You are right, Jeff, there are quite a few things to do when you make a cannon tube or a Rifled Cannon Blank. Just to give some of the new members an idea of what is involved in taking two inches of the muzzle of the tube off after rifling to insure the best quality rifling exists there at that crucial location, we will post a few pics. Two of these were posted before on a 7" Brooke update, but are required for this series to be complete.
Mike and Tracy carefully load a rifled tube into the lathe for a muzzle cut-off operation. Not shown is Mike's remembering to block the end of the cascabel with a little 1/2" thick piece of wood to keep the chuck jaws away from the finished reverse radius on the breech.
Seen there is one of many steady rest rings we have made, this one with a tapered I.D. to fit the tube's chase properly. The roller steady rest must have a cylindrical surface to run on. The tube is barely held for the photo, still left to be done is extending the tailstock arbor and live center so the tailstock body can be moved to the right and the saddle moved to the right and then the steady rest moved, closed and tightened and finally the
3 jaw chuck tightened and the chuck wrench removed. We ALWAYS look at the chuck BEFORE we lift the GO lever!!
Proper adjustment of the steady rest on the ring is important if a smooth cut is to be made. No jumping or wobbling tubes allowed!
you can see the cut off tool or "parting tool" is shown starting the cut.
The parting tool deep into the cut just before separation occurs. You have to watch the muzzle section like a hawk here for the first signs of wobble. We stop the lathe at this point and finish with a hacksaw. We DO NOT want the cut off piece to fall down and pivot, jamming and possibly damaging the muzzle!
Here you can see the light colored grooves and the darker lands of the 1 in 55" R.H. Brooke triangular or modified hook-slant rifling. Notice how smooth the face of the cut off piece is, evidence of a perpendicular to tube axis cut off tool and Plenty of dark cutting oil.
Cannon Cocker, this is just one of 22 tasks we have to do on each Rifled Cannon Blank before shipment. One of those tasks takes a full day or two depending. Each of these set-ups takes as much care as the maker is able to muster for an excellent outcome to occur. The rifling process is very repetitive and boring, yet one mistake can ruin the whole effort. We know; we have made them! In fact, in Mike's basement there is a bench under which there is a bunch of rifling mistake tubes stacked up like cordwood. The important thing is this: "We never sold one to a customer". 3,000 dollars of scrap, learning curve, tubes are waiting for a larger size, 1/6 scale cannon to be wanted so they can be reamed out and rifled again. Cannon Cocker writes: "I as a future buyer must say that it looks like you could whip one up for me very quickly." Thanks for your vote of confidence! Time will tell.
I like how freely the cut seems to be. But there has to be some simple procedural change that would eliminate the walking back and forth; that seemed to take almost half of the time for each stroke.
George, The hook cutter is as sharp as we and diamond wheels can make it. The Swedish tool steel that we use can cut two of these tubes without sharpening, more than two thousand strokes. The reason for all the walking is that when we switched from practice tubes to customer cannon tubes we went from 1018 and 1026 steel to Rc 30 pre-hardened 4150 steel, modern high pressure ordnance steel, and to avoid the cutter skipping and gouging the bore surface as it dug in from near the end of the blind hole we had to introduce a positive way to keep the hook cutter support wedge, rock solid. A heat treated rod goes through the 4130 thick walled tube that forms our rifling head shaft into a threaded hole in the back face of the wedge. Just before cutting a new groove the wedge is immobilized by tightening by a nut at the other end. After the stroke, the nut is loosened to allow the cutter to drop a little on the way back.
Victor, We don't see Servo-Shift in the description. but we will check this out. Thanks!
GOW, We try NOT to buy the wrong tool, then two weeks later buy the Right one. Unfortunately, we have done that before.
Tracy