Was hoping to get some thoughts on this.

What would you guys consider as a reasonable minimum number of threads to be engaged on a bolt action receiver screws.

Considering a Winchester 70, I have seen/read where it has been suggested that a minimum of 3 threads is enough.

However, on a pillared stock where I am going around 50 in-lbs, I would like around 5.

Thoughts?

I’ve always understood in general the engaged threads should be the minimum depth of the bolt diameter.

consider the thread pitch...22TPI would logically mean less threads engaging than 32 TPI

quote:

Originally posted by BaxterB:
I’ve always understood in general the engaged threads should be the minimum depth of the bolt diameter.

Yes, that is the rule of thumb as they say, that the depth of thread engagement should be approximately equal to the diameter of then bolt.

So for a .25 inch dia action screw that is .25 in of engagement. As Duane points out, the Win screws are 32 TPI, so for .25 in of depth that would give 8 threads of engagement as “ideal”.


I suppose my question stems from the thought that most rifles don’t achieve this, and what the guys here felt was a reasonable minimum, in their experience.

Thanks guys!

One diameter is the usual goal, more in soft materials. But, you're not trying to hold a wing on an airplane. A few threads is probably good enough. ...don't over-torque it though.

What is the issue? Screw is not long enough? Hole is not deep enough? If it strips out, then you can always go to the next larger screw or repair it with an insert that might be a stronger material.

You all do realize that for round receivers, and many others, one thread diameter of thread engagement is impossible. Receiver rings are not that thick. Lucky to get 150 thou.
Seems to work though.