marlinguy wrote on Nov 27^th, 2017 at 11:22am:


Stevens workers with the job of assembling brl to frame didn't have to choose one--they probably had a bucket of them to choose from, so if one screw felt too loose or too tight, due to machining tolerances, they could select another.  This is the way bolts were fitted to new '03 Springfields--by trying as many as it took until one was found that achieved proper headspace.   

Redsetter wrote on Nov 27^th, 2017 at 12:21pm:


Are you suggesting Stevens intentionally made slightly different thread pitches, or threads per inch so a sloppy threaded hole could be tightened up with a slightly mismatched screw?
I've heard of firearms makers in the old days having various spaced links, or parts so they could change them out quickly during assembly to align things. But different threads or thread sizes is a new one to me.

marlinguy wrote on Nov 27^th, 2017 at 9:03pm:


"Due to machining tolerances" seems self explanatory to me.  Parts might be interchangeable, but that didn't mean they fit together perfectly, as you often find when trying to swap parts from guns made years, or maybe only months, apart.  The same thing Eli Whitney discovered when he tried to implement his "interchangeable parts" idea; turned out an "old school" assembler with a file got the work done faster & therefor cheaper.   

No doubt computer-controlled machine work has today minimized this problem, but as long as cutting tools & other machine parts still are worn down as they are used, there will have to be manufacturing tolerances.

All of the action screws seem interchangeable between receivers, why do you think this is the only screw that won't?
Tried it on my 44's, no problem.
What am I missing here? 
It seems to overcome any tolerance build-up (of which there is almost none) you just tighten the screw a little farther
Are you guys re-inventing the wheel when the problem can be solved for $10?
Aaron
ps. I know some toolmakers that will spend all day making a $5 part they can just go buy.

I guess I'll have to relearn how to use that microscope.   Dug out my Whitworth gage, and the thread does match the 30 tpi leaf.

My South Bend 10" Heavy has 30 tpi in its' gearbox.  I'd guess others do, too.

Redsetter wrote on Nov 27^th, 2017 at 10:15pm:


That all explains what I already knew. That parts on old guns were often individually fitted. But not an answer to my question on screw differences. I've never seen a screw on an old gun that wasn't interchangeable.