Seacoast Artillery to Re-Create Krupp Seacoast Gun

[seacoastartillery]

     Thanks, fellas, for all these neat ideas.  I believe we have enough now to craft a prototype.  A blend of your ideas with our own should be enough to see a preliminary set of drawings completed by Monday evening and maybe even a mock up of the breech mechanism in wood. 

     Mr. Gaskill,  when you finish that Disappearing Rifle for Fort MacArthur, let us know.  We will come over to see it!  As for making one of those, well, it could be a retirement project, I guess.  As a money-making project, no way, no how!  You, however, have a distinct advantage over us, you could make your own castings, a definite plus!  Allen, we have looked for dimensioned drawings, nothing so far.  Line drawings are easy to find and not worth much.

      Victor3,   I think we can make it a straight cylinder in cracker size, but a salute gun with it’s bigger bore and bigger charges, maybe not; experiments will tell us what’s necessary.  A re-creation of the hand wheel or t-handle on the exposed end of the breech block is something we were thinking about too.  “Tap it out to load, tap it in to seal & fire.”  Good idea.

      “ Ignition? I like Gary's idea of a nipple. You could install it on top and a small brass hammer could be used to fire it, and also to tap the breech pin in and out.”  We like the nipple idea too, but will probably go with the remainder of his breech mechanism idea, an internal, spring-driven striker.  This gun is not going to weigh enough for hammer firing to be practical.
 
     “ The 'shell' could be a cracker with a teensy-weensy foil bag charge attached. Pierce the bag through the nipple hole. After firing and removing the breech block it would be a breeze to swab it straight through from the rear.”  Yes, we agree, although maybe nitrated paper would work too.  The breech block has to be cylindrical, because of cost considerations, not ‘D’-shaped as the original.  Although we would love to run our shaper to cut a D-shaped hole, the time for that is just not there.  I think a ball detent with two positions would work well, one for loading with the breech block extended to the left, with the ‘fire-channel’ from the nipple to chamber in the “up” position for 10 gr. FFg  loading and also for pipe cleaner cleaning.  The other would be the firing position with the breech block pushed back into the back end of the cannon breech, a “horizontal”, ball detent, position for firing with the nipple cone and #11 percussion cap to the rear and flash channel pointing ahead to the firecracker chamber.  Hard to follow?  Drawings coming Monday night should make it easier. 

    “ Fixed elevation? Hmmm. I don't know 'bout you, but the 1st thing I wanna do when I see a small cannon is fiddle with the barrel; I want it to move. If you decide on the howitzer, the major weight looks like it could be made to be rear of the trunnions and you could add a simple jack screw.”  Yea, you and everyone else, including Mike and I, so the tube will have some elevation and depression movement.  How about a rack and pinion gear mechanism with a T-handle outside the carriage cheek at the right rear.  We can make a simple rack in 10 minutes and a gear to match in 15.  Drill 5 small holes, a little shaft, a little pin and a pinch of silver solder and voila!  The tube, she moves!

    “Just some ideers...”  Thanks very much; they are good ones!!

     Double D,   you need to go to more gunshows to sharpen those negotiating skills.  $10 and some beer?  Heck, DD, we had to promise everyone else FREE HOWITZERS to buy their votes!! ……………………………………………Only kidding.

    LS,   Sorry ‘bout that, but we only have room for a #11 nipple and cap.  Smaller cannons, smaller caps.

    Frank,    Whoa!  50#??  How about 15-25?  If a 50 pounder fell off your shelf or desk, your foot might be in real trouble!

    Thanks Dom;  Mike wants to make one of those mug-style breech loaders in a larger size, maybe 2”, someday.   They are visually very interesting. 

Tracy and Mike

[seacoastartillery]

     Sorry Tim, I almost forgot to mention, Mike and I fired up the Cray computer today to calculate the probability of another person in the American workforce today having the same type of manager that you have.  We found out, after the Cray strained for 6 hours of solid calculation, that it's just you and 36 other members of the workforce, which means that you are in the 5.5 millionth percentile.  He he.  You are a lucky, lucky, lucky, lucky, lucky guy.  Mike and I are genuinely happy for you,Tim. 

