5/8 X 24 Tenon

[DaveTooley]

I lean towards the loose side. Loose threads mean the shoulders can square up before tightening. I've done I don't know how many hundreds of gas gun barrels where I time the gas port to fall in the groove. Some good extensions and some not so good extensions. The loose threads, 2A, made the rotation of the extension predictable. YMMV

 

[VA_XTC_Shooter]

I lean towards the loose side. Loose threads mean the shoulders can square up before tightening. I've done I don't know how many hundreds of gas gun barrels where I time the gas port to fall in the groove. Some good extensions and some not so good extensions. The loose threads, 2A, made the rotation of the extension predictable. YMMV

When would you, if ever, want 3A/3B threads on a rifle?

 

[DaveTooley]

When I'm talking shop with the unenlightened I use these words.
Parallel, perpendicular, concentric and stress free. Meaning every part has its own natural resting place. Let it find that spot, don't try to engineer/machine into a place it doesn't like. Makes things much easier to trouble shoot. Again YMMV

 

[Jonnyofalltrades]

Pitch diameter is the critical measurement. Major diameter of external thread has a mile of allowance vs pitch dia. Invest in a set of thread micrometers.

What can a thread mic do that wires can't do for a tiny fraction of the cost, with way more versatility?
Call me weird, but I prefer using wires. I don't find them awkward at all.
Must be all those extra thumbs of mine, finally being useful....

 

[ELR LVR]

What can a thread mic do that wires can't do for a tiny fraction of the cost, with way more versatility?
Call me weird, but I prefer using wires. I don't find them awkward at all.
Must be all those extra thumbs of mine, finally being useful....

When I was taught to use the 3 wire method...it felt like I needed 3 hands, 4 would be better lol
There's def a technique to it
Using mic's is just quick and easy peasy and can easily be done with the barrel set up in the lathe and keep checking as often as one likes.
I would not want to have to keep 3 wiring while the barrel is still setup on the lathe and the awkward positions one must have to get in to do so when I can simply grab the Mic's real quick and sneak up on the measurement a couple tenths at a time.
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You still need a micrometer of some sort going down to 0.0001" even to use the 3 wire method right?
So why not just use 1 tool instead of 4?
They're only $70

 

[DR_2297]

What ELR said…

 

[Fast14riot]

When I was taught to use the 3 wire method...it felt like I needed 3 hands, 4 would be better lol
There's def a technique to it
Using mic's is just quick and easy peasy and can easily be done with the barrel set up in the lathe and keep checking as often as one likes.
I would not want to have to keep 3 wiring while the barrel is still setup on the lathe and the awkward positions one must have to get in to do so when I can simply grab the Mic's real quick and sneak up on the measurement a couple tenths at a time.
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You still need a micrometer of some sort going down to 0.0001" even to use the 3 wire method right?
So why not just use 1 tool instead of 4?
They're only $70

Lol, a small dab of grease holds wires in place pretty good

 

[ELR LVR]

Lol, a small dab of grease holds wires in place pretty good

I bet it does
But there's been recent advancements in technology
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But then again some guys are so stubborn they stick to Old School methods and won't hop on board
(Even if a new better way is more faster and more efficient, time = money for some of us.
Saving time, is a no brainer in business)
But then again I'm one of them stubborn Old School Types in certain ways too, so I get it
I mean like a DRO?
They're really neato and all that
But I will never buy one for myself, I trust my manual dials.
I have 2 digital mitutoyo calipers, hardly ever use them because I trust my B&S dial calipers more

 

[LVLAaron]

I stick'em in a a little piece of Styrofoam.

 

[ELR LVR]

I stick'em in a a little piece of Styrofoam.

Ummm, I think he meant grease allows the wires to stick to the threads.

But Styrofoam is a good way to store them

 

[AccelR8]

Another good reference:

Unified Screw Threads, Standard Series

www.efunda.com

 

[DR_2297]

A long time ago in a job shop far away I was a young engineer who was tasked with running jobs when slow on design work. One day I was running a job that had me cutting threads on the old LeBlond lathe. I didn’t have any tools since I was the resident engineer and machining wasn’t my primary job so I wandered up to one of the journeyman machinists and asked for a micrometer and set of wires and the conversation was very frank… Time is money and you don’t have time to be dicking with wires, here is a set of thread mics… it has stuck with me ever since and while I own a set of wires I have not used them in years. I do have a couple of sets of thread mics that I use for every thread I cut.

 

[ELR LVR]

A long time ago in a job shop far away I was a young engineer who was tasked with running jobs when slow on design work. One day I was running a job that had me cutting threads on the old LeBlond lathe. I didn’t have any tools since I was the resident engineer and machining wasn’t my primary job so I wandered up to one of the journeyman machinists and asked for a micrometer and set of wires and the conversation was very frank… Time is money and you don’t have time to be dicking with wires, here is a set of thread mics… it has stuck with me ever since and while I own a set of wires I have not used them in years. I do have a couple of sets of thread mics that I use for every thread I cut.

Sound advice

 

[WSnyder]

and while I own a set of wires I have not used them in years.

Same, I have a brand new set of Pee-Dee wires from Fisher machine that have never been used. They've sat in the drawer probably 10 or more years where the thread mic's are used often

 

[SKWERLZ]

this is a nice to have

Thanks for that

 

[SKWERLZ]

Precisely!
And some Hardcore Machinists may dog this but I have a set of Shars thread pitch mic's
0.0001" resolution
I try to avoid cheap/china if possible but bought them in a pinch and was planning to upgrade later
Although, I have to say I was very impressed for their price, so impressed I see no need to upgrade yet
However this is the only Shars item I own so cannot comment on any of their other products...
The thimble threads are smooth as silk like a Mitutoyo, with no play, tight, rough spots
Came with all necessary anvils for different pitch threads

Thread pitch mics and full profile inserts made getting threads right easy for me.