I've got a 1927a1 that I'd like to make another bolt for. It's .45 ACP,
and strictly a blowback mechanism. Any hints on which alloy of steel to
use, and/or what hardness to "shoot" for when heat treating? Seems
pretty soft as shipped and the grinder test doesn't seem to tell me
there's a whole lot of carbon, but it's been a long time since I've had
someone teach mhow to read sparks to guess at alloy.

Thanks
Dave

Ask on the gunbroker.com forums lots of gunsmiths post there including
me and somone would surely know. Theres probably quite a few choices
for what you could use as for hardness I don't know off hand I could
probably find out but it would take time, which I currently don't have.
Sorry.

P.S. have you thought about just buying a new bolt? Would probably be
cheeper time wise in the longrun.

On 17 Mar 2006 01:14:37 -0800, redice wrote:
Ask on the gunbroker.com forums lots of gunsmiths post there including
me and somone would surely know. Theres probably quite a few choices
for what you could use as for hardness I don't know off hand I could
probably find out but it would take time, which I currently don't have.

I'll take a look over there, thanks.

P.S. have you thought about just buying a new bolt? Would probably be
cheeper time wise in the longrun.

Well, cheaper isn't the point. It's a fairly complex part, and I'd
like to test my skills by making one. By using something that's easy to
test, I can spend some quality shop time and make something useful in
the process. The finish quality on the Kahr manufactured bolts is not
very good, and I'm hoping to improve on that as well.

Thanks,
Dave

"Dave Hinz" wrote in message
...
I've got a 1927a1 that I'd like to make another bolt for. It's .45 ACP,
and strictly a blowback mechanism. Any hints on which alloy of steel to
use, and/or what hardness to "shoot" for when heat treating? Seems
pretty soft as shipped and the grinder test doesn't seem to tell me
there's a whole lot of carbon, but it's been a long time since I've had
someone teach mhow to read sparks to guess at alloy.

Thanks
Dave


Don't know if this is any help but Hatcher's Notebook shows a M1 Garand bolt
of 8620 treated to Rockwell C 55 to 59 and the M1 Carbine bolt of 4140
treated to Rockwell C 48-54. I thought I remembered Thompson info in the
book also but was incorrect.

Steve.

On Fri, 17 Mar 2006 10:06:39 -0500, SteveF wrote:

Don't know if this is any help but Hatcher's Notebook shows a M1 Garand bolt
of 8620 treated to Rockwell C 55 to 59 and the M1 Carbine bolt of 4140
treated to Rockwell C 48-54.

Ah. Of the two, the carbine's is probably more relevant - I'm not
locking any lugs into anywhere, And, I have 4140, so it's a good
starting point. Thank you.

I thought I remembered Thompson info in the
book also but was incorrect.

Yes, I thought he wrote something about it also. I've got I think all
of his books, so it may take some digging.

Dave

On 17 Mar 2006 16:51:35 GMT, Dave Hinz wrote:

On Fri, 17 Mar 2006 10:06:39 -0500, SteveF wrote:

Don't know if this is any help but Hatcher's Notebook shows a M1 Garand bolt
of 8620 treated to Rockwell C 55 to 59 and the M1 Carbine bolt of 4140
treated to Rockwell C 48-54.

Ah. Of the two, the carbine's is probably more relevant - I'm not
locking any lugs into anywhere, And, I have 4140, so it's a good
starting point. Thank you.

I thought I remembered Thompson info in the
book also but was incorrect.

Yes, I thought he wrote something about it also. I've got I think all
of his books, so it may take some digging.

Dave

I think you would be golden with 4140

Gunner


"The importance of morality is that people behave themselves even if
nobody's watching. There are not enough cops and laws to replace
personal morality as a means to produce a civilized society. Indeed,
the police and criminal justice system are the last desperate line of
defense for a civilized society. Unfortunately, too many of us see
police, laws and the criminal justice system as society's first line
of defense." --Walter Williams

On Fri, 17 Mar 2006 17:42:36 GMT, Gunner wrote:
On 17 Mar 2006 16:51:35 GMT, Dave Hinz wrote:

Ah. Of the two, the carbine's is probably more relevant - I'm not
locking any lugs into anywhere, And, I have 4140, so it's a good
starting point. Thank you.

I think you would be golden with 4140

Good to hear. Any thoughts on where I should shoot for on the
hardening?

Dave

Have you developed your methodology?

In my recollection, the 1927A1 bolt is a bar stock part , rectangular in
cross section with a round turned projection in the front about 2~3" long
that accomodates the ctg head at the end.

If you heat treat after machining you will be susceptible to warping,
dimensional change, and scaling of your machined surfaces.

So, are you planning on surface , slot, & cylindrical grinding after HT?

I don't believe the factory bolt was heat treated, really no need for it.
It's an unstressed part for a low pressure ctg. I also believe the extractor
is staked in place, furthering the need for metal that is suitable for
deformation.

I think any un-heat-treated steel available from 1018 to 4140 would fit the
bill.

Tony


"Dave Hinz" wrote in message
...
On Fri, 17 Mar 2006 17:42:36 GMT, Gunner
wrote:
On 17 Mar 2006 16:51:35 GMT, Dave Hinz wrote:

Ah. Of the two, the carbine's is probably more relevant - I'm not
locking any lugs into anywhere, And, I have 4140, so it's a good
starting point. Thank you.

I think you would be golden with 4140

Good to hear. Any thoughts on where I should shoot for on the
hardening?

Dave

On 17 Mar 2006 18:16:42 GMT, Dave Hinz wrote:

On Fri, 17 Mar 2006 17:42:36 GMT, Gunner wrote:
On 17 Mar 2006 16:51:35 GMT, Dave Hinz wrote:

Ah. Of the two, the carbine's is probably more relevant - I'm not
locking any lugs into anywhere, And, I have 4140, so it's a good
starting point. Thank you.

I think you would be golden with 4140

Good to hear. Any thoughts on where I should shoot for on the
hardening?

Dave


50-52//just as a gut feeling.

Is the sear carried on the bolt?

Gunner


"The importance of morality is that people behave themselves even if
nobody's watching. There are not enough cops and laws to replace
personal morality as a means to produce a civilized society. Indeed,
the police and criminal justice system are the last desperate line of
defense for a civilized society. Unfortunately, too many of us see
police, laws and the criminal justice system as society's first line
of defense." --Walter Williams