Cheap no-machining jackshaft

[McDesign]

I had an interesting idea this weekend as I bemoaned my lack of a lathe.

I've had success making good, durable power by over-volting 250W brushed motors. But, it's hard to deal with the resultant 5000-6500 rpm when we're limited to an 11-90 maximum reduction (plus those 11t sprockets are noisy!). Kids' scooters have good torque around the yard, but way too much speed on the road - over 30.

Obviously, a two-stage reduction (jackshaft) is needed - but that involved various maching steps.

But - just take an old wheel -


Cut of the spokes and smooth it -


Now you've got it! Put a freewheel or solid mount on either side, bearings and an axle through it, and all you need are holes to mount the axle - doesn't even need to be adjustable!

Forrest

 

[veloman]

Nice. Put up some more pics of your final design if you can. Good thinking.

 

[spinningmagnets]

This is a seriously great idea! These rear wheels are available new and used. It looks like one end takes a freewheel, and one end can accept the screw-on disc brake flange, to which a large chainring can be adapted...

There is another no machining jackshaft idea along the same lines, using an Azonics BMX stem.
http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=22245&start=0

 

[amberwolf]

This is a good idea that I *almost* had first...but I stared and stared at the scooter wheels I had laying there next to the bike I've been building this month, and somehow never got my brain past the point of seeing them as wheels and not just the core and shaft. :lol:

I will ahve to ponder this idea, as I have a couple of such wheels that have bolt-ons on one side for band brake and/or drum brake, and freewheel threads on the other side. Hmm...


BTW, how are you getting the freewheels off of these? I haven't had any luck so far (and also have a bike hub with one of them on there I need to get off).

I'll go take some pics of the above wheels and stick them in this post in a bit.

Ok, here's the pics:
off a razor kid's "pitbike" looking thing, but with 3" wide 8" diameter wheels. thread-on bandbrake one side, fw on the other (just liek what you have above)

Front wheel of this is about the same, but no threads.

Unknown source, drum brake on right side, #25 chain mount on left (at least, that's the orientation it was on the partially-built project given to me for parts)
View attachment 2
View attachment 1
both sides use 3 bolts to secure them. Same size wheel as the other one. Front wheel of this is the same, but no boltholes, and has been ground/sanded some by whoever was building something with them.

I wonder if this latter type might make it easier to do some types of jackshaft stuff?


bike wheel I wanna get the fw off of to use on my new bike's jackshaft (the thing in the center is a BB cup to thread a second fw on).

 

[McDesign]

Ah - to get the freewheels off. I have a shop table that is a solid-core door, okay?
Has a doorknob hole along the front edge
Put the protruding side of the wheel hub in the hole; put Put the wheel rim against your stomach.

Put a small nailset / center punch into the left hand of the two tiny holes in the face of the freewheel at a shallow angle; whack it with a hammer toward you (CCW). Rotate 180°, do it again. Repeat.

Usually comes off in a few whacks.

Forrest - with strange pain in my stomach