View Full Version : Bolt thread info needed
May 9, 2011, 02:25 PM
Doing a rebuild on a savage model 342 b/a .22 hornet, made sometime from 1950 to 1955. Would like to replace the original factory slotted-head action screw with a new allen / torx head screw.
Question: Does anyone know the correct thread pitch for the action screw on this rifle ?????? Thanks for any assistance with my question.
May 9, 2011, 02:57 PM
You will likely need to use a screw check plate (available from Brownells and other distributors) to find out what pitch your action screws are. Many firearms use USS threads, others use NF, and a few use proprietary pitch screws.
May 9, 2011, 06:38 PM
Had a strong hunch a reader would say what you did. Just thought someone might know off-hand what i might need. Btw: I sent the same ????? The the guys @ brownell's gun tech.
May 9, 2011, 08:49 PM
Have you got a Fastenal dealer nearby?
Locations around Sealy are at
Take your screw in and see if they will check it for you.
Or just go through the specialty screw drawers at Lowes and see if you find a nut that it fits; then get the appropriate screw.
May 9, 2011, 08:59 PM
Planning on a visit to my friendly "ace hardware" store in sealy. They typically have a good selection of both metric, sae, nc, & nf socket head screws, in carbon steel & stainless. The store is only about 4 miles from my home.
Thanks for the assistanace with my question.
May 10, 2011, 07:23 PM
Good news to share----received a response today from one of the guys @ brownell's tech department. This model savage uses a 1/4" - 32 bolt---the same as the winchester model 70 !!!!!
Had some winchester model 70 allen head action screws in a bolt gun, removed one, & tried it in the savage model 342-----perfect fit !!! Yeee--haw.
May 10, 2011, 08:34 PM
Just make sure you use a torque wrench when using the modern screws, those torx head screws are harder than then metal of your action and you can easily strip the threads.
May 14, 2011, 05:56 PM
Went to see the folks at ace hardware in my hometown of sealy, texas. Had nothing close to what i needed. Lots of other sizes in stock, but ho joy for me. Ordered a set of winchester model 70 action screws from brownell's and will cut one to the length i need for this old savage bolt gun.
Thanks again to all the gun folks who assisted me with my question.
May 21, 2011, 04:34 AM
The obvious answer is look at the manual or hope that somebody like Brownells can tell you. But if you have the original its easy isn't it ? First mike it. Most screws are slightly under nominal diameter, so if it mikes 0.245 you know its quarter inch. Then lay it on a sheet of white paper alongside a ruler, and count how many turns in one inch. I have machined quite a few gun screws by that method, and have never needed a thread pitch gauge. But that is not deny their usefulness, they are cheap and worth having.
If you don't have the original screw, its a bit more tricky. But you rely on the balance of probability. Mike the ID of the female, which is the minor diameter. The odds are that that will tell you what the thread is likely to be. Then try a screw of that diameter and pitch to see if it fits. If it doesn't, you might have a fine pitch instead of the standard pitch. All the metric threads have both standard and fine pitches.
I fell foul of that some years back, when a thread pitch gauge would have saved me some work. A customer had lost the little striker locking screw from the bolt of his SMLE. They are not as available as they used to be, so, not being able to locate one, I set about making one.
The screw from another SMLE measured 3.60mm diameter, and my crude method of measuring the pich indicated it to be 40 TPI. When I had made the screw it would enter the female only two turns. Close examination of the factory thread revealed it to be # 4 BA, which is something like 38 TPI. BA threads are actually metric, so # 4 is not exactly 38 but very close. So I reset the lathe gears and made another screw, which thankfully fitted.
Of course, the diameter of 3.60mm should have warned me to check further. Mistakes always cost something.
May 21, 2011, 05:59 AM
Just in-case you haven't done it before.
If you have to shorten a screw, run a nut up the screw past where you need to make the cut.
Use a fine file and chamfer the threads slightly at the cut to make starting easier.
After you are finished cutting and chamfering, when you take the nut off the nut will reform the threads that were distorted by the saw blade ;)
May 21, 2011, 07:30 AM
Muchas gracias amigos----thanks for the great info regarding the care & feeding of screw threads. Your suggestions have been beneficial.
I used the shortest of the three model 70 action screws i received from brownell's & it was a perfect fit in the old savage 342 b/a.
May 21, 2011, 09:07 AM
I love it when a plan comes together!
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