I need to chase the threads in the receiver (front action screw hole) of a 98 action I have - what size tap do I need? I'm hoping it is a somewhat common size.

Thanks,
Todd

It looks like 1/4-22 to me, which is not a standard thread.

20, 24, and 28 TPI are the standards in "Machinery's Handbook"



But even though the idustrial suppliers, like MSC, do not have the tap for $1.50 import and US from $3 to $5 like other 1/4" taps, Brownell's does at a premium price:



748-203-142 1/4-22 Plug Tap $16.48

748-203-143 1/4-22 Bottom Tap $16.48

Clark is right, they are 1/4x22. Unless it just happens to be a 98/40, they are .275x26. Go figure.

Todd
I had the same problem years ago. Could not find a tap at any price so I made a chaser !!

You most probably have an old junk mauser screw with good threads, just cut two small opposing gooves with a needle file or (shutter) dremmel tool. Then cut a little backside relief so it can cut. Heat to cherry and douse in water. Presto you have a great thread chaser.

I made two, one with a tapered head, one flat bottom for that front hole. I don't think they could cut a full thread, but for chasing they worked great. Now I use them to clean the threads of releasing cmp after bedding.

You might give it a try.

Roger

Thanks for the replies, and for the thread chaser idea. That worked quite well, I couldn't believe the amount of crap I got out of that hole. No wonder the screw was tight. I think I got an extra four turns on it. I've soaked it with Kroil, and will try again tomorrow.

Todd