Victor3 wrote:
“Are you gonna stay with the angled finger relief, or use a ball end mill to make a slot to match up with the groove on the end of the block so the cracker can drop straight in?”
The original idea was to use an angled finger relief groove, but trying to get a cracker inserted into the bore’s end was impossible because of the angle of approach. We decided against relieving or enlarging the bore at the intersection of the bore and the breech block. We wanted to contain the gas and residue of each firing as much as possible, so we opted for an in-line insertion of the cracker. But we are getting ahead of the actual chain of events.
First, we wanted to check the striker assy. off on our list of difficult obstacles to overcome. We were not disappointed. It was a bear! Contributing to our misery was the terrible quality of lumberyard AND hardware store springs. 100% junk! They ALL took a set (stayed shorter after compression) and propelled the striker as if in slow-motion. We will order the final prototype’s springs and those for the production cannon from Wolf Gunsprings, a company that makes quality gunsprings which have some ‘Spring’ to them.
Long story short, we now have a breechloading cannon with a functioning Striker assy. and a loading port which allows loading from the side as did the original Krupp Howitzer, M1866. Getting to that point was a 3 day adventure best explained in pictures.
The Broomfield Cannon Manufactory is almost silent these days, despite frantic activity in the R&D Department. The chimneys are not belching black smoke; the mules which haul the steel from the canal to the various shops are getting fat. The 200 ton forge is silent and the Puddling Furnace is cold.
Tracy and Mike
The second striker with more weight for more energy. .500" diameter head, .250" dia. stem. with room for spring. This one would pop a percussion cap, but the release was unpredictable. I had visions of sear releases, levers, set-triggers and such. Mike wanted a real simple release, but, in the end, it's concept of catching the back edge of a milled notch in the stem on the outside of the rear, captive, washer was not reliable because the springs pushed the stem back to the center of the hole. Despite the angles on both the washer and the stem notch, we could not get it to stay cocked reliably. On this one we ran out of metal in which to cut more notches!
The concept tried next was a lever-actuated, external release effected by a flat, hardened trigger being withdrawn from a sear notch in the stem. This got the sear and trigger away from those *^%#*)^* springs! My contribution was placing the entire striker assy in a can so it could be removed as a module for adjustment or cleaning. Here we are boring a larger two dia. , 1.000" and .750", hole for the 'Can'.
Here the Can is inserted in the bored hole. The two screws for those holes keep the striker assy. captive. A larger, rotating, half-head, screw keeps the Striker Assy Can captive. It also, being a screw, pushes the Striker Assy forward slightly, taking up any looseness and locking the Breech Block against the rear of the Bore for more a more complete gas seal just prior to Firing.
The 'Can' before the end was bored to make it conform to the cylindrical Breech Block.
Yes, yes, I know; we are using a wood-worker's clamp to hold the Can in place for boring. Please remember that gunsmiths, even good ones, are allowed to use whatever they can find in order to get a job done. Quality No-Twist clamps beyond 12" are obscenely expensive!
What the side-loading port looks like, ready for cracker loading. Oops, my pic of the bored Can end is lost, so use some imagination. Without something for scale, you can't see what we discovered is wrong now.
Still hard to tell, but at 1.5" long, the cracker is impossible to align for bore insertion (see next photo), so we found another 'Can' modification necessary. Focus is not perfect, but you can see the angle which stops insertion.
A groove is milled in the 'Can'. This and a set-screw with a cylinder-tip, coming in from the breech's bottom, allows the Can to slide backwards .500" which is more than the .400" we needed to fit the projectile.
Viola! The firecracker, she fits! Finally, we can drop an air-burst projectile in this breech loading, black powder cannon without any hassle.
More later, as I get a chance to take in-focus photos of all the breech parts laid out and a detailed disassembly of the striker as well, which will show Exactly how this piece is fired. If we work steadily, maybe we can show the breech block rotation and transverse movement groove and guide pin assembly too. We will.
