Broaching

[Shox Dr]

I need to broach a 1/8" keyway into an arbor. Depth is 32mm.
When looking for a broach all I’ve found so far state a max depth of 25-28mm.

How do you broach deeper holes

 

[MBB]

Probably cut with a shaper or slotting att 32 mm is deep. Post a drawing to give a better idea

 

[nick952]

The standard Max depth of 25-28mm broaches will do deeper, IF you pre-drill to remove some of the material. I make up a bung to fit the bore to be broached (of similar material to the job) and just drill slightly undersize half in the bung and half in the job.
You may need to make a longer than normal guide, to support the broach all the way though the job and have something available to push the broach through the last extra bit.

Deep through broaching is usually done with a Pull Broach.

 

[Maker]

I imagine you'll need to make a longer guide as Nick says, otherwise the broach might flex at the bottom of the hole and not cut to full depth.

I can't see why there should be an upper limit on the depth, at some point the gullet of the tooth will get full but that would be a very deep hole.

 

[ronan]

I cut two keyways in bores this week using the lathe. I ground up a simple tool the required width (3/16"), put it in a boring bar and pushed it in and out until i was at depth. Works well and not as time consuming as you would think. The length of the bar is the only thing limiting the depth you can reach.

 

[Pete.]

I cut two keyways in bores this week using the lathe. I ground up a simple tool the required width (3/16"), put it in a boring bar and pushed it in and out until i was at depth. Works well and not as time consuming as you would think. The length of the bar is the only thing limiting the depth you can reach.

I've done several of these recently. I make the cutters from broken 6mm carbide end mills.

 

[Shox Dr]

I cut two keyways in bores this week using the lathe. I ground up a simple tool the required width (3/16"), put it in a boring bar and pushed it in and out until i was at depth. Works well and not as time consuming as you would think. The length of the bar is the only thing limiting the depth you can reach.

Probably what I’ll end up doing. It doesn't need to be all the way through as the key only sits in 20mm.

 

[eLuSiVeMiTe]

Probably what I’ll end up doing. It doesn't need to be all the way through as the key only sits in 20mm.

Be the type of job I'd get my little hand shaper out for.
Still haven't actually cut metal on it but couldn't resist buying it.