lug seat cutter

03 August 2022, 20:12

Duane Wiebe (CG&R)

lug seat cutter

A 280 I built 30 years ago is in the shop..hard bolt lift. upon firing.

Wow! I've never seen such bad gas cutting on the bolt face. checked head space..go gage just fine..NO GO ..resistance until bolt about ready to close fully, then drops without effort

Took the barrel of, and as suspected, pretty severe set back.

Had to happen sometime..my first hands on experience with a soft 1909!

Seems to me someone offered a lug seat cutter..jog anyone's memory?

03 August 2022, 23:10

dpcd

I would just set it up and cut it with a boring bar. Or use a mandrel piloted in the bolt raceway with a cutter on it.
I see pitted bolt faces too; I still can't believe that reloaders allow that to happen.

04 August 2022, 01:42

Duane Wiebe (CG&R)

Thanks,DPCD...Yep..done it with boring bar.....kinda complicated by an extended tang...Just looking for an easy way out
Now..don't ask me why extended tangs on a 280...I just turn on the blue lights for the guy that wants a blue suit

04 August 2022, 02:14

Jim@IMReps

Perhaps PTG, D Manson or J Wisner might have what you are looking for or know where to source.

04 August 2022, 03:27

dpcd

PTG and Manson don't all such tooling is geared toward 700s. Not much demand for truing Mauser lug seats. You usually just throw the receiver away and use another one.
But it would be easy to make the mandrel between centers with the cutter inset into it. Drill a hole for the cutter, Drill another one 90 degrees and tap for set screw.A boring bar between centers. Put the receiver in the lathe vise. It would self center.

04 August 2022, 03:36

Duane Wiebe (CG&R)

I think that would be the way to do it! The Mauser inner ring does add another factor, and I'll have to utilize some sort of adjustable stop to not over do it.

With the extended tang already there, a new action wouldn't be an easy option.

04 August 2022, 04:11

Rockdoc

Might be lug setback on an 09 but the gas cutting seems to indicate the culprit!

Have you talked to Dave Manson? Have found him very helpful in the past, when he was Loon Lake Precision.

Good luck. Would love to see some before photos and the result after machining the lugs.

Would you need to re-heat treat the lugs after machining? Not meaning to open up a big can of worms, just curious.

04 August 2022, 04:21

pointblank

https://pacifictoolandgauge.co...tion-truing-kit.html

04 August 2022, 07:37

dpcd

None of those tools cut the receiver locking lug seats.
Would you need to have the receiver heat treated after you cut it? YES.
No lugs need machining; it is the receiver bolt lug abutments that need it.
Just cut until you hear the cutter cut all the way around. Or look inside and when it is all bright; stop cutting.
Dave Manson sold his company in April. They don't make that tool either.

04 August 2022, 08:05

Timan

I've always set them up in a Tannel 8 screw cat head then dial the whole thing in with 12 inch range rod in bushings that fit the bore and two dial indicators. Dial in until there's zero run out then recut the seats with a Micro 100 solid carbide bar. This bar is designed for turning internal grooves and has 2 degrees of draft on both sides perpendicular to the bore, cuts 09's like butter. Go in touch of on the seats take .005 back out look in there see if it's cleaned up, Never had to take more than .008 to achieve cleanup with a nice finish, then off to heat treat. I use a 15" x 60 Clausing Cholchester lathe with 2-1/16 spindle bore in it. The tangs don't present a challenge as there's plenty of clearance in that lathe bore. I would guess heat treat might warp the tange some. If so anneal it and bend it back.

04 August 2022, 18:01

Jim Kobe

Duane, how do you handle the headspace issue after re-cutting the lug seats? It would seem to me the barrel needs to be set back and if sights or a quarter rib on it would complicate things, not to mention the barrel fit to the stock.

04 August 2022, 18:42

dpcd

It will now be a 280 Improved.

04 August 2022, 19:03

J Wisner

This little tool.

