Turning problem

[J. Foster]

I am using a K&M tool to turn necks for a .269 chamber 6 PPC. I have been frustrated for almost 10 years on this and finally decided to ask for suggestions. My problem is that no matter what I do, the tool doesn't seem to hold its setting. typical example is I will start with a .0120 neck and by the time I have cut 20 necks I will be cutting .0123 or 4. I keep the tool at the same temp within a few degrees and have used every lube known to man. I am driving the case with a DeWalt power screwdriver and use a K&M mandril for expanding the necks.
I have 3 tools in .22, 6mm, and .30 and all do the same thing to one degree or another. WHAT AM I MISSING??? Thanks for your help. Jack Foster

 

[vinny]

I've cut thousands of necks with the same K&M turner in 30 & 338 and have yet to experience what your describing. Honestly I don't see how its possible once you have it cutting at .0120 how can the cutter or mandrel move if everything is locked in place? What I have found is if I turn my necks in increments of say .0005-7 as to not take too much off in one pass I always realize a better more consistent cut. I also anneal my necks first to make them a little more forgiving. Just to make sure I'm cutting with uniformity I measure each neck with a mic.. Sorry I couldn't be of more help.
Have you tried calling Ken? Hes a great help!
vinny

 

[chris 308]

Ditto what lynn said...i set my k&m in a tupperware bowl with ice water in between cuts...i had the same problem also...all my cuts now are +- .0001 i also take some very fine emery cloth and do a "shoe shine" thing on the mandrel every 10 cuts or so...be sure to get the carbide mandrel as the other ones tend to heat up and and get a brass build up...

 

[vinny]

I took for granted the thermal factor meaning you suppose to cool the cutter off over ice or dip it in alcohol after each cut(Learned that from Ken). I lay it on ice then blow it off with my compressor it works fine. On occasion I experience some build up on my mandrel and like you describe Chris, I clean it up with 600 emery. I always take the mandrel off and polish it when I'm done cutting my brass. It helps me keep the cutter clean.
cya
vinny

Do you think that build up of brass on the mandrel can scratch the inside of the neck?

 

[Cheechako]

Jack

No one has suggested the obvious. Do you have everything tight? By that I mean the locking screws. I have a K&M that I use exclusively for my 6PPC and I set it back in the 20th Century. When I turn a neck today I get exactly the same measurement that I was getting 10 years ago.

Ray

 

[C.L. Peterson]

My solution was 3 fold
1.) Use carbide mandrels only
2.) use cutting oil (1-2 drops) on the mandrel while cutting
3.) I cut fairly fast (low speed with electric drill)

The key for me was not to let the mandrel get hot--Carbide mandrels do not get hot with the above procedure. I have never experienced galding with the carbide mandrels.

Hope this helps
DOC

 

[Dave Short]

The increase in wall thickness is because the tool body grows as it warms, just as others have said. The K&M tools are great; I have several and wouldn't part with them. Just like most things, though, we have to dance with it in order to get the best possible results. My approach is a little different than those described. I warm the tool in my pocket while I get everything in order to cut the necks. After each pass I lay the tool on a 2 1/2" cube of aluminum while I change to the next case. I work at a quick & steady pace so that the tool stays warm, but not hot. If for some reason I have to spend a little extra time between cuts I take the tool off of the block so it doesn't cool too much. It doesn't take long to get used to the feel of the tool and how long to let it cool. I get a very uniform wall thickness on any caliber I turn using this procedure. I use only steel mandrels, and have little to no build-up problems. After two passes each on 100 cases I put the mandrel in the lathe and polish it at 1000 rpm with Flitz. For whatever reason the Flitz prevents metal pick-up on the surface.

-Dave-

 

[Boyd Allen]

I take a rough cut with an old Sinclair tool that has a smaller mandrel. It stays cool because of the fit. Then, I take a finish (less than .001) cut with my carbide mandreled K&M. The first cut results in less interference and heat on the second. The other tricks are to keep the RPMs low, use a good lube, and leave something behind while cutting to the shoulder so that there is something to cut ( and keep the neck pinned to the mandrel) on the trip back to the case mouth. IMHO turning that generates a lot of heat is an indication that the difference between expanding and turning mandrels needs adjusting. Just as a test, I have been able to hold good tolerances with a loose fit, as long as I let the tool and the driver float and self align, and go on fast and off slow (feed rates).

