[Jon[_4_]]

"Randy" wrote in message
...
I was looking to buy some bore cleaning brushes to clean out small
holes, have some in .38 cal. Well I found out the larger shotgun bore
brushes have a 5/16-27 thread on them, thought this to be very
strange, the smaller ones are a standard 8-32.

Where did a 5/16-27 come from? common on other gun stuff?

Good place to buy them cheap? or other small wire brushes to use
instead of bore brushes?

Thank You,
Randy

Remove 333 from email address to reply.

MSC has that tap, HSS Special hand tap, plug 04841201 $14.44, bottoming
04841219 $14.44
these are imports, btw

gun screw threads are strange ducks, but, I dunno why this one is what it is

[DrollTroll]

"Jon" wrote in message
news%%mk.394$ZV1.194@trnddc07...

"Randy" wrote in message
...
I was looking to buy some bore cleaning brushes to clean out small
holes, have some in .38 cal. Well I found out the larger shotgun bore
brushes have a 5/16-27 thread on them, thought this to be very
strange, the smaller ones are a standard 8-32.

Where did a 5/16-27 come from? common on other gun stuff?

Good place to buy them cheap? or other small wire brushes to use
instead of bore brushes?

Thank You,
Randy

Remove 333 from email address to reply.

MSC has that tap, HSS Special hand tap, plug 04841201 $14.44, bottoming
04841219 $14.44
these are imports, btw

gun screw threads are strange ducks, but, I dunno why this one is what it
is

Singer (the sewing machine people, who also have a repertoire of nifty
industrial products), were legendary for their in-house oddball screw
sizes/pitches.
Which, of course, you had to order from them. Beautiful plated/SS screws,
tho, often oval/filister headed, shoulder, etc.

Also, hazarding a guess, I think some oddball sizes were created here to
match foreign/Bri'ish threads, and sometimes to serve as "jam threads", by
just being a tad different from a std thread.

Just 10-32 and 10-24 throws me for a loop.... Also #12, 14 screws....
--
DT

[Randy]

I was looking to buy some bore cleaning brushes to clean out small
holes, have some in .38 cal. Well I found out the larger shotgun bore
brushes have a 5/16-27 thread on them, thought this to be very
strange, the smaller ones are a standard 8-32.

Where did a 5/16-27 come from? common on other gun stuff?

Good place to buy them cheap? or other small wire brushes to use
instead of bore brushes?

Thank You,
Randy

Remove 333 from email address to reply.

[Paul K. Dickman]

"Randy" wrote in message
...
I was looking to buy some bore cleaning brushes to clean out small
holes, have some in .38 cal. Well I found out the larger shotgun bore
brushes have a 5/16-27 thread on them, thought this to be very
strange, the smaller ones are a standard 8-32.

Where did a 5/16-27 come from? common on other gun stuff?

Good place to buy them cheap? or other small wire brushes to use
instead of bore brushes?

Thank You,
Randy


I suspect that just about anything with 27 tpi evolved from gas piping.

Back when homes were lit with gas, there was a lot of small piping needed.

A quick check shows 1/16 in nominal pipe had 27tpi and an OD of .313"

Sounds like the ticket.

Paul K. Dickman

[Wes[_2_]]

Randy wrote:

I was looking to buy some bore cleaning brushes to clean out small
holes, have some in .38 cal. Well I found out the larger shotgun bore
brushes have a 5/16-27 thread on them, thought this to be very
strange, the smaller ones are a standard 8-32.

Where did a 5/16-27 come from? common on other gun stuff?

Good place to buy them cheap? or other small wire brushes to use
instead of bore brushes?

Thank You,
Randy

Remove 333 from email address to reply.

http://jtsmachine.com/jtswebshop/Taps_Dies/T058.asp

Wes
--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller

[Mark Rand]

On Fri, 08 Aug 2008 14:03:30 -0500, Randy wrote:

I was looking to buy some bore cleaning brushes to clean out small
holes, have some in .38 cal. Well I found out the larger shotgun bore
brushes have a 5/16-27 thread on them, thought this to be very
strange, the smaller ones are a standard 8-32.

Where did a 5/16-27 come from? common on other gun stuff?

Good place to buy them cheap? or other small wire brushes to use
instead of bore brushes?

