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All Springer/NP/PCP Air Gun Discussion General => Machine Shop Talk & AG Parts Machining => Topic started by: SynRodSteve on December 21, 2016, 07:49:39 PM
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I make hammers for the Marauder. The most recent one is being made out of some sort of 1.25" axle shaft. I turned it down to diameter on the lathe with no issues, and drilled thru for the striker hole and spring counter bore with no problem. When I went to cross drill it for 8-32 and 10-32 tapped holes, the cobalt drill wouldn't touch it. What type of drill bit do i need to drill this HARD steel?
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Honestly ... SKIP that step and use / prep the striker screw threads with VIBRA-TITE thread locker.
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When I'd ruined several HSS drill bits even after attempting to anneal the work piece with a high RPM nail cutoff (yes it was cherry red!), and ruined even a carbide tipped masonry bit trying to drill some air hardening spring steel....
I broke down and bought a set of Bad Dog Drill bits. Never had a moments trouble drilling that stuff again! Of course the drill set cost $90, but I made that back after I made and sold four tools made possible by the drill set, at $25 each.
Check 'em out here:
http://www.baddogtools.com/ (http://www.baddogtools.com/)
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Please excuse me. I don't have a solution, but another problem..
In 2011, I bought a Gamo Whisper with a synthetic stock, and it HAD two screws holding the butt plate. After a couple of months, one screw broke and a gunsmith told me it was a hardened steel that could not be drilled.. Making a long story short, the solution would be .. a brand new stock!? Since then, it has some glue and silver tape holding the butt plate (and one original screw).
Any suggestion?
Thanks.
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You might be able to back it out using a reverse twist drill/ EZ-out set. It might just back out using the LH twist drill. If you go this route, be sure to make the end of the screw is flat (grind it if necessary) so that you can use a center punch to ensure the drill starts dead center of the screw. I've drilled out hardened screws before, but it's a tricky business. You might try the Bad Dog tools drills because they'll drill through hardened steel.
I'd try several other things first.
- If you can get a vice-grip pliers on it, try backing it out with that first.
- Next you could try using a chisel or center punch on the edge of the circumference to unscrew it.
- Next you might try a plug cutter around the screw to remove enough stock to get hold of the screw and then back it out. You'd probably have to use some epoxy on the stock after that...
- You might even try heating the end of the screw with a soldering iron to soften the plastic up a bit in order to help get the screw out.
All of these have the potential to be destructive, so try the least destructive method first, and work your way up...
And if it all fails, then what have you lost? You can always put a boot type butt pad on it...
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Thx Underdog. I'll check that out.
Motorhead, not sure I understand. I make custom hammers with cross drilled holes for nylon tipped set screws. I have to drill and tap those, as well as drill and tap the lug screw hole. Not sure what 'step' you're suggesting I skip.
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Steve, instead of making your life difficult by using axle shafts, why not get some 1144 steel and make then from that.... It machines nicely, and if you want to harden it, you can do that too.... BTW, I've never bothered hardening any hammer I have made, and haven't had a problem yet....
Bob
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Rsterne, it was free stock I had on hand so I tried it. It MACHINED very nicely but when I started on the small holes...not so much! SOOOOOO hard!! :) The last ones I made were of some other unknown material but machined AND drilled nicely. This stuff is super hard. Thanks for the advice on suitable material.
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Thx Underdog. I'll check that out.
Motorhead, not sure I understand. I make custom hammers with cross drilled holes for nylon tipped set screws. I have to drill and tap those, as well as drill and tap the lug screw hole. Not sure what 'step' you're suggesting I skip.
Was "Guessing" hole you were drilling was to form a pocket to hold a binding material for stroke adjuster like OEM hammer does.
If not the case .... disregard comment made previous.
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Thank you, Underdog.
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Steve, instead of making your life difficult by using axle shafts, why not get some 1144 steel and make then from that.... It machines nicely, and if you want to harden it, you can do that too.... BTW, I've never bothered hardening any hammer I have made, and haven't had a problem yet....
Bob
Any chance you've a source for a foot or two of that 1144 stressproof in Canada Bob? Have been looking, and although I can get a 12' length without issue, finding lengths of a foot presents a problem. Metal supermarket lists it....but they don't actually CARRY it...at least not when I checked.
TIA,
Al
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Sorry, I just have a little bit left, I got some from Sean a couple of years ago, and have been using it sparingly / hoarding it.... ::)
Check with Lloyd Sikes, he seems to be able to get all sorts of oddball materials.... likely from McMaster-Carr....
https://www.mcmaster.com/#grade-1144-steel-rods/=15ug8xk (https://www.mcmaster.com/#grade-1144-steel-rods/=15ug8xk)
I see they even have 125Ksi Yield "Fatigueproof" 1144.... :o
Bob
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I make hammers for the Marauder. The most recent one is being made out of some sort of 1.25" axle shaft. I turned it down to diameter on the lathe with no issues, and drilled thru for the striker hole and spring counter bore with no problem. When I went to cross drill it for 8-32 and 10-32 tapped holes, the cobalt drill wouldn't touch it. What type of drill bit do i need to drill this HARD steel?
Carbide drill should get through it. Otherwise you'll need a torch to anneal the steel.
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You might want to try to spot anneal it using a car battery and a carbon rod. An old G I armorer once told me that's what they did to receivers in order to tap them for scope mounts in WWII