What method are the resident 'smiths here using to make the extractor cut for Win M70 CRFs? Mill? Palmgren or Palmgren-like milling attachment for a lathe? Hand cut?

Palmgren and lathe.

Been thinking about getting a Palmgren for some time now.

How's the runout using the 3 jaw chuck to hold the endmill rather than a collet?

It's just an extractor cut which requires a little clearance to begin with. I usually have to remove material from both the top and bottom edge of the cut just so the extractor will clear. The 3 jaw works perfectly. I used to use a milling machine and a rotary table but found this set up is much faster and every bit as accurate for the majority of stuff.

I can see how the Palmgren would be a nice quick way to do a cut like that.
Even quicker if you don't have to remove your chuck.

Thanks.

I also use the Palmgren to make extractor cuts. It's quick and easy. In the past I have used a mill, a file, or a cutoff disc in a die grinder! The end result was the same in all cases but the milling attachment in the lathe is my favorite. GD

I use the knee mill and an extractor cutter from PTG.. Brief touchup with a file at the corners finishes the job..

I want a knee mill so badly!

Even well used Bridgeports are expensive.

I use a Palmgren on the the lathe. Setup is quick, easy and accurate enough.

When using the knee mill, do you just secure the barrel in a Kurt (or similar vise)?

Yes, but I also anchor the muzzle end to ensure nothing moves.. Whole thing takes about 15 minutes.. (except for any touchup)..

I do mine in the mill. On a model 70 I have a print that locates the depth of cut. Just can't beat a milling machine to make a cut for a milling cutter.

What do you do if you run across one that is outside the parameters of the print?

Please clarify that! Like what for instance? Normally the distance from the face of the receiver to the extractor is very close,within a few thousanths, and my measurments are taken off that and the centerline of the barrel tenon.

Try this. Under "Normal" circumstances they probably are within a few thou. The point is, why would you even need a "print" to tell you what the cut should be? It's an easy thing to figure out without the aid of a "print".

Dammit....I REALLY wish I was a machinist.

FAR more interesting than hepatospleenoportograms....

I had been doing them in a Bridgeport, but have only a small table mill now. I used a piece of aluminum about 10" long x 6" wide x 2" thick, and milled a "V" in one end and drilled and tapped 2 holes in the end. Then made a "V" cap to bolt to it. I bolted the block to the table so the "V" clamp extended over the back of the table, clamped the chamber end of the barrel in the block, and swiveled the head over to it. Indicated the barrel, touched off, set the bezel ring on the knee and came out milling. If I had something bolted to the table I did not have to move it. Using the lathe now, I think it is faster.

Do you indicate the bore in any way, when using the above anchoring method?

It's not necessary for a simple extractor cut..

$.02 worth. Make sure you get your threads seated up. tighten and loosen the barrel several times.

My nuckledragger method to locate the cut is to use a long file sharpened like a chisel in the lugways, just line up on the top and bottom and give the file a love tap on the back of the barrel.

I just use a couple of vee blocks in a mill vise to clamp on the barrel cylinder and cut as little as possible with a woodriff cutter to clear the extractor. Thats what your after to make the cut while giving the cartridge as much support as possible. Cut til your "file marks" are gone so the exractor does'nt bind. Deburr with a wire wheel. Dale

There are many ways to obtain the same result.. After I get the threads done and barrel hand-tight on the receiver, I make a witness mark at recoil lug center.. Then put the barrel in the vise and tighten/loosen 2-3 times, then make one more witness mark after tightening.. That one will be the operative mark.

Remove barrel, set up in mill with the 'tight' witness mark on top.. Center the mark with a TDC locater, then install the cutter.. Touch the threads, move it off, and drop down .5" plus 1/2 cutter diam. (.215).

Piece of cake..

I take it that with a .215 dia cutter that the resulting extractor cut has a slight radius on each side - correct, and if so, does this require a minutely deeper cut?

The cutter is .430 in width, not .215.. Therefore, when you 'touch' the threads, you dial the quill down .5 + .215 and you're centered for the cut.. It actually has a little tighter radius than it should (IMHO, and this is a PTG cutter specifically for the M70 cuts..) The depth of the cut is specific to the extractor nose extension.. All that's needed is to exceed that by a few thou to ensure no contact, dress the edges, then relieve and polish the cut surface at the chamber mouth and you're good to go.. Ensure that last part is done - always.. Or else the owner can get some real scratches on cases and you'll end up having to remove the barrel again and do it then..

I am old and I forge5 easily. I look and the print, center up the barrel and move to the correct "print dimension" and make the cut. Never had one fail to no be correct yet.

WiFowler
Another option I didnt see mentioned....just dont make an extractor cut. I've been flat breaching them like a Mauser for years and haven't had any problems. An old smith/friend of mine turned me on to that. He ask me one day why it must have the cone....I still havent found a good reason.
Charlie

And there you have it, folks; a man with balls enough to admit to doing something contrary to convention. The only real reason for doing the cone and the extractor cut is because that's the way the factory did it and most figure you have to have it that way. I've not seen where the cone helps feeding and I have seen where the extractor cut hinders feeding. One of my own model 70's has the barrel fitted with a flat breech and it works fine; better than fine, in fact. I still prefer to fit the barrel as the factory did but I don't look down my nose at those which are installed flat. Rugers are flat and they seem OK. GD