Thank You,
Randy

Remove 333 from email address to reply.


5/16-27 is a British, gas (brass pipe) thread. Might not be of any help
though...


Mark Rand
RTFM

[Richard J Kinch]

Paul K. Dickman writes:

I suspect that just about anything with 27 tpi evolved from gas piping.

Sure, but that just defers the questions as to why 27 at all? Market
manipulation?

[DoN. Nichols]

On 2008-08-08, Randy wrote:
I was looking to buy some bore cleaning brushes to clean out small
holes, have some in .38 cal. Well I found out the larger shotgun bore
brushes have a 5/16-27 thread on them, thought this to be very
strange, the smaller ones are a standard 8-32.

Where did a 5/16-27 come from? common on other gun stuff?

Common on lamp sockets and the tubes which carry the wires to
them. I think that they were originally the thread on indoor gas
lights.

And 5/8-27 is a common microphone mount thread.

Some lathes with quick-change gearboxes can cut 27 TPI (like my
Clausing), some can not (including at least *some* South Bend lathes).

Of course pretty much any lathe with manual change gears can be
set up to cut that.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

[David Billington]

Mark Rand wrote:
On Fri, 08 Aug 2008 14:03:30 -0500, Randy wrote:


I was looking to buy some bore cleaning brushes to clean out small
holes, have some in .38 cal. Well I found out the larger shotgun bore
brushes have a 5/16-27 thread on them, thought this to be very
strange, the smaller ones are a standard 8-32.

Where did a 5/16-27 come from? common on other gun stuff?

Good place to buy them cheap? or other small wire brushes to use
instead of bore brushes?

Thank You,
Randy

Remove 333 from email address to reply.



5/16-27 is a British, gas (brass pipe) thread. Might not be of any help
though...


Mark Rand
RTFM


Mark,

Are you thinking of BSB (British Standard Brass, although not as far as
I am aware a BS standard) which is a 26 TPI constant pitch series with
55degrees Whitworth form and often confused with some of the 26TPI
members of BSC which uses a 60 degree thread form. I looked up BSP
yesterday but thread of this size in BSP use 28 TPI.

[Grumpy]

"David Billington" wrote in message
...
Mark Rand wrote:
On Fri, 08 Aug 2008 14:03:30 -0500, Randy wrote:


I was looking to buy some bore cleaning brushes to clean out small
holes, have some in .38 cal. Well I found out the larger shotgun bore
brushes have a 5/16-27 thread on them, thought this to be very
strange, the smaller ones are a standard 8-32.

Where did a 5/16-27 come from? common on other gun stuff?

Good place to buy them cheap? or other small wire brushes to use
instead of bore brushes?

Thank You,
Randy

Remove 333 from email address to reply.



5/16-27 is a British, gas (brass pipe) thread. Might not be of any help
though...


Mark Rand
RTFM


Mark,

Are you thinking of BSB (British Standard Brass, although not as far as I
am aware a BS standard) which is a 26 TPI constant pitch series with
55degrees Whitworth form and often confused with some of the 26TPI members
of BSC which uses a 60 degree thread form. I looked up BSP yesterday but
thread of this size in BSP use 28 TPI.


It may be an American 1/8" NB pipe thread. That has a 27 TPI pitch

[BillM[_2_]]

1/8" NPT threads, shotgun cleaning rods, the
copper pipe on Victor torch rosebuds
are the 27 TPI applications I've run into.
No idea where it actually originated. My South
Bend won't do it. I'm sure some lathes
will, I just haven't seen one.

Bill

[Polymer Man]

Yup, that sounds like an 1/8" straight pipe thread which is a
variation of the more common tapered pipe thread. You should be able
to screw it to any standard 1/8" pipe fitting. So, I'd wager they were
using standard pipe as the rod and using a standard pipe thread for
the connections. Why use an odd thread pitch on pipe threads? Perhaps
to prevent people from attempting to screw standard fasteners into the
tapered threads. That would deter folks from trying to cap a pipe with
a standard screw, which would not seal well due to a lack of taper.

If memory serves me, garden hose threads, which are referred to as
3/4" GHT, are 1 1/16 by 11 1/2 TPI. Now there is an oddball thread...

