Can someone tell me the number of thread per in and major diameter of the Charles Daily Mark X Mini Mauser barrel shank? I thank you kindly gentlemen!

.860" OD x 1.5mm pitch.

quote:

Originally posted by Jim Kobe:
.860" OD x 1.5mm pitch.

Thanks Jim.

Hi Olcrip,
Actually the size is 22 mm X 1.5 mm which converts closely to .866" X 16 3/4 T.P.I.. Hope this clears it up more for you. Paul...

Closer to 17 TPI then 16 3/4.

1.5 Pitch = .05905"
17 TPI = .05882"

For a barrel tenon of say .750" or less it is essentially the same

If you have a one inch mic, it don't matter if it in mm's. If you can thread a mm pitch it is the correct way to do it.

I stand by my original post; why complicate matters?

And there in lies the problem. Not knowing what machinery is available to the OP.

My ancient Southbend lathe only cuts SAE threads. So i have to convert mm pitch to TPI and hop I can find something close.
If you have access to a lathe that cuts mm threads Great.

quote:

Originally posted by kcstott:
And there in lies the problem. Not knowing what machinery is available to the OP.

My ancient Southbend lathe only cuts SAE threads. So i have to convert mm pitch to TPI and hop I can find something close.
If you have access to a lathe that cuts mm threads Great.

So what you are saying is you are cutting a bastard thread? Pretty lame, I would turn down the job if it were me.

quote:

Originally posted by kcstott:
And there in lies the problem. Not knowing what machinery is available to the OP.

My ancient Southbend lathe only cuts SAE threads. So i have to convert mm pitch to TPI and hop I can find something close.
If you have access to a lathe that cuts mm threads Great.

kcstott, your taking shortcuts with pressures in the 40 to 50,000 PSI range on your face and next to your eyes? There is no project that is worth that risk. Either they match as designed or it DOES NOT GO TOGETHER in my small shop. Shooting is supposed to be a gratifying pleasure not a risk. Enjoy your shooting, don't take chances with your life!

Ok for one I'm not cutting the thread. Two it's .00023" per thread off and most likely only over a little more then a half inch. ANSI allows +/- .00015" for a 16 to 18 TPI thread. It's within tolerance.

never assume your lead screw is perfect, as it's not.

Have you ever looked at a thread you've cut on your lathe under a microscope and verified the pitch? I'll tell you on a factory new machine it is off, Just a wee bit but it is off. Lead screws have tolerances and they are not as close as you would hope. Gears have tolerances too. gear boxes wear. So even setting it up on a brand new machine with the correct pitch gear box it still will not be exact.

What I'm saying here is we live and breath tolerances and as long as you stack them in your favor Nothing is going to happen

I agree it should be cut on a lathe with metric threads positions. But in all reality how many 98's are floating around with barrels with 60 Degree threads???
And how many Smiths out there know what a class 4 thread is? I'm not saying you guys I'm talking in general. How many are cutting threads to 75% engagement?? And do they know how to calculate thread engagement? and class of fit? Do they know how to measure pitch diameter? I say that because a little slop in a proper cut thread is worse then a converted inch to metric.

Now keep in mind I'm not a paid Smith Nor do I consider my self to be a smith. I work on My stuff and my stuff alone. The parts I build for customers is what I'm legally allowed to build without an FFL. Liability is a factor and may be the reason you'd want to make it text book perfect and there is nothing wrong with that.

The above post perfectly describes the reason that single pointing the threads in a military Mauser is a waste of time. But there will be folks to whom it is over their head who would rather argue their position than actiually learn how the world works.

From a psychologist's approach, many find comfort in knowing something has been done. I myslef do things that I know really do not matter, but it gives me peace of mind. Makes no sense on paper, but if I am happy that is all that matters to me. So if someone wants to spend the money to chase Mauser threads, go ahead. I don't care and do not care if you try to convince me it matters. I will listen politely, smiling and nodding. if it makes you happy, do it. Maybe it is beacuse I grew up in South Louisiana, but I feel that if voo doo things make you happy when building a rifle, cleaning a barrel, or loading ammo, then be my guest and do it to your heart's content. But i am under no illusion that any of the voo doo matters

You are correct for the most part.
The tenon threads would have to be bored considerably cock eyed for it to make a difference how the C ring and breach seat.

Even on a non C- ring action the thread would have to be way out of kilter.

