Aluminum Idler Wheel
by SingularityU, published
Description
Recent Comments
view allMIght want to make it from 12l14 steel instead, I'd be concerned about the aluminum cracking from the heat. Aluminum is susceptible to hot short cracking. I'd get some 12l14 round and do it up on a lathe, bore the interior and machine the outside. If possible, I'd modify the OD to 1.750 - maybe even do it with drill rod and save having to machine the OD.
I tried that when i got my new idler wheel (acrylic sadly)....but i facepalmed myself when i realized that as i heated my acrylic i heated the wheel (it was stuck)
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Instructions
Outer diameter = 41 mm = 1.614in
Inner diameter = 21.9 mm = 0.862in
Thickness = 1/8 in
Start with a plate of 1/8 inch aluminum.
We wanted to make our aluminum wheel so that it would bond to the bearing without relying on glue, so we milled an inner hole that was smaller than the the specified acrylic hole, 0.806 inches in diameter. We milled the outside diameter according to the spec of 1.61 inches in diameter.
We then heated the wheel over a gas flame to expand the hole so that the bearing fit easily inside. We set the wheel on the makerbot washers to get the right height and then placed the bearing in the hole. We cooled the wheel quickly with water so that the bearing lubricant would not heat up too much as the wheel cooled. The cooled wheel has a permanent very tight bond to the bearing.
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I tried that when i got my new idler wheel (acrylic sadly)....but i facepalmed myself when i realized that as i heated my acrylic i heated the wheel (it was stuck)
That heating/cooling trick is a great idea for a really secure idler! Nice work, thanks for sharing!


MIght want to make it from 12l14 steel instead, I'd be concerned about the aluminum cracking from the heat. Aluminum is susceptible to hot short cracking. I'd get some 12l14 round and do it up on a lathe, bore the interior and machine the outside. If possible, I'd modify the OD to 1.750 - maybe even do it with drill rod and save having to machine the OD.