Presses and techniques for 1/2" HEX broaches

[Cory]

Originally Posted by asid61

I feel like I'm missing something. What's wring with just using the 1/2" shank on the bottom of the broach to keep it straight? Is that not good enough?

All the presses I've seen that use bottle jacks have very sloppy tolerances that allow the ram to shift position laterally. It is virtually impossible to get a consistent result without constant fiddling with the broach/part, even with a fixture.

In general, if you know that whatever you're inserting the shank into is perfectly perpendicular to the table, that is a suitable means of aligning the broach.

To the earlier question in the thread, rotary broaching is viable, but it is also finnicky to get a good fit. We have been using a rotary broach for 5 or 6 years now, but almost every rotary broached part we make, we run a push broach through afterwards to eliminate the "twist" you get in the hex profile due to the way rotary broaching works. The nice thing is no alignment is necessary for this, as the existing hex guides the broach.

I would HIGHLY recommend against using anything with bearings to broach (a lathe, drill press, mill, etc). You can brinnell your spindle bearings and destroy them.