I thought this was going to be big? 
You know DD, we thought it would be nice to offer you a chance to touch off the first PMM round at the shoot as a thank you for putting all this together. But now.......well, we still will make that offer, but we may misplace the 7 foot long linstock at the last minute. You will be forced to light that 12" long quill with a Bic lighter. The look on your face when two pounds of powder BLAST that barrel of concrete toward the horizon should be priceless!!
Victor, We think that 8 oz. to 12 oz. should get our concrete mortar projectiles to 100 yards. We will start with 6 oz. The tube will fit on the rifling machine with a large aluminum rifling head with steel wear pads. The Paulson brothers have made a bigger mortar; we saw their shop built 1861 13" Seacoast Mortar when we visited in Dec. of 2006. The seizmo thingy better be wireless, or we may have to draw lots to see who will man it's controls within the impact zone.
Ex 49'er, Someday we hope to be able to figure out a well shielded and anchored chronograph. With the huge shadow that the big jug will cast, the sensors shouldn't have to be too close, should they? I was just thinking about the Casper shoot today, shooting up there in Wyoming for the big money Mortar prize at 400 yards might be a lot of fun. We will see if two pounds will get us to 400 or not.
A few pics for today's platform build and flip are included below. Mike and I say Thank You!! to Gary, Bruce and my son for their invaluable assistance today.
Mike and Tracy
The secret to accurate hole placement for the 1/2-13 all-thread rod is to select straight timbers at the lumber yard and clamp them to an angle plate or other known square surface on your drill press table. Also measure both holes from the same spot on the same end.
After deciding where to anchor the shell hoist, we built a three part anchor. The piece shown is the bottom plate which is shown on top so it could be traced around and the wood routed out to 1/2" to fit the plate's thickness. The other two parts are an identical plate which goes on top of a double thick timber pedestal and a steel cylinder, welded to the top plate and fits within the large hole in the bottom plate.
The plate fits in it's recess, and, after the platform flip-over, will be on the bottom, between the trailer deck and the bottom platform
surface. In this position the hoist will be able to lift objects from the ground and mortar ammunition from the short side of the platform and feed the muzzle of the mortar on the other side. The mortar position is central to the platform's length and even with the edge of the platform closest to the targets.
A few inches of excess length from the lifting arm guide of the shell hoist anchor provides a handy way to lay out out a unique hole in the platform to be drilled and then sawed. The lower end of the 2" Dia. Shell Hoist lifting arm goes into the 2.030" Dia I.D of the heavy-wall tube which joins the two plates. The O.D. is 3.0".
With Gary as the rock steady cameraman, the lift begins after a short safety discussion. Note the anti kick-back stakes pounded into the ground along the left edge of the right hand ground support beam. These resist sudden movement of the platform as it touches the trailer's edge on the way down.
Relief is felt as the heavy platform reaches vertical. Tracy notices, however, that it is 3/8 of an inch off to the right.
Bruce provides some sideways movement with a 12 Lb. persuader. Wrinkled edges on the trailer are not allowed!
Coming down! Boy did that platform ever get heavy as it reached a point 6" off the trailer. NO pinched fingers!!
One more 1-2-3-HEAVE!! That mass of wood slid very nicely to within 1" of the stop line. Not Bad. A little more sledge-hammer work and she was on the line. All in all, a very good day. Tomorrow we build the upper shell hoist anchor structure and bolt it all together with 3/4-10 bolts and install and TEST the Shell Hoist with it's authentic wooden blocks and sisal rope tackle.