My Father designed and built it over 40 years ago now. It has saved us several times over the years in re-cutting set back lug seats

The smooth ring on the right top is a stop ring/thrust bushing.
The right knurled side of the tool is a threaded adjustment, and part of a built in micrometer
The small smooth ring in the middle is simply a micrometer zero indicator that is movable when you start.
The larger knurled ring is the sleeve which screws into the front of the receiver and when tightened in place acts as the base for the rest of the adjustment tool.
The cutter is in a square notch and can be sharpened if needed, and adjusted out or in to match the lug recess diameter

The knurled ring in the back ground is for the small thread Mauser receivers

No power tools here, all turning and cutting is done by hand power and a wrench.

The last receiver I had to recut was a 1948 FN C ring, that has been in 220 Swift for years. It has set back about .002", yes when doing this by hand you can feel the lug seats shaving, and even when the cutter comes around and hits the lug set back areas. Just make a small adjustment, then turn the tool with a wrench several times to shave a bit off the lug seat. Slowly work your way in shaving the lug seat until you feel the tool cutting all around each lug seat.

Then reheat-treat the receiver, lap the lugs in. Then deal with the barrel and the new longer headspace

Yes, Duane has not said yet if the barrel has a 1/4 rib or sights yet, that will create its own issue once the receiver set back has been fixed.

A repair for that would be to make a new oversize bolt head to lengthen the headspace, and join the new bolt head under the extractor collar, then machine the new bolt face to the headspace you want. But that is a story for another time.

J Wisner

04 August 2022, 20:02

Duane Wiebe (CG&R)

Now THAT is exactly the ticket!!

04 August 2022, 20:52

richj

Wheeler makes\made a lapping tool that screwed into the receiver threads. can't find it anymore.

have one I never used. looking for it.

04 August 2022, 21:06

richj

never mind. it's used to apply pressure to the bolt.

04 August 2022, 21:10

Don Markey

quote:
Originally posted by richj:
Wheeler makes\made a lapping tool that screwed into the receiver threads. can't find it anymore.

have one I never used. looking for it.

Those were for lapping the inner ring where the barrel meets the receiver, not the lug seats.

The one you showed is for lapping the lugs, different that recutting. I never gave to much thought into Mauser lug lapping since they way they are made the pressure is different on the top and bottom lug anyway. His issue is setback (glad to see Duane finally found one I though I was just unlucky with the two I had!) it’s not practical to lap away setback.

04 August 2022, 21:20

gunmaker

quote:
Originally posted by J Wisner:
This little tool.

My Father designed and built it over 40 years ago now. It has saved us several times over the years in re-cutting set back lug seats

The smooth ring on the right top is a stop ring/thrust bushing.
The right knurled side of the tool is a threaded adjustment, and part of a built in micrometer
The small smooth ring in the middle is simply a micrometer zero indicator that is movable when you start.
The larger knurled ring is the sleeve which screws into the front of the receiver and when tightened in place acts as the base for the rest of the adjustment tool.
The cutter is in a square notch and can be sharpened if needed, and adjusted out or in to match the lug recess diameter

The knurled ring in the back ground is for the small thread Mauser receivers

No power tools here, all turning and cutting is done by hand power and a wrench.

The last receiver I had to recut was a 1948 FN C ring, that has been in 220 Swift for years. It has set back about .002", yes when doing this by hand you can feel the lug seats shaving, and even when the cutter comes around and hits the lug set back areas. Just make a small adjustment, then turn the tool with a wrench several times to shave a bit off the lug seat. Slowly work your way in shaving the lug seat until you feel the tool cutting all around each lug seat.

Then reheat-treat the receiver, lap the lugs in. Then deal with the barrel and the new longer headspace

Yes, Duane has not said yet if the barrel has a 1/4 rib or sights yet, that will create its own issue once the receiver set back has been fixed.

A repair for that would be to make a new oversize bolt head to lengthen the headspace, and join the new bolt head under the extractor collar, then machine the new bolt face to the headspace you want. But that is a story for another time.

J Wisner

The depth of knowledge on this board never ceases to amaze me. Heirloom Wisner wisdom there

04 August 2022, 22:19

dpcd

For one receiver, just make the mandrel/cutter and do it in your lathe vise.

