Removing brass buildup on neck turn cutter

Steve Lee

Active member
I have a pumpkin neck turner and am in the middle of turning around 500 cases. The cutter has developed a small build up of brass on the blade. In the past I have cleaned vigorously using bore solvent and a q-tip, but this seems to be very persistent.

Any suggestions?
 
Steve ...

When I get brass shavings in my K&M turner I use an "old tooth brush" to remove them. It works very efficiently. You might give that a try. Art
 
You might be able to clear your "Built-up edge" by prying it off with something soft like an old bullet or a case head. If you have to, scrape it off from the side opposite the cutting edge with a utility knife or something similar.....but be careful of the cutting edge! Getting a build up like that indicates that you might want to slow your speed down or try a different cutting oil.

-Dave-:)
 
Steve, prying off BUE (built up edge) is not a good idea. You can break off the cutting lip. More cutting should replace what is on there with more BUE. Try using some sizing wax on the to-be-turned necks and see if that gets and keeps the BUE off. Honing the cutting edge after it is clean with a hard Arkansas stone being careful to make sure the edge geometry is not changed by honing.

If this does not work, you can hone the BUE off. It's just more difficult to do it this way since the BUE is not the same geometry as the cutters cutting edge.

500 cases?? Can I borrow about 300 or so?
 
Steve, prying off BUE (built up edge) is not a good idea. You can break off the cutting lip. More cutting should replace what is on there with more BUE. Try using some sizing wax on the to-be-turned necks and see if that gets and keeps the BUE off. Honing the cutting edge after it is clean with a hard Arkansas stone being careful to make sure the edge geometry is not changed by honing.

If this does not work, you can hone the BUE off. It's just more difficult to do it this way since the BUE is not the same geometry as the cutters cutting edge.

500 cases?? Can I borrow about 300 or so?

LOL! I hate turning cases so when I do it I like to turn enough to do me for several years. I've got all but about 100 done and I started getting the occasional bump...bump...bump as I pull the case back off the mandrel after turning. When I examined the cutter I saw a small buildup on the edge just back from the radius. I've seen this before and normally can get rid of it by alternating soaking with bore solvent with scrubbing with a q-tip. I tried this last night and it got rid of most of it, but not all. I've left it soaking overnight (saturated patch Montana Extreme pushed up against the edge) and I'll take a look this evening. Maybe that will clear it up.

I use a turning lathe (motor with gearbox) and the speed is fine, so I'm not turning too fast. I did change the lube this time. I normally use engine pre-lube, but it is messy so on the recommendation of a guy at Sinclair I'm using FP-10 this time. It's been working fine, but this may be a side effect.

If anyone has a definitive answer on how to clean this off (easily) I'd appreciate it. Otherwise I'll just keep at it. I wonder if Sweets would get it off?
 
Steve,
If normal cleaners don't get it off....I use sweets and it always gets the job done. I use a machine cutting oil and that has almost eliminated the build-up and makes what does build up come off easily. I think its similiar to the assembly oi (which I have heard of before). I recommend calling Ron Hoehn and ask him....they turn a lot of brass (they might us a lathe though).

Hovis
 
LOL!
If anyone has a definitive answer on how to clean this off (easily) I'd appreciate it. Otherwise I'll just keep at it. I wonder if Sweets would get it off?

Next answer. If the BUE is not effecting the case neck finish, just keep turning as you are. And yes, the lube change may be part of the problem.

The guys at Sinclair are just trying to sell you the new Sinclair turner. Jim ordered 3 of them and they came in a few days ago.
 
This was at the Super Shoot and the Sinclair guy just mentioned that it was a good turning lube in addition to the use I had planned, so I tried it.

Hovis...what machine cutting oil do you use?
 
Steve ...

Here's a simple solution often overlooked, one that's always worked for me, the one I prefer to use: Go directly to the source. In this case, the inventor and designer of your turner:

PUMPKIN NECK TURNER
Don Nielson - pkin@sbcglobal.net
20456 Hart Street - Winnetka, California 91306
Phone (818) 883-5866

Give Don a call. I'm sure he'll have a good answer for you. Art
 
I haven't seen the cutting tool that is used in the Pumpkin, but if it is a HSS tool without a chip breaker I doubt very much you'll chip the edge if you use a soft material to pop the build up off of the tool. I also doubt that the tool will cut as well if you stone it off...if you don't use a stoning fixture the edge will likely end up with a small radius that will cut like an upside-down rock.

It sounds like abintx may have given the most definitive answer....call the tool manufacturer.

-Dave-:):)
 
I haven't seen the cutting tool that is used in the Pumpkin, but if it is a HSS tool without a chip breaker I doubt very much you'll chip the edge if you use a soft material to pop the build up off of the tool. I also doubt that the tool will cut as well if you stone it off...if you don't use a stoning fixture the edge will likely end up with a small radius that will cut like an upside-down rock.

It sounds like abintx may have given the most definitive answer....call the tool manufacturer.

