need #6-48 tap

[kielbasavw]

Well I was hoping to get my scope mount mounted to my win94. Need a hole drilled and tapped into the top of the rear barrel band, but ran into a snag when I found out the screw is a 6-48.... never knew there was such a thing. Guess I gotta wait and order one or something.
Oh well

[jfifer]

Let me see if I have one at work still. But, if you break it you buy it!!!

[ar15barrels]

6-48 is the most commonly used screw size for attaching scope bases and sights to guns.

[kielbasavw]

I'm a mechanic, and never seen such a fine thread screw. So I was surprised to find something new. And sucks no store caries it locally except for master carr but its almost $30, im already over budget with the scope and mount. Midway has the #32 bit and tap for $10 but also gotta pay shipping, gotta find parts I need for other projects to make it worth it I guess.

Also do you have any recommendations for marking the center of the hole on the barrel band through the scope mount hole? Scope is attached by one rear screw and was thinking of using a drill bit with the same diameter as the mount screw hole so it would self center then drill a quick little center mark for the #32bit. Does this sound okay or is there a better way of going about it?

[kcstott]

Do you have access to a mill?? that would be the best way if not they sell jigs for these things.
My only suggestion is you need to be dead on accurate with the placement of your holes as to not have to use up all your windage adjustment just to get on paper. over a 4" ring to ring distance .001" of variation in your hole position equals 1 MOA or 1" at 100 yards. so if you miss punch a spot .010" off now you're going to be 10" off at 100 yards. you can see how fast you can use up your adjustment because most scopes don't have a bunch of windage.

Now as to your screw. Brownells is you best bet. Small stuff like that they charge a $6 shipping fee the other thing is there is a reason for the ultra fine threads. It prevent the screws from backing out do to vibration. the fine threads have a very shallow helix angle and therefore have a higher resistance to backing out.

[kielbasavw]

I suppose I could use a buddies mill, but finding the center of the hole would be just as tricky I feel by drill press. Unless doing my idea of using a larger drill bit to self center, then change to the smaller bit.

[kcstott]

If your buddy has a mill. Do some measuring and dial off your distance. Finding center is easy with an edge finder, Your buddy should have that to.

A mill with a few tools is the only way to accurately drill and tap a scope base.
a drill press is a step up from a hand drill. better because you can get things square but location is only as good as the jig.

[kielbasavw]

Ill talk to him about it. But I figured using the mount itself as a jig would be pretty accurate aslong as a bit the same size as the hole is used.

[Gunsmith Dan]

FYI since you will already have everything lined up in the mill to drill holes you can also hand TAP the holes in the Mill as well.

[kielbasavw]

Well I dont want to drill and tap the barrel band attached to the rifle, I don't want to touch the barrel itself. I would need to mark the the hole while attached to the rifle, then remove for drilling and tapping. Which then I could use the mill no problem.

[kielbasavw]

This is what I'm working on.

[kcstott]

that mount is designed to be mounted to the barrel with screws. not to the band. The band is not stable enough to hold a scope in position.

You need to drill and tap the barrel. But you also need to leave enough wall thickness in the barrel to support the bore. You should really consider taking this to a pro.

[kielbasavw]

This mount is from the 60s, made by leupold specifically to mount a scout scope on a winchester 94. And IS Designed to be screwed to the band

[kcstott]

Well do what you want but in my experience that's not strong nor stable enough to do the job

[kielbasavw]

http://www.ebay.com/itm/360680672459?redirect=mobile

There is the add for the setup "no drilling of the barrel" I cannot find the instructions ill have to look later. But it is designed to mount on the band. There are only two mounting hole in the base. One screws to an adapter that ffits into rear sight dove tail, and other is right above the barrel band.