The squareness and concentricity of the C ring to the action centerline axis is what matters.
And on a Non C ring rifle it's the action face to action centerline axis. Square and concentric threads will help but to get thing to bind up they would have to be off a good amount. Like say .010 or more

I just used chasing the Mauser threads as an example because a lot of folks happened to be talking about it at the time. I was basically just backing up your post and extrapolating it to cover so many other things that we “know,” fret over, and spend money on. It applies to a hell of a lot of things. “It” being so many variables that must answer the questions such as does it have an impact, if so, how relevant is it. To answer that you need to know what are the other variables and what impact does each of them have on the total equation.

Then you have to look at what can be measured, how to properly measure it, and what sort of confidence you can have in the measurement. Don't even get me started on the whole topic of metrology. The lowest on the rung hack machinist in a grungy job shop knows more about real world meaningfulness of measurements than a lot of PhD engineers I know. I remember one particular post here regarding chambering and how this one person was getting super-turbo-nija-kickass tight tolerances on cutting chambers. It was physically impossible to hold those tolerances with his set up and it could not have been measured to that accuracy in that shop anyway.

You mentioned the true pitch of lead screw. How many folks know how their lathe cuts threads at various spots along the length of the bed? Just about anyone who has seen more than a couple of used lathes has seen a machine with obvious wear near the headstock. But the lead screws are all made to a certain tolerance and on some machines the difference is greater than others.

There are a ton of other variables that go into how accurate threads cut by a particular operator on a particular machine. Additionally there are the variables involved in measuring the threads. And to top it off, there are the female threads in the action and all of their variables.

We can easily get side tracked chasing tighter tolerances on variables that have no meaningful impact on the big picture. So, so, many many things that do technically on paper have an impact on an outcome are so small that they are lost in the noise of the overall equation. You get into statistics, confidence values, etc. and can quantify it all. But most of the time the machinist/engineer/whatever gets challenged and asked for ridiculous equations that no one keeps memorized and on top of their heads. You try to explain it as best you can without getting too technical or general, yet continue to get pestered to “prove” it. A person eventually gets to the point where all they can say is, “Please just trust me on this one.”

You made an excellent point on threading for that pitch. I did not know that , but I did understand what you were saying and enjoyed reading the post.

Maybe I should have rephrased my initial statement. Instead of saying "you are correct", I should have said "I agree for the most part".

But you are correct that we the general gun crowd fret over things are are in the end of little value to the end effect or result.

And the Trust me on this phrase comes up more then once in a while. Like you said detail get lost in the noise of the over all big picture. i.e. tolerance stacking just to point the finger at one variable

I just hope the guy you mention dialing in a chamber to super tight ninja kickass tolerances wasn't me. As I do remember posting about how close I dialed in a barrel. IIRC I think I said something like .0005" run out. Which is damn close but not kick ass tight. Know if I would have said .00005" now we are talking a boat load of BS, As my indicators will only repeat that close let alone measure an absolute dimension.

quote:

it's .00023" per thread off and most likely only over a little more then a half inch. ANSI allows +/- .00015" for a 16 to 18 TPI thread. It's within tolerance.

Since the .00023 is on the minus side.....this makes it not per ansi spec....

+/- is from a "0" point and this spec is all to the minus! Per your own data, I'd say this is out of spec....

I've had a miserable time trying to make metric threads with my lathe....every time I think close enough is fine the thread sucks....

Ok You got me there.
But a wee .00008" is nothing to fret about.
I'd be very surprised if 80 millionths of and inch really mattered.

Vapodog You caught me. But what I'm getting at here is thread can be off a wee bit and ti will not make a hill of beans. But to be clear Anytime I can cut a metric thread on a lathe that is equipped with the metric gears to cut the thread properly I take advantage of it.

Kobe Is correct no mater how you look at it. It is a bastard thread. But in hopes of making one with in tolerance is the key.

I'll say this I've cut a bunch of half assed metric threads with various lathes but I have yet to cut one for a rifle barrel tenon.

On my stuff I would do it and on a case by case basis I'd do it for a customer. But using my experience as a tool maker I'd borrow my buddy's
machine and do it right

For what it's worth, I was a quality engineer for 30+ years for John Deere and other companies. If you have 50% thread and 1 dia. of engagement on mild steel you will twist the bolt off before you will strip the thread. This holds true as long as both parts are the same strength steel....Tom

quote:

Originally posted by Tapper2:
For what it's worth, I was a quality engineer for 30+ years for John Deere and other companies. If you have 50% thread and 1 dia. of engagement on mild steel you will twist the bolt off before you will strip the thread. This holds true as long as both parts are the same strength steel....Tom

Thanks for that advice. You have just cemented my decision to buy a Case-IH

KC-

it wasn't you maing the uber-ninja tolerance chambers in that thread. It was someone else, who honestly beleived it and was 100% sincere. He was not trying to mislead us. It was just that because a number can be read, does not mean that number is actually meaningful and true. But the guy saying it was aying it good faith.

