Started with a piece of 0.750" OD DOM steel tube. The ID was 0.606" and a close fit to the barrel. Chucked in the lathe and faced one end.
With the compound set by eyeball, a shallow taper was cut to the breech end. The taper allows for clearance while cocking to insure there's no contact with the wood stock. Could've done a more abrupt bevel, but to me, this is better looking.
Better pic of the taper. Click any pic to enlarge.
With the taper done, I cut the piece just shy of finished length with a hacksaw and came back to the lathe and squared up the end.
Then, over to the mill in a collet block. Scratched two lines to denote the length and location of the tunnel front sight and I was ready. Oh yeah, I set the table stops to stay inside the lines.
Started milling out a slot for the sight.
Test fitting consisted of attempting to fit the front sight into the hole. Once I could see the dovetails on the ID, I dialed down a couple more thousandths and called it good. A quick test fit on the gun (collet block still in place) showed that the front sight would clamp to the dovetail. Now it just needs some set screws for mounting.
Without removing the sleeve from the collet, I turned it over in the vise and found center with a very simple center finder. Chuck, then lower the indicator until the V is against the work. Adjust lateral position until the marks on the indicator line up.
These work great for quickly locating the center of round stock in a mill or drill press. Not as accurate as a "real" edge finder or wiggler, but for non-critical work this is absolutely ideal.
Not removing the work from the collet block also ensured that the set screw holes would be dead opposite from the milled slot. Did the usual spot and drill, repeat two more times.
Tapped these by hand. Faster than using a machine set up and more than precise enough to hold a tube to a barrel. Tapped M4 x 0.7mm.
Needs a finish.
Sanded it in the lathe to 500 grit. then finished by hand with oiled emery cloth.
The slurry gave it a matte finish.
Looks like dull hard chrome. Almost a raw titanium color.
Three coats of Van's Cold Blue followed by 0000 steel wool had it looking like an integral part of the HW.
Clean fit with the sight.
Could've tweaked the length another 0.010" but it's fine--and better than too short.
The sleeve adds 11.3 oz. and doesn't look like an afterthought to the lines of the gun.
Should be back to work on the Patriot in a few more days. Thanks for reading.