-Dave-:):)
If the cutting tool does not have a lip, please explain to me how stoning off the BUE will degrade the cutting surface????

Upside down rock? Which part of a rock is the top? I know, the part on top.
 
This was at the Super Shoot and the Sinclair guy just mentioned that it was a good turning lube in addition to the use I had planned, so I tried it.

Hovis...what machine cutting oil do you use?


Steve, I just don't remember. I picked it up at a local machine shop and wrote the name on the bottle but it's came off. I think about any good grade cutting oil would work. If jackie see's this, he can probably give better advice. But if you have a local (good) machine shop, stop by and ask, I know if made a little difference when I told them what I was doing.

Wish I was more help.
Hovis
 
Here's a simple solution often overlooked, one that's always worked for me, the one I prefer to use: Go directly to the source. In this case, the inventor and designer of your turner:

PUMPKIN NECK TURNER
Don Nielson - pkin@sbcglobal.net
20456 Hart Street - Winnetka, California 91306
Phone (818) 883-5866

Give Don a call. I'm sure he'll have a good answer for you. Art

Hey...that's too obvious. Besides I know Don will fuss at me for using the wrong lube!

If my current plan doesn't work I'll break down and give him a call.
 
Steve ...

The wonder potion/lube that I use is Redding's Imperial Sizing Die Wax. I put a little on a cotton swab, rub it around inside the case neck, and rub some on the mandrel and then turn. I've never had a problem. It might be a little slow for your project ... but I never work in bulk. Art
 
If the cutting tool does not have a lip, please explain to me how stoning off the BUE will degrade the cutting surface????

Upside down rock? Which part of a rock is the top? I know, the part on top.

Here is how the edge can be degraded by stoning (I borrowed it from your earlier post):
"Honing the cutting edge after it is clean with a hard Arkansas stone being careful to make sure the edge geometry is not changed by honing.

If this does not work, you can hone the BUE off. It's just more difficult to do it this way since the BUE is not the same geometry as the cutters cutting edge."


I'm about ready to just order him a new cutter after all of this.........I simply offered a (very common) possible solution. You know, just trying to be helpful.

-Dave-:)
 
If this does not work, you can hone the BUE off. It's just more difficult to do it this way since the BUE is not the same geometry as the cutters cutting edge."


I'm about ready to just order him a new cutter after all of this.........I simply offered a (very common) possible solution. You know, just trying to be helpful.

-Dave-:)
Dave, I wrote that because it would be easy for a non-machinist to try to attack the BUE with the hone held at 45 degrees to the edge since that would seem to be the fastest way to get the brass off. Order Steve a new cutter. That way he may offer to turn all our cases for free.

Kevin, turning case necks on a lathe, other than an occasional film of sizing wax on the arbor, no lube is needed since the turning tool should be a fairly positive rake. If you used this much positive rake on a hand held tool, the cutter possibly grab and cause injury.
 
Kevin, turning case necks on a lathe, other than an occasional film of sizing wax on the arbor, no lube is needed since the turning tool should be a fairly positive rake. If you used this much positive rake on a hand held tool, the cutter possibly grab and cause injury.

I've always used zero rake on cutting tools for brass. Positive rake leads to "grabbing" and "digging in" for me. Especially with drills.
 
I've always used zero rake on cutting tools for brass. Positive rake leads to "grabbing" and "digging in" for me. Especially with drills.

Yep. The "proper" rake for brass is zero, and is sometimes even run at negative angles....even on the lathe. And as Jay says, especially drills...they'll snatch a brass part out of your vise or chuck in the blink of an eye! And maybe it'll even hit you in the eye.

Jerry, I figured "What the heck, I might as well reply...I've already had my flame-proof suit tested a couple of times today..."

-Dave-:)
 
Ok! Enough! I didn't mean to start a war here! :)

First...I ain't gonna turn everyone's brass! I do bulk because I don't want to do it again for another four or five years! (Actually I might for $5/case)

Second...I'm not competant to try stoning the cutter, and in any case I'd have to remove the cutter. Setting up one of these gadgets is such a pain (even the pumpkin) that I haven't touched mine in over five years! I bought a carbide mandrel set from Don in 2004 and haven't installed it because I don't want to have to re-adjust everything!
 
Ok! Enough! I didn't mean to start a war here! :)

First...I ain't gonna turn everyone's brass! I do bulk because I don't want to do it again for another four or five years! (Actually I might for $5/case)

Second...I'm not competant to try stoning the cutter, and in any case I'd have to remove the cutter. Setting up one of these gadgets is such a pain (even the pumpkin) that I haven't touched mine in over five years! I bought a carbide mandrel set from Don in 2004 and haven't installed it because I don't want to have to re-adjust everything!

Hey Steve, there's no war! Just a little friendly banter.;)

Jerry didn't say everyone's brass, I think he just meant for him & me.........C'mon, not even for a free cutter?

Now you have a bunch of info to consider.......best of luck getting your tool to dance with you again.
-Dave-:)
 
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