Mike and Tracy

[Cat Whisperer]

Thanks, M&T - it is indeed one of the finer pleasures in life to work for the folks that I do.  I even made a tee shirt that says WWMD and listed some of  his quotable sayings (the plant manager's first name is Moe.  He was appropriately embarrased when someone explained it to him.)

[RocklockI]

What are you doing CW bucking for a raise ?  With any luck there wont be a Curly or ...god forbid a Larry ?

Do any of you guys know anything of wall guns ? The later 1760s type that GW may have had ?

I know where a piece of one inch bore by two inch OD heavy duty DOM tube is . Rumor has it that it has been used for 'High Pressurre tests for rifling large projos (really large) .... and  'things .

sometimes these things take on a life of their own ..... JAT   ,Just Ask Tracy !

Hey Larry Hey Moe ? Hey Gary 

[Frank46]

Mike & Tracey, well someone did say big. bet there wouldn't be too many krupp 1000 ton models that fire floating around. Frank

[Cat Whisperer]

...
sometimes these things take on a life of their own ..... JAT   ,Just Ask Tracy !
Hey Larry Hey Moe ? Hey Gary 

 

[Victor3]

 "How about a rack and pinion gear mechanism with a T-handle outside the carriage cheek at the right rear.  We can make a simple rack in 10 minutes and a gear to match in 15.  Drill 5 small holes, a little shaft, a little pin and a pinch of silver solder and voila!"

 Careful there. I have a stopwatch. 

[seacoastartillery]

     Gary,   Before you go off half cocked attempting to build a wall gun,, be sure you take the time to view Squire Robin's 'Wall Gun Movie', the link being at the bottom of his salutation block on his most recent posting.  Maybe seeing it go off will dissuade you from making one!
Yes, I will admit that the Paixhans Monster Mortar took on a life of it's own and placed huge demands on the cannon making duo, which became a cannon making quartet, with Bruce and Gary joining us as the Montana Model Cannon Shoot Date loomed closer and closer.

     Frank,   Do you really mean 1,000 Ton?  I've seen pics and video clips of a 100 ton Armstrong on the Island of Malta in the Med.

     Victor, Victor, Victor;  Do you mean to tell me that I can't get away with anything with you and the other southern Californian checking my numbers?  Just a little poetic license, no that's not what it is, just a little Hyperbole, that's all.  Harmless assertions with a wee bit of inflation!
     Everyone knows that the ancient Romans had great engineers, but they also had excellent philosophers and rhetoricians.  As for a definition of 'Hyperbole', the learned Roman Rhetorician, Quintilian wrote that:  "Hyperbole isn't a deceitful lie", he insisted, but rather "an elegant surpassing of the truth".  Or in the words of the philosopher Seneca, hyperbole "asserts the incredible in order to arrive at the credible".   
     In defense of hyperbole as a unique, useful, figure of speech, we found that this example, from United States Folklore, which illustrates the concept best:  from the Paul Bunyon Tale, "Babe the Blue Ox" comes this example of Paul Bunyan's Winter.

                        "Well now, one winter it was so cold that all the geese flew backward and all the fish moved south and even the                                  snow turned blue. Late at night, it got so frigid that all spoken words froze solid afore they could be heard. People had to                     to wait until sunup to find out what folks were talking about the night before."

A more perfect defense, we could not hope to find elsewhere,

 Tracy and Mike

[RocklockI]

Thank you for pointing out that wall gun video . I must have one now ....No doubt .

 

[KABAR2]

Thank you for pointing out that wall gun video . I must have one now ....No doubt .

 

Gary,
they are fun to shoot, I liked those almost as much as a swivel gun.

I have had two, one German brass mountings 6ft long 75 cal.swamped octagon barrel rifled it looked like a Yeager rifle on steroids, had a pin through the stock 
and was used like a match lock musket, the yoke on the staff had forked ends for the pin to set in, was very accurate,
the other was also huge, 1 inch bore octagon barrel swamped smooth bore never got to fire that one.

