Comments on: Shop Doc – Vexed Hex

By: Polygon

Polygon — Thu, 23 Dec 2010 19:30:45 +0000

Vexed,
Since your original comment suggests only one part, why not set it up on a Bridgeport? Bring the broach to the part, set your alignment, and wala! This video shows the broach holder in a Bridgeport… http://www.youtube.com/watch?v=uTsPXFy7Xx0

By: Phil Atkins

Phil Atkins — Fri, 15 Jan 2010 22:24:47 +0000

Of course we don’t know what the rest of the story is. I think a Drive dog mounted as part of the
rotating took holder or maybe a formed bush which would pick up on the Component. A driver in the Nose Cap would probably make X slide ops impossible The broaching can’t be very deep. Don’t think you can drive the broach as Work spindle gears “hunt”. Need to fit “even” gears , not practical. I’ve assumed a Gridley, or B & S style. Better a BSA!!

By: Don Taylor

Don Taylor — Wed, 13 Jan 2010 21:21:30 +0000

Slater is correct (the other guys could be also, just not sure). You could put a spring loaded locater on the broach holder and the mating ‘hole’ on the collet to time them. That is trickey to set up but it would work without spending a lot of money. it just requires a bit of finesse.
Don

By: Frank Maiocco

Frank Maiocco — Thu, 07 Jan 2010 21:47:47 +0000

This has worked for me on several occasions, but the first part you run is a throw away because the broach isn’t “parked” yet.

Use G32 instead of G1 for your in-feed and then orient your spindle while the broach is still at the bottom of the hole and pull the broach out of the hole with the spindle stopped and oriented, then adjust your Z axis starting positon to adjust the radial orientation of the broached feature.

Example:

M3 S1000
G00 Z0.2 (ADJUST HERE FOR RADIAL ORIENTATION)
G32 Z-0.3 F.001
M50
G28 H0.0
G00 C0.0
Z-0.2

Radial tolerances are commonly +/- 1/2 Degree

It’s a little bit hair-ball, but a hell of a lot cheaper than a machine with a B-axis. Not recommended for a turret mounted position where centrifugal force could rotate the broach.

And check your parts more frequently than you normally would!

By: Del Robben

Del Robben — Fri, 18 Dec 2009 17:50:08 +0000

My brother Pat accomplished that task 40 years ago on a Brown & Sharpe OG before there was CNC Machines

By: Jeff Kovalenko

Jeff Kovalenko — Fri, 18 Dec 2009 17:40:37 +0000

If a secondary operation is acceptable rotary swaging can be a very good method for creating especially a blind internal hexagon, with or without a helix.

By: Slater Tools Inc.

Slater Tools Inc. — Tue, 08 Dec 2009 19:33:03 +0000

Dear Vexed,
I’m not sure if this will work on your machine, but we have many customers using a Broaching Orientation Dog with their rotary broaching tool holders to create polygon forms in relation to milled features. Standard sizes are available for all rotary broaching tool holders, however some fixturing of your machine is required. This method of broaching also eliminates the risk of spiral or twist mentioned above.

Get more information and see a demonstration video at: http://www.slatertools.com/rotary_broaching_orientation_dog.htm