On Friday 31 August 2012 21:02:20 Stuart Stevenson did opine: > One thousandth repeatability of tool and/or insert replacement is almost > impossible. Considering cutting forces the turning repeat is impossible. > Which puts me in a time wasting loop when I go to make another nipple for a #209 primer.
First, I mount a tool that cuts to the left, and cut the first 3 of 5 diameters on a hunk of drill rod. This I have been able to hit within a thou by measuring and using the offset. Then I change to a single tooth threading tool and cut a 1/4-28 thread about 1/4" long on the center of those 3 diameters. I usually wind up taking a couple of hours, touching x off a thou at a time & re-running the G76 until a breech plug used as a threading gage just fits. Then, using a cutoff tool, I move left enough to clear the area that will have a hex nut carved on it, then take it down to about .375 for about the width of the cutoff blade, move left and plunge the cutoff into it deep enough to hide a spring wire about 3 turns wide below the wrench flats that aren't carved yet. Then move left another 100 thou and reduce the diameter there to be similar to the other side of the groove. Then move left again and plunge the cutoff tool, leaving a flange to retain the spring that is about 50 thou wide as it is cutoff the end of the drill rod. Next, I have a 3" piece of cold roll that is tapped to match the breech plug. Its installed and trued up to within a thou, the length of the nipple is dbl checked, s/b around .925", screw it into the cold rolled jig, and bore a .125 hole .850" deep in the center. My tailstock is not that square, so that is usually done from a drill chuck mounted to the toolpost. Once that is done, the toolpost gets turned about 5 degrees CCW, and the bit is checked to make sure a cutting edge is on center. Now it can be used as a boring bar, and a bit of code then expands the first .228" of that hole to about .235 & the touchoff a thou per run gets it to .240" internal. A friction fit on a #209 primer is the target fit. Then a #68 drill is run from the bottom of the 1/8" hole, on thru the end, forming the first of 5 flash holes. The lathe work is done and by then so am I for the day. :( The jig is transfered to the chuck on the rotary table of the mill, and the wrench flats carved. Then it is removed from the jig and turned around so the small diameter stem with the flash hole in the end is sticking out, and the table, axis aligned with X, is positioned to place that same drill bit is about 70 thou from the end, and a #68 hole is drilled all the way thru. The table is rotated 90 degrees and a 2nd #68 hole is drilled all the way thru, making 5, the side holes 4 creating a ring of fire around the central orifice. So its about 2 days to make one of these things. Obviously I'd buy it if I could, but the only one TC makes is side vented, throwing away around 95% of a shotgun primer because true black doesn't take much to light it. It can't light Blackhorn-209 powder without putting 5 grains of one of the other more sensitive powders like pyrodex rs or 777 under it to function as an igniter charge. That multiplies the fouling rapidly, whereas BH209 can be fired 75 times in an afternoon and the last bullet rams as easily as the first, doesn't even need a spit patch between shots. Similar idea as the 16" guns on the Iowa, which I am told use a 12 gauge shotgun shell half full of Herco in order to properly ignite the 40 pound bags of black that are rammed in after setting the shell into contact with the rifling. Note plural of bags, depending on the range there could be 5 or 6 40 lbs bags of powder in one of those guns. A final small bag of smokeless is placed next & the breech closed and the shotgun shell is loaded. The smokeless is said to blow most of the blacks fouling overboard. So said Col Townsend Whelan in his classic ordinance book. Anyway, being able to set some of this up in the tool table sure would seem to be a good idea. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> is up! "Pull the trigger and you're garbage." -- Lady Blue ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