[Frank46]

Mike & Tracey, I have a copy of "Munitions of War" that shows the woodcut drawing of the krupp cannon on your first post.
According to the book the gun weighs 112,000 lbs and fires a 1000 pound shot. So maybe thats where I got my numbers confused. Frank

[Victor3]

"Victor, Victor, Victor;  Do you mean to tell me that I can't get away with anything with you and the other southern Californian checking my numbers?  Just a little poetic license, no that's not what it is, just a little Hyperbole, that's all.  Harmless assertions with a wee bit of inflation!"

 Please forgive us. We in CA are regularly forced to double check numbers to make sure the state isn't robbing us any more than they're allowed. Just got the bill for my truck's registration tags; $430

 BTW, I was planning on saying that "I have a calender" not a stopwatch, but then I'd be countering your hyperbole with hypocrisy since I haven't even finished my Morko yet.

[seacoastartillery]

     I guess this is only a third of the whole drawing, but I'm just too tired to do more tonight.  The size of the beast is revealed tonight, with it's lengths and diameters.  The carriage will be about as long, I suppose.  I will try real hard to get the breech-block mechanism drawn tomorrow and maybe the carriage too, but I can't promise that, because there are still a couple details to work out on the sliding breech-block.  I am quite sure you will be interested to know how it works.  Function drawings will accompany the dimensioned engineering drawing tomorrow.  It will be quite a beast of a cracker cannon and I'm estimating the weight will now be 20 to 25 Lbs.  The reinforce is going from 2.00" to 3.00" which will allow a much closer duplication in 1:20 scale of the original Howitzer.

Well what do you think?

Tracy and Mike


The tube.

[Victor3]

 Wow.... Looks great. That should be sturdy enough, eh?

 So it's gonna have a separate reinforce (I see hidden lines there)? Won't that be more spendy to make than turned from solid?

 Hmmmm.... Sliding breech block but no hole out the back. Maybe a slot milled on the R/H side behind the block to load the cracker.

 Am I getting warm?

[seacoastartillery]

    Victor,   You are particularly observant this morning.  We have 20 feet of 3" O.D. X 2" I.D. DOM 1020 Tubing, bought way back for who-knows-what project, so why not use it?  The 1018 main round is 2.0625", so a little tickle on the lathe, and Bingo, a .002" interference fit for assembly via shrink fitting will exist.  Just pop that hoop in the oven at 400 deg, F. for 30 min. with one of my super crispy homemade pizzas and voila!  She expands, slides on and clamps down, perfect! 

     I think I smell cork burning!  Rotating that tube around in your mind, you were!  With the spatial relationships processor going full tilt, he observes no dotted lines going to the rear, tube rotating about the -Z- axis, the rear comes into view, ah, ha, No thru hole!  Rotate another 45 deg. and the thumb slot, .75” dia. at 30 degs. to bore axis comes into view.

     That clever Kraut!  His grandfather must have been Pioneer Sgt. Kunze, who, in WWI, captured the entire garrison of Frenchies at the huge Verdun fortress, Douaumont by sneaking in through an empty revolver-cannon embrasure and locking the whole bunch up in their own dining/meeting hall in 1916 and then going to get some breakfast for himself!  Actually my grandfather came to America in 1904 to avoid the German Army's press gangs who were working hard to fill the Kaiser's ranks.   I'm glad he did!!

      But wait, he's not so clever after all, just a slave to historical detail, I am seeing a side load situation in the old howitzer drawing!  Yep, that's right, we are gonna load our crackers just like they loaded those 1,000 Lb. shells, well...almost.  With no pinched fingers, either!

Thanks to Gary Lorenz with help from Victor3, we have this design and will do our best to execute it precisely in steel.  The function of the breech block will be explained with drawings, tonight.

Tracy and Mike

     

[RocklockI]

Like it ! 

 

[Double D]

Looks to me that a person could drill the bore out to 11/16" and slip in a piece 50 cal Muzzleloading barrel liner and have a shooter also.  Probably would void the warranty.

