How to install new machined rear sight on P58?

[Maillemaker]

So being dissatisfied with the cast sight on the Pedersoli P58 that did not have enough spring tension to keep the sight leaf/ladder held down in the full-down position, I bought a machined 1100-yard sight from S&S.

The P58 sight is screwed to the barrel. The screw that holds the leaf spring in place passes through the sight and into the barrel.

The S&S machined sight screw will not do that - it is not long enough to pass through the sight base into the barrel.

I thought I might use the screw from the original P58 sight and use it with the new sight, but the new sight is about .125" thick whereas the old sight was .09" thick, so the screw won't be long enough.

My first thought is to go to Home Depot and find the correct size screw thread screw, chuck it up in my drill press and take a file to the head until I machine the head down to the correct diameter, then trim the screw to length. Then I'll drill out the tapped hole in the new machined sight and screw it to the barrel just like the original cast sight was.

But I'm wondering about soldering it to the barrel.

Both the bottom of the machined sight and the barrel where the sight goes are blued. Should I remove the bluing before soldering?

What sort of solder should I use? I've heard "silver solder". Can I get that at Home Depot/Lowes?

How does one go about it? Clamp the sight in place and then heat it up with a torch until the solder melts?

Thanks in advance,

Steve

[Ron/The Old Reb]

You want to use silver solder and you can get it at Lowe's. But silver soldering is a little tricky. I would go with the screw.

[Maillemaker]

Can you silver-solder against bluing or should the bluing be removed where the soldering is going to take place?

I would assume you want to solder against bare metal with flux?

Steve

[Rebel Dave]

Rough up the area under the sight with some 400 grit sandpaper, just under the sight so as not to see it when thru soldering. Rough up under side of sight. Take new sight apart so you are just working with the base. level bbl in vise with old sight on, to use as a reference point. Then remove old sight. You might have to find some thing to hold the sight in place (which is the real tricky part, as you don't want the sight to move at all), as the torch will blow it off. A 3in "C" clamp should work. I have a little jig that I made. You want to keep most of the flame on the sight base. USE PASTE FLUX under sight base. You will know when solder is "taking" as it will flow to under side of sight base. You can usually solder from the inside of the base. The flux will remove bluing, so you will have to touch up with some bluing agent when done.

I hope this helps some, I'm in the middle of casting bullets.

Rebel Dave

[Blair]

Steve,

Just a suggestion on my part...
Forget the solder! High temp, low temp, what ever.
Go with the screw attachment, if everything lines up correctly.
The choice is yours.
My best,
Blair

[Maillemaker]

Well, I went to Home Depot today, but I could not determine the thread size of the sight screw.

Does anyone know what the thread size is for the rear sight screw on a Euroarms/Pedersoli P58?

I also bought solder and paste but I'm going to go with the screw if I can find what size the thread is.

I figured it would be metric but it was neither M3 nor M4. It kinda wanted to be a #6-32 but wasn't.

Steve

[Eggman]

Assuming Home Depot has the same, Lowes has a "screw checker" hanging somewhere that you can take a screw you're trying to duplicate, turn it into the proper hole, and then find out what you need to buy. If there isn't one, just keep pulling nuts out of the nut drawers until you find the one that matches your screw, note the size, and then buy the corresponding screw. I went throuhg this process to replace the notorious clean out screw on the Smith. I matched that little bugger's thread size and then trimmed it off to fit the hole. The end will erode some but I still have at least half a dozen threads holding it it place. The only thing, these metric screws only come with phillips heads. I inquired on this forum if that was an isssue and no one here seemed to care. I guess folks feel that not drilling the guy next to you with a 17 caliber screw was more important than an authentic screw head.

[Muley Gil]

It is probably a "gunsmithing only" thread. Check with Brownells. They should also have the correct bottom tap.

www.brownells.com (http://www.brownells.com)

[Maillemaker]

Assuming Home Depot has the same, Lowes has a "screw checker" hanging somewhere that you can take a screw you're trying to duplicate, turn it into the proper hole, and then find out what you need to buy. If there isn't one, just keep pulling nuts out of the nut drawers until you find the one that matches your screw, note the size, and then buy the corresponding screw. I went throuhg this process to replace the notorious clean out screw on the Smith. I matched that little bugger's thread size and then trimmed it off to fit the hole. The end will erode some but I still have at least half a dozen threads holding it it place. The only thing, these metric screws only come with phillips heads. I inquired on this forum if that was an isssue and no one here seemed to care. I guess folks feel that not drilling the guy next to you with a 17 caliber screw was more important than an authentic screw head.

