Scope mounts

[GregLaROCHE]

Has anyone machined scope mounts? Any advice?
Thanks

[Nobade]

Yes. Don't do it unless you have to.

[country gent]

If you can the first step is an 1/8" hole thru on center line and a measured distance from back edge. This is the xo-y0 and used to recatch the block / base when flipping over or setting up again. If you have to leave the blocks base long on one end for this hole. It can be cut off after the base blocks are done. After this all details are machined from center line. Working in a vise use thicker stock so the parts can be machined on 5 sides complete (top sides and ends), then cut off and finish bottom. This saves a lot of set ups. Better is a fixture bar to bolt the base to it on the finished bottom then machine the top.

Once you have it thought out and have your means of locating and re locating the bases it becomes much easier. A set of angle cutters is a big plus. I have a form cutter ground up that cuts the weaver / Picatiny 90 vee in one pass with the bottom relief space. This makes it easier but it can be done with 2 45* cutters.

The big thing is once you start a surface dont break the set-up down until its all done. Have the machine trammed in and vise squared as close as you can .001 is good .0005 or closer is better.

Tooling:
a good set of parallels
various end mills
45 degree cutters both a vee and single and dove tail cutter
a good indicator finger style .0005
drills and counterbore.

If you want to put some elevation in the base then a fixture par is best as it can be set to the amount and the bases machined to this. You can set the fixture bar at the desired angle by indicating this in over the length. Here remember you are working in Minutes of a degree IE 20 mins is a 3rd of a degree. The amount of measured angle is small.

[Cap'n Morgan]

Unless you have access to a CNC mill, it's really not worth the bother. But if you insist, the easiest way is to skip the picatinny bases and have the lower part of the mount sit directly on the action. That way you can make the mount as a single part on a manual mill, drill & tap the mount and then use a slit mill to separate the parts.

I have made an awful lot of this type of mounts for various old 22LR rifles (from a time before bases and threads weren't incorporated in the design), but also made several where I wanted the scope to just clear the barrel or to have a cantilever design for getting the correct eye relief on the odd rifle. This picture show a Mauser 98 with aluminum mounts painted with a coat of matte black.

[405grain]

Cap'n Morgan: That's an unusual low scope safety. Is it an aftermarket item or home made? I have made some scope mounts. It's a choir. Unless you have access to a milling machine and some decent tooling I would recommend against it.

[Cap'n Morgan]

Cap'n Morgan: That's an unusual low scope safety. Is it an aftermarket item or home made? I have made some scope mounts. It's a choir. Unless you have access to a milling machine and some decent tooling I would recommend against it.

To be honest, I can't remember making that safety, but it's clearly a homemade design. The rifle is a converted 6.5x55 target rifle based on the large number of German Mausers left here when the war ended. You can still see the holes where the rear aperture was attached. At first, only barrels and stock was replaced and target sights installed. Later on an excellent two-stage trigger was added. The work was done by the Schulz & Larsen factory (their rifling machines from 1910 are still producing target barrels for Scandinavian shooters)

[Nobade]

Even better than a CNC milling machine is a wire EDM. Years ago I had to make several sets of custom mounts like that for some F class shooters back when that sport was just getting started. They wanted built in cant for long range, and there wasn't anything like that available yet so we made them out of thick plate on an EDM, with the cant built in so there wouldn't be any stress on the scope tube when they were installed. Basically really fancy Tally style mounts. It worked great but now that pic rails are available and canted rings are common there's no reason to do that any more.