Birdcage side clearance

I recently read an article that stated birdcages need side clearance between them and the axle clamps holding them in place to allow for expansion as they heat up. This article stated that grt recommended .08-.120 clearance. They said with no clearance, the cage and bearing can heat up and cause a band if they don’t have room to expand. I’ve never heard this before but it makes sense I suppose. Is this common knowledge that I’ve somehow missed? If so is grt’s recommendation a good rule of thumb for all birdcages?

Most axle clamps I've seen have a step where the part that touches the bearing race extends past the rest of the side of the clamp. I've never had one of those not have enough clearance. It would take a lot of heat to grow it .125".

You would only be looking at the change in length from the inner bearing race to the outside of the cage. For that bind. But, let's just assume cage barrel is 6" long and the whole expansion matters. A rise in temp from 75 to 300 is around 30 thousandths.

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Originally Posted by MasterSbilt_Racer

Most axle clamps I've seen have a step where the part that touches the bearing race extends past the rest of the side of the clamp. I've never had one of those not have enough clearance. It would take a lot of heat to grow it .125".You would only be looking at the change in length from the inner bearing race to the outside of the cage. For that bind. But, let's just assume cage barrel is 6" long and the whole expansion matters. A rise in temp from 75 to 300 is around 30 thousandths.

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As masters stated every modern set of bird cages and clamps I've seen are stepped and bird cage bearings have a wider inner race that when everything is made right creates the necessary clearance

The aluminum cages on my rocket have the clearance you guys are talking about. I was thinking more in the line of the steel cages on my mod. Guess I should have mentioned that. Those clamps do not have clearance for the inner race. They butt right up against it. I realize it takes a lot of heat to make it expand quite a bit. Just didn’t know if it was something to think about or not. Thanks