Broaching problems

really 0.75 inch? That seems long for chatter. Can you cycle the machine with no broach at all to see if anything that is supposed to be still is actually leaping around?

That is my next step, I thought I would check here first. I check out the site but there is not a lot of info there. HH Roberts is a dealer and has a copy of the manual on their site but there is no troubleshooting section.

I think its aprox the same as the pitch of the broach, its fairly smooth but sort of a ripple surface. Almost like its pushing off to form these peaks and valleys. Short of dismantaling the whole machine and rebuilding it from scratch, I havn't been able to think of anything.

That seems like a clue that would be useful to the Experienced Ones.

My mere speculation - could this be from the successive first engagements of the broach teeth with the workpiece, to be helped by making a tapering approach 'ramp' where the keyway will be?

What happens when you do a second pass on the broach? I assume that you are lubricating the broach as you use it. Have you changed the lubrication recently?

-- Why isn't there an Ozone Hole at the NORTH Pole?

Have you tried Hansford themselves for advice?

machineman wrote in news:9ObOd.29487$tU6.22867@edtnps91:

Did you also replace the backing collar when you replaced the broach? Since replacing the broach made no difference, the type of problem you describe would almost have to be in the backside support for the broach. That, or a feed speed problem (cyclic speed increase/decrease).

I talked to Hansford's tech line today. they suggested that the operator vary the release point at the bottom of the stroke. By backing off the pressure at the same point every time it may contribute to the problem. I guess the end of cut builds up and turns into the peaks and valleys.