Tuesday, March 09, 2010

Mounting the Williams FP-94/36 - not that hard or costly

Here's another post from Paco Kelly's Leverguns forum that I have permission to share. I'm not responsible for anyone's use of the information provided. I suggest that you carefully read the entire post several times before following the suggested methods. Even an experienced person can have a drill wander if you feed it too quickly into the work. Many thanks to Dr. AJ for permission to republish his work here.

Several folks have recently inquired about sight installation, and I thought I'd post some pics about mounting the Williams FP 94/36. If I can do it, anyone can. Anyway, hope this helps get someone started who needed a bit of encouragement.

Here's all you need: Tap is 6-48, and drill is supposed to be a #31, but I used a slightly smaller #33. I like the 'straight-flute' carbide ones. (...the 'guide' I have says use #33 for a 6-48 but #31 for a 6-40...?). I got Tap Magic at the Ace Hardware in town. A good center-punch is a must, and drill press.

Here's the specific parts I ordered from MidwayUSA:
- Drill Bit - $20.99
- Tap - $2.29
- Handle - $4.49

I may have done overkill on the drill bit, but it cuts through gun receivers like they're butter. Also, I wound up liking a tap handle I bought locally a bit better (deeper divet in the top for guiding on drill press).

The sight needs to be far enough rearward that the case will eject; a bit behind the boltface's rearmost travel seems to work fine. If you haven't deactivated the semi-safety, you shouldn't cover it up.

Drill the first hole.

Then TAP the first hole. I like using a piece of rod or bolt that fits in the top end of the tap handle, and have the drill press 'guide' (no pressure downward) the tap as I turn it by hand, backing up a partial turn for every turn or so clockwise. Use lots of Tap Magic; it does seem to make a difference vs. 'WD-40'. I tap clear through and when the tap turns very easily you're done and can raise the chuck and back the tap out.

Countersink the holes very slightly or otherwise de-burr them.

Mount the sight with the first screw, and level it front to back before center-punching the second hole. Ideally your punch should be 'snug' enough in the sight's hole to be centered; 'eyeballing' it is too tricky. Some folks use a smaller drill bit just fitting the sight hole, or they will slip a very small bit inside a 'bearing' sleeve of tubing that fits the sight hole, and use the drill to 'mark' the second hole and start it at the same time.

Drill the Second hole.

Both holes drilled now.

Put it all back together. (You might want Steve Young's DVD for this part...)

Andrew Johnstone, RPh/MD
Doctors for Sensible Gun Laws

-Drill, Tap & Install Receiver Sights By J. Marshall Stanton

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