As for being a little out of spec on the barrel tennon threads, who the hell knows how close the famle action threads really are? The pitch you can cut on the South Bend may actually be a better fit than a tennon cut to book specs. But yes, i think we should all try to cut the very best fits we can and we have to make so many assumptions about so much in the world.

It is like when people have a baby about opening up a Mauser to hold a .375H&H and cutting metal from behind the rear lug seat. An ungodly number of shooters would be blown away to learn just how many rifles are performing yeoman's duty year after year with only ONE of the actions two lugs touching touching their seats.

Not wanting to start a never-ending debate but does this make a case for re-cutting the thread on the receiver? If the lead screw is off but will repeat the threads on the barrel and receiver will match if cut on the same lathe. Bastard thread or not it will match. The next rebarrel will get interesting though.

I only know of three ways to make a female thread.

1. with a tap (cutting or forming)
2. CNC thread mill.....and that is frequently done with a multiple fluted tool such that only one turn might be required for the rifle thread

3. CNC single pointed lathe


All three are incredibly precise and reliable ways to make a thread.....but they can sure be muffed up if one isn't watching.....

That said, the method of gauging is primarily with a go-no go thread gauge for pitch diameter and a plug gauge to measure the minor diameter.

Assuming any reasonable quality checks by the factory, one can assume his female thread is "just fine"

IIRC there's 10 threads in a mini mauser and to be "off" by .00023 per thread is to be off .0023 overall.....and I'm usually trying to make my headspace to less tolerance than that....

Personally, .0023 error in the lead of the thread is excessive IMO



You guys do as you see fit!

Vapodog, I use these threading tools (style Z) on a regular bases to thread internal threads in a manual lathe. http://www.criterionmachineworks.com/Catalog/yz.htm

Vapodog

No one here Well at least I'm not trying to say "Do it this way every time and you'll be fine"

This is just one way to "make due" It should not be construed as a standard form of practice. It is IMO safe to do so as long as you pay attention to your tolerances. When in doubt find a lath with metric threads

Yes I've done it many times in the past on parts other then rifle barrels. I have yet to try to improvise a thread on a barrel tenon.

CNC thread milling and CNC Single point on a CNC lathe are nice but some of us have to make due with sixty year old machines.

J zola: As per the same lathe thing well if you want to get technical no. As you would also have to cut the thread using the same segment of lead screw as well. But that is really splitting hairs.

If you have a copy of a machinery's hand book Look up the tolerance on the pitch diameter of any class three thread pitch. It will blow your mind.

Take a 7/8 18 UNS thread. (the closest I could find to the .866 X 17)

You have .005" between the Min max on both the Major and pitch diameter. Internal threads give you. Internal threads allow a little more. But this is a class 2a/b thread so cut the tolerances in half give or take for a class 3 to four fit.

quote:

If you have a copy of a machinery's hand book Look up the tolerance on the pitch diameter of any class three thread pitch. It will blow your mind.

Mr Scott,
Please don't confuse the issue of lead error with the issue of pitch diameter tolerance.....they are not at all the same.....but I think you know this....I think you're saying that the lead error is so little that it can be compared to the pitch diameter tolerance......and this is where I lose the analagy.

The geometry and method of calculation of error due to lead error is more than my 64 year old brain wants to contemplate.....I'll accept that you have successfully threaded a 17 pitch in lieu of a 1.5 mm pitch...my hat is off to you!

When I want a barrel for a mini I buy it from Douglas long chambered and pre threaded.....long chambered because I usually don't have the reamer and pre threaded because the only time I ever tried to "fudge" a metric thread it turned out so bad I tossed the barrel.

Best of luck to you!

Vapodog

Not confusing them at all. You are spot on. They are a completely different set of tolerances and control different features of the thread.

I was trying to point out how some dimensions can have an effect on other dimensions. as in how much slop you're allowed on the diameters let alone the pitch lead.

I guess I just add more crap to a crap sandwich.

Not to change the subject but you guys hijacked my thread for your personal pissin match. I just wanted some simple dimensions so that I COULD POSSIBLY USE A BARREL OUT OF MY BARREL CANISTER.

quote:

Originally posted by olcrip:
Not to change the subject but you guys hijacked my thread for your personal pissin match. I just wanted some simple dimensions so that I COULD POSSIBLY USE A BARREL OUT OF MY BARREL CANISTER.

With all due respect sir.....your question was answered with the very first post by Mr Kobe!

You forgot one

quote:

Originally posted by kcstott:
You forgot one