DD's Winter 2010-2011 projects- K.I.S.S. the Can Mortar

[Double D]

Okay step one of this winters first project.

I have been shooting steel golf balls out of my K.I.S.S.  golf ball mortar.  The K.I.S.S.mortar is just fine for golf balls, but the steel balls are heavier and recoil is robust in this light gun.  I think I want something a bit heaver fo shooting steel.  Last year Southpaw and  I scrounge up an 8 foot  piece of  2 5/8 inch round 1018  a mortar tube made for this material should work better.

First step is to come up with the numbers.  I have two numbers I am working with.  The 2 5/8 inch diameter of the 1018 I have and the  1.72 inch bore needed for a golf ball mortar. Using the numbers from Antique Ordnance Plan set 22, for the 24  PDR Federal Coehorn mortar I made a conversion chart in excel



Those of you who remember the Golf ball mortar contest may remember my "dri-erase board' drawings.  I decided to upscale by using my old Autosketch program and make real drawings...thanks George for copying the 5 1.4 floppys to DVD.   Well Windows Vista is not very Ms-dos friendly and I could not get the program to load.  I dropped back a generation and got out the T-square and drawing board.  Been a long time since I did any drafting and the conventions are faded memories, so I used the conventions shown in the AOP drawing and made my drawing.

Here is the first drawing.



I am going to have to make a second drawing detailing the bore and and round end of the tube.

[dan610324]

please make a full radius in the bottom of the chamber

[Double D]

please make a full radius in the bottom of the chamber

I was schooled primarily in job machining. Chamfers, stress riser reliefs, counter sinks and such are all given parts of the work, unlike production work that requires call outs especially for CNC Machining,  for every operation.

[seacoastartillery]

     I just have one question for you Double D.  How do you plan to cut that 13.25 deg. taper chamber?  Please give us an answer, then we will tell you what happened to us and our tool when we tried a very similar machining challenge.  No silly reamer stuff, please!  We are talking about serious material removal, as in a drilling op.

Thank you,

Mike and Tracy

[Double D]

    I just have one question for you Double D.  How do you plan to cut that 13.25 deg. taper chamber?  Please give us an answer, then we will tell you what happened to us and our tool when we tried a very similar machining challenge.  No silly reamer stuff, please!  We are talking about serious material removal, as in a drilling op.

Thank you,

Mike and Tracy

I haven't got a clue.   I'll deal with that when I get there.

How about hanging my boring bar out about 4 1/2 inches on the compound turned about 13 or so degrees. Run the bar in with the compound feed.  Control depth of cut with the cross feed.  Go slow and small cuts...

[GGaskill]

Well certainly you would drill the  minor diameter to get some room for the boring bar.

[Cat Whisperer]

I've seen some tapered reamers of about that size used for cutting the taper in a barrel for the plug (to keep the beer in).  Works well on wood.

[seacoastartillery]

    I just have one question for you Double D.  How do you plan to cut that 13.25 deg. taper chamber?  Please give us an answer, then we will tell you what happened to us and our tool when we tried a very similar machining challenge.  No silly reamer stuff, please!  We are talking about serious material removal, as in a drilling op.
Thank you,
Mike and Tracy

I haven't got a clue.   I'll deal with that when I get there.

How about hanging my boring bar out about 4 1/2 inches on the compound turned about 13 or so degrees. Run the bar in with the compound feed.  Control depth of cut with the cross feed.  Go slow and small cuts...

     That would work, but we are wanting to know if you guys are willing to try something which will drill an extremely straight hole and is a lot quicker than the old slow and boring, boring bar.  Take a look at the tools below, especially the top one.

Guns drills we make and buy to drill short and deep holes.





     We made the bottom two and the top one, a 1.500" diameter gundrill, that sizzles through 30" of kiln-dried white oak (end-grain) with compressed air chip removal in about 3 minutes.  The others are made by Sterling gundrills of Vermont and are solid carbide.  Each can drill through about 100" of pre-hardened to 32 Rc,  4150 alloy steel before resharpening, ( 3 cannon tubes for us).

