parting question

Back in the day when I worked on screw machines, a little trick was to grind a slight angle on the cut-off blade so the part to be cut off came away clean without the usual small burr. You just go a little deeper to clean up the bar. Those Brass pieces would not have that stub on them with this grind. They would be clean. I still grind them that way and only have an ocassional problem.

"Billy G" :))
 
Bill Gruby said:
Back in the day when I worked on screw machines, a little trick was to grind a slight angle on the cut-off blade so the part to be cut off came away clean without the usual small burr. You just go a little deeper to clean up the bar. Those Brass pieces would not have that stub on them with this grind. They would be clean. I still grind them that way and only have an ocassional problem.

"Billy G" :))
Click to expand...

Bill,

I do that as well on small parts with minimal overhang, it makes a nice clean cut on the part. The caveat is that the deeper the parting cut, the more the tool will tend to deflect sideways and you start getting dished ends on the parts. I assume that's what you mean by "occasional problem". :thinking:

Tom
 
Yes Tom, that is the occasional problem. Once in a while a small chip breaker will help. depending on the material being cut.

"Billy G" :))
 
Last edited by a moderator:
gt403cyl said:
Not to reiterate but I mostly work with brass and the odd stainless I have found slow with lots of fluid works best so long as tool height is good and tool is sharp.

Not to go off topic but looking at the pic of brass above the tool height might be off, when I set my qctp I go for the same finish as facing, no nub. That said that's how I set it but I mainly work on brass.
Click to expand...

I set the tool height with an Edge Technology Speedy Lathe Gage

As this was the first time I tried to use it with carbide inserts I most likely didn't have it on the cutting edge itself but on some other part of the insert. This is the setup being used:



Anyone have suggestions for how to properly "center" with carbide inserts? Other than "eyeballing it" that is? :biggrin: Oh, and I don't disagree about using plenty of cutting oil when parting but so far all my parting has been done "dry".

I was also using the "neutral" cutting tip whereas using one of the other options (left/right) should have the same effect as grinding an angle on the face of the cutter.



-Ron
 
Last edited by a moderator:
I sometimes run a good sharp pointed center up in the tailstock to gage center, I sometimes measure from a known OD with the dumb end of a pair of dial calipers, and yes, I sometimes eyeball it.
 
Tony Wells said:
I sometimes run a good sharp pointed center up in the tailstock to gage center, I sometimes measure from a known OD with the dumb end of a pair of dial calipers, and yes, I sometimes eyeball it.
Click to expand...

"sharp pointed center up in the tailstock" - sounds like a quick and simple solution. I'll see if it makes a difference.

Thanks Tony,

-Ron
 
i think i put close to 30 hours on my lathe this weekend. for the parting all i parted was aluminum and that all went great except for once, it bound and snapped my cutter. i picked myself up a nice oil can from the matco truck, and got some stinky dinosaur oil. parting is much simpler now.

also ran a set of threads for the first time, takes some patience but i got it done. found out i ordered a few of the wrong cutters from mesa tools so i need to see about returning them for the right ones. i really appreciate all of the help you guys have given me, makes the learning process a lot cheaper and safer haha. (and im having a blast schooling myself.)
 
Moparfever said:
I always center it by pinching a steel rule between the tool and the workpiece, then fine tune if I get a pip.
Click to expand...

That's the ruler trick I alluded to in my post up above. I don't remember which forum I read it on but that was one of the best things I ever learned for the lathe.
 
You must log in or register to reply here.
Back
Top