 

[alinwa]

Wow Dave!

Ingenious but WOW, seems like a lot of work




Like some of the others I keep the whole tool in a bath of water......UNlike the others I just use room temp water in a small container BUT with a gallon bucket close to hand......I use the small container for about 5-10rds and then dump it, swish the tool and rescoop for the little container. Much quicker than it sounds. I keep a toothbrush and a tool brush in the pan and hang a towel. THE TRICK IS to keep the tool cool. Jack, I know that your OP says that you "keep the tool within just a few degrees"....... if this is true then my other suggestion is that maybe you're getting some wobble or sidepressure from the way you hold the apparatus???

Here's a picture of my setup using a cheapo 39dollar chinese drillpress. This allows me to actually hunker and rest me' forearms and block me' shoulders and square me'self up well. It's less fatiguing and has produced very consistent results with my 3 brands of handheld turner. I use Assembly Lube for lube, STP or generic "Engine Rejuvenater Oil Additive" which is hyper slickery also works quite well but you've almost got to cut the strand off with a scissor. It's stinkin messy. IMO any good stiff (90wt or so) oil is all same-same.

I follow with a debur, inside and outside and endwipe with steel wool and then I reach in with a Q-Tip and pull out the nasties that may be left.

I feel that the endwipe with the steel wool is absolutely one of the most important parts of the process. It really turns the neck entry point into a smooth and burr-free surface. I bear right down on it both times.

This is all more than anyone prolly wants to know and slightly off topic but maybe with all the suggestions Mr Jack will hit upon his formula for success.....

Here's hoping.

al

 

[Jay Idaho]

Would a "heat sink" help on the K&M? I think that Joel Pendergraf sells them, for those that do not have a mill handy. It is intended to be a "handle" for the small bodied K&M.
I use a turning mandrel with a bushing, similar to those used on reamer pilots. And for lube, I use a grease stick of sorts, it is a hard wax type of material with MOS2 in it, originally used on the beads on auto body draw dies.
I have seveal turners but mostly use a Sinclair that I've modified to make adustment easier.
My power source is a Taig baby lathe that I've slowed down to about 300 rpm by using a jack shaft. The Taig's lowest speed is about 600.
My final polish is with a piece of fine Scotch Brite from 3M.

 

[chris 308]

Vinny, yes 600 emery...I put the cutter in a vise and do a shoe shine thing to clean it up...I've done my 6br's for a .262 neck in 3 stages all with the ice water thing and have no more than .0001+- variation...dont be in a hurry though..alinwa you da man as always!!!!!! Lynn...i will try the alcohol though...never thought of that...you da man too!!.......

 

[J. Foster]

Many Thanks!

I should have added that since I am turning for a .269 neck on the PPC I am only taking off .001 to .0015. Also my method of keeping cool is that I keep a 10 lb hunk of steel in the freezer. When I turn, I set the tool on the frozen steel whenever it starts to feel any warmer. This is usually every three rds. or so. It is only on the steel long enough for the next rd. to be put into the screwdriver collet. Also, I have ended up using Imperial die wax as my lube. It is about the only thing that I don't seem to ever get any brass build up on the mandrel.
I'll be trying all of your suggestions. It just buggs me that I have to go over and over the brass and constantly resetting the tool to get good brass.
Usually I am using new brass but this week it was stuff I had just annealed. Jack

 

[H."Snuffy"Smith]

A BR advertiser made an adapter....

that acted as a "heat sink". I'm not sure he is still around ?? He said he made for hand comfort (arthritic pain), but it was good heat sink.
The PUMPKIN neck turner is round and much larger than a K&M I did use a K&M for a while, Ken is a great guy and the price is very fair. The PUMPKIN is a bit pricey, but a great design and "COOL"

"Snuffy"

 

[alinwa]

Jack
Jay
If you look at the enclosed pictures from Alinwa he is using that same 3 jaw Lee tool my father and you like so much.
Lynn

I've been posting about that Lee iris tool for over ten yrs now, I LOVE the thing..... but Lee STILL requires that you either buy the stupid liddle handcranker device just to pirate the stud or that you buy one of THESE [ http://www.leeprecision.com/graphics/parts/3561.jpg ] the Lee Case Spinner Stud because if you just go to Midway and order THIS [ http://www.midwayusa.com/eproductpa...ource=nextag&utm_medium=cpc&utm_campaign=9315 ] you'll be muy pissoffed.....