     We are proposing to drill 1018, 1020 or 1026 rounds with a gundrill of proven design made from heatreated and hardened steel, 4140, 4142, 4150 or similar, commonly available steel.  We simply do not have any time right now, but we are willing to supply a drawing of the gundrill we made if anyone with a mill is interested.  The drawing has the compressed air delivery plumbing, going to the very point of the drill, detailed as well.

     George, you have a mill, what say you?  With short cutting distances, lubrication can be accomplished by hand.

M&T

[Double D]

Drill a formed hole, is that what you are saying?  Cool.   

Gundrilling requires some high pressure air or fluid delivery doesn't it?  I not sure my  20 gal 125 psi, 3 HP comprssor is up to it....is it?

[GGaskill]

Sure, post a drawing.  Additional knowledge is always good.

[seacoastartillery]

Drill a formed hole, is that what you are saying?  Cool.   

Gundrilling requires some high pressure air or fluid delivery doesn't it?  I not sure my  20 gal 125 psi, 3 HP comprssor is up to it....is it?

     No, your compressor won't do it if you drill the hole in a conventional manner; Mike and I have to use our shop compressor, a two-stage, 5 HP, 12.5 CFM, 60 gallon and TWO auxiliary rented compressors of similar CFM to further pressurize the 60 gallon tank to get water-sol cutting fluid into our 1.167" dia. bores to drill continuously to the bottom of the 26" long bore and remove chips.  Gundrilling usually requires high pressure oil, about 900 PSI for a .243 Cal. barrel or 90 PSI for our water-sol delivery.  However, we believe that you can hand lubricate with regular dark cutting oil if your advance is of a short length, approx. 1/4" or so, then clear chips with a normal hand operated shop air nozzle.  It still would be faster than drilling and boring from 3/4" dia. to 1.72" dia.  A 1/2" pilot hole would be drilled first, but the gundrill would not follow it, so a nice straight bore of consistent size will result.

     You can make the drill with a tapered form with a spherical radius tip if you are willing to experiment a bit.  Just try to stay away from angles under 17 degs.  Advice from a deep hole drill designer we know.  It's good advice too, our first 15 deg., gundrill exploded within the first inch of travel down the first proto Brooke tube we made.  Braised carbide was not strong enough to do it, even at $280 per drill.  We went to a solid carbide and that has worked for four tubes so far.

     

Sure, post a drawing.  Additional knowledge is always good.

     Please read the modified offer again above.  Lack of interest has caused us to remove the free material from the offer.  The drawing is of a proprietary gundrill design, ours, and Will Not be published willy nilly all over the net.  Someone who commits to make one of these for their own use and report the results on GBO Mortar and Cannon board can recieve a copy for Non-Commercial use Only.  It's O.K. if no one is interested; we simply will do it ourselves between the end of Krupp and the resumption of 7" Brooke production and report the results, good or bad.

T&M
     

[Cat Whisperer]

I am VERY much interested in the geometries, have a milling machine, and will report all results.

I'm looking a plunge cutting a grooveless shape into both a pair of mould-halves and into a swaging die.

Also a function would be to cut the various forms into the depth of bore for the powder chambrer and ball-seat of a mortar.

[seacoastartillery]

        Thanks for your interest Tim.  Although another member contacted us yesterday and basically impressed us so much, that we committed to sending him the drawing and the steel, we will certainly be glad to send you the drawing as our budget is very meager and can't take another outlay of tool steel.  I will tell you this, however, I believe, even after using 0-1 tool steel for just about everything in gunsmithing and quite a bit in cannon making as well, my studies of the types available point strongly to A-2 as a solid, effective choice for these tools.  It is used extensively in reamer production, which are very similar to gundrills in their method of use.  Another important reason to like A-2, is it's extremely simple hardening and tempering proceedures compared to 0-1.  We will make the same offer to you on the gundrill project, in that we will provide free heat-treatment services to you if you use A-2, if you make two drills, one for you and one for us.  And that about says all there is to say about this project.  That also is the end of any and all offers from us on this topic.  We simply don't have the time these days to deal with more people on this.  We look forward to some published results to be shared with the membership in the future!