I tried the various screw checkers. It's not M3 (too small) and it's not M4 (too big). Nor was it English.

It's possible it's an oddball size. Easy to get through McMaster. I have emailed Pedersoli and posted on their facebook page to see if they can tell me the screw size.

Since I'm assuming it's the same as Euroarms has always been, I was surprised I could not turn up a size from a google search for "Euroarms rear sight screw thread size".

Steve

[Blair]

Steve,

Which screw, and from which sight Base are you trying to get your measurements?

I can tell you the thread dimensions on a Euroarms three bander I have... based on American Standard thread and dia. How that relates to metric, I have no way of telling you.
I would have to assume Pedersoli uses the same metric threads that Euroarms used

However, the new machined sight you have has the threads in the base of the sight. You need a screw that in not only longer, but you may have to drill out those threads so that the screw will thread into the barrel, not the base of the new sight.
I don't know if I am making myself clear... but you need to tell us which screw you are trying to get to fit into which barrel threads.
I hope this helps.
My best,
Blair

[Maillemaker]

Yes, the new machined sight screws the sight leaf spring into the sight base and no deeper, as I said. It is designed to be soldered to the barrel.

So if I want to screw it to the barrel I will of course have to drill out the threads in the machined sight base.

What I need to know is what size are the threads for the Euroarms/Pedersoli P58 rear sight screw. I'd expect the 2-band and 3-band to be the same, but I don't know.

Steve

[Blair]

Steve,

Here you go for a Euroarms "Enfield" Rifle Musket,
(all US measurements)

TPI=42
OD=.130"
Screw shaft length= .190"
Screw Head dia.=.180"
Hope this helps.
My best,
Blair

[Maillemaker]

Sounds like it might be an M3.5 x 0.7 screw.

3.5mm = .138 inches
.7mm = .028 inches pitch = ~36 threads per inch

Steve

[R. McAuley 3014V]

Don't guess it would do any good to suggest you use the ribbon (silver) solder rather than the wire type, uh? Brownells sells both, and the Silvaloy 355 works great and has the lowest flow temperature of any cadmium-free commercial high-silver content silver solder available, but go ahead and poison yourself with the cheap stuff if you like. Not my lungs! Yours. But yes, the two surfaces must be "prep'd" to receive the solder, and Rebel Dave has provided most of the steps involved. If you follow Blair's advice and just screw-anchor the rear sight in-place, you may want to use some Super-Glue to hold it in the same place unless it mates perfectly with the surface of your barrel and has no high spots or uneven surfaces, and the sight base doesn't wiggle to the side like some do. All I can add is "Good luck".

[Rebel Dave]

Steve

If you are going to solder, or screw the sight base to the bbl, do this. Take a piece of sand paper (again 400 grit), and wrap it tight around the bbl, at the point where sight will be, then run the sight back and forth across the sandpaper, till it the underside of the base is all cleaned up. This will get rid of the imperfections on the under side of the sight base, and form it to the bbl. Hope this helps

Rebel Dave

[Maillemaker]

I ended up measuring the screw and determined that it was an M3.5 screw. I ordered some from McMaster-Carr and have screwed the new machined sight to the barrel just as the cast one was. Unfortunately the only screw I could get was stainless steel, so it is shiny instead of black, but that's OK.

Steve

[John Harkness]

The rear sight on my antique P58 ("bayonet bar on band" model) Enfield Rifle was originally soft-soldered to the barrel. The screw in the leaf spring only held the spring to the sight base & did not pass through the sight base to engage a threaded hole in the barrel. I had a target barrel made for the P58 about 1968 & soft-soldered a replacement antique Enfield rear sight to it. Barrel was "in the white" and I emery-papered the underside of the antique sight to bright, also lightly cleaning the whole sight as bright as I could. I "tinned" the sight underside with a thin, continuous coating of lead-tin solder (the historically correct joining material), then applied flux, clamped the "tinned" sight to the barrel & re-flowed the solder layer with a small gas torch flame applied just to the sight base. Only took a few minutes. Sighted barrel was then degreased & rust-browned. I shot that P56 some 10-12 THOUSAND rounds in N-SSA meets and the sight stuck fast ... it is still firmly in place almost 50 years later.