[Paul K. Dickman]

"Richard J Kinch" wrote in message
...
Paul K. Dickman writes:

I suspect that just about anything with 27 tpi evolved from gas piping.

Sure, but that just defers the questions as to why 27 at all? Market
manipulation?

Gas lighting was starting to spread while Maudslay was still inventing the
screwcutting lathe.

My personal guess is that 27tpi is as fine a thread that men can reliably
chase freehand.

Paul K. Dickman

[F. George McDuffee]

On Fri, 08 Aug 2008 23:34:32 -0500, Richard J Kinch
wrote:

Paul K. Dickman writes:

I suspect that just about anything with 27 tpi evolved from gas piping.

Sure, but that just defers the questions as to why 27 at all? Market
manipulation?
===============
That was the change gears installed on the lathe when the rush
order for some 5/16 screws came in?

[Jim Wilkins]

On Aug 8, 3:03*pm, Randy wrote:
...larger shotgun bore
brushes have a 5/16-27 thread ...
Good place to buy them cheap? *or other small wire brushes to use
instead of bore brushes?
Randy

Enco 319-6373 $14.27 for the plug tap, 319-6469 $13.96 for the die.
They also have 1/4-80 if you ever need one. The few things I've bought
from them recently were good quality.

The South Bend 10L can cut 11-1/2 and 27 TPI.

Jim Wilkins

[Gerald Miller]

On Sat, 9 Aug 2008 09:31:43 -0500, "Paul K. Dickman"
wrote:


"Richard J Kinch" wrote in message
. ..
Paul K. Dickman writes:

I suspect that just about anything with 27 tpi evolved from gas piping.

Sure, but that just defers the questions as to why 27 at all? Market
manipulation?

Gas lighting was starting to spread while Maudslay was still inventing the
screwcutting lathe.

My personal guess is that 27tpi is as fine a thread that men can reliably
chase freehand.

Paul K. Dickman

I have run across a close approximation to 1/8 - 27 NTP but with 28
TPI, and since I was rejuvenating junk, I just ran the 27 TPI tap in
and used a bit of extra pipe dope.
Gerry :-)}
London, Canada

[Paul K. Dickman]

"Gerald Miller" wrote in message
...
On Sat, 9 Aug 2008 09:31:43 -0500, "Paul K. Dickman"
wrote:


"Richard J Kinch" wrote in message
.. .
Paul K. Dickman writes:

I suspect that just about anything with 27 tpi evolved from gas piping.

Sure, but that just defers the questions as to why 27 at all? Market
manipulation?

Gas lighting was starting to spread while Maudslay was still inventing the
screwcutting lathe.

My personal guess is that 27tpi is as fine a thread that men can reliably
chase freehand.

Paul K. Dickman

I have run across a close approximation to 1/8 - 27 NTP but with 28
TPI, and since I was rejuvenating junk, I just ran the 27 TPI tap in
and used a bit of extra pipe dope.
Gerry :-)}
London, Canada

The Brits use 28tpi in the same small nominal size pipes. It also has a
55deg thread.

Paul K. Dickman

[DoN. Nichols]

On 2008-08-09, Richard J Kinch wrote:
Paul K. Dickman writes:

I suspect that just about anything with 27 tpi evolved from gas piping.

Sure, but that just defers the questions as to why 27 at all? Market
manipulation?

To discourage using homebrew devices in a safety-sensitive
application is my guess. This eliminates using standard screws drilled
hollow as fittings, since you can't find a standard screw at 27 TPI. :-)

And in those days -- it was not just fire/explosion danger. The
gas used did not have the butyl mercaptain (sp?) additive to give it an
odor, so it was easy to be killed by a leak.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

[Martin H. Eastburn]

Pipe threads would be rough on a lathe - having to do it on a taper
and having the cutter perpendicular to the face.

Martin

Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
TSRA, Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal.
NRA Second Amendment Task Force Charter Founder
IHMSA and NRA Metallic Silhouette maker & member.
http://lufkinced.com/


BillM wrote:
1/8" NPT threads, shotgun cleaning rods, the
copper pipe on Victor torch rosebuds
are the 27 TPI applications I've run into.
No idea where it actually originated. My South
Bend won't do it. I'm sure some lathes
will, I just haven't seen one.

Bill




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