He's not alone. (and I know Charlie knows what he's doing, obviously) Other smiths have ignored the cone and just breeched it like the Mausers. IMVHO, that cone is what makes the M70 feed very, very well when compared to some others.. If the installer does not fully relieve the edges of an extractor cut including the edge next to the chamber, the resulting sharp edges can hinder chambering and/or cause case scratching. With all edges dressed and relieved, (and coupled with a properly tensioned and fitted extractor) this won't happen. Done properly and finished well, the cone will allow feeding of any style bullet - whereas, I've had some flat breeched models have certain bullets jam against the breech.. If everything's perfect, the cone won't matter as much.. But seldom is everything (feed rails, magazine, bullet style) perfect. Look at the cone as 'insurance'.. Why, if the flat breech is ok? (not a flame, Phil, honest) So are Mausers etc... And like you said - they seem ok.. But I've had a few Rugers in that cam jam a bullet nose.. Also those CZs - last one was in .458 Lott and it jammed the bullet nose against the breech about 40% of the time.. Really great problem in a DG rifle..

Knee mill, barrel secured through my index, with a woodruff cutter

The method I'll probably end up using. Thanks all for the input.

Did anyone notice how clean Malm's lathe was? Wow! Tell me you cleaned before pics. DH

I did notice that!

My grandfather kept his lathe that clean too when he was still using it.

I'm always suspicious of anyone who has their lathes and/or mills spotless...

Anyone care to post a pic of their mill (vertical) setup for extractor cut? I'm a "visual learner" . . . . besides which I toyed with a setup this weekend and am either being anal, over-thinking the process, or missing something simple. Not knowing the OD of the PTG cutter Redneck references, but using his setup method with a 1" OD woodruff cutter, it sure seems like there is a potential for the cutter to cut on both sides of the chamber.

Only if you go way too deep.......

If you flat breech a M70 or 03 Springfield, would that not make for a stronger action?

From what I have read, the cone does not support the case head as well as a flat breech.

This is a rough sketch of how I envision the setup in a vertical mill.

Maybe this will help:



This is a closeup of the cutter at work. I have to make two passes with this cutter to get the width that I need.


Good luck!

Clemson

There's no perceivable strength gain by flat-breeching an 03 or a model 70.
The Mauser has more meat to begin with, which makes it stronger, but in actuality, it's kind of a mute point. Winchesters and Springfields have proven their strength and worthiness for a number of years.

When you flat breech, you're going to have to remove a pretty fair share of material off the nose of the extractor to accommodate.

For an operation that is as easy to do as the extractor cut, as well as the better feeding properties that are normally obtained with the cone breech, I think I'd stick with it.

Bottom line is, a guy that knows what he's doing can make either one work like a charm. A guy that doesn't, will tell you why you can't.

Perfect !!!

Thanks, Triggerguard.

Many years ago, when I re-barreled some actions, it occured to me that you could make an 03 flat breeched.

I never tried it, because I had never read of it ever being done. I'm not going to do it now. I just wondered if it was possible.

The PTG cutter is set up for magnum chamberings.. I use a 1/4" keyway cutter for standards.. Just center it on the bore, cut once, then back up and move the quill up .090 for the top cut and down .090 for the bottom cut.. Equals .430 which is standard M70 barrel cuts..

If you have the tenon cut at correct length, it's easy to dial in .200 of depth and make your cut.. If in doubt (and it's ALWAYS good to double-check) measure the original barrel for tenon, depth of extractor cut and distance of it from the shoulder.

As far as 'cutting into the chamber', you'll note that many factory barrel extractor cuts are (a)either into the belt cut (magnums) or (b) into the web a hair on standards.. It all depends on the measurements of your action, bolt, extractor and chambering..

Measure 2-3 times, and then measure again just to be sure..

Keep in mind, once the extractor cut's done, you still need to relieve the edge that meets the chamber to ensure no burr's there to scuff up new cases..

Just an observation, but I would not do it Clemson's way.. There's nothing to lock down that muzzle in case something gets loose.. I mount mine parallel to the table and ensure that muzzle is anchored.. NOTHING gets loose this way and eliminates a potential tool breakage or damage to the barrel..

Just my .02... Take it for what it's worth..

I'm about ready to take a drive to Redneck's and get some hands-on tutoring . . . . seeing it done is learning. Seeing it done properly is even better !

'Observing' will cost ya $90/hour.. And if you were a Queens fan, it doubles.. PLUS ya gotta bring me a good bottle of bubbly..

I ain't cheap.. Heheheheheee...

I bought the PTG model 70 extractor cutter some time back. I did a trial run on some scrap with a 257 Roberts chamber hole; then compared to the pre64 70's take off barrel. The specialized cutter's arc is pretty small(maybe 0,380" diameter roughly), so have a large hump in the middle of the cut slot. The original pre64's barrel extractor slot was blended to the chamber cavity nicely. Looks like the arc across each tooth could be made larger, but then have to figure in the 473 and 532 heads and perhaps have to own two specific cutters etc.

I was hoping to save some labor with a specialized cutter, but if I do use it, it still takes a lot of filing etc to blend(get rid of the middle hump) like the originals. With that said, most of the time, I just reach for a 1/4 straight and finish up with a file.

I thought that perhaps I did not understand everything yet about using the cutter, but the curvature of each tooth has me perplexed......and it mostly sits on the shelf.

Clemson would gain a great deal of rigidity by clamping with vee blocks(would probably need a mill vice).

Note that the vise I use has vee's cut in the jaws.

Clemson

So does mine.. I still anchor the muzzle...

But then, maybe I'm a tad anal..