Tool problem, or measurement problem
- Thread starter memilanuk
- Start date
memilanuk
Gold $$ Contributor
I've got some goodies on order from K&M... I figure for what they cost I've probably gotten my monies worth out of the pilot, cutter and expander over the years.
I've used die wax as lube on the pilot for years with no issues. I do have some Sinclair 'neck turning' cutting oil... didn't notice any appreciable difference in cut quality or finish. Did notice a PITA increase in having to get that nasty stuff out of the cases before loading, though.
I use one of the neck-turner 'holders' sold by Joel Pendegraft (years before K&M finally started making something comparable) that doubles as a heat sink. If I'm doing an extended session (like hundreds of cases) I will put a small zip-loc baggie of ice in a bowl and set the turner/holder down on it between cuts while changing cases.
I've used die wax as lube on the pilot for years with no issues. I do have some Sinclair 'neck turning' cutting oil... didn't notice any appreciable difference in cut quality or finish. Did notice a PITA increase in having to get that nasty stuff out of the cases before loading, though.
I use one of the neck-turner 'holders' sold by Joel Pendegraft (years before K&M finally started making something comparable) that doubles as a heat sink. If I'm doing an extended session (like hundreds of cases) I will put a small zip-loc baggie of ice in a bowl and set the turner/holder down on it between cuts while changing cases.
I don't know to what level you or your equipment can shoot....but check out Jack Neary's Rifle Tuning Session Part 1 on You Tube.....you might have an equipment problem with your neck turner or mic.....or you may be making the whole process more difficult than it has to be. Again, the most important measurement is the OD of a seated bullet (@ the pressure ring if it has one) ....and maintaining at least 0.002 total clearance.
Keith Glasscock
Gold $$ Contributor
As a long-standing member of the US team, I think he has that part down. 
Monte,
Are the thin and thick spots 180 out from each other? You might seat a bullet in one and see if there is any disruption to the OD. If there isn't give the runout a try. That, to me, would define whether the case is in fact being cut crooked.
On another thought, how loose is the neck to pilot fit after expanding? If it is loose enough, you could be geting a little piece of crud under the neck. Second thought, take a few minutes and measure away at your expander mandrel. Make sure it is absolutely round and doesn't have anything on it - mine picks up a little brass string every once in a while because I use it to expand cases after resizing.
There has to be a simple cause for this problem. It's just a matter of finding it.
Monte,
Are the thin and thick spots 180 out from each other? You might seat a bullet in one and see if there is any disruption to the OD. If there isn't give the runout a try. That, to me, would define whether the case is in fact being cut crooked.
On another thought, how loose is the neck to pilot fit after expanding? If it is loose enough, you could be geting a little piece of crud under the neck. Second thought, take a few minutes and measure away at your expander mandrel. Make sure it is absolutely round and doesn't have anything on it - mine picks up a little brass string every once in a while because I use it to expand cases after resizing.
There has to be a simple cause for this problem. It's just a matter of finding it.
memilanuk
Gold $$ Contributor
A lot of things to check tonight, for sure. The gun shoots... pretty well, when I do my part. The tolerances/methods involved in point-blank BR (aka Jack Neary) and what I do... are some what different.
The .30 cal expander and pilot have seen a lot of use... and abuse... over the last few years. Particularly from expanding a bunch of particularly nasty Winchester brass that left a *lot* of residue/build-up behind, despite using copious amounts of lube. Had to spend a fair amount of time/effort removing that crap using both chemical (copper solvent) and mechanical (#0000 steel wool) methods. Everything is about as clean as I can get it... but by no means pristine. Hence the new parts on order.
