How hard is it to drill and tap a hole for a tang sight.

[kid_couteau]

Hi All

I am pretty handy and I do know how to run a drill and tap

I have a drill press, a machinists vise, transfer punches and other tools.

My question is what can I do to guarantee the hole I drill will be perpendicular?

Tricks? tips?

Thanks
Kid

[Pete44ru]

FWIW, I plumb the receiver side, then level the tang surface before clamping the sight base to the tang for use as a drilling guide. (I use the tang screw to screw the tangs together with a spacer between ILO the buttstock).

I may be preaching to the choir, but additionally I would use a center drill bit, fed slowly so as not to crater the hole edge.

.

[Tycer]

I attached mine with the one tang screw and went out and shot it. When I was happy with the alignment I centerpunched it and then drilled and tapped it. Worked great. FWIW, the hole is not perfectly centered on my tang. I undid the front screw at the range and centered the front of the sight on the tang and the aperture appeared oval. Moved it back to the hole and the aperture is round again.The sight is aligned perfectly, but the hole is off a tiny bit. Prolly my eyes.

[adirondakjack]

Sometimes, tangs can be harder than petrifed goat poo at well. If ya break a tap or drill..... I had one marlin that was brutal. LGS broke a carbide drill bit, mangled a tap...

[KCSO]

Mostly it depends, if you don't care if it's straight it's pretty easy. If you want it plumb that's a different story.

First of all is you drill press leveled? If not you need to figure how to get the tang level so the holes don't cant. Now is the tang straight? Some of the cheaper levergun have tangs that are anything but. Shimming will take care of some error but it isn't really the way to go. So Level your press and make sure the quill is square. Start your holes with a starting drill and finish with the right drill for the tap size. USE cutting oil ! Leave the tang in the press and tap STRAIGHT using the quill to center the tap. If your tang is visibly off center or uneven you might have to square it as best you can and sometimes even draw file the tang straight. Hopefully you won't need to go quite that far.

[AJMD429]

If you have the receiver assembled (you can leave the bolt out), the tang screw should give you a good enough reference for 'up & down', and you can easily strike the midline with a scribe. A scrap board with the right tang-to-tang (upper & lower) spacing will serve as reference if you use square lumber stock, whether using a drilled hole and pin or a square on the edge of the board, to align with 'up'.

As far as the potentially tough steel, I'd recommend a straight-flute carbide bit, and a tap holder with a hole in the top so you can guide it using the drill press...

Here's a semi-related post, with some pictures, if that helps:

http://www.levergunscommunity.com/viewt ... =1&t=25689

[Chuck 100 yd]

I drilled and tapped my last two Uberti 73`s for tang sights by just installing the sight using the rear tang screw and making sure the sight is plumb. Next use your transfer punch to locate the screw hole. remove the sight and stock,using my HAND HELD Makita cordless I drill the pilot hole using a sharp center drill. Next enlarge with a Sharp drill of the proper size.
Run your tap through, deburr the finished hole using a center drill.
Install the sight and go shooting.

I own a milling machine,lathe and drill press. It is such a simple job to drill and tap for a tang sight why do so many people make such a big deal out of it??

If the sight sets straight when it is tight to the tang, it will set straight when you are done.
If it is crooked when held on by the rear screw only, you have other problems and the straightest hole in the world wont bring that sight back to plumb.