A guy just emailed me to comment on my "taptips" page,
http://www.spaco.org/taptips.htm

I said that I don't allow any (plain)carbon steel taps in my shop.
He commented that gunsmiths DO use carbon steel taps because they tend to
break a lot, but are easy to remove by smashing them.
I don't do any gunsmithing- the idea of drilling into someone's gun
barrel scares the dickens out of me. But here's my question:
Isn't maybe, the REASON the little taps break often that they ARE carbon
steel?

And just for information, how DO you tap a 2-56 or 4-40 or whatever hole in
a gun barrel? If you can only go 2 or 3 threads deep, you can't start with
a taper or even a plug tap, can you?

Are gun barrels hardened/hardened and tempered or are they just an annealed,
tough steel like 4140?

Pete Stanaitis
---------------

"Pete S" wrote in message
...
A guy just emailed me to comment on my "taptips" page,
http://www.spaco.org/taptips.htm

I said that I don't allow any (plain)carbon steel taps in my shop.
He commented that gunsmiths DO use carbon steel taps because they tend to
break a lot, but are easy to remove by smashing them.
I don't do any gunsmithing- the idea of drilling into someone's gun
barrel scares the dickens out of me. But here's my question:
Isn't maybe, the REASON the little taps break often that they ARE carbon
steel?

And just for information, how DO you tap a 2-56 or 4-40 or whatever hole
in a gun barrel? If you can only go 2 or 3 threads deep, you can't start
with a taper or even a plug tap, can you?

Are gun barrels hardened/hardened and tempered or are they just an
annealed, tough steel like 4140?

Pete Stanaitis
---------------

Most holes for sights are 6-48.
The barrels are usually just tough steel, but the receiver is where you do
most of the drilling and tapping, and they can be all over the place.
You start the tap with a guide so a lot of starting taper isn't needed.

Carbon steel taps are slightly harder than HiSpeed. They are also more
brittle and shorter lived. That's ok, most gunsmiths I know only use them
once.
They also grind the shank on them down to weaken it. That way, if it breaks,
it'll break at the shank and not down in the hole.
The real old timers would reharden them to cut really hard materials.
Also, if it does break off, You can soften a carbon steel tap with a torch.
It is easier to drill that way.


Paul K. Dickman

On Sat, 11 Jun 2011 10:09:15 -0500, "Pete S"
wrote:

A guy just emailed me to comment on my "taptips" page,
http://www.spaco.org/taptips.htm

I said that I don't allow any (plain)carbon steel taps in my shop.
He commented that gunsmiths DO use carbon steel taps because they tend to
break a lot, but are easy to remove by smashing them.
I don't do any gunsmithing- the idea of drilling into someone's gun
barrel scares the dickens out of me. But here's my question:
Isn't maybe, the REASON the little taps break often that they ARE carbon
steel?

Yes. But the fellow was absolutely correct as well. Ive had to EDM out
strong taps..and carbide ones. Not fun..not fun at all.

And just for information, how DO you tap a 2-56 or 4-40 or whatever hole in
a gun barrel? If you can only go 2 or 3 threads deep, you can't start with
a taper or even a plug tap, can you?

Yes. Grind off the point and start the threads, then put in a bottoming
tap..or grind a bottoming tap from a regular one.

Are gun barrels hardened/hardened and tempered or are they just an annealed,
tough steel like 4140?

All of the above G


Pete Stanaitis
---------------

"As physicists now know, there is some nonzero probability that any object will,
through quantum effects, tunnel from the workbench in your shop to Floyds Knobs,
Indiana (unless your shop is already in Indiana, in which case the object will
tunnel to Trotters, North Dakota).

The smaller mass of the object, the higher the probability.
Therefore, disassembled parts, particularly small ones,
of machines disappear much faster than assembled machines."
Greg Dermer: rec.crafts.metalworking

On Jun 11, 9:09*am, "Pete S" wrote:
A guy just emailed me *to comment on my "taptips" page,http://www.spaco..org/taptips.htm

I said that I don't allow any (plain)carbon steel taps in my shop.
He commented that gunsmiths DO use carbon steel taps because they tend to
break a lot, but are easy to remove by smashing them.
* I don't do any gunsmithing- *the idea of drilling into someone's gun
barrel scares the dickens out of me. *But here's my question:
* Isn't maybe, the REASON the little taps break often that they ARE carbon
steel?

And just for information, how DO you tap a 2-56 *or 4-40 or whatever hole in
a gun barrel? * If you can only go 2 or 3 threads deep, you can't start with
a taper or even a plug tap, can you?

Are gun barrels hardened/hardened and tempered or are they just an annealed,
tough steel like 4140?