[seacoastartillery]

     Well a day late but no dollars short!  Thanks, Gary.  And thanks for your inspired design.  Double D says, "Looks to me that a person could drill the bore out to 11/16" and slip in a piece 50 cal Muzzleloading barrel liner and have a shooter also.  Probably would void the warranty." Yes you could do that, but not without redesigning the breech block lock-up and gas seal.  The present design is that of a firecracker cannon NOT a high pressure, heavy projectile, gun.  And you are correct, doing that would void the warranty!  A few little changes here and there and I believe we have a buildable prototype BL cannon design very similar to those built in the 1870s by Krupp.   The drawings pretty much tell the story.

Turning tube steel this weekend,

Tracy and Mike


My drafting corner.  I have all I need with a Drafting Table, a T-square/36" scale, two triangles, a protractor, a 12" steel scale, a circle guide, a lettering guide and a .5mm and .7mm mechanical pencil.  That stuff and UPS/Kinkos is all I need.  On the wall behind my chair is a drawing I made of the tube and trunnion details for the 150 Pdr. (8") Armstrong Rifle used at both Battles of Fort Fisher, North Carolina.  Nobody had a drawing before Mike and I studied that beautiful seacoast rifle at Fort Fisher for 3 days in 2006 and made 16 pages of field drawings and notes which I condensed into a large format drawing with 2 sheets, then sent five copies to the US Army at the United States Military Academy at West Point, New York and five to the State of North Carolina at Fort Fisher.




Making the Firecracker Krupp drawings.




Breech Block details of the Krupp Seacoast Howitzer.




Firing Mechanism and Ball Detent Positions in the breech of the Krupp Howitzer




Ball Detent Position #1 drawing.




Ball Detent Position #3 drawing.




Ball Detent Position #2 drawing.

[Victor3]

 Beautiful design for sure, but didn't someone say...

"Think lower cost!  We want to keep the price closer to $200 than $300 or $400!!"

 I'm now thinking I'll have to have one of these things if the price tag is still near 2 bills

 Just trying to digest your drawings here; they're kinda fuzzy on my screen so I can't read everything...

 On the ball detent assy, are you going to make it captive? One thing I'd suggest rather than a permanent, peened ball/spring in a blind hole is a set screw in the opposite side so that if fouling were an issue one could remove and clean it. Can also adjust spring pressure on the ball that way.

 You're going to cut internal grooves for the ball to seat into on both ends of the bore, right? Just curious; do you have a Wahlhaupter or similar boring/facing head to do this or are you planning on moving the mill table X&Y to acheive the groove? Some other method?

 Again, not being critical, just curious...

"...and the thumb slot, .75” dia. at 30 degs. to bore axis comes into view."

 From what I can see in Ball Detent Position #1 & Firing Mechanism and Ball Detent Positions in the breech of the Krupp Howitzer drawings, it looks like a 3/4" end mill will have to remove a lot of material and will create sharp edges all around the bore ahead of the breech block that isn't shown in the shaded area. Are the drawings correct? I'd think you'd have to go in with a bore-size end mill ahead of the breech block in order to retain sufficient material in the area.

 Also, have you determined how heavy a spring will be required to pop the cap? I'd think it would need to be fairly substantial, considering the limited run the striker appears to have.

[RocklockI]

I like it !

[seacoastartillery]

  Victor3,   Glad you like the design.  You are right; it won't be quite as cheap as we had hoped.  Who knows.  maybe we'll have to go back to a muzzle stuffer to get that 200 dollar price.  Excellent idea on the ball detent assy.  Yes they will be captive as the left hand one will be exposed while the breech block is to the left during capping and loading.  Cleaning would be a good idea in a black powder residue environment. Set screw with threaded through hole is a good improvement.

