Single tooth hand broacher tool profile?

That process is an abrupt cut on every tool advance, this is unavoidable.
I often use a Morrison Keyseater, it is a loud and brutal method but works well, it sounds like something is going to break the entire time.
These machines have an over arm that supports the top of the arbor which is not seen here.



Like so, a random pic from the web
 
great white said:
I've pretty much decided that anything mounted to the QCTP is insufficient for the task, at least on my rig and in anything harder than aluminum.

I designed mine that way so I could have some height adjustment, but the tool post will creep under the force of cutting causing it to "dig in" at some point and require readjustment to keep the cutter parallel to the work.

The one I made works, but it's a frustrating process. Something more robust (and precise) would at least make the process less frustrating (IE: grabbing, stalling, etc) even though it would likely not cut any faster.
Click to expand...

When you say that the tool post "creeps" under load, do you mean it's rotating around the bolt holding it down? If so, cut a single sheet
of paper bag as a packing between the tool post and the compound and re-install. Sounds like a lash up, but it works.

Also, some of your flex could be coming from the compound as well, even with the gibs snugged down. If you fabricate a solid mount
to replace the compound when you don't need it, you'll gain some rigidity as well.
 
I know these 'in-lathe' broaching mechanisms are relatively light duty (or maybe should be). When you see the beefyness of key seaters like post #11, shapers, arbor presses... I really wonder if this repeated, axial thrust action is good for lathe spindle bearing assembly? I don't have a spindle brake and even so I think they generally just clamp & prevent spindle shaft rotation. But the broaching reaction force is still concentrated on the bearing itself, no? The bearing balls/rollers are stationary through the entire operation so to me it seems the action is (albeit slightly) hammering the race together over & over. I dunno... personally I'm fussy about stuff like this.
 
You are probably right, but after you do it once, you right arm will tell you emphatically NO MAS. So it won't be an everyday abuse but a once in a blue moon kinda thing.
 
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