Pete Stanaitis
--------------- *

The pros use a bushed fixture like this:
http://www.forsterproducts.com/store...33&catid=19938

And barrels are EASY to drill. They have to be drilled the long ways,
after all, at least once, plus reaming and rifling. So can't use
really nasty machining steels for that. No, the problems are with
drilling and tapping military bolt actions. Post-WWII commercial
actions usually come with holes already in them, just turn out the
plug screws and mount the appropriate base. Military bolt actions in
the really old days were mild carbon steel that was machined and then
pack-hardened. Those are a bear to do, fortunately, the guns are
getting too valuable as collector's items to make into sporters now,
they went for as little as $10-20 back in the '50s and '60s. You can
sink more than the cost of a new commercial rifle into such a sporter
and reduce the value to half what you spent, now. On those case-
hardened actions, these days you can get carbide drills to make the
holes, old-timers had to use mercury-hardened carbon steel drills and
even then sometimes didn't manage to chew through the skin. Heavy
black sulfur cutting oil is the best stuff for tapping. Bushing-
guided fixtures are a must for drilling and tapping, just asking for
trouble without them. That's the reason that Forster fixture has been
in production for decades.

Fine-pitch screws are used, usually not in the standard series. 6-48
and 8-40 are common, taps are a little more robust, too. Carbon steel
taps are more than adequate for barrel steels and cleaning out
buggered threads on commercial guns. A small dogbone tap wrench gives
a good feel, you can tell when a tap starts winding up and back off
before it goes. Shallow holes where there's about 5-6 threads, use the
fixture with a 2nd tap to start followed by a plug tap.

Stan

Stan

On Jun 12, 12:57*am, wrote:
...On those case-
hardened actions, these days you can get carbide drills to make the
holes, old-timers had to use mercury-hardened carbon steel drills and
even then sometimes didn't manage to chew through the skin.
...
Stan-

I read somewhere that melting a blob of solder on the receiver would
anneal the case enough for drilling and tapping. I haven't tried it.
Case-hardened scrap hydraulic cylinder rod cuts well enough with
carbide.

jsw

"Ed Huntress" wrote in message
...

"Jim Wilkins" wrote in message
...
On Jun 12, 12:57 am, wrote:
...On those case-
hardened actions, these days you can get carbide drills to make the
holes, old-timers had to use mercury-hardened carbon steel drills and
even then sometimes didn't manage to chew through the skin.
...
Stan-

I read somewhere that melting a blob of solder on the receiver would
anneal the case enough for drilling and tapping. I haven't tried it.
Case-hardened scrap hydraulic cylinder rod cuts well enough with
carbide.

jsw

Case-hardened '30 actions

That's '03 actions, plain carbon and case-hardened. You can tell by the
serial numbers which ones were made this way.

--
Ed Huntress


can also be spot-annealed with a cut-off nail in a
drill press. You just use friction to get a small spot very hot.

As an earlier poster says, this is not something one would do today with a
rifle that old.

--
Ed Huntress

On Sun, 12 Jun 2011 05:06:40 -0700 (PDT), Jim Wilkins
wrote:

On Jun 12, 12:57*am, wrote:
...On those case-
hardened actions, these days you can get carbide drills to make the
holes, old-timers had to use mercury-hardened carbon steel drills and
even then sometimes didn't manage to chew through the skin.
...
Stan-

I read somewhere that melting a blob of solder on the receiver would
anneal the case enough for drilling and tapping. I haven't tried it.
Case-hardened scrap hydraulic cylinder rod cuts well enough with
carbide.

jsw

No..a dab of melted solder doesnt do a damned thing for anealling a
Springfield receiver for drilling. The closest thing I found..was a
tiny little jewelers torch used properly

And thats a pain in the ass.

Gunner

"As physicists now know, there is some nonzero probability
that any object will,through quantum effects, tunnel from
the workbench in your shop to Floyds Knobs,Indiana
(unless your shop is already in Indiana, in which
case the object will tunnel to Trotters, North Dakota).

The smaller mass of the object, the higher the probability.
Therefore, disassembled parts, particularly small ones,
of machines disappear much faster than assembled machines."
Greg Dermer: rec.crafts.metalworking

Thanks for all the good info. My son just got one of those old rifles and
he asked me to drill for sights. Now I know enough to find a gunsmith, or
wait until I can build a fixture.

I summarized all of your inputs and added it to my taptips page at the
bottom, "tapping holes in gun barrels":

http://www.spaco.org/taptips.htm

If you check it out and find that I have screwed up in any way, please let
me know.

Pete Stanaitis
----------------