Antique arsenal machine shop in operation, overhead belt drive

[cannonmn]

Hopefully this is within scope enough to post here.  The shop is at Watervliet Arsenal Museum and some of the machines are old enough to have worked on black powder weapons, so maybe that will help.  Sorry the sound on this video isn't good, the acoustics in that building were terrible and my video equipment not very sophisticated.  You will probably have to turn the sound up on your computer so you can hear some of what the man is saying.

http://www.youtube.com/watch?v=dFN1yEvAhyc

[GGaskill]

It would have been real interesting to see that last machine in action as it had a Welin breech block on it and I have always wondered how that stepped, interrupted thread was cut.  I had guessed a shaper of some kind and at least that guess was confirmed.

[Double D]

Boom lover,

Foster Garage still around?  They had abunch of machines including a big lathe that ran on over head belts like this.

[cannonmn]

how that stepped, interrupted thread was cut.

That's a good question.  The tour guide mentions that the breechblock would have been on the shaper in a position rotated 90 degrees clockwise from how you see it in the video, then the straight channels would be cut to cause the interruptions in the thread.  Since the thread grooves are curved, the shaper wouldn't be able to do that.  I'm still wondering.

[GGaskill]

Could you tell if there was a run-off groove at the end of the threads that butted against the next larger set of threads?

[cannonmn]

Could you tell if there was a run-off groove at the end of the threads that butted against the next larger set of threads?

I can't answer that, but I uploaded onto you-tube some cut footage so you could see more of that 16-inch breechplug.  I put it under title of "Modern Cannon Breech Demo" since there's some of that in it.

Go to:  http://www.youtube.com/watch?v=KkP-R9RDYVs

[Victor3]

Could you tell if there was a run-off groove at the end of the threads that butted against the next larger set of threads?

 I'm thinking that the threaded areas were cut on a milling machine with a tool ground to an angled point (like a 'drill mill').

 A mill setup using a rotary table attached via shafts, U-joints and gears to a table/saddle/knee screw was probably used to produce the helix. I have an old book somewhere (Practical Treatise on Milling by Brown & Sharpe) that describes this with pictures. Maybe I can dig it out and scan them.

 It appears that the shaper might have been employed to make a groove between each stepped section, removing the radius on the thread flanks left at the end of the cut by the tool.

[cannonmn]

It appears that the shaper might have been employed to make a groove between each stepped section

That's what Bob, the tour guide, said was done.  I don't how audible that was on the video.

[Victor3]

 Found the book (1948)...





 This pic gives the general idea...



 I've got overhead projector transparancies from when I taught machine shop classes that show different mill setups for cutting threads, helical gears, etc. on huge Cincinnati and K&T mills. I'll have to find them. Amazing what they could do before CNC came along.

[GGaskill]

I've cut a spiral groove using a setup similar to that. 

It looks like the thread form in the Welin breech block is 90° included angle which would be possible to make with an end mill.

By the way, the Welin breech was invented about 1890.

[Victor3]

I've cut a spiral groove using a setup similar to that. 

 When I worked at McDonnell Douglas in the 80's they still had one large mill with a similar setup that was never torn down, used to make one special part. Only one old timer knew how to run it.

 Right before I left the company they were getting rid of all of the similar tooling. They tossed all of the gears, shafts, fixtures and cutters into bins. The rotary tables (one ~4' in diameter) and dividing heads were strapped to pallets. I was told that the whole lot went for the price of scrap metal. I thought that was awful.

 Looking at the steps in the breech block reminded me of a poem...

 The Successful Designer

The designer bent across his board
with wonderful plans in his noggin stored.

He said as he rubbed his throbbing bean,
“How can I make this tough to machine?”

If this part here were only straight
I’m sure the thing would work first rate.

But ‘twould be so easy to turn and bore
it never would make the machinists sore.

I’d best put an angle right in there
to watch them suckers tear their hair.

I’ll put the holes that hold the cap
way down inside where they’re hard to tap.

This part won’t cut, I’d bet a buck,
for it can’t be held in a vise or a chuck.

It can’t be drilled and it can’t be ground.
In fact the design is exceedingly sound.

He looked again and said “At last!”
Success is mine, it can’t even be cast!

