Broaching

[KJS]

I was wondering if anyone out there does any broaching on lathes or screw machines.I'm specifically looking for any info on broaching hexes for hex wrenches. Any advice on speeds and feeds would be great. Thanks for any help.

[Tom Dorgan from American Precision]

KJS,

My last company broaches keyway slots (5 at a time) in aluminum on screw machines. I don't remember the exact feeds & speeds but I do know you better be deadnut on centerline. If no one else pops up here I will try and get that info for you. What material?

[The Iron Chef]

Rotary Broaches are the way to go

[KJS]

Tommy,

Thanks for the help. The material is 304 stainless.

[Tim Johnson]

+1 to The Iron Chef.

We use Slater Tools and they work fine.

We've also made our own broaching tools for internal keyways and screwdriver slots and used the G92 canned cycle for our passes.

[cncchuck]

we have a couple jobs we broach hexs in (3/16 & 1/8)on lathes. be sure your spindle doesnt turn on , broaches dont like that .

[Tim Johnson]

cncchuck,

With the rotary broaches the spindle remains on and you can broach much quicker and the cutting inserts last a lot longer.

[cncchuck]

tim, just checked out that rotary broach site, i was impressed. going to look more into it.

[Tim Johnson]

You'll love it. We use ours for all different materials.

Two notes;

1. When running sst we have a longer insert life when we feed the broach out. We usually feed ours out at 3*feedrate.

2. If you run heavy production you will want to give the broaching tool a squirt of grease a couple times a day or so.

[mross]

we cut plastics and do some broaching sometimes...I don't know if it is applicable, but...PH Horn has some good broaching tooling...check their website here.

[Tom Dorgan from American Precision]

+10000 on the rotary broaches. Only way to go. That is what we used on our screw machines.

[Dave anderson]

I have a dumb ? lets say you wanted to broach a keyway in aluminum eg a blower pulley. could you use a boring head put in the tail stock of a lathe with a tool inserted in the tailstock boring head that came out with like a single point broaching tip something like a boring bar and chuck your piece in the lathe chuck perhaps lock spindle in a low rpm to make somewhat rigid and use the tailstock to feed broach into your piece and pull out then adjust the boring head for the next cut ? what do you think would this work?

[PE @ IHS]

Hey Dave

 

What school do you go to in Northern Ontario? P.S. you can't load any tools into the tailstock of a CNC lathe whatsoever. It works completely different than a conventional lathe.

[KJS]

Thanks to all who helped. My next question is this: If I'm broaching a hex for a .050 hex wrench, how much deeper should I drill my pilot hole? For instance, if I want my hex to be .060 deep, how deep should the pilot hole be. Thanks again.

[Tim Johnson]

For a .050 hex I would think .010 should be all you need. I go .020 deeper with a 5/32" hex.

[Tim Johnson]

Sorry, with a rotory broach I go .020 deeper. Drill it out with a .052/.055 dia drill. (depending on material)