Barrel Threads--Tight or Loose?

[Dgd6mm]

Well I'm just a dumb ole fart we have threaded a lot of barrels over the year's using this set-up.

What, a purple stool?

 

[Stan Taylor]

What, a purple stool?

Dag gone it was free.

 

[hoz53]

Thread classes of fit are standards.
Threading to fit a part in hand is creating your own class of fit. Itll work, but no promises that itll fit the next action that was threaded to a standard class fit.
Say you thread a bbl for your own action, to a "perfect" fit..and choose to sell it. Because action makers are doing an excellent job at being consistent, it just might work but there are no guarantees. That's what standards are for. If the Male and female are properly threaded to a particular class of fit standard, you can guarentee fit.
BAT and Kelbly, for example give a more precise spec that is pretty much in the middle (iirc) of a class 2.

This is a great app for your phone or computer.
http://theoreticalmachinist.com/Threads_UnifiedImperial.aspx

Kelblys print calls for 1.071 pitch diameter +0.000/.002...over.032 wires.
That's a proper print.

BAt says 1.023 pitch diameter. The main difference is that BAT does not state tolerances. This is an example of an incomplete print.Everything has tolerances.

Thanks for that Mike— I don’t think I’ll be selling any barrels I thread- never know—. I’d like to know this though so I’ll start measuring them. I have a machinery’s handbook to. Ill look at it a little more.

 

[hoz53]

I use wires. Every action I have worked on I have specs for, and tenon diameter and wire measurements are included, as well as where to mark the barrel for caliber. Never need that action again to do a barrel.

A thread mic would certainly be faster than wires, but it's what I started with.

Sounds like a good way to do it—thanks

 

[gunsandgunsmithing]

Sounds like a good way to do it—thanks

I just prefer mics over twiddling with wires but the mic can be tough to get the female anvil on the Crest of a very fine thread. I use magnifiers for the finer threads. Helps a lot. I can see this as a reason for using wires at times. Either will work

 

[hoz53]

I just prefer mics over twiddling with wires but the mic can be tough to get the female anvil on the Crest of a very fine thread. I use magnifiers for the finer threads. Helps a lot. I can see this as a reason for using wires at times. Either will work

Ok- the way my eyes are these days I need some of those magnifiers

 

[338 Mollett]

Untrained fool here ,Half way to screwing on an action I like to feel about an 1/8 wiggle what ever fit measures out to be.

 

[Shawnba67]

Ok Thanks, I will work on that

Once you have a thread micrometer you can also check your threads for taper, how many spring cut passes are enough?? 1" stock is surprisingly springy!!
You can also check the work of others, I bought a handful of take off barrels partly to rechamber to something fun cost effectively partly to measure the work of good smiths!

 

[hoz53]

Once you have a thread micrometer you can also check your threads for taper, how many spring cut passes are enough?? 1" stock is surprisingly springy!!
You can also check the work of others, I bought a handful of take off barrels partly to rechamber to something fun cost effectively partly to measure the work of good smiths!

Those are good ideas Thanks. Gotta decide which ones I’ll get but it won’t be long.

 

[Dusty Stevens]

Youre welcome

 

[338 Mollett]

^ Now we're talkin !

 

[gunsandgunsmithing]

^ Now we're talkin !

Yes, I've got the same set and they are fine for the purpose. Frankly, its different than measuring with a standard micrometer and thread mics are more dependent on the user's "feel" than the tools absolute accuracy. These dont read in tenths but no need, in their application.

 

[Will Henry]

For comparative purposes, any tool which will measure on the slope of the thread will work just fine; even calipers will work well. For absolute measurement, I like wires just fine. WH

 

[Dusty Stevens]

Yes, I've got the same set and they are fine for the purpose. Frankly, its different than measuring with a standard micrometer and thread mics are more dependent on the user's "feel" than the tools absolute accuracy. These dont read in tenths but no need, in their application.

They do measure in tenths. If you look close you can see it on the barrel. No need to measure in tenths but it tells you if youre on the high or low end of a thou.

 

[hoz53]

Yes, I've got the same set and they are fine for the purpose. Frankly, its different than measuring with a standard micrometer and thread mics are more dependent on the user's "feel" than the tools absolute accuracy. These dont read in tenths but no need, in their application.

I wondered how good those were as they are so much cheaper than some of the others- there are times comparing is what I’m looking for and other times I want it to match the print/spec dimension. thanks

 

[ridgeway]

Youre welcome
[/QUOTE
I got the same set Dusty. They collect dust, lol. I still prefer wires and ring gauges...]

 

[DaveTooley]

I wondered how good those were as they are so much cheaper than some of the others- there are times comparing is what I’m looking for and other times I want it to match the print/spec dimension. thanks

For the most part expensive or cheap they all work equally well for awhile. You're paying for quality construction which means longevity. Hitting a tread spec is like shooting at a car hood. It ain't hard to do.

 

[gunsandgunsmithing]

They do measure in tenths. If you look close you can see it on the barrel. No need to measure in tenths but it tells you if youre on the high or low end of a thou.

Mine don't. But you can do as you said and guesstimate at what fraction of a thou you're at. I bet itd be tough getting consistent measures in tenths with them.

 

[gunsandgunsmithing]

For the most part expensive or cheap they all work equally well for awhile. You're paying for quality construction which means longevity. Hitting a tread spec is like shooting at a car hood. It ain't hard to do.

That's how I look at it as well, Dave.

 

[DaveTooley]

Tenths on threads would require grinding not turning. Tenths on anything we do is gilding the lily.