     V-Grooves will be cut via a different method.  Remember Mike and I were trained as gunsmiths first and as machinists second.  We know how to do a lot with very little equipment, mostly old equipment at that.  We are very familiar with machines that have a "War Finish" plate on them belying their WWII vintage.  That said, you will not be surprised to hear that we are using the old flea-bay Criterion with a home made, 90 deg.  V-tip (.010" radius), grooving tool.  After finish boring the breech block hole in the cannon breech, we plan to switch to the v-groover and, after finding the correct depth, put a .002" to .003" 'preload' on the boring bar shaft and doing several revs, and repeat until the depth is .030".  This avoids lots of set-up hassle and rotary tables (heavy to lift), etc.  After all, if we can penetrate the 4150 tube steel pre-hardened to 30 Rc, when doing 'Blind Hole' rifling, we can certainly do this minor boring job on 1018!

     Yes, we will need a heavy spring, but our 1/4" striker will be almost as heavy as a percussion 'squirrel rifle' hammer, so if we can propel it quickly enough, the energy will be there to pop those light duty #11 caps.  The thumb relief groove is not perfectly depicted; you need another top view, or better yet, a sectional view, A_____A to convey the correct amount of material removal in that area where the cracker enters the bore at a shallow angle.

     Although we are going to turn the tube this weekend, we still need an upper carriage drawing.  We have found an example of the rack and pinion elevation gear I mentioned the other day.  Photos from Fort Trumble near New London, Conn. show that type of elevation gear which is used to elevate and depress the tube of a 10" Rodman Gun in the Water Battery in front of that fort.

Maybe a simpler way to connect that elevation mech. to the tube can be devised.  Hope so, there are too many parts!

Tracy and Mike


Far side rack and pinion in view.




Method of attachment visible on left side gear in this photo.  Two racks are evident, one for each side.




These pinion gear hand wheels gave plenty of mechanical advantage to drive that 10,000 pound tube up or down.  They look great too!






                                              

[wolff]

"These pinion gear hand wheels gave plenty of mechanical advantage to drive that 10,000 pound tube up or down.  They look great too!"

Yes, they look great, and maybe even sexy!  I'm sure you all know the term Watchmakers (and watch Sellers) apply to fabulously intricate mechanical movements: "Complications"  -- used in a good way too! 

I like both, and my vote's for stubby - and if a cool, yet functional, traverse mechanism could be offered up... even an updated "take" on period mechanicals could look great.  As it is, I think the Howie's barrel looks sooo old, that it looks kind of futuristic - Steam Punk they
call it 

brad wolff

[Victor3]

 I do hope you can make them as a breechloader. It's cool and I'd like to have one.

 I never thunk about making an internal groove thataway. I'm gonna file your method away for future reference.  Might save some time if you were to rough it out by going +X, -X, +Y, -Y first, then use your small increments to finish. Also, the tool point doesn't have to begin from a dead stop while dug into the material that way; chipping it during the operation would be a bummer. 

 An alternate method of doing the detent that would be less labor-intensive is to put the grooves in the breech block instead of the bore, drill/tap two holes in the rear of the bbl and use these goodies...



 I think I got them from Mcmaster-Carr.

[RocklockI]

Rack and Pinion gears !!

Yea baby now thats a cool touch!

I am offically placing my oder here and now ,   . I'll take one please .

If these things work ...... well knowing Tracy ....... well There will be bigger ones .

I dont see any reason the design couldnt be enlarged to nearly any size . Pretty soon you'd run out of powder space in the rotating breech block .

Then it would becaome a 'bag gun'with a chamber inside the tube for the projo AND a bagged charge .

I'm not too sure about that angled cut relief on the barrel chamber ...? might be a big time gas leaker .


Of coure rifling it would be next  

 As long as you keep calling it a "Krupp" inspired pre 1897 gun you shouldnt have problems .

No I am not a Lawyer ,but If you get thrown into jail over my contribution to the breech loader design CALL ME personaly I will WILL Bail your gun out of hock !  


Come on guys you know you want one . There will be a muzzle loading one for sure ,but a breech loading cracker thrower !

