Securing Machine Keys

[JamesCH95]

A set-screw isn't a bad way to go, I've drilled and tapped set-screws with a cordless drill and hand tap. I like the set-screws with knurled or pointed tips and a little bit of blue Loctite to keep them from backing off.

Recently I've come to the conclusion that as along as the key can't slide out along the keyway it will be fine for FRC purposes. Close-fitting axle spacers work well, and this year we've tried peening the keyway closed at the end, so far so good.

[BurtGummer]

At a competition, the key kept sliding out from our drive gearbox. The solution: Krazy Glue.

[R.C.]

Depending on the situation and motor:

For cims we use these:

McMaster: 94800A730

For other various applications we avoid keys for multiple reasons:

-You lose them easily
-A pain to put in and take out
-Would rather use HEX shafting.

If you are left with a key:

-Use PushNuts (Linked Above)
-Clamp Collars work great if you have clearance.
-Snap rings work great (Need a lathe of some sort)

-RC

[rsisk]

Originally Posted by R.C.

Depending on the situation and motor:

For cims we use these:

McMaster: 94800A730

For other various applications we avoid keys for multiple reasons:

-You lose them easily
-A pain to put in and take out
-Would rather use HEX shafting.

If you are left with a key:

-Use PushNuts (Linked Above)
-Clamp Collars work great if you have clearance.
-Snap rings work great (Need a lathe of some sort)

-RC

Would these solutions work just as well for steel hex shafts? If not, is there a good retainer for steel hex shafts?

[tsaksa]

I have at times cross drilled a shaft starting right in the key-way. A cotter pin then can be used to secure both the gear and the key. But of course this assumes that you have clearance for the cotter pin, and are able to cross drill the shaft, which are sometimes hardened to the point where drilling is extremely difficult. In this case a small diameter carbide tipped concrete drill (one that has never been used even once on concrete) can be effective in drilling some of the hardest materials. But always exercise extreme caution when working with such hard materials.

[Taylor]

If you need an 1/8" key, the VEX axles work great.

[pfreivald]

You can put a small tack from a welder on either side of the key in certain applications (but cover the keyway to avoid spatter).

We have in times past mangled the keyway with a chisel on either side of the key, thus preventing the key from sliding loose. It never failed us, but there are generally better ways to do things.

[Nick Lawrence]

We just use a bit of crazy glue, and glue the key to the gear/wheel/vial of winsauce.

-Nick

[pfreivald]

Originally Posted by Nick Lawrence

We just use a bit of crazy glue, and glue the key to the gear/wheel/vial of winsauce.

-Nick

I don't believe winsauce is COTS!

[Nick Lawrence]

Originally Posted by pfreivald

I don't believe winsauce is COTS!

It's a custom component.

-Nick

[artdutra04]

Originally Posted by rsisk

Would these solutions work just as well for steel hex shafts? If not, is there a good retainer for steel hex shafts?

If you are referring on how to capture hex shafts so they don't move, my preferred method is to capture it by turning the ends on a lathe into round and using flanged bearings on either side. I've also used a combination of Delrin spacers with either shaft collars, E-clips, or tapped ends of the shaft (with fender washers) to retain it.

In the case of the shaft collars, I had the section of hex turned down to round and used an aluminum split shaft collar.