No4 Problem

[Calif-Steve]

My nice No4 has a problem with the rear guard screw. The screw hole is stripped out, not smooth but the screw does not bite at all. Any ideas? I have looked around for British issue oversize screws, but no luck. Any other ideas? Thanks all.

[ssgross]

usually its the screw that strips, as the hole is supposed to be harder material than the screw, but I'm not doubting your problem. Just something you may want to confirm if you haven't already.
I'm sure there is a member here that will turn you out an oversize screw if needed. If you have a set of index pins, you'll want to gauge the actual id of the receiver hole to determine the dimensions of your replacement screw. Will also tell you if you just need a new standard screw. Individual index pins are about 1.99-5.99 on amazon, 2 inches long.

I just had a similar problem on the Parker hale 5B I just found. Too many people before used the standard length screw on it, which only engages 1 or 2 threads, which reams out the hole in the sight with even the slightest tightening. I have no lathe (yet, still), so I used 0.1 index pin (amazon 2.99), annealed it, cut it to length, lightly polished off a few thous on both ends so as to thread to thread the needed 3-56. My die was adjustable so I could make one end a bit oversize. On that end I threaded on a 3-56 nut with permanent red loctite, filed the top and edges to shape and then slotted it. After chasing the hole with a tap, that almost unobtainium PH5B pulls tight against the receiver with no issues. If you can't have your screw made on a lathe, you can perhaps go this route although I would silver solder the head on instead since you need to put more torque on it than my sight axis screw.

[Alan de Enfield]

My nice No4 has a problem with the rear guard screw

Do you mean the rear trigger guard screw ?

If so it is a 4BA thread, readily available from hobby/model shops and commonly used on making model steam engines

[Peter Laidler]

As a matter of interest, the body of the No4 rifle is a tough material - but only marginally tougher than mild steel! There are only two hardened spots. The bolt locking cams.

Simple problem to solve. Just over bore the hole, insert a steel insert, silver solder in place, drill and re-tap and send over to the phosphating bay!

[Surpmil]

If you want save a bit of trouble and can find a 4BA nut deep enough, you could just cut the head off a screw if the shank is long enough, and chuck that in your drill, spin the nut on and file it down to the size of round you need to fit the hole you drill.

And if you want to be super clever and have a suitable small reamer with a long taper, you could ream that hole you drill out and then shape your threaded sleeve (ex-nut) to suit the taper, then it will never pull out when you tighten the screw.

[Peter Laidler]

The problem, if it is a problem as such, is that the little 4BA screw thread is bored through the outside part which is at a slight angle. To insert the insert, the rifle needs to be set up on the engraving jig and the hole over=bored with an end mill.

Then send it over to the phosphating and painting bay! We did hundreds of them. No8's No5's No4's