Strange collet problem

[zooma]

On the last run of a P class boat, the two grub screws fell out of the collet and it must have spun around the 5mm motor shaft until it jammed onto the shaft. I didn't notice it until post-race maintenance. I was able to pry it off with a screwdriver blade (have no gear puller). There were a couple of burrs on the shaft that I dressed with a small file. However, neither that TFL collet nor any other new TFL, Aeromarine or Octura collets will fit. Can't even get them started. It's like the motor shaft got swollen from the friction and heat.

Anybody know about this?

[ray schrauwen]

That's called friction welding.

https://www.youtube.com/shorts/iBaanKLvLGw

Not sure if it can be viably fixed unless the motor shaft is properly turned to 5mm. It's hardness is now also compromised.

[Peter A]

Did the shaft discolor from heat? You could run the motor and use some emery tape or similar to polish it to size.

[1coopgt]

Did you measure the shaft in a couple of places with a pair of calipers to see how bad it is?

[zooma]

Did you measure the shaft in a couple of places with a pair of calipers to see how bad it is?

Getting 4.9 to 5.1 with Harbor Freight sliding caliper. Can't get really repeatable measurements.

[zooma]

Did the shaft discolor from heat? You could run the motor and use some emery tape or similar to polish it to size.

No discoloration. Will try the emery tape.

[fweasel]

You can open the ID of the collet in a lathe of you have access to one. Otherwise, emery cloth on the rotor shaft sounds like the best bet.

[Shadow99]

Don?t forget to remove the burrs from between the slots of the collet, if there are any burrs in the slots of the collet, they will reduce the clamping pressure of the collet to the cable, & will probably cause slippage again.
I?ve used a thin jeweler?s file &/or a piece of emery cloth to remove the burrs in the slots before.

Shadow

[zooma]

Don?t forget to remove the burrs from between the slots of the collet, if there are any burrs in the slots of the collet, they will reduce the clamping pressure of the collet to the cable, & will probably cause slippage again.
I?ve used a thin jeweler?s file &/or a piece of emery cloth to remove the burrs in the slots before.

Shadow

Never noticed that. Will check the ones that I have.