05 August 2022, 00:26

richj

The one I posted applies pressure to the face of the bolt so you can "create setback" without firing a round :-)

it was meant to be used to lap the bolt lugs to the seat of the lugs , probably better used on a weatheby or 788 :-).

05 August 2022, 20:53

Duane Wiebe (CG&R)

I think James Anderson meant to say "Never ceases to amaze"...etc

Anyway...After dealing with the lug seats, I'll have the action re heat treated... the extended tangs...would really like to NOT have it hardened, so called Blanchard's.

They told me that black oxide will act as a shield to prevent hardening..."You mean as in bluing?" Answer was "Yes"

This is news to me...Am I the last person to find out?

05 August 2022, 21:12

gunmaker

oops... fixed it

As for the shielding, I would expect it depends on how the heat treater is going to impart carbon into the surface of the action. Gas, pack, etc. I tried using stop off for case hardening on a 22 bolt handle project and where I painted on the stop off it was just as hard as the rest of the part. I used the pack hardening method. Guessing gas carburizing might have been deterred a little more???

Copper plating is promoted as stopping the case hardening as well. I have done this on a 98 project years ago sending it out for copper plate then stripping the copper off where I wanted more carbon sending it off to heat treat and having it chemically stripped afterward. The surface finish of the action was almost as brite as the polished action I sent for plating in the beginning.

NO clue on bluing. sounds too easy

06 August 2022, 00:43

dpcd

A few enumerated bullet points which might, or might not, be of interest:
1. Blanchards is not a process; it is the name of the company that heat treats metal.
2. They use gas to impart the carbon. Not packing.
3. Bluing does NOT impede the carbon from penetrating the surface. Yes I have talked to Blanchards about this; once it gets up to temp, the bluing is gone anyway.
4. Your tang will be hardened to the same hardness as the rest of the action. If you what it soft you will have to draw it when you get it back.
5. You have to specify the hardness and depth you want. They don't do anything without the customer telling them.
6. When you get them back, they are smooth gray. I have send at least a dozen Mauser receivers to them, various makes.
7. I specify RC35-40, with a case depth of .010-.015.

06 August 2022, 03:46

Duane Wiebe (CG&R)

No 1...no reason to disagree
No 2. ditto
No 3. I was looking for possibilities.. Who to call? Oh...maybe Blanchard's? Got the answer I posted...Unless a politician, I tend to take such information as a "possible"

In the late 60's, maybe early 70's a gentleman from Blanchards dropped onto my shop in Lafayette CA. Neat guy, middle aged then and I do not recall his name.

Has a great conversation about heat treating, but the bottom line is he told me that they had analytical data on virtually every 98 produced.

So my position has always been that they have forgotten more about the metallurgy of 98's than most of us will ever know.

I tell them the caliber, and "do what's required"

Never been disappointed. Recently, got back a Mexican 98 RC 35 .015-.025 case..Finest glass beading took care of surface, no precipitable distortion

06 August 2022, 22:41

Duane Wiebe (CG&R)

Here are a couple shots of the problem. you'll have to look closely at the faint yellow colored arrow to see the set back. Of course, re heat treat is in order. While the photo is up there..any thoughts about trying to clean up the bolt face? Pretty bad!

...I'm leaning toward a new bolt,... has a checkered knob I'd like to save...an alternative might be to install a whole new forward section.

Then...of course a headspace issue with the barrel..might go to a new barrel...talk about a cascade of events! On the plus side, he could get rid of a crap (in my opinion) caliber and maybe go to an 06.

07 August 2022, 00:23

rcraig

Micro-tig for the bolt face ?

07 August 2022, 02:00

Duane Wiebe (CG&R)

Hmmm...there IS a fair amount of material abound the FP hole. Like to hear further on the idea

07 August 2022, 02:13

metal

Get it laser welded. Had some done recently, perfect weld with virtually no heat.
I see a ring on the boltface, about where the rim would be.
Is that deformation?

07 August 2022, 03:22

Duane Wiebe (CG&R)

No that's where I most likely would have taken a light truing cut across the face. Laser weldI'll look into that thanks

07 August 2022, 03:41

squeezenhope

Laser weld was my first thought, but how about a bushing?

