?

 

[juanjo]

no.ok thanks

 

[juanjo]

https://pin.it/5dgHzbp

I say build one like this

 

[Ecyclist]

https://pin.it/5dgHzbp

I say build one like this

You are recommending to build a poorly designed unfinished kit which weighs a ton.
You can still buy Lightning Rods kit. This wheel was already invented.

 

[juanjo]

Lightning Rods does not ship to Spain

 

[Ecyclist]

That is very unfortunate, but I'm not surprised. I don't ship to southern Europe either.

 

[juanjo]

Does anyone have the plans to build Dave's astro flight kit?

 

[amberwolf]

Does anyone have the plans to build Dave's astro flight kit?

I didn't know he gave away or sold the plans?

 

[juanjo]

How much do the plans cost?

 

[amberwolf]

How much do the plans cost?

There must be a communication problem.

AFAIK the plans are not available.

AFAIK no one but the original maker has them.

AFAIK the original maker hasn't been seen for more than three years. (at least, not here on the forum).

One post

Dave's 80:1 RC mid drive kit build log

Bearing shot or gears cracked. Best to pop it open and have a look....

endless-sphere.com

shows someone was able to find and contact him, but that info wasn't made public.

Hopefully someone else here has better news for you.