Colson Wheels to 6mm Shaft

[Judge]

I have the 5" x 7/8" Colson Performa wheels: http://www.trossenrobotics.com/store/p/4272-Colson-Wheel-5-x-7-8-.aspx
I have the Wheel Hub, Colson 7/8" Wheel, 6mm: http://www.trossenrobotics.com/store/p/4275-Wheel-Hub-Colson-7-8-Wheel-6mm.aspx
I have the Lynxmoton Planetary Gear Motor - 12vdc 91:1 65rpm (6mm shaft): http://www.lynxmotion.com/Product.aspx?productID=515&CategoryID=71

How do I connect all 3 pieces together using standard garage tools?
Do I hammer the hub into the wheel?
How do I mount the hub to the 6mm shaft of the motor?
Will there be a substantial loss of rotary motion due to this assembly?

Thanks!

[Adrenalynn]

I tap the Delrin freewheel bearing out with a pin-punch over a vice. Then I put the 6mm couple against the wheel and tap it to start it straight (using a mostly closed vice for wide area support of the wheel), then I put the wheel with partially inserted coupler into the vice and slowly apply pressure to squeeze it in.

I put them on the shaft with a large pair of channel lock pliers. I personally feel that steady force is less stressful to the bearings and windings than would be sharp high-g force from a hammer method.

If the coupler is unkeyed, I find widening the base side of the coupler just a wee bit in the drill press helps get them started straight and guides them on the shaft. Not terribly deep, though! Take off too much material and they're garbage [don't I know]!

Others may have different methods, and I'd personally love to hear the creative means people have for these things.

[Judge]

So, essentially, you squeeze the coupler to fit/conform to the shaft, correct?

Is it that easy to bend the coupler by hand? And won't that create a "wobbly" wheel?

Also, do you think it is an efficient method of transfering the motor's rotary motion to the wheel? Does it slip at all?

Would you recommend drilling and tapping for a set-screw, or is the channel lock plier method easier/better/more efficient?

Thanks Ma'am :wink:

[JonHylands]

Personally, I like to machine my hubs so I can easily take the whole thing apart. I can't remember how many times I've taken Seeker 2 (http://www.huv.com/miniSumo/seeker2) apart in the five years I've had it - probably a few dozen at least.

The hubs have a 2mm hole drilled through the center, with a pair of #4-40 set screws to hold it in place. The hubs started life as a piece of 1" diameter brass rod, and then turned to shape on the lathe. Then the wheels slide onto the hub, and are fastened in place with #4-40 cap screws.

Seeker 3 (http://www.huv.com/miniSumo/seeker3) is done the same way - you can see details in this picture (http://www.huv.com/miniSumo/seeker3/Wheel-Assembly-2.jpg). Seeker 2x (http://www.huv.com/miniSumo/seeker2x), my latest mini sumo (still under construction), doesn't really have space for hubs, since the wheels are only 1" in diameter, so I have #4-40 set screw channels going right through the wheels (http://www.huv.com/miniSumo/seeker2x/Seeker2x-Wheel-02.jpg) to the motor shaft.

- Jon

[Adrenalynn]

I wouldn't say I'm "bending" the coupler, more compressing it. It's a snug but doable fit. I haven't noticed them any more out of round than any other wheel. These things tend not to be machined to all that tight a tolerance anyway.