07 August 2022, 07:08

els

I am Not a gunsmith. That said I wonder how many 70,000 + psi / almost a 7mm magnum loads it took to do that much damage to the lugs and bolt face??? inquiring minds.

07 August 2022, 19:33

dpcd

As has been discussed many times here before and elsewhere, some small percentage of Pre WW1 Mausers are soft and will set back with normal loads; meaning from a 30-06; I have never seen one set back still in 7.65 or 7mm but that doesn't mean it couldn't happen. Heat treatment was in the Stone Age then; remember we were case hardening Springfields with charred leather. And all of those are unsafe. (Ok, for another discussion)
So, it didn't have to be high pressure; 55K psi will do it. A common ploy by Potomac Arms and others was to rechamber 7.65s to 30-06. Those will set back X percent of the time with regular 30-06 ammo.
Now, as for the bolt face cutting, he might, or might not, have loaded hot. As stated above, if you have a bad (soft) lot of brass, or primers, you will get gas cutting with normal loads.
In any case, if you use pre ww1 actions, you are rolling dice. Not made by Mauser; they were dedicated to the Turkish contract at that time.

07 August 2022, 21:03

Duane Wiebe (CG&R)

I think it just boil's down to a darn soft action. I can easily a "bite" on the lug recess with a carbide scribe.

But ..laser welding... Anyone heard of Laserstartv they have facilities in three locations across the US, apparently attend NRA and SHOT shows. Makes me believe they must know about firearms.

I'm a 20th century dinosaur, so; "welding without heat"...stretches my brain cells.. As I told Metal...next thing will be warm ice cubes.

08 August 2022, 00:47

2152hq

I would have figured a bushing in the face of the bolt.
But the latest is Laser Welding it seems.
I'm not a welder, don't know anything about Laser Welding and don't pretend to.

So with that, but with all the great things that are said to be done with Laser Welding..

It seems that the bolt face injury could be easily (for someone who does that work) to be Laser Welded back in and then remachined.

IF there ends up being a Headspace problem after recutting the locking lug seats..
Would you think it would also be possible to use the same bolt face Laser welding to not only repair the present damage, but to also build up the face sufficiently to allow remachining and leave excess length to the face to take care of the HS issue.

The fit of the extractor would be effected I would assume, is there enough material there to re-fit?

It seems like if it's possible it would be much simpler than fashioning a new forward bolt section to splice on or fitting an entire new bolt.
But then again, I'm not the one doing the work..

You would save the checkered bolt handle!

08 August 2022, 01:22

metal

https://youtu.be/YNGuALnRQe0
My laser guy here in oz knows guns, knows the metallurgy required and can lay down whatever steel you want. Hard or soft or anything in between.
Shotgun smiths love him.

08 August 2022, 01:34

setters5

quote:
posted August 07, 2022 11:03 AM Hide Post
I think it just boil's down to a darn soft action. I can easily a "bite" on the lug recess with a carbide scribe.

But ..laser welding... Anyone heard of Laserstartv they have facilities in three locations across the US, apparently attend NRA and SHOT shows. Makes me believe they must know about firearms.

Try Glenn Fewless Mook Machine Works ACGG member 262-534-5154

08 August 2022, 05:00

custombolt

Duane,

Have you considerd building up the bolt face with 95% of the bolt submerged in coolant? I built up a butchered cocking piece safety lever notch that way using a mig for about a half second at a time. It was a hard after as it was before the weld and the shear face was also unaffected. No file or emory would touch it. Just a thought.
I suspect that the freshly machined, heat treated bolt face should impress the owner nicely.

Final pics are always appreciated.

08 August 2022, 05:38

MNR

Hey Duane,
You may want to check with Glenn Fewless. He did a bang up job with some laser welding for me last year.

08 August 2022, 19:49

Nick Hughes

Bush the bolt face? You can reduce the firing pin diameter in the process which will greatly reduce or eliminate blown primers. Could even leave the bushing a bit proud to compensate for the lug repair. The quick and dirty way I would deal with the lug seats is to make a guided tool similar to the one above but use sticky back sand paper and grind or lap them down. As long as it's guided to remain straight will work just fine.