Finding the "Lee Case Spinner Stud" is an exercise in frustration.

Lee calls it the "Three Jaw Spinner Stud" and doesn't really sell it.....they have a picture of it in "parts"....

Cheaper than Dirt has one HERE [ http://www.cheaperthandirt.com/40786-1.html ]

And Midway has one HERE [ http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=174316&t=22164010 ]


But the whole thing is just vaguely ridiculous...... WHY DOESN'T LEE JUST SELL THEM AS A UNIT?????? Muy estupido.....

Great tool, poor execution IMO


BTW there are some tricks to using the tool, don't give up if it tends to set offcenter for you or produce wobble at first. It must be kept lubricated lightly, it takes practice to get just the right wrist twist for reloading it.... a bit of finesse is required but in the right hands it's the slickest and bestest thing going.

al

 

[alinwa]

Lynn,

I can't disagree with your choice. I've got the K&M as well as the Sinclair and the Hornady ones too. For pure-dee perfect concentricity of spinnage the Lee wins hands down.

WHEN you get the bugs worked out!

The stud thing though is just STUPID......

al

 

[Jay Idaho]

I am using a K&M tool to turn necks for a .269 chamber 6 PPC. I have been frustrated for almost 10 years on this and finally decided to ask for suggestions. My problem is that no matter what I do, the tool doesn't seem to hold its setting. typical example is I will start with a .0120 neck and by the time I have cut 20 necks I will be cutting .0123 or 4. I keep the tool at the same temp within a few degrees and have used every lube known to man. I am driving the case with a DeWalt power screwdriver and use a K&M mandril for expanding the necks.
I have 3 tools in .22, 6mm, and .30 and all do the same thing to one degree or another. WHAT AM I MISSING??? Thanks for your help. Jack Foster

Jack,

When you complete a session and quit, everything goes back to ambient, etc. So, what are the results with the first few cases that you turn at the NEXT session, using the tool setting that worked at the end of the former session? Do things change over time with the tool just lying in a drawer?
That might tell you something about the cause of the changes that occur during a session.

 

[Dave Short]

Wow Dave!

Ingenious but WOW, seems like a lot of work

Al, I guess I see what you mean...............I have to lay the tool on the block, make sure I take it off before I answer the phone or go take a whiz, and remember to pick it back up before I make another cut...WOW.........................and then theres that 5 minutes to take the mandrel out after only 200 cuts, spin it against a patch coated with Flitz, and put the mandrel back in..................Man, I'm going to have to re-think this whole thing................................Pure TORTURE! UGH!

What I'm trying to say, Al, is it's a breeze.
-Dave-

 

[rstreich]

I just got one of Joel Pendergraft's whatever he calls them and it made a big difference with the last batch of brass that I turned. This was a batch of .17 cal stuff that's normally a real problem because the skinny mandrel heats up so fast. But it's not so much the mandrel heating up that seems to be the problem, it's the mandrel heating the body up that seems to cause the inconsistency. With that big hunk of aluminum on it, I quit using the cooling bath. Instead, I just slowed down and let everything come back to room temperature between cuts. It only takes a minute or so for everything to cool.

 

[Wilbur]

Much too tight

Mandrel too tight, turning too fast, and criteria too tight.

Loosen the mandrel fit, slow down the cut and measure your loaded necks with a caliper....just to ensure some clearance.

 

[Dave Short]

Try hand turning your next batch of brass. If the heat generated expands your mandrel using the power source it should be much less hand turning. My cases after turning measure .0000-.0002 difference.

Stephen Perry
Angeles BR

If the mandrel is heating up because of too tight of a fit, I agree that hand turning would reduce the heat. The real likely culpret, though, is that the fit is too tight. Fix the expander/mandrel relationship and the excess heating should go away, and he can continue to turn his cases under power. It sounds like the tool body is just expanding normally......it has to be controlled in order for the tool to produce consistent wall thicknesses.

-Dave-