I know. I know. We haven't been posting. Some stuff came up that kinda pushed airgun tinkering to the back burner. Waaaaaaay back on that back burner. I'm gonna try to ease back in.
So, the, uh, Marksman 56-FTS. Right. It needed some screw cups and maybe a nice barrel shroud. Right there is part of my blogging conundrum. Speaking only for myself, I waffle about posting another blog about something so mundane as screw cups. Nick has shown how to make them. I've done the same. We hit the wall sometimes on new material. Nevertheless, its screw cups that I need so it's screw cups for the blog.
Cut off an even smaller piece.
Face one end.
See how the shank flares slightly just below the head? If the through hole is too close to the screw diameter, this can hang up and not let the base of the head seat flush.
Cut off, flipped and faced to an unshown predetermined length.
Screw cup number two ended up about .010" larger in diameter to best fit the factory counterbores.
Removed the stock from the Marksman. That screw cup goes here. Provides a metal to metal bearing surface for the stock screws to tighten against. This is helpful because it stops the screws from slowly digging through the wood.
Before I got started, I looked at some of the other existing hardware on the rifle. The cheek piece fasteners are blued steel. I'll follow suit and go the same route so it looks like this was actually planned in advance and not designed by the party committee.
Rather than try to measure directly, I grabbed some transfer punches. The graduated sizes are pretty handy for a quick reference.
Best fit was a 13/32" (decimal equivalent 0.406")
Found a scrap of .500 diameter 12L14 steel in the scrap pile.
Cut off an even smaller piece.
Face one end.
Turned down to just over 0.406'
0.408" and a couple tenths should be close enough. I'm looking for a snug fit.
Some M5 socket head cap screws.
Through drilled
Testing for clearance.
Drilling a counterbore to recess the head of the fastener.
To produce a flat bottom in the hole, I'll finish it with an end mill. Seems like I never have the diameter I want...
Just took out the drill point and made a flat bottom in the counterbore.
Test Test.
See how the shank flares slightly just below the head? If the through hole is too close to the screw diameter, this can hang up and not let the base of the head seat flush.
Rather than making the through hole larger, chamfering the top of the through hole will fix it.
Cut off, flipped and faced to an unshown predetermined length.
Screw cup #1.
Now for the second. Since I've made screw cups for various air rifles before, I know that they're not necessarily identical in diameter or depth.
Screw cup number two ended up about .010" larger in diameter to best fit the factory counterbores.
Test x 3
Blue time.
And finally, installation and the glamour shots.
Just what I wanted. Looks like they were there all along.
Next up, I'd really like a full length shroud. Like it to look like the muzzle weight, but run the full 16" barrel length. The metal is on the work bench, but I'm unsure if I can do the machining here at home or if I'll need a larger mill. More soon.
Side notes of note:
I met up with renowned air gunner and just generally good guy, "Volvo", the other day. I still re-read his blog and wish I had the style and quick wit he wrote with.
Ray, thanks for sending me an email checking in with me. It was good to hear from you
