Just in the process of threading a 98 barrel (my first rebarrel). I’ve ground a HSS cutting tool. I’ve read references to original barrels being cut with a sharp pointed tool. Whitworth has an awkward radius (apparently). A radius would be stronger obviously. What do the general consensus?

It don't matter. You aren't going to strip those threads no matter what shape they are. Just grind your cutter to fit the profile of an original barrel; but I now just use carbide inserts. Don't tell anyone.

Thanks. That’s not a bad idea - shame I got the receiver bare! I might just ground to 55* and stone the point off... I’m sure replacement tips make it very quick and easy, but I don’t cut enough threads to justify buying a holder

I got tired of sharpening the HSS ones.

I always grind a HSS cutter to 55 degrees then under magnification stone a small radius with a fine india stone. I use Rex 95 cutoff blanks, very rigid, smooth finish.

Hmm. The strange things a guy finds in his tool chest.

I, humbly, recommend you do as Paul Mauser intended and cut 55-degree threads. It's no harder than cutting 60-degree threads, and it's the right thing to do.

I confess to being more than a little anal about barrel threads. Cutting precise barrel threads is important, yet a lot of the "custom" barrels I remove look they were gnawed by a blind beaver. It's common to find loose, undersized threads. While one can get by this way, such indifference to quality work usually shows up with poor accuracy.

If this is your first barrel, I suggest you practice threading common round stock until you can cut chatter free, good fitting threads. You'll run less risk of screwing up (pun intended) the barrel threads and feel better in the morning.

Cheers and good threading.

quote:

Originally posted by dpcd:
It don't matter. You aren't going to strip those threads no matter what shape they are. Just grind your cutter to fit the profile of an original barrel; but I now just use carbide inserts. Don't tell anyone.

For the pro, there's just no reason NOT to use carbide inserts. They are as precise as can get.

Nice grinding gauge, more specific than mine. I also use it for getting the cutter perpendicular to the workpiece.


I’ve cut the thread - took a while and by the end I was only taking 0.001” or less per pass. Used some cutting oil and I’m actually really pleased with the finish (low res photo, doesn’t look as good due to reflections) - I generally get at least some tear out when cutting threads but these are smooth and clean (first timing using proper cutting fluid and hand stoned cutting bit). The receiver screws on about 3/4 of the way by hand them needs a tool to finish it off, feels good.





As I’ve started a thread I might as well ask another question - what’s the ideal headspace for a hunting rifle? I don’t want to make it too tight due to potential “adverse conditions” and unforeseen brass etc., but don’t want to go too far. I’ve borrowed a go and no go gauge. how would go + 0.004” be? Would go + 0.002” give me enough leeway? It’ll never get a scope this rifle, may end up with a receiver peep though.

quote:

Originally posted by RogersGunWorks:
I, humbly, recommend you do as Paul Mauser intended and cut 55-degree threads. It's no harder than cutting 60-degree threads, and it's the right thing to do.

I confess to being more than a little anal about barrel threads. Cutting precise barrel threads is important, yet a lot of the "custom" barrels I remove look they were gnawed by a blind beaver. It's common to find loose, undersized threads. While one can get by this way, such indifference to quality work usually shows up with poor accuracy.

If this is your first barrel, I suggest you practice threading common round stock until you can cut chatter free, good fitting threads. You'll run less risk of screwing up (pun intended) the barrel threads and feel better in the morning.

Cheers and good threading.

thanks for advice. Well I’d already ground the tool when I started the thread, I was only wondering about radius. However, it is my first barrel. But not my first thread - I’ve done a few, but am just a self taught hobby grade “machinist” so don’t have any formal grounding. But I have done my research, and have been using a lathe every now and then for the last 10 years. I cut a thread for a receiver leading-edge truing tool to a snug fit so considered it my practice run. No chatter as I was running it at 16rpm. Did sometimes have a little in facing/turning down the Knox but got round it by reducing spindle speed and grabbing the barrel with my left hand.