Thanks to both of you,

Tracy and Mike

[Double D]

Tracy,

I hope you have encouraged everyone to post pictures of there progress.  The skills I think are need are skills I don't have and would like to learn.

I always like to learn new things but some times  I don't do well with just printed instructions. Pictures help but hands instruction is the best way for me ot learn...

George is try to teach   Intelicad, I still can't draw a straight line

[GGaskill]

Visit your PM mailbox.

[seacoastartillery]

     I did.  Hunker in your bunker; counter-battery fire is on the way.

T&M

[seacoastartillery]

Tracy,
I hope you have encouraged everyone to post pictures of there progress.  The skills I think are need are skills I don't have and would like to learn.
I always like to learn new things but some times  I don't do well with just printed instructions. Pictures help but hands instruction is the best way for me to learn...
George is try to teach   Intelicad, I still can't draw a straight line

     I have suggested that these fellows tell us of their progress, but I neglected to mention photos.  Good idea!  Everyone likes in-process photos, I still haven't figured out why some are reluctant to show them.  I think your T-square and pencil drawings look very nice, I just don't understand why people who do one or two drawings a year think they have to learn all the new-fangled electronic software stuff to accomplish a simple drawing, even a not-so-simple one.  If I have have a tough time drawing a straight line, I grab a 6, 12 or 24 inch steel scale!  I bet George is a good teacher and you, being just a young fellow, will pick up those computer drafting skills pretty soon.

T&M

[Cat Whisperer]

Tracy & Mike -

I keep A2 in stock.  Looking forward to the dwg's.  The motivation is a real-life application, as I noted before.

Thanks,

I can take pix Tim.

[Double D]

Well back to my winter projects...I changed projects.  I am working on the K.I.S.S. the Can mortar.  This is an up sized K.I.S.S. golf ball mortar for shooting popcans.

I started with a piece 3 1/2 " x 6 1/2" tubing with a 2.565 ID  that I acquired....thanks George.  For breech plug I used a piece of the rotary oven shaft  Southpaw and I rescued last winter.



The tube was bored out 2.690".  5 1/2"   deep.  This left a 1 inch section of   ID that is rough 2.565 or so..  This section is not true round. In order to leave a maximum amount of metal to support the plug I left this section unmachined.

The breech plug material is 2.685" diameter and 2" long and slips in bored out section of the tube without machining. I turned a .995" inch long section of the plug 2.540"  so that it would slip fit  in the unmachined section of the tube.  In the opposite end of the plug I drilled a 1" hole, one inch deep for the powder chamber.  As drilled the hole held 160 grains of Cannon grade powder. I bored the hole flat, leaving a small radius in the corners and the chamber now holds 220 grains of Cannon grade.  This leaves a flat face to the plug so my large swab will have to have a flat face.

Here is the tube and plug with pop can full of cement and pop can diameter zinc round ball and a K.I.S.S. golf ball mortar tube



Next trunnion attachment.

[Double D]

Here's one I finished today....

[Zulu]

DD,
You didn't paint!
I'm proud of you!
Looks nice.
Zulu

[Double D]

DD,
You didn't paint!
I'm proud of you!
Looks nice.
Zulu

Your glasses must still be fogged up that thing has half a can of spray paint on it and then there is the  hand rubbed boiled linseed oil- four coats!!!!

[Double D]

I have been really busy getting ready for the road trip in two weeks.  Lots to get done , especially K.I.S.S. the Can mortar.  I will get the mortar done, but I probably won't have a drawing for you folks until later.  I have been so busy that I keep forgetting to take pictures as I work.




I have got the  Metal work completed on the mortar.  The trunnion was made from a piece of  1 1/2' round cut and faced 6 "  I drilled the holes in trunnion for the screws.  The holes are counter-bored for the cap screws. 



Breech plug is drilled and tapped for the trunnion and vent liner.

I made a jig to