Due to family activities we will have to postpone our Cape Hale shooting session until the weekend after next, but that's O.K. because the Plater said that we had to have all parts ready for black oxide at 8:00 AM tomorrow. When you are right in the middle of a gundrilling session that saw ALL of the .354" (9mm) bores drilled on 18 tubes, you don't ever jump up and start doing some completely different thing if you are serious about keeping costs and thus prices, low. The only exception to that would be to respond to a customer emergency, I guess. We never had one of those!
Skipp, you can still pick either the .312" Dia. 'firecracker' bore or the multi-purpose, 9mm bore size. All guns will be blued; there is no option there. Just send us an email by close of business on Friday and we will give you your choice. Use this email: seacoastartillery@gmail.com Thank you.
Double D, Sorry, but we won’t be doing that archive thing you mentioned. Maybe after retirement we will have time. The info will have to be strictly generic, numbers of what type sold, etc.
Mike proved his worth today as he does almost every day. While I did the "grinding to the line" job on the cheek pieces, he halted the gundrilling of the 9mm bore tubes and re-sharpened the carbide cutting tip on that gundrill with only 3 pieces to go out of 18 total of that size. He told me that the cutting edge was eroded just under the very edge and that tool failure was possible. We bought a new diamond cup wheel last week from MSC and it worked very well indeed after very careful set-up on the mill. Angles were checked on the Optical Comparator first, so they could be accurately duplicated. After 2 hours of grinding and inspecting Mike said it was as good as new. It drilled the 7" deep hole in the last three tubes just as nicely as the first three.
Today we will deep hole drill the seven .312 dia bores in the remaining tubes and sand the cheek bottoms on another 30 parts and maybe start drilling the 1/4" dia. bottom edge bolt holes in the cheeks.
Thanks for a firecracker primer, Gary and thanks Andy for a clarification of the options available.
Cat Whisperer, As to your acceptance of a 'second' (wink, wink), I guess that would make it a first, first Proto and a serial Number of FF Proto #1 would be appropriate. We would never propose to giving an exhaulted east coast moderator or anyone a -2 or minus anything! We have our standards to maintain, you know. Tim, it's good to maintain your sense of humor as you go through life. Fortunately for us, you do.
That's it; enjoy the pics.
Mike and Tracy
P.S. Now I know what you mean, DD. And thanks for the "Made in China" comment too. Sure do appreciate that!! DD, do you remember what the 'Soup Nazi' said to George Costanza in that most famous of "Seinfeld" episodes. When George fumbled around and wasted his time, the soup vendor said to him: "NO SOUP FOR YOU!! ONE YEAR!!!" We, unlike the soup vendor, would really hate to say: "No Krupp for You!" but, if pushed, you never know what could happen. Wink, wink, wink.
This is what my daughter had to face as she was going to work in Boulder, Colorado this past Monday. This is Colo. Route 36 just before it makes a bend to the north to become 28th street. The most destructive fire in Colorado history raged just 4.5 miles from where she works.
We thought it would be interesting to show you guys what equipment you need to use to drill a gundrilled hole deep into a steel 'round'.
Although there are other ways to do it, we find the Water Soluable Coolant/Lubricant, Compressed Air Driven, Pump by Sterling Gundrills, Inc. works extremely well for us. You can lubricate the tool, cool it and flush the chips with 900 PSI cutting oil too. But if a hose bursts or a clamp lets go, LOOK OUT!! Your entire shop would be completely bathed in cutting oil in just seconds. Ahhhhh, NO Thanks!!
In this photo you see the pump on the right and cutting fluid and compressed air lines within a spiral, plastic shroud leading to the air/fluid mixer, a venturi device attached to the large, mono-block which holds the drills and reamers rigidly.
This is a close look at the drill-holding fixture we made to provide exact alignment of deep hole drills and reamers, boring bars and finish reamers. We call it the Mono-Block and it weighs almost 20 Lbs. It has a series of bushings, having various I.D.s to hold gundrills large and small. We can hold drills up to 1.500" with this tool. It has a neoprene 'O'-Ring near the bottom to seal the pressurized cutting fluid and direct it down the long feed hole that is within each gundrill which emerges at the cutting tip of the drill.
First a medium sized, precision, Albrecht drill chuck is installed. A stout, stub, twist drill is used to pilot drill an undersize hole in the howitzer muzzle, guided by the center-drilled hole already there.
Next the work piece is placed in the 3-jaw chuck and moderately tightened. The chuck is slowly turned by hand and a test indicator checks the T.I.R. (total indicator runnout) of the workpiece. F.I.M. (full indicator movement) is checked at the same time. We need a reading of less that .0005" (5 tenthousanths of an inch) before drilling. We DO NOT bang on the workpiece with a large mallet to shift the work piece into alignment! We loosen the chuck slightly, rotate the tube 5 deg. then re-tighten the chuck until we get an indicator reading of less than .0005". Nothing is damaged that way!!
Here the twist drill drills a short pilot hole about .500" into the muzzle. This new drill bit was carefully inspected before being used. Remember, 'New' does not always mean Good!
We like reamers which cut .005" at this .3125" size. You can see the full chip load from reaming that much from the undersize hole. It cuts .0003" over to .3128" dia. to properly accept the gundrill at .3125" dia. The precision of these pilot holes is very important for the gundrill. It drills straight ahead no matter what the attitude, so you better have a good accurate guide hole BEFORE using a gundrill.
Bushings are switched and one made specifically for the .3125" gundrill shank is placed into the Mono-Block. The air compressor is started and cutting fluid level checked. Speeds and feeds are 1330 RPM and .0005" per revolution. This makes drilling this hole a bit more than 8.5 minutes duration. All of the preparation, tool changes and clean out steps makes it about 1/2 hour per hole, with distractions and lunches it takes two days to do 25 pcs.
The gundrill bit is brought up to the reamed guide hole. It is gently guided into the hole by hand as the lathe carriage is advanced, and halted just short of the bottom of the guide hole. The lathe is run up to 1330 RPM AFTER the Misting pump is started. The carriage advance is then started to begin feeding the bit into the whirling Krupp tube. As 7.000" is reached an automatic shut-off halts the feed. The lathe spindle is turned off next and the coolant/cutting fluid pump LAST.
What the drill shank and bushing look like as they are rigidly held in the deep-hole drilling fixture, the Mono-Block. Gundrilled, thin, crinkle-folded, ribbon-type chips are lying on the block's right edge.