I even got a name "The Krupp Baby Cracker Killer"  

[dominick]

Could a couple of mini lathe change gears work for a rack and pinion?  I saw a full scale bowling ball cannon on youtube that used a section of automobile flex plate /starter ring gear and the starter gear is fixed to a crank handle. The hub of the ring gear is at the trunnion centerline.

[Victor3]

 Aren't those two rack gears at the back of the bbl?



 If so, you could probably use rack & pinion gears from an RC supplier. They use them for steering cars and boats and they make bronze ones. I think I have a set around here somewhere.

[RocklockI]

Good work thinking Vic ,there another good idea ! Tracy there's a nice RC store right here on Main St .

They have ALL replacment parts for RC Trucks ,Cars , Airplanes ,Helicopters ......

I got to know them fairly well after I decided to become a helicopter flyer ...........
Oh yea ,they got parts !

Frames ,gears ,rotor ,blades ,on and on . They ought to just give you the little indoor helcopter ,cause evn so they make big money on blades , little baby squash plates , batteries .

Vic between you and I all the hard part is done ,Tracy just has to biuld to our specs !

Gary

[seacoastartillery]

     Brad,   I think I am at least a full generation ahead of your 'Steam Punk' terminolgy, but I was curious, so I Googled it.  Hey, that's the stuff I like!  Tom Swift novels, old steam engine technology with gleaming stainless steel, futuristic, sheet metal.  Art Deco stuff.  'Rocket Man' movies.

     Thanks Brad, now I have a name for the way I see the world.  When completed, the cannon should reflect some element of this.

Top of the Chrysler Building to you!

Tracy

Victor3 writes:  “I do hope you can make them as a breechloader. It's cool and I'd like to have one.
 I never thunk about making an internal groove thataway. I'm gonna file your method away for future reference.   Might save some time if you were to rough it out by going +X, -X, +Y, -Y first, then use your small increments to finish. Also, the tool point doesn't have to begin from a dead stop while dug into the material that way; chipping it during the operation would be a bummer.   

 An alternate method of doing the detent that would be less labor-intensive is to put the grooves in the breech block instead of the bore, drill/tap two holes in the rear of the bbl and use these goodies...”

     We WILL make these as breechloaders and the details they have are interesting enough to imagine making 10 or 20 of them instead of only 5 or 6, which would help bring the price per each down.
      File that internal grooving method under, “Unorthodox Methods used by Gunsmiths to Achieve CNC Machine Shop results”.   While you are certainly correct that a breech plan which featured a grooved block would be more quickly done on the lathe, the placement of the threaded holes, for the ball detent assys. (thanks, we just ordered a new McMaster-Carr Catalog) would not be simple or quick with this design.  You would be drilling down into the 2’’ dia. Breech, within .300” of the end of the block, leaving insufficient length of threaded hole for your ball detent assy.  Also, spotfacing before drilling would be required.  The hole from the back end of the breech would be really long, about 2” and would have to be counterbored to avoid a super long threaded section.  Pulley tap time!  No thanks, I’ll use our design, but I will use your +X, –X, +Y, -Y roughing method.  Although the grooving tip will not be a sharp’V’, but rather, have a .010” radiused tip, this would allow the tip to start in a recess which would be easier on the tool. 
      Several emails asked, “How are you going to stop the breech block from rotating.  Our drawing really does not show the ball recess well, but it’s there, of course and that’s why we have ball end mills in lots of sizes.  Fortunately we need a small one for this job.  Small ones are Cheap.  Big ones are VERY expensive.

Gary Rocklock Lorenz writes:  “ Rack and Pinion gears !! 

Yea baby now thats a cool touch!

I am offically placing my oder here and now ,    . I'll take one please .

If these things work ...... well knowing Tracy ....... well There will be bigger ones .

I dont see any reason the design couldnt be enlarged to nearly any size . Pretty soon you'd run out of powder space in the rotating breech block .

Then it would becaome a 'bag gun'with a chamber inside the tube for the projo AND a bagged charge .

I'm not too sure about that angled cut relief on the barrel chamber ...? might be a big time gas leaker .

