Mounting a Williams peep sight on a Rossi 92

T

Thumbcocker

Active Member
I have the proper sight to mount on this rifle. I have a drill press and am thinking I can probably drill and tap the necessary holes. A couple of questions:

Is there any place on the receiver to avoid? I'm thinking I need to avoid the locking bolt channels.

Should the holes be drilled all the way through? Doesn't seem like it would hurt anything since the factory drilled several holes through it. I figure I may have to smooth off some burrs on the inside. If it requires blind holes i will have to outsource.

Any advice on what type of bit to use? I'm willing to spring for a good bit .
 
JWinAZ

JWinAZ

Active Member
I have drilled and tapped a Marlin 1894 to take a Williams that mounts to the top of the receiver. The steel was pretty soft and easy to drill and tap. After center drilling, I used a short screw machine drill, fast twist, cobalt, split point. For the tapping I used a Reif & Nestor tap from Brownells.
 
P

Petrol & Powder

Well-Known Member
I'm sure the machinists on this forum will chime in but I’ve done similar work in the past and it’s pretty straight forward.

I assume that because you’re dealing with a Rossi 92 and Williams sight that you will be drilling the left side of the receiver. Once you determine where the sight needs to go and where the holes will be, you’ll have a good idea of the parts (if any) behind those locations. Obviously, you want to avoid other screws and critical parts but that should be easy. A through hole is not a problem if you can reach the back side to de-burr.

I can recommend a cobalt drill bit, but any good bit will do if it is sharp, and you use some cutting oil. Take your time to fixture the receiver properly as that is most of the job. I have generally not been impressed with the “titanium” coated bits sold in most big box stores.

Select the drill bit according the tap you will be using. Center punch the locations to be drilled and don’t force the bit.

When taping the holes, TAKE YOUR TIME and use a quality tap. Clear the chips frequently, use oil, don’t get aggressive. Those are small taps and breaking one off in the hole is not fun.
 
J

Jeff H

NW Ohio
Thumbcocker said:
I have the proper sight to mount on this rifle. I have a drill press and am thinking I can probably drill and tap the necessary holes. A couple of questions:

Is there any place on the receiver to avoid? I'm thinking I need to avoid the locking bolt channels.

Should the holes be drilled all the way through? Doesn't seem like it would hurt anything since the factory drilled several holes through it. I figure I may have to smooth off some burrs on the inside. If it requires blind holes i will have to outsource.

Any advice on what type of bit to use? I'm willing to spring for a good bit .
Click to expand...

I did mine several years ago and it was a snap - nothing like the case-hardened Mausers.

I located the sight so that the horizontal part of the beam lay across the section of the receiver where the locking lugs run up and down. If I remember correctly I found that one of the holes was ok as a through-hole but one was better as a blind hole, and the blind hole may have been the screw over the locking lug race, the one behind the beam.

I used a Williams sight for a Remington 760 and flattened the back to match the receiver.

The receiver is relatively "soft," meaning no need for a carbide drill to break the case,like on a Mauser.

Spot the first hole, drill, tap, attach the base.

Then, spot the second hole with a drill as large as the clearance hole in the base.

Remove the sight, drill, tap and you're in business.

I use RTV to "glue" the sight onto the receiver to check alignment, position, square/level, etc. and spot that first hole with a drill the size of the hole in the base. JUST SPOT THE HOLE WITH THAT DRILL. It's too big for the threads required, but the hole in the sight base serves as a drilling guide to spot the holes.
 
J

Jeff H

NW Ohio
Petrol & Powder said:
....

When taping the holes, TAKE YOUR TIME and use a quality tap. Clear the chips frequently, use oil, don’t get aggressive. Those are small taps and breaking one off in the hole is not fun.
Click to expand...

YES! My dad was a tool & die maker for 40+ years and about the only thing he taught me was "setup is EVERYTHING." It may take two hours to set up to drill one hole, but that one hole will be there forever (unless you know a good welder and get it reblued cheap).

One other thing he imparted upon me was to never run a tapered tap all the way through a hole. Stop JUST short and leave a teensy bit of taper on the exit side of the hole. Your screws won't wobble that way. Not all drills/taps are made to the exacting specifications as those sourced by toolrooms, so find a drill/tap chart and note that smaller drills will leave you with more thread engagement and larger will be looser. A selection of fractional, number and letter drills can be handy - as long as you have a micrometer to check them. Doesn't hurt to drill/tap a piece of scrap steel first to see how the fit comes out for you.
 
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