Looking at your setup I have to ask. How do you determine if your threads run concentric to the bore?

quote:

Originally posted by brnomauser:
how would go + 0.004” be? Would go + 0.002” give me enough leeway?

Go +/- 0. I set mine up to "just" close on a go gage. Since brass all too often runs small, why cut a long chamber? In the very unlikely event that you do run into brass that is too long, unless it is grossly so, you will be able to close the bolt with minimal effort.

Forget the go gauge and use the specific brass you have as the go gauge. For best case life. Good thing about doing it yourself is you can always lengthen the chamber (or make it shorter). A slight feel on closing is fine, for me, anyway.
Now, for sloppy reloaders and those who use random ammo, yes, you might use the go guage.

Interesting to hear your thoughts, I thought there’d be some advantages to a bit of Lee-way... one thing I have noticed is I tried forming a cartridge from 30-95 and it actually measures bigger than the no go. I did have the die (Lyman) turn about 1/4 up from the holder, maybe I should have it all the way down and try again... I’ve got unfired Norma which is small, and a federal that’s been fired in another rifle but I reckon it’s not fully sized as it’s quite tight. I want to switch to RWS long term but don’t have any at the moment (Im rural and nothing is local).

Surely theres no disadvantage to running a slightly longer chamber and adjusting the FLS or neck did to suit? Apart from a very mild Initial fire forming it’ll achieve the same thing. I bought the barrel long chambered - I don’t have a reamer. So I can make the chamber shorter, but Not longer. Although then I’d have re time the open sights...

quote:

Originally posted by Jim Kobe:
Looking at your setup I have to ask. How do you determine if your threads run concentric to the bore?

First I mounted the breach end in the 4 jaw, muzzle in the tail stock (gently). Indicated the breach, checked the OD at the muzzle for concentricity. It was ok. Then mounted the muzzle in the 4 jaw, the chamber in the tail stock (bare in mind I need to face off 0.108” nominal off the chamber face so a little potential marring of the chamber chamfer isn’t a concern). I skimmed the area in front of the Knox until it was concentric. I mounted the steady on this portion. I set it so when I removed the tail stock, a dial indicator didn’t move in three different spots relating to the three fingers. I then checked run out of the bore before and after threading - at both times it was 0

Well,,,sure not trying to start a dog ight..BUT..gages are the only way to absolutely determine that the chamber is within -+ tolerances..at least in head space.

Reloading whims have no place and should receive no consideration

quote:

Originally posted by Duane Wiebe (CG&R):
Well,,,sure not trying to start a dog ight..BUT..gages are the only way to absolutely determine that the chamber is within -+ tolerances..at least in head space.

Reloading whims have no place and should receive no consideration

I agree, and I never suggested otherwise - i wasn’t considering making it longer than the no go gauge. But there’s 0.010” between, so suggesting to put the headspace between them is essentially saying that 0.010” is up for grabs. I’m suggesting shooting for somewhere in the middle might be less limiting than a minimum chamber, and the argument for a tight chamber as far as I can tell is made up for by adjusting the reloading dies.

However, if there’s still more good reasons for a tight chamber that trump the potential Disadvantages I’m still interested

I just built a 270 for a guy who likes to make his brass absolutely the shortest, so I re fitted his barrel to .002 under the go gauge.

quote:

Originally posted by dpcd:
I just built a 270 for a guy who likes to make his brass absolutely the shortest, so I re fitted his barrel to .002 under the go gauge.

so why is this a better option than adjusting the dies to suit the chamber?

Brnomauser: .010? I think you may be referring to the 06 go and field gage? The go to no go gage is only .006.

That field gage is used to determine when the rifle should be taken out of service.

Stay with tolerances as determined by a good set of gages and you'll have a safe and proper set up that will be safe and proper even to a new owner down the road.

quote:

Originally posted by Duane Wiebe (CG&R):
Brnomauser: .010? I think you may be referring to the 06 go and field gage? The go to no go gage is only .006.

That field gage is used to determine when the rifle should be taken out of service.

