Finally done! Repro Longbranch No4 MkI* (T) First range day today!

(Quote) Just don't be like me and go with HSS bits and taps. Cobalt or carbide! (Quote)
There is a tremendous difference in the quality of drills and taps. Carbon steel is brittle and only good for soft materials (wood). High Speed Steel is better, but there is a big difference in what is advertised as HSS. Carbide masonry drills are not sharpened to the right angles for drilling hardened steel. The taps and dies you get in cheap sets aren't worth taking home. I don't know the British barand names, but Ingersoll or Butterfield are much better. A good machine shop supply company may be helpful, or if you can contact the manufacturers, they have specialized taps ground to different angles for different materials.
 
Bushwacker, mine were bought from Tracey tools in the UK and were specifically suggested by Peter Laidler. After doing this conversion it is my opinion that even these high quality HSS bits are not hard enough to cut through the hardened sections of Long Branch receiver near the bolt way. Masonry bits are a trick learned from an old tradesman who has forgotten more about metalwork than I could ever hope to learn. The masonry bits will cut the hardened steel. They will not pull strings of steel because as you say the angles are not right. The harder bits were suggested by Wheaty and I guarantee you he was right. There could be a better type of HSS bit out there that will get the job done, I'm just not sure where.
 
I can heartily recommend Tracy Tools in the UK for any supplies you need if you want to be 100% traditional with the BA4 screws for the pads. I've used the guys at Tracy for many years and often I will order supplies on a Sunday evening and have them by Thursday afternoon the same week (Canadian dealers take note). Tracy will take Visa and their shipping rate is very reasonable.
If you don't see it on the web site just ask as Russell probably has it. One of his best deals and don't spread this one around or Snap On will be after me, but they have a series of left hand drills for around 5 quid (9.00 Cdn). The brands are mixed but all are top quality drills and they are worth their weight in GOLD when trying to remove that broken screw in a rifle or a manifold. The heat generated by the drill, vibration and when they grab they will normally back out a broken stud or screw.
 
I'll second Wheaty on the quality, service and delivery time from them. Their prices were awesome too, I bought 4 4BA taps, 3 1/4BSF taps and three of each drill bit needed and I think all in shipped it was about $50. I did break one of the 4BA taps but it was definitely operator error, I got way too greedy. But no broken teeth on the leading edge or anything. The bits did need sharpening often but again if I had a drill press shoving me into a heat treated bolt way I was never meant to cut I'd get pretty dull too. They did eventually get the job done though.
 
You can regrind masonry carbide bits into a better configuration with the right green stone. ;)
 
RRCo. said:
You can regrind masonry carbide bits into a better configuration with the right green stone. ;)
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You can, but a solid carbide drill makes a much nicer hole both in finish and dimensions. The only caution with solid carbide drills is a very rigid and solid setup is required to avoid breakage. The last thing you want to do is break a carbide drill off in the workpiece. They work beautifully in hard steel.
 
The incredible hardness of the receivers is why Long Branch started doing the drilling for pads before the hardening was done, on their sniper line.

As many have found out, including the factory....
 
If I wind up doing another down the road I now have much better tooling and I think it would go way smoother. I'd use my spindle drill chick on the lathe and hold the action in the milling attachment and feed it at a much lower rate of speed. I think heat may have been a factor there. I also won't be using high speed steel bits again!

Gonna miss the old girl, she's headed to a new home today.
 
flying pig said:
If I wind up doing another down the road I now have much better tooling and I think it would go way smoother. I'd use my spindle drill chick on the lathe and hold the action in the milling attachment and feed it at a much lower rate of speed. I think heat may have been a factor there. I also won't be using high speed steel bits again!

Gonna miss the old girl, she's headed to a new home today.
Click to expand...

Actually I was told...some use spot annealing. It's a method to remove the hardening just in the one spot you're drilling. Personally I didn't like the sound of it.

http://www.cnczone.com/forums/general-metalwork-discussion/2826-drilling-hardended-steel-update.html

Probably getting the whole receiver annealed, drilling the holes and then getting it re-heat treated is the way to go.
 
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