[seacoastartillery]

 Right before I left the company they were getting rid of all of the similar tooling. They tossed all of the gears, shafts, fixtures and cutters into bins. The rotary tables (one ~4' in diameter) and dividing heads were strapped to pallets. I was told that the whole lot went for the price of scrap metal. I thought that was awful.

     That's one specially shaped milling tool and if you think the breech block threads are hard, just contemplate the female threads in the end of the breech!  I've seen what various companies do when they go out of business too.  Like those big screws with the leades rusting at the scrap yard out in a field of daisies and weeds.  Your poem reminded me of one that I wrote a long time ago.  I  probably had a typical inspector's "bunker mentality" at the time.  Or maybe I wrote it after hearing the standard greeting from, yet another new, Quality Assurance V.P., "Hi, my name is Blah Blah; my job is to make your job obsolete, Ha, Ha, Ha."  We just smiled sweetly, and thought, "just what we need as the company spirals downward toward bankruptcy, another effing moron!"  Don't know how I made it for 30 years in manufacturing, but writing the following poem sure helped.

                     The Inspector

The inspector sits down on his familiar stool,
And from his rollaway selects his favorite tool.

It's a nit-picker, and with it he can pick nits so small,
That ten thousand into a thimble could fall.

He loves to hear schedulers rant and bellow,
They must think he is a really mean fellow.

Buyers with their bags always packed for far away places,
Cringe when his D-Stamp appears, you should see their faces!

The Production Manager truly has trouble,
A bad drawing threatens to burst his bubble.

Five machinists and three engineers, try as they might can't figure the math,
They call the inspector, and for him, clear a path.

With eyes wide open and a stride most steady,
The inspector approaches with his calculator at the ready.

With pencil and pad he scribbles a triangle here and a triangle there,
The errant dimension appears as if from thin air.

His work complete, he departs with a smile,
Satisfied he's needed, once in a while.


Regards,

Tracy

[Victor3]

 LOL! That's good Tracy

 I have to say, I'm currently in the most comfortable relationship between management (me), QA and engineering that I've ever seen. We actually try to help eachother to achieve company goals, not derail them with "nit-picking." What a concept, eh?

 As far as the female breech threads go, I think they were probably cut on a mill using a form tool on an arbor. I suspect that the relief grooves between the stepped/threaded sections are wider than the ones on the plug to account for the longer runout required.

 I still don't understand why a stepped thread configuration was used. Seems like a needless hassle.

[GGaskill]

I still don't understand why a stepped thread configuration was used. Seems like a needless hassle.

It allows the breech to open with a fraction of a turn yet gives a high percentage of thread engagement when closed.  The block is turned only one step of threads and it will open because the threads are then in an area that is clear because it has a set of larger diameter threads in it.  Only the segment for the largest diameter threads is thread free (when open) and if the block has three steps of threads, it has 75% engagement when closed; 4 steps gives 80%; etc.  Its higher percentage of engagement allows the block to be thinner (and operate easier) than a cylindrical block.

[Cat Whisperer]

I can only say:

1. When I taught machine design I made EVERY effort to ensure the designers were atuned to ease of manufacturing, ease of assembly and operation.

and

2. We inspect to detect.  The objective is to make good products, not FAIL for whatever reason.

These are principles to live by in manufacturing.  It may not seem that way, because often one sees only one side of the picture.  But as a designer or inspector one MUST look at all perspectives and comunicate such - even if no one else does.

 

[Victor3]

When I taught machine design I made EVERY effort to ensure the designers were atuned to ease of manufacturing, ease of assembly and operation.

 The best designer I ever worked with was a Russian guy. Leonid told me that the first thing they were taught in engineering school in the USSR was "Make it simple, make it strong, make it work."

 By looking at various Soviet-designed military items, you can see how they took this philosophy to heart; maybe a little clunky and rough around the edges, but uncomplicated, easy to produce and durable.

 Leonid would bring new designs to the shop floor and review them with us before releasing them, and would always start with the question "Would this be difficult for you to make?

[subdjoe]

When I taught machine design I made EVERY effort to ensure the designers were atuned to ease of manufacturing, ease of assembly and operation.

