Rebuilding my little CP (735H) impact. After getting it apart I found some rather bad rust inside the bore and it had apparently chewed up the vanes. Anyway, I got the rust flakes out, but it's still rough in there. Anyone know how much you can open that air motor bore without causing problems? Seems like all I would lose is a little efficiency unless I get it big enough to let vanes fall out of the rotor. And I don't suppose a cross hatch pattern would be ideal in an iron bore with plastic vanes, so what suggested ways of smoothing things out after honing? Bore is about 1.5 inches across. Naturally, plan B is to buy a replacement bore, but that's if this turns out poorly.
Hone out an air motor?
Feb 20, 2006
5 Replies
The only suggestion I would have would be very time consuming, and may not work depending on how much you need to take out. I would consider plan "B'
Yeah, I was afraid of that. But I'm curious, what's your idea anyway?
Greetings, Years ago I had an air tool that was damaged by rust flakes in the air. The bore was chewed up as were the vanes. The vanes appeared to be made from phenolic. I asked the hone guy where I worked to clean up the bore and he removed about .004" on the diamater. I sanded the edges of the vanes to remove all the little grooves. That was at least
15 years ago and the tool still works well. It's one of those die grinders that are about 1.375" dia and are very common. I bet a brake cylinder hone would work for air tool. ERS
If it ends up as a true cylinder and parallel to the axis it's meant to be, then you can probably go wild in there. For most designs the vanes float and they just don't care about radius. Even going off centre isn't too bad, so long as it's all still parallel.
Just be sure the vanes don't extend to far out of the slots. A rebore and a little wear could get you too far out. New vanes used to be pretty cheap.
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