VEXPro Ball Shifter Shaft Malfunction

[BrendanB]

Originally Posted by Kevin Sevcik

That.... is a very astute observation, sir.

Anyone in this thread that's had a hex shaft come out: Are you retaining your sprocket with a bolt at the end of the shaft? Is it possible that you're tightening the bolt so much you're literally pulling the shaft out of that coupler?

I will check tonight when I can get a close look at the transmission. It is possible but IIRC after inspecting the completed drivetrains those hex sprockets had a little bit of play in them.

Very good observation though!

[Jimmy Nichols]

Originally Posted by Kevin Sevcik

That.... is a very astute observation, sir.

Anyone in this thread that's had a hex shaft come out: Are you retaining your sprocket with a bolt at the end of the shaft? Is it possible that you're tightening the bolt so much you're literally pulling the shaft out of that coupler?

We are using the timing belt pulley's which were far enough from the end of the shaft that the bolt tightened into the end of the shaft with some slop left on the pulley.

[Nemo]

Has anybody intentionally removed these press-fit shafts in order to install longer hex shafts?

[tribologist]

Originally Posted by Nemo

Has anybody intentionally removed these press-fit shafts in order to install longer hex shafts?

It is very easy to remove. The anodization, left over schmutz and grease makes it a week bond. Clamp the shaft in a vise and tap it off with a brass drift (or that screw driver you don't like).

When you make the new shaft you need to drill out a hole at the end so that the spool is not blocked. Measure the hole on the old shaft.

Use Loctite 603 and be very careful to clean everything before bonding. You are best off lubricating after assembly.

Ulf

[Jimmy Nichols]

Originally Posted by BrendanB

Thank you for the suggestion we might try that solution as a precautionary measure after we get a replacement shaft!

That is what we did after the 4 we had failed. The new ones that were shipped were drilled and pinned before ever seeing the robot and drive time. We have not had any issues since.

[fox46]

Good to hear!