Stay with tolerances as determined by a good set of gages and you'll have a safe and proper set up that will be safe and proper even to a new owner down the road.

the 7x57 gauges I’m using have 0.009 between them. I borrowed them off the barrel maker - they’re their secondary set so maybe it’s a field gauge? Either way I’m thinking I’ll make it Go Gauge + 0.004” seeing as I can’t see a good reason for a tight chamber

Ok so now the no go won’t chamber, the go will with a 0.0025” shim but won’t with a 0.005” shim. I’m going to leave it there.

How much should I chamfer the end of the chamber?

Just try a slight radius, just break the sharp edge and polish it.

You also need to chamfer the od at the breech to prevent the first thread from shearing off.

Getting concentric threads requires that the setup be made before the chamber is cut, and the threads cut with the tailstock engaged in the bore. You also have to true the od where the steady rest is going to run. I assume this was done. But the problem I find with this chambering setup is the steady rest gets sloppy as you cut the chamber. The brass wears even with plenty of oil.

Brno; because the guy is old, and set in his ways, and insisted that his ammo was good; so I made the chamber to fit it. It is super accurate, BTW!

Russ,

My steady rest is almost as old as Duane and the inserts are the originals. I’ve chambered many many barrels with it. Never had an issue with the brass (if that is what it is?) wearing before I got a chamber finished.

Might try slower speeds, better lubricant, or something?

Through the headstock is best in my opinion, but some barrels and most lathes don’t lend themselves to that.

Anyone still using White lead for lube on the steady.
No, what's your choice for lube?

I use this from AR Warner
https://www.arwarnerco.com/Kit...ader-NV-p/kit-18.htm
They sell 55 degree as well as 60 degree HIGH SPEED STEEL inserts.

I also have laydown carbide tooling in 55 and 60 degree. However when threading in manual mode $hit happens pretty fast when threading 12 TPI against a shoulder if using correct surface feet for carbide. HS gets used for most of my Mauser barrels.

quote:

Originally posted by TCLouis:
Anyone still using White lead for lube on the steady.
No, what's your choice for lube?

We used to use white lead for a lube when pressing in large bushings. I understand this stuff is now considered a hazardous material and is banned.

I've got a small can of the white Lubriplate under the lathe bed and apply it with a small brush; never had a problem

White lead is banned as well as a lot of good old stuff. I guess we're too stupid to protect ourselves when using hazards products.

Dave

I was taught that brass/steel equals almost no wear on either. Of course, use lube..I like Lithium grease on steady rest and dead center.

quote:

I use this from AR Warner
https://www.arwarnerco.com/Kit...ader-NV-p/kit-18.htm
They sell 55 degree as well as 60 degree HIGH SPEED STEEL inserts.

Me too. With my technique I get a better cut. ymmv

I used way oil on steadies.

Dave

quote:

Originally posted by Russ Gould:
You also need to chamfer the od at the breech to prevent the first thread from shearing off.

Getting concentric threads requires that the setup be made before the chamber is cut, and the threads cut with the tailstock engaged in the bore. You also have to true the od where the steady rest is going to run. I assume this was done. But the problem I find with this chambering setup is the steady rest gets sloppy as you cut the chamber. The brass wears even with plenty of oil.

Yep did all that, trued the area just in front of the (0.2” long) Knox. double checked run out of chamber once I steady and the needle didn’t move on my M&W metric dial indicator.
I set up a can with 90w gear oil with a slow drip onto the steady fingers where they meet the barrel. I checked at the end and there was no slop in the steady. When first setting up unadjusted the steady so that when I removed the tail stock the indicator didn’t move when placed on the OD where I was about to cut the threads, in three separated places corresponding to the three fingers. Did the same check at the end - still no change.
28” long barrel and 38” long headstock, no option but to go between centres. Can’t see how it’s any less accurate than between centres and heaps easier to dial in with less expenditure on gear to get there?

I didn’t so much chamfer the threads as cut a slight counter bore so that the face just didn’t gaul at the C cut

For the steady rest I use STP.