“Of course rifling it would be next   

 As long as you keep calling it a "Krupp" inspired pre 1897 gun you shouldnt have problems .

No I am not a Lawyer ,but If you get thrown into jail over my contribution to the breech loader design CALL ME personaly I will WILL Bail your gun out of hock !   


Come on guys you know you want one . There will be a muzzle loading one for sure ,but a breech loading cracker thrower !”

     Gary,   Rifled, maybe, bigger maybe, but legal hassles, No.  The only bail we  will be discussing is the one which will be under your chin after we pull the paint bucket down over your head if you persist.  As I explained to you on the phone today, the relief cut will not be a gas leaker at all, but I don’t have time to make three more drawing views to make it absolutely clear.  Your order is accepted and appreciated!

Dominick writes:   “Could a couple of mini lathe change gears work for a rack and pinion?  I saw a full scale bowling ball cannon on youtube that used a section of automobile flex plate /starter ring gear and the starter gear is fixed to a crank handle. The hub of the ring gear is at the trunnion centerline.

     Great idea Dom, where can I get an 8” dia. Ring Gear and .5” to .75” pinion gear to match?  Sure beats making them, depending on cost, of course.  Straight racks which can be thinned and bent to a 4” radius and matching spur gears are available from Small Parts, Inc. and others for about 15 dollars per set. 

     Those are racks at the rear of the breech and a portion of the reduction gear-train coming from a hidden handwheel somewhere.  Victor, there are too many parts which yields too much assy. time.

    Gary writes, “Vic between you and I all the hard part is done,  Tracy just has to build to our specs !” 

     This latest blurb from you proves that you are truly delusional.  Maybe even certifiable!  How can you treat me so disrespectfully?  Remember that idea you had at first to turn those bronze cannon tubes out of wax and spray paint them bronze, saying, “They’ll never know the difference?”  I talked you out of that didn’t I?  I’m your buddy, right?   Well then, be nice!

Tracy and Mike

[Victor3]

    While you are certainly correct that a breech plan which featured a grooved block would be more quickly done on the lathe, the placement of the threaded holes, for the ball detent assys. (thanks, we just ordered a new McMaster-Carr Catalog) would not be simple or quick with this design.  You would be drilling down into the 2’’ dia. Breech, within .300” of the end of the block, leaving insufficient length of threaded hole for your ball detent assy.  Also, spotfacing before drilling would be required.  The hole from the back end of the breech would be really long, about 2” and would have to be counterbored to avoid a super long threaded section.  Pulley tap time! 

 So the detent assemblies need to be 90 degrees to eachother?

 I was thinking parallel from the rear, on either side of the striker. The smallest of the detent thingies I show has a 10-32 thread with a 3/32" ball. A 10-32 tap is ~2.5" long, so no pulley tap required. The other ones are 1/4-20 & 5/16-18.

 Anywhoo, just trying to offer possible ways keep them affordable for day laborers like me. 

[Victor3]

     
 Several emails asked, “How are you going to stop the breech block from rotating.  Our drawing really does not show the ball recess well, but it’s there, of course and that’s why we have ball end mills in lots of sizes.  Fortunately we need a small one for this job.  Small ones are Cheap.  Big ones are VERY expensive.

 Okay guys, allow me one more question and I won't bug you anymore...

 Are you going to set the bbl (or head) at 45 degrees, go in and cut one 1/8" dia dimple in the groove for the R/H ball to fall into at the firing position (I note that you said "recess" not recesses)?

 And I'll make one more 'appeal' for recesses in the breech block if I may.

 You could, I think fairly easily, put three dimples in grooves in the block; two for powder loading & capping in the R/H groove, one for firing position in the L/H groove.

 (This would be assuming two parallel detents from the rear as described in the previous post. Actually, a single detent assy on the L/H side would do the job)

 Also, you could heat treat the breech block pin so it won't be as subject to wear. Seeing as how hardened balls under spring pressure will be contacting either the breech block pin or the breech itself (depending on where the detent assys are installed), hardening one or the other might be prudent.

 I'll be quiet now...