Re: [Emc-users] Any idea how they machine these?

2016-02-08 Thread Gene Heskett
On Monday 08 February 2016 08:39:10 Marcus Bowman wrote: > On 8 Feb 2016, at 12:49, Peter Blodow wrote: > > In other words, you pretend to cut a left-hand thread but have the > > machine run in reverse so it turns out right hand? > > Peter Blodow > > Yes; kind of I prefer to think of it as

Re: [Emc-users] Any idea how they machine these?

2016-02-08 Thread andy pugh
On 8 February 2016 at 16:12, Gene Heskett wrote: > > One question remains: Does the thread even have to have a spiral > component, eg does it need to actually advance into the hole as it > turns? Common sense says it should, in order to achieve a gas tight > seal against a

Re: [Emc-users] Any idea how they machine these?

2016-02-08 Thread andy pugh
On 7 February 2016 at 23:37, Marcus Bowman wrote: > Easy. mount the tool upside down, and start at the blind bottom. Sorry, I am not quite understanding your description? -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto

Re: [Emc-users] Any idea how they machine these?

2016-02-08 Thread Marcus Bowman
On 8 Feb 2016, at 10:04, andy pugh wrote: > On 7 February 2016 at 23:37, Marcus Bowman > wrote: > >> Easy. mount the tool upside down, and start at the blind bottom. > > Sorry, I am not quite understanding your description? > Yes; apologies; my rather

Re: [Emc-users] Any idea how they machine these?

2016-02-08 Thread John Figie
On Feb 8, 2016 5:02 AM, "andy pugh" wrote: > > On 8 February 2016 at 10:42, Marcus Bowman > wrote: > > For an internal right-hand thread, the problem is often that the tool feeds into the hole from the right, and bumps into the bottom of

Re: [Emc-users] Any idea how they machine these?

2016-02-08 Thread andy pugh
On 8 February 2016 at 10:42, Marcus Bowman wrote: > For an internal right-hand thread, the problem is often that the tool feeds > into the hole from the right, and bumps into the bottom of the hole. It would > be the same for an external thread bumping into

Re: [Emc-users] Any idea how they machine these?

2016-02-08 Thread Peter Blodow
In other words, you pretend to cut a left-hand thread but have the machine run in reverse so it turns out right hand? Peter Blodow Am 08.02.2016 11:42, schrieb Marcus Bowman: > On 8 Feb 2016, at 10:04, andy pugh wrote: > >> On 7 February 2016 at 23:37, Marcus Bowman >>

Re: [Emc-users] Any idea how they machine these?

2016-02-08 Thread John Thornton
When I worked in the shipyard we cut the gun mounts with pretty conventional home made boring bars made out of H beams and other stuff with a star wheel on the outside that hit a stob welded to the wall to increment the tool out. It was turned by a gear motor attached to the ceiling. Took

Re: [Emc-users] Any idea how they machine these?

2016-02-08 Thread Marcus Bowman
On 8 Feb 2016, at 12:49, Peter Blodow wrote: > In other words, you pretend to cut a left-hand thread but have the > machine run in reverse so it turns out right hand? > Peter Blodow > Yes; kind of I prefer to think of it as cutting a right hand thread upside down (or is that inside out?).

Re: [Emc-users] Any idea how they machine these?

2016-02-08 Thread Gene Heskett
On Monday 08 February 2016 11:23:58 andy pugh wrote: > On 8 February 2016 at 16:12, Gene Heskett wrote: > > One question remains: Does the thread even have to have a spiral > > component, eg does it need to actually advance into the hole as it > > turns? Common sense says it

Re: [Emc-users] Any idea how they machine these?

2016-02-08 Thread Ed
On 02/08/2016 11:14 AM, Gene Heskett wrote: > On Monday 08 February 2016 11:23:58 andy pugh wrote: > >> On 8 February 2016 at 16:12, Gene Heskett wrote: >>> One question remains: Does the thread even have to have a spiral >>> component, eg does it need to actually advance into

Re: [Emc-users] Any idea how they machine these? (Cannon, techical not for problem with neighbours)

2016-02-08 Thread Nicklas Karlsson
> >> Screwed breeches of the Welin or de Bange type are only used with > >> bagged charge guns. They both use a de Bange obturator for sealing > >> whereas a brass-case gun used the case for obturation. > >> This might mean they need no lead, but the pictures seem to indicate > >> one. > > Krupp

Re: [Emc-users] Any idea how they machine these? (Cannon, techical not for problem with neighbours)

2016-02-08 Thread Ed
On 02/08/2016 01:56 PM, Nicklas Karlsson wrote: Screwed breeches of the Welin or de Bange type are only used with bagged charge guns. They both use a de Bange obturator for sealing whereas a brass-case gun used the case for obturation. This might mean they need no lead, but the

Re: [Emc-users] Any idea how they machine these?

