Saturday, January 12, 2013

Walther Sight Cover Plate

Nick and I are now at 650 rambling airgun posts and counting. Yeeeow!

I need a cover plate for the Walther LG55 target rifle formerly owned by Volvo.  Apologies, as I've blogged cover plates for various rifles before and they're always pretty much the same.   With all the various airguns in the pile, there are a multitude of small projects like this--and right now, this one is calling.

Look at the gaping holes on top of the base block probably made for some field sight that I don't have and likely never will.  This rifle is set up with a target aperture at the end of the spring tube and there's really no place for an open notch sight on this kind of gun.  Has anyone even seen such a sight for a 55?  There's even a counterbored hole for a pin to resist recoil.   Yeah, Walther goes all in.  However, the holes for this nonexistent mid-ship sight are tapped M4 x 0.5mm.  This is not the normal 4mm pitch--which is 0.7mm.  I looked pretty hard and couldn't find any M4 x 0.5 screws in the US.  It was easy to find both taps and dies, but the actual fasteners?  Nope.  None.  Of course, in my haste, I'd already cut the plate, squared the sides and done the layout before realizing this.  So, the plate sat on the bench.

Finally, I went through my box of airgun pieces parts.  There, I found some extra grip screws for a Weihrauch HW45/Beeman P1 in the correct pitch.  Maybe this fastener is common in Europe.  The project was back on track.

Try to keep this short.  0.500" wide cold rolled piece of steel.  It's 0.125" thick.  Cut to length, did some layout for the mounting hole locations and started drilling through holes.  Used a #25 bit. 

Couldn't find a suitable endmill to counterbore for the screw heads, so I had to make a suitable cutter from a reground drill bit.  Had to cut it really short to minimize flex. 

Milled the front and back edges to match the angles on the Walther's breech block.

Gave the sides a finish pass.

And a 0.750" endmill to take a clean up pass on the top.  Probably should've used a fly cutter, but the machining marks polished out without too much effort.

Wet sanded it (WD40) down to 420 grit on a granite plate.

Hit it on the buffer for a few minutes, then blued it with Van's cold blue.

Installed and done.  Angles carry over pretty well.

Looks like it's been here all along.

More soon with blog #651.