03/A3 scope base

[Elvin]

Are used a solid carbide drillbit and got the holes nicely done and finished but I cannot find a tap that will even touch this metal it is harder than the hubs of hell any suggestions

 

[Ggmac]

Spot anneal . It's usually done before drilling so it's easier . Is it an 03--A3 or 03 ?

 

[Ggmac]

Are used a solid carbide drillbit and got the holes nicely done and finished but I cannot find a tap that will even touch this metal it is harder than the hubs of hell any suggestions

Do you have or can you make a carbon spot anneal tool . Easy to make .
Get a 12 v garden tractor battery or sealed lead acid battery , solid heavy copper 5-6' , wrap around carbon , insulate end to hold and hook up to battery ( just long enough to get it HOT )
Sorry no coffee yet ! I'll find the directions in one of the old books . I have carbon I can send .

 

[Elvin]

Do you have or can you make a carbon spot anneal tool . Easy to make .
Get a 12 v garden tractor battery or sealed lead acid battery , solid heavy copper 5-6' , wrap around carbon , insulate end to hold and hook up to battery ( just long enough to get it HOT )
Sorry no coffee yet ! I'll find the directions in one of the old books . I have carbon I can send .

It is a 03/A3

 

[kendog]

Drilling these is seldom a problem, but as you have found, tapping is another story. I drill the holes with a carbide 2 flute spade bit, then spot anneal with a Smith micro Oxy/acetylene torch while it is in the vise or fixture. The little bitty torch makes it easy to pinpoint the heat. Polish the area just around the hole bright, heat the hole only with slightly carburizing (soft) flame till just the bright area turns blue and immediately hit it with 320 or craytex in a dremel to bring it back bright. Do this quickie heating till the blue starts to come back on its own after you brighten it (usually by the 4th cycle on the ring, less at the bridge), let it cool naturally and it is ready to tap, with the critical areas unaffected by the heat. All you want to anneal is a few thou of the hole sides all the way through. You will know it if you didn't do it enough when the tap tries to cut the back side of the hole. It is just as hard on that surface, too! I have found 03-A3's to be way more in need of spot annealing than 03's.

Wish I could say I came up with this on my own, but this procedure is described in one of the Gunsmith Kink books from Brownells. I have tried a bunch of different ways, this one works for me the best. Good luck!

 

[Elvin]

Hey thanks so much you guys I appreciate it I will give it a go

 

[akajun]

If you don’t have a small enough torch tip
Stick a tight fitting welding rod or other metal rod in your holes and heat the rod up till it’s glowing on both sides of the holes then let it cool
May take 2-3 cycles but it will work

 

[fguffey]

In the day of the Internet the old ways no longer work, I am glad I kept all of my old tools even thought I have been told they no longer work, I believe there is a remote chance my old tools are not aware the old ways still work.

F. Guffey

 

[fguffey]

In the beginning movie projectors used carbon torches. I have a carbon torch welder, it took a little getting used to because of the high temperature.

In the old days I used pencil thin carbon torches to anneal small areas on receivers to spot anneal. Most simple; attach one lead of a battery to the receiver and the other to the carbon torch, problem? Do not make sparks, attach the leads and then make contact with the receiver "AND THEN turn it on". It is not necessary to stare at it because it gets hot in a hurry.

F. Guffey