Antique arsenal machine shop in operation, overhead belt drive

[seacoastartillery]

 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?

     We think a helix shape in the mating threads would be necessary.  There is not a single rotary, bolt-action military rifle without one. The tremendous leverage can overcome a little grit on the cartridge case or a nick in the rim or other anomaly which would prevent the action from closing without that extra crushing power of helical shaped locking lug recesses.  

     We believe that the large bag guns, like most of the naval artillery using the Welin Breech block with De Bange obturator would need  helical threads as well to overcome the firing residue which builds up just ahead of the obturator disk under the mushroom.  Without time to clean this critical area during a rapid or sustained fire mission, we believe the seating power of the helix would be required to reliably seat the breech block to it's correct position.  

    They were lighter, they were quick, they were dependable, but the big disadvantage was their susceptibility to damage and posible jamming during use.  One button torn off a uniform during the serving of gun could jam these very precisely machined assemblies.  A  fumbled wrench could put the breech block out of action with a dented thread.  The German naval gun designers were big on reliability.  They had sliding breech blocks all the way up to 15" Naval Artillery.

     Victor,  your method of large dia. thd. spud and mating female thd. ring fixture sounds pretty good, but our automatic quill feed for boring is broken and would have to be fixed or another method of advance used.  Yep, the 90 deg. head would be needed.  Would the work need to be at 45 deg. to get the 90 deg. included angle thread form?

    Subdjoe is right, we always learn something from a new project and you learn more from one that "pushes the envelope".  When we built that rifling machine, we were building a fairly basic machine, but we learned so, so much about alignment and grinding that we never had to know before and have used several times since.

     As far a doing this, we think 1/4 scale would be a good size, say for an 8" original or maybe a 6" like the British Army Gun, Model 1925, but we have 4 Brookes to build and one big mortar.  The rosewood for the 150 Pdr. Armstrong Rifle upper carriage is waiting to be whittled too.  Had to go to British Columbia to get it, but it was easier to find than white oak!!

Regards,

Tracy and Mike

[Victor3]

"There is not a single rotary, bolt-action military rifle without one."

 If the female grooves (if they're not threads) in the Welin breech had a bevel on one flank at the rear of each start, it would seat the block forward pretty much like a Mauser, which has no 'true' helix, just a similar bevel.

"Victor,  your method of large dia. thd. spud and mating female thd. ring fixture sounds pretty good, but our automatic quill feed for boring is broken and would have to be fixed or another method of advance used.  Yep, the 90 deg. head would be needed.  Would the work need to be at 45 deg. to get the 90 deg. included angle thread form?"

 I was thinking of making the spud/ring with a tight fit on the threads and rotating the part into the cutter by hand. Not sure how you're thinking of using the quill feed

 No 45 deg; you could use an end mill ground to a 90 deg point. Come to think of it, there would be no need of the 90 deg head if you were to mount the spud parallel to the table on an angle plate or something...

[Double D]

Mauser Original designs all had helix bolt lugs and bolt seats seats.  It's one of the features that make the Mauser so expensive to make.  The helix along with the sloppy loose sliding bolt fit that everyone complains about were specific design features made to overcome dirt and debris on the battlefield. 

[thelionspaw]

Twenty-five years ago, when I was doing a demonstration for the arsenal, the museum was going to start a machine shop with the overhead and asked me if I might know where they could get the overhead drive shaft. Being an experienced Dumpster Diver, I just happened to know where we could get one, i.e., in my neighbor's collapsed 100+ year old farm machinery shed.

Years ago, the pickin's were great. Even a water powered generator in another farm's collapsed millhouse.

As for a inquiry post I just read elsewhere: I'll see what I can come-up with on the 2 guns from NYC at the Arsenal. Years ago, my cousin was a colonel there but she is long gone.

It's nap time!

Richard Zzzzzzzzz

[MikeR C]

Well hello Richard. It's good to have you back.

Its bed time ZZzzz

[Victor3]

 This appears to employ the same idea as the Welin but with a taper...

http://www.cannonsuperstore.com/New_Folder/PICT0005.JPG

[seacoastartillery]

     Ah, the taper!  Let's see if we can make a difficult machining even more tricky.  Nice photo, Victor, how about this one we found in New England?  Look how Armstrong-Whitworth complicated manufacture even more with a half tapered and half cylindrical breech block lock-up.  What was the advantage of the taper?

T&M

[cannonmn]

It's a cryin' shame the school lets that very rare piece rust up like that.  As I recall they have two of them, and they are the only two I've seen in the world.

[GGaskill]

It's a cryin' shame the school lets that very rare piece rust up like that.

True, but it could be much worse.

What was the advantage of the taper?

Breech block didn't have to move back before it was free to open?

[seacoastartillery]

It's a cryin' shame the school lets that very rare piece rust up like that.  As I recall they have two of them, and they are the only two I've seen in the world.

     Actually, there are three; the one pictured is at the north end of the upper parade, adjacent to the 25 foot flag pole.  The other two are near the south entrance of Plumley Armory.  When I was a cadet in the mid sixties, the two in rough shape, were in in pretty good condition, well painted and in a much more prominent location.  They were in front of my freshman dormitory, Goodyear Hall, flanking the main entrance walk-way and laid in a north-east and north-west battery configuration.  The right hand gun was pointed at Dodge Hall, and the left hand gun at Alumni Hall, my residences in subsequent years. 

     While a freshman, I used to watch with extreme envy, as the upperclassmen loaded these cannon with empty soda cans and propelled them to 40 or 50 yards with M-80s and cherry bombs.  Yes, the breech blocks functioned back then, until one day when some dunce fired a "live round", an unopened can of Coke, at Dodge Hall.  The Yayhoo leaning out of the second story window disappeared in a hurry as that soda-pop shell whistled up toward him.  It just missed the window opening, exploding on the brick wall, but it was close!  The breech blocks were locked open after that incident.  I always regretted not having an opportunity to bring in rounds onto the upper parade.  I did blow up a section of the Dog River one winter afternoon, but that's another story.

     It is a shame they are not well cared for, you can see what a difference there is between the iron stock on the different guns in those pics.  A volunteer restoration was done 5 or 6 years ago on the "evening gun".  The breech block is modified for 10 GA blanks, and is quickly removed and locked up to prevent pranksters from practicing their trade.  Unfortunately, private military colleges like Norwich University do not have budgets even close to those enjoyed by the service academies.   

Regards,

Tracy and Mike

[seacoastartillery]

What was the advantage of the taper?

Breech block didn't have to move back before it was free to open?

     George,   Mike and I agree with you in that one downward pull on a lever can rotate the block, unlocking it, and swing it immediately along an arc of a circle until it unmasks the chamber.  Mike points out that there are added benefits too, like a notable reduction in the number of parts and assemblies necessary to facilitate breech block movement.  You don't need any lever linkages to force the cylinder shaped block along slides which allow it to move straight back, out of breech engagement.  No cams or rack and pinion gears to assist this movement.  No heavy forged arms to support that heavy block.  No final cam to change block movement from a straight line to an arc for swing out.  These are very significant advantages and don't forget cycle time, pretty darn important, especially if you are firing a counter battery mission.  Thanks for your thoughts on our ponderings.

Regards,

Mike and Tracy

[Victor3]

 Another advantage - The tapered hole would make it easier (if a separate powder bag were used) to load. Not as apt to catch the projectile, charge or gunner's fingers on the female threads

 Ever try to feed a baby some kind of nasty mush?

 "Open wide now Jimmy!"