 The best designer I ever worked with was a Russian guy. Leonid told me that the first thing they were taught in engineering school in the USSR was "Make it simple, make it strong, make it work."

 By looking at various Soviet-designed military items, you can see how they took this philosophy to heart; maybe a little clunky and rough around the edges, but uncomplicated, easy to produce and durable.

 Leonid would bring new designs to the shop floor and review them with us before releasing them, and would always start with the question "Would this be difficult for you to make?

Yeah.  The Russians and Soviets used the concept of 'krepki ne kracivui" Strong, not beautiful.  Design it so an illiterate peasant can operate and service it without breaking it.  And, I'm not knocking illiterate peasants, my grandparents were all that kind of stock.  But plenty smart.

[GGaskill]

Design it so an illiterate peasant can operate and service it without breaking it.

This policy has its advantages from the perspective of limiting the amount of training personnel require to be able to do the job.

[Victor3]

I still don't understand why a stepped thread configuration was used. Seems like a needless hassle.

It allows the breech to open with a fraction of a turn yet gives a high percentage of thread engagement when closed.  The block is turned only one step of threads and it will open because the threads are then in an area that is clear because it has a set of larger diameter threads in it.  Only the segment for the largest diameter threads is thread free (when open) and if the block has three steps of threads, it has 75% engagement when closed; 4 steps gives 80%; etc.  Its higher percentage of engagement allows the block to be thinner (and operate easier) than a cylindrical block.

 Makes sense. The more common cylindrical interrupted-thread design with two lug areas would only give ~50% engagement and require a ~90 degree turn.

 Hope it was worth the extra effort; I'd estimate the machining time on the Welin plug to be at least 10x that of a cylindrical one near the same diameter. The setups must have been a machinist's nightmare for both plug and receiver.

 Maybe seacoastartillery can whip one up for us.

[seacoastartillery]

 Hope it was worth the extra effort; I'd estimate the machining time on the Welin plug to be at least 10x that of a cylindrical one near the same diameter. The setups must have been a machinist's nightmare for both plug and receiver.

 Maybe seacoastartillery can whip one up for us.

     I had no more mentioned your comment to Mike, when he looked at me with big cow eyes and said, "Just think of it......what a project!"  Without further thought, he grabbed the "15pounder", that's what we call the MSC catalog, and he was off and running.  With him mumbling, "air grinders, air grinders, 80,000 RPM air grinders" as he flipped through the pages, I became more thoughtful and began to examine the possible benefits and also the detriments of such a project.

     First, I had to determine why we both are so fascinated by the prospect of accomplishing such a complicated machining.  Considering the negatives first, I went back to the year of our Lord, 1600, to try to understand our motivation.  William Shakespeare, when he wrote The Merchant of Venice, brought forth the concept of blind attraction to a destructive force.  He wrote, "Thus hath the candle singd the moath."  Today we would say, "Attracted like a moth to a flame."  Also, you should always answer the question, "What is the cost of accomplishing your goal?" 

     With the cost of equipment and learning curve time in mind, someone contemplating such a project as this would be smart to remember what happened to King Pyrrhus of Epirus when he fought the Romans at Heracles and Asculum in 280 and 279 BC.  Although Pyrrhus won both battles against the forces of Rome,  he used up such a substantial percentage of his army winning these battles that Plutarch related, "If we are victorious in one more battle with the Romans, we shall be utterly ruined."  So, as much as you would like to accomplish a lofty goal, you should guard against succeeding via a Pyrrhic Victory. 

     The benefits of successfully making such a complicated breech would be fairly few, primarily because so few people would understand all the money, sweat and headaches that the makers would have to invest to see it through to completion.  We believe the single most important benefit would be in the maker's sense of accomplishment upon successful completion of this very high order project.  This benefit put's this type of project squarely in the arena of the retired, former machinist except for the money.  However, as many of us know, most of the money problems can be overcome with ingenuity and willingness to do some operations the long, hard, way.

     Victor3,  Thank's for getting us excited and enthusiastic, and while we can't say, "look for photos next week", we can tell you that we have added this worthwhile project to the list that we look forward to building upon retirement in about three years.

Not sure if we could make one, but it sure would be a lot of fun to try!

