drill bolt carrier for charging nandle

[mcmillan762]

Good point, not sure about soldering but I don't see why you couldn't press fit one in there. Might even be easier to do, would take some different tools though...

[ar15barrels]

And the last one...

I should have clarified that I meant a high quality (USA made) drill bit.
The fact that your center punch even made a dent on that drill bit tells me it is softer than a bolt carrier.

[Don Edmondson]

Don't forget you have to remove the new handle to remove the bolt so don't solder it there other things you will have to do best to send RANDELL your stripped upper and the bolt carrier assembly

[mcmillan762]

No matter how drunk I was last night no way would a drill a giant hole in a nice drill bit... was only making a point to the OP that if they are willing to try it's not as daunting as it might seem....

[Whiterabbit]

Don't forget you have to remove the new handle to remove the bolt so don't solder it there other things you will have to do best to send RANDELL your stripped upper and the bolt carrier assembly

I did forget. duh. ha!

Once could still solder in a threaded insert on an oversized hole and file to re-profile, if the bolt can wet tin solder.

Or maybe the question should be, what does one have to do to tap a 55 Rockwell C piece of metal? The risks are clear, so what procedure must one follow to cleanly tap a BCG body? It doesn't involve de-heat treat and re-heat treat, does it?

Another idea, can drill and thread the CH so you put a fastener in from the other side. Yes I know that would imply a whole new set of geometry challenges. I just wouldn't want to take the bother of heat treating parts if that was what was needed to tap the bolt.

I still don't know if there is a straightforward way to tap hard steel.

----------

Googling yielded this, looks like fun times

http://www.cnczone.com/forums/general-metalwork-discussion/36301-tapping-hardened-material.html

[mcmillan762]

Yes, it's just patience and going slow. Practice truly does make perfect... and really the name of the game is a good lubricant. There is a really good tapping gel that you can get from fastenal or Abba bolt that works AMAZING! In a pinch you can even use the good 'ol WD40. And what I mean by going slow is to continually break the chips up, which means you turn the tap handle a quarter turn then back up a half turn or so... repeat this process whith STEADY down pressure and before you know it you'll be through. Just don't rush it! Don't want to break your tap, then the real fun starts!!! The pic below is of the stuff I use, guess it's made by Boeing and it's only $6-7 for the small container. Best of luck to you!

[mtenenhaus]

thanks....nice job

[kcstott]

Oh sure it's not hard let me show you by D&Ting a chunck of butter, Sure If i drilled and tapped a drill bit that went in Grandpa's brace and bit, no problem. Try that with a piece of P-20 let alone a full hard BC (BTW P-20 is prehard 4140 at 38 RC and is F'n tough stuff)

Bolt carriers are typically 8620 steel, hardened as Randall said 55Rc, A common piece of HSS is just at or slightly over 60Rc good luck drilling with anything other then Carbide and tapping with anything other then a Cobalt or Carbide tap designed for hardened materials,

You're not going to go down to the Hardware store and pick a tap off the shelf go home and have a go,

You can order a tap from the cutting tool makers, R&N, OSG, Emuge a 1/4' or a 5/16" tap for hardened material will set you back about $60 each give or take, depending on coating and if you want helical flute for bottoming. Drill bit will cost about half that.

Love his recommendations on tap fluid. You can tell he's never done but one or two holes at a time. WD40 on anything other than one hole in sheet metal or on aluminum is a straight death sentence for a tap. There are no EP properties in WD40 and sure you might be able to get one hole in mild steel done with WD40 anything more then that and you'll be posting up a new thread on asking how to remove a broken tap.

They make make special fluids just for this stuff.. Good ol' Rapid tap is my favorite due to how well it works and it don't stink up the shop. although I do have a bottle of Anchor lube that works extremely well on hardened materials it's just messy stuff.

you know it would be cheeper to just buy a BC done or send it to an EDM shop and tell them to orbit a thread in there for ya. cost would be about the same. $150 and up.
Fun costs money how much do you wan to have?? Sorry for sounding extra Crotchety Getting over the flu sucks
On that note remember Cartridges have no headspace

[kendog4570]

Oh sure it's not hard let me show you by D&Ting a chunck of butter, Sure If i drilled and tapped a drill bit that went in Grandpa's brace and bit, no problem. Try that with a piece of P-20 let alone a full hard BC (BTW P-20 is prehard 4140 at 38 RC and is F'n tough stuff)

Bolt carriers are typically 8620 steel, hardened as Randall said 55Rc, A common piece of HSS is just at or slightly over 60Rc good luck drilling with anything other then Carbide and tapping with anything other then a Cobalt or Carbide tap designed for hardened materials,

You're not going to go down to the Hardware store and pick a tap off the shelf go home and have a go,

You can order a tap from the cutting tool makers, R&N, OSG, Emuge a 1/4' or a 5/16" tap for hardened material will set you back about $60 each give or take coating and if you want helical flute for bottoming. Drill bit will cost about half that.