2016-02-08 Thread Gene Heskett
On Monday 08 February 2016 14:21:35 Ed wrote: > Rifled Breech Loader Thanks Ed. Educational reading to be sure. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page

Re: [Emc-users] Any idea how they machine these?

2016-02-07 Thread Stuart Stevenson
Andy, I saw a 60 taper machine in storage here in Wichita. It was from an arsenal. The machine was huge. I would think it could cut the threads with a thread mill or single point tooling with the size of the adapter. I had never imagined an adapter that size. The attached picture shows a

Re: [Emc-users] Any idea how they machine these?

2016-02-07 Thread tom-emc
Super sized machines are still made. IMTS (in Chicago Sept 12-16 this year) has had giant lathes in the past. I was amazed at one that had what looked to be a railroad car axle with wheels which appeared to be turned from a single billet of steel (that must have been enormous!). By the way,

Re: [Emc-users] Any idea how they machine these?

2016-02-07 Thread John Kasunich
Considering that it was the 1940s, I'm not sure how common thread-milling was. Plenty of room inside that breech - maybe a cam-operated "rapid retract" single point threading tool? Found this page, doesn't explain how they cut the threads but does elaborate a bit on other construction features.

Re: [Emc-users] Any idea how they machine these?

2016-02-07 Thread Jack Coats
When in college at TAMU, the mech engr machine shop had some big equipment. One lathe would swing about 6' dia, and 20'+ length in the bed plus head stock. That was the largest engine lathe I have seen. I never saw them use it, but it was kept in usable shape and yes, they kept some standard

Re: [Emc-users] Any idea how they machine these?

2016-02-07 Thread John Kasunich
A post on this page: http://yarchive.net/metal/artillery_thread.html says: In full size practice the male and female threads are SCREWCUT (not Milled) on specially adapted, relieving lathes with an interrupted indexing motion. This usually takes the form of a special, heavy duty, "geneva" type

Re: [Emc-users] Any idea how they machine these?

2016-02-07 Thread andy pugh
Maybe I should have been more explicit about the question... How do you machine an internal part-thread that ends hard against a shoulder? -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto

[Emc-users] Any idea how they machine these?

2016-02-07 Thread andy pugh
https://en.wikipedia.org/wiki/Welin_breech_block#/media/File:Sailor_looking_into_the_breech_of_16_inch_gun_aboard_USS_Alabama_(BB-60).jpg I suspect an extremely specialised machine for the internal version. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto

Re: [Emc-users] Any idea how they machine these?

2016-02-07 Thread Bruce Layne
I have a friend who is a mechanical engineer at the Naval Ordnance Station in Louisville. I inquired about the machining on these big naval guns, and he told me that most of the drawings are from the 1940s, and in general, the machining is manual and conventional, although the lathes and

Re: [Emc-users] Any idea how they machine these?

2016-02-07 Thread John Kasunich
On Sun, Feb 7, 2016, at 04:18 PM, andy pugh wrote: > Maybe I should have been more explicit about the question... > > How do you machine an internal part-thread that ends hard against a shoulder? > Very carefully :-) This pic http://www.eugeneleeslover.com/PAGE_56_Figure_5B10_C.JPG shows

Re: [Emc-users] Any idea how they machine these?

2016-02-07 Thread Ken Strauss
bruary 07, 2016 4:47 PM > To: emc-users@lists.sourceforge.net > Subject: Re: [Emc-users] Any idea how they machine these? > > A post on this page: > http://yarchive.net/metal/artillery_thread.html > > says: > > In full size practice the male and female threads are SCREWCUT

Re: [Emc-users] Any idea how they machine these?

2016-02-07 Thread Marcus Bowman
> From: John Kasunich [mailto:jmkasun...@fastmail.fm] >> Sent: Sunday, February 07, 2016 4:47 PM >> To: emc-users@lists.sourceforge.net >> Subject: Re: [Emc-users] Any idea how they machine these? >> >> A post on this page: >> http://yarchive.net/metal/art

Re: [Emc-users] Any idea how they machine these?

2016-02-07 Thread Marshland Engineering
In a shaper where the part being machined rotates. If you look closely there is a small relief slot at the end of each thread. -- Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM +

Re: [Emc-users] Any idea how they machine these?

2016-02-07 Thread Stuart Stevenson
Andy, Now I see what you are asking. It would be educational to look at the part to see what the tooling marks show. You may be able to identify a pattern to know how they were cut. On Sun, Feb 7, 2016 at 3:18 PM, andy pugh wrote: > Maybe I should have been more explicit

Re: [Emc-users] Any idea how they machine these?

2016-02-07 Thread Ed
On 02/07/2016 02:15 PM, andy pugh wrote: > https://en.wikipedia.org/wiki/Welin_breech_block#/media/File:Sailor_looking_into_the_breech_of_16_inch_gun_aboard_USS_Alabama_(BB-60).jpg > > I suspect an extremely specialised machine for the internal version. > I restored a 75mm Krupp that had a similar