The .30 cal expander and pilot have seen a lot of use... and abuse... over the last few years. Particularly from expanding a bunch of particularly nasty Winchester brass that left a *lot* of residue/build-up behind, despite using copious amounts of lube. Had to spend a fair amount of time/effort removing that crap using both chemical (copper solvent) and mechanical (#0000 steel wool) methods. Everything is about as clean as I can get it... but by no means pristine. Hence the new parts on order.
holstil
Silver $$ Contributor
My reasoning was deduced on assuming your using the newer palma brass as opposed to older brass. Your difference from last time turning good brass to this time turning bad brass would be the brass. The brass thickness is likely thinner now. You are cleaning up less neck and the part that is passing through the cutter is thinner. The thickness that is cut effects accuracy. Kinda like sneaking up on the last couple thou. but wanting at least .0005 to cut on the lathe. Go thinner, and it won't cut accurately. Your tooling is not quite as sharp as it once was, could be compounding it.
I'm not sayin I'm right, brass is pretty soft. I've had bogus readings neck turning brass and this is what I chalked it up to.
I would like to see what happens if you set the cutter .0003 or 4 deeper.
I am interested in hearing what you learn.
Jim
I'm not sayin I'm right, brass is pretty soft. I've had bogus readings neck turning brass and this is what I chalked it up to.
I would like to see what happens if you set the cutter .0003 or 4 deeper.
I am interested in hearing what you learn.
Jim
memilanuk
Gold $$ Contributor
holstil said:
All one lot/batch, 1000 pcs, purchased at one time from one vendor. All got weight sorted last year. Some got processed and shot immediately; the rest got bagged and set aside til now.
Bad news is I started screwing around trying to 'zero' the spindle on the ball mike (always been a few tenths off)... and managed to royally screw up and snap off the anvil arm
So, along with a bunch of other small pieces on order, I should be getting another ball mike (unknown brand, carried by Russ Haydon) this week. Planning on getting another one of the modified Mitutoyo ones when time/money allows.One of the earlier questions was whether the case mouths were getting expanded consistently... all the virgin brass I've got sitting around measures .303" ID which is considerably smaller than any of the mandrels or pilots, so I'm guessing it got opened up okay...
memilanuk
Gold $$ Contributor
An update...
I think I found the problem... after replacing enough parts to essentially build a new neck turner - which is basically what I needed
I'd noticed the visual appearance of the cut had gotten pretty bad a little while before realizing the actual measured quality had gone to pot - which is why I started this thread. At the time, I'd mentally written that off to simply feeding the cases into the cutter too fast (long story as to 'why'). But in the process of trying to figure out why the readings were varying so much, I slowed the feed speed way down... and the cut quality (visual) still sucked out loud. I thought maybe the new cutter would 'fix' the problem - but it didn't.
At that point I had to sit back and reassess what was going on - it looked like the cutter was dragging the corner, rather than cutting with the flat. Then I seemed to remember the cutter - and the massive Pendegraft holder - getting knocked off the bench during one of the sessions not too long before I started noticing the visual cut quality problems. Best guess: something got tweaked/bent to where the cutter/pilot alignment was off, causing the corner of the cutter to drag (and artificially wear early) leaving a very nasty finish.
I ordered a new body for the tool, and when I got back from a match yesterday evening I put the bits-n-pieces together and voila, nice *clean* consistent cuts that measure like I had been expecting previously.
Problem solved.
I think I found the problem... after replacing enough parts to essentially build a new neck turner - which is basically what I needed
I'd noticed the visual appearance of the cut had gotten pretty bad a little while before realizing the actual measured quality had gone to pot - which is why I started this thread. At the time, I'd mentally written that off to simply feeding the cases into the cutter too fast (long story as to 'why'). But in the process of trying to figure out why the readings were varying so much, I slowed the feed speed way down... and the cut quality (visual) still sucked out loud. I thought maybe the new cutter would 'fix' the problem - but it didn't.
At that point I had to sit back and reassess what was going on - it looked like the cutter was dragging the corner, rather than cutting with the flat. Then I seemed to remember the cutter - and the massive Pendegraft holder - getting knocked off the bench during one of the sessions not too long before I started noticing the visual cut quality problems. Best guess: something got tweaked/bent to where the cutter/pilot alignment was off, causing the corner of the cutter to drag (and artificially wear early) leaving a very nasty finish.
I ordered a new body for the tool, and when I got back from a match yesterday evening I put the bits-n-pieces together and voila, nice *clean* consistent cuts that measure like I had been expecting previously.
Problem solved.
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