Love his recommendations on tap fluid. You can tell he's never done but one or two holes at a time. WD40 on anything other then one hole in sheet metal or on aluminum is a straight death sentence for a tap. There are no EP properties in WD40 and sure you might be able to get one hole in mild steel done with WD40 anything more then that and you'll be posting up a new thread on asking how to remove a broken tap.

They make make special fluids just for this stuff.. Good ol' Rapid tap is my favorite due to how well it works and it don't stink up the shop. although I do have a bottle of Anchor lube that works extremely well on hardened materials it's just messy stuff.

you know it would be cheeper to just buy a BC done or send it to an EDM shop and tell them to orbit a thread in there for ya. cost would be about the same. $150 and up.
Fun costs money how much do you wan to have?? Sorry for sounding extra Crotchety Getting over the flu sucks
On that note remember Cartridges have no headspace

Come on, Man... dont sugar-coat it. Say it like you really mean it! ;-)

All ya gotta do is.....

[ar15barrels]

All ya gotta do is.....

Just...

[gemini1]

A little thread drift. KC, Ken or Randall. How about titanium? will those tap/drill sets at Home Depot work, or will you need to buy one of those special ones KC mentioned, above?

[ar15barrels]

A little thread drift. KC, Ken or Randall. How about titanium? will those tap/drill sets at Home Depot work, or will you need to buy one of those special ones KC mentioned, above?

Titanium is not hard.
Titanium is gummy.
Lots of drill bit relief angle.
Medium cutting pressure and slow-medium speed works good.
Just don't push so hard that the bit grabs and breaks or too light that you make strings.

[kcstott]

What he said ^^^

Drills? you can get away with M42 or Cobalt 5% HSS drills. Use screw machine length and 135˚ split point when ever possible. run at 1/4 the cutting speed of Steel. 30 SFPM 50 SPFM if you have flood coolant

As for taping well thats where its get funky. Tapping titanium with a conventional tap is the same as intentionally ruining a part and breaking a tap.

They make special taps for Ti for a reason, Ti doesn't like to be rubbed and to much contact allows the material to grab the tap as you try to reverse it. tap don't move, machine tries to keep going, and pop...

Titanium taps have a different rake angles and loads more clearance and less bearing surface. Emuge has a nice video on how there stuff is made. explains it quite well.

The key with titanium is keeping your cutting tool cool. Ti doesn't conduct heat well at all. so your tool absorbs the heat,enough heat and your roll the edge of your drill bit or lathe tool or end mill over increasing the cutting pressure, contact area and heat and your tool just folds up like it was butter.

there is a reason why Ti work cost what it does. and it's because its abusive to conventional tooling.

Spend the money on good tooling, proper coatings, and if Running CNC, proper tool paths that get in and out of the cut right now to allow the tool time to cool between plunge cuts and your tools will last production goes up and parts get cheeper.

Funny thing is there's always one guy that wants a Ti firing pin for some rifle that no one make a pin for, Mini 14/30 comes to mind. and I get hit up to make one. tell them it's going to be expensive and they are like "Yeah I know" and I'm like "no you don't" like half the cost of the rifle expensive for a single Ti firing pin. Sure if I had the time to make a dozen of the damn things I might be able to sell them at a reasonable price.
then There is the fact that I hate Ti, I've machined enough of that crap to develop a good amount of discontent toward that material. it's just not easy to work with. I'd rather work with Inconel or Monel Two other tough as tough gets materials but opposite ends of the spectrum

[gemini1]

Thanks Randall & Kc.

[mcmillan762]

Wow way to encourage someone who wants to get something done! (Fun costs money) Love how everyone's quick to criticize but short on advise to help. As far as the WD40.... well hate to break it to ya, but I machined THAT from scratch on THAT machine using WD40! Just trying to help someone out by offering what humble advise I can in the presence of such clear masters... (you can tell he only taps one or two holes at a time)... and yes, unfortunately I know how to tap... this site sucks, I won't be coming back. Have fun with your ARs!