The method I am going to use to build this Mortar is the technique I used to build K.I.S.S. Golfball Mortar.
I am in the process of building a pop can caliber mortar in this technique. Tracy can correct me if wrong, but I believe when Mike and Tracy built the Monstre Mortar the used a similar technique.
Do you really mean that I can correct you THIS time?? This is a rare opportunity; I better not blow it! Ha......only kidding. Actually, your design is definitely stronger, especially when higher pressures are encountered during the firing of heavy projectiles in smaller caliber mortars. Our design, you will notice, in the marker board drawing below, does not have a mechanical locking feature built in to the design via mating shaped tube and plug. We used, instead a 1" thick base plate which supports both and 20 grade 8, 1/2"-20 bolts which tie everything together. The bolts don't have to handle any of the pressure generated during firing. They are there ONLY to hold everything together on the rebound after recoil drives all of the assy. into the wood of the mortar bed slightly.
So, Double D, while it's close to the same, it's not exactly the same as you can see by the drawing below which is very close to the produced design. There were 4 or 5 "redline" features or dimensions which included in the 'C' revision of this drawing which we failed to photograph. The Cosmetic shrould dia. went from 23 to 25 inches, the delrin obturation ring was eliminated and a .250" x .250" notch on the face of the Chamber Piece at the periphery was added for high temp, silicone rubber gasket goo. Another ring of 8, 1/2"-20 bolts was added to the tube near the bottom. The Chamber Piece was changed from 1018 to A-36 and the Tube material was changed from D.O.M. 1026 to Seamless, A-36 precisely machined to fit the Chamber Piece with a small, .003" gap all-around.
We are starting another thread called "A discussion of Mortar Designs, Materials, Methods, Strengths and Weaknesses" ,so as not to hijack this interesting one. We are looking forward to lots of in-process photos Double D. Spend some good money on that crane that George suggested, save your back!
Mike and Tracy