Mike and Tracy

[cannonmn]

M&T, I take it that since I've seen you posting over the past few days, you, like me, skipped the Mansfield OH Civil War show this year?  Or did you fly out there?

[seacoastartillery]

    We had to skip it this year, John; we are just too busy to do it.  Hopefully we can get there next year to study the items on your fascinating table and show some new stuff on our's as well.  It's a great show and is really worthwhile attending.

M&T

[cannonmn]

Thanks.  I checked around with some friends who were there and they assured me I didn't miss anything.

[Victor3]

"Not sure if we could make one, but it sure would be a lot of fun to try!"

Mike and Tracy

 M&T,

 I was thinking the same. I'm quite sure you guys could make a 1/4 scale one.

 I've figured a possible way to make the plug complete on a Bridgeport without the use of a complicated dividing head setup. It would require some fairly simple tooling and a Bridgeport 90 degree milling head (which IIRC, you have).

 Hint on making the threaded sections - A short, large diameter threaded spud fixed to the table (I suppose 'leadscrew' would be an appropriate term for it) and a female threaded piece to match attached to the workpiece. For the internal threads on the barrel; similar setup but rotated 90 degrees 

 What say you???

[GGaskill]

An interesting question:  is a Welin breech block threaded (do the ridges advance with the turning of the block) or are the ridges perpendicular to the axis of the block?

[Victor3]

An interesting question:  is a Welin breech block threaded (do the ridges advance with the turning of the block) or are the ridges perpendicular to the axis of the block?

 Hmmm.... Now there's a twist (or removal of one, if it isn't a thread) to the discussion. Hard to tell from the video.

 Would a helix be required?

 I could be wrong, but I'm thinking that they would have wanted the block to be seated at the front in order to eliminate play between the male/female interface. This would most probably involve a helix.

 However, if a cartrige case contained the charge, the design wouldn't be much different than a large bolt-action rifle (no helix).

 Anyone know how the ammo worked in the Welin?

[Double D]

Bolt action rifles have a helix or else the bolt won't close on the cartridge.  The helix provides the cam power.

[cannonmn]

One "finer point" here regarding Welin-  I think Welin applied only to bag guns which of course had no cartridge case and no great need for camming as the threads engaged and turned.  The sealing was normally obtained by the De Bange or other expanding gas-check pad or mushroom head.  That being said, I don't know whether a bag-gun with Welin stepped, interrupted thread system was cut with a helix or not.  Also, I can't say positively that a Welin-type breech plug was never applied to a cartridge-type weapon.

[subdjoe]

        The benefits of successfully making such a complicated breech would be fairly few, primarily because so few people would understand all the money, sweat and headaches that the makers would have to invest to see it through to completion.  We believe the single most important benefit would be in the maker's sense of accomplishment [/i][/u]upon successful completion of this very high order project.  This benefit put's this type of project squarely in the arena of the retired, former machinist except for the money.  However, as many of us know, most of the money problems can be overcome with ingenuity and willingness to do some operations the long, hard, way.

    Mike and Tracy

I think that the challange - Am I good enough to do it? - is what drives people to try things like this, so yes, the sense of accopmplisment is high on the list.  Also in the mis is "What can I learn from this?"  The chance to learn some new trick or technique to make your next project better or easier.

[Victor3]

Bolt action rifles have a helix or else the bolt won't close on the cartridge.  The helix provides the cam power.

 Yes and no.

 The typical Mauser-style action uses a slight bevel (that acts similar to a helix) at the front ends of the receiver rails that initially engage the bolt lugs to force the cartrige into the chamber. After the lugs rotate past the bevel and headspace the cartrige, there is no further forward motion of the bolt; the rear of the lugs and their mating surfaces in the receiver are perpendicular to the axis of the bore.

 The Schmidt-Rubins used a helix on the bolt lugs and mating surfaces in the receiver (surfaces not perpendicular to the bore).

 Some early bolt-action rifles using straight-wall rimmed cases did not employ a camming feature to seat the cartrige (these headspaced at the rim).

 I was thinking that a cartrige for the Welin (if it used one) might be a straight-wall, rimmed case that was pushed into the chamber manually, then seated by the bolt face until the rim stopped at a shoulder. In this case, there would be no need for a cam/helix to close the bolt.