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Large shank Savage pitch diameters

Doug Beach

Silver $$ Contributor
For those of you who measure such things, what range of barrel pitch diameters do you end up with on the large shank (~1.125”) Savages?
I know what they “should” be, I’m curious what you actually find.
Thanks.
 
Umm, that's major dia.
PD or pitch diameter will be less, and am trying to do a s.w.a.g. guess at a 20 tpi class 2. I'm thinking maybe .004 or so thou tolerance, high to low PD.
Anyone have a Handbook handy before I Goog it?
 
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The last three I’ve done have all fit up nicely at 1.133, measured over .029 wires. I was wondering what others had found, are they largely consistent?
 
Doug Beach said:
The last three I’ve done have all fit up nicely at 1.133, measured over .029 wires. I was wondering what others had found, are they largely consistent?
Click to expand...

I'd be careful with that size. That's 7 tenths over the max 3A spec and over 0.029 wires gives a pitch diameter of 1.0882. A 3B receiver thread could be as small as 1.0875 and still be in spec. That would be a gall waiting to happen.
 
The Savage barrel thread spec: 1-1/8-20UN-3A, PD limits 1.089-1.091, Max dia. under the locknut 1.115. This info from the Savage spec sheet.

RWO
 
That .0035" off the crest per side is less than a phardt in a whirlwind. The crest adds nothing to thread strength.
Knocking a couple of thou off with 240 grit for the wire edge, when finished, meh.
Now Acme or buttress thread, a different story but you still don't want extreme minimal clearance at the root. No room for dirt, trash or swarf that will bind things up.
 
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TAJ45 said:
That .0035" off the crest perp side is less than a phardt in a whirlwind. The crest adds nothing to thread strength.
Knocking a couple of thou off with 240 grit for the wire edge, when finished, meh.
Now Acme or buttress thread, a different story but you still don't want extreme minimal clearance at the root. No room for dirt, trash or swarf that will bind things up.
Click to expand...
All very very true, but its still a 1.062 thread and not a 1.055. As seen in above posts that affects proper pitch diameter.
 
Shawnba67 said:
All very very true, but its still a 1.062 thread and not a 1.055. As seen in above posts that affects proper pitch diameter.
Click to expand...

Hmmm, not really. The Major Dia is the o.d.
The wires make contact WITHIN the vee. The wires are not affected by the crest height.

Yes, engagement will suffer if you end up with very flat topped threads. .125 x pitch is book on crest width.
Consider this: 1/4-20 2A bolt Maj Dia runs down to .2419. Your 1.055 squeaks in. ;)
One thing I finally realized into my apprenticeship is that a 20 tpi/pitch has .050 from crest to crest, the depth to the thread root is the same, No Matter the Diameter..... all 20 pitch threads have the same basic numbers whether wrapped around the quarter 20 or a telephone pole.
Overall dia needs to be added, of course, but, the pd tolerance for a class 2A 20 tpi will vary but .0037.
 
TAJ45 said:
Hmmm, not really. The Major Dia is the o.d.
The wires make contact WITHIN the vee. The wires are not affected by the crest height.

Yes, engagement will suffer if you end up with very flat topped threads. .125 x pitch is book on crest width.
Consider this: 1/4-20 2A bolt Maj Dia runs down to .2419. Your 1.055 squeaks in. ;)
One thing I finally realized into my apprenticeship is that a 20 tpi/pitch has .050 from crest to crest, the depth to the thread root is the same, No Matter the Diameter..... all 20 pitch threads have the same basic numbers whether wrapped around the quarter 20 or a telephone pole.
Overall dia needs to be added, of course, but, the pd tolerance for a class 2A 20 tpi will vary but .0037.
Click to expand...
I mis spoke.
I meant the calculation of proper pitch diameter. Its just a peave of mine. Calling it 1.055 seems like mis-information to me. Even if it is the nominal max diamter.
Plug 1.055 into the theoretical calc and cut it to big side of pitch dia for it and you still wont get a fit youll like.
Guess how I know!!
 
It would be nice to know what spec Savage actually claims to use. It would be odd to call out a pitch diameter based on one nominal OD but then specify that the actual OD be different.
 
Pitch diameter is specific for a give spec'd thread. It doesn't change. Henry Ford figured that out. You could turn the tenon .020" undersize and the pitch diameter doesn't change. I once had a custom action that had treads cut with an insert with a broken tip. No good.
 
So then, what is a good OD to turn the tennon too? Would 1.058" work then change tooling to thread insert and get after it?
Curious to know what's the OD max prior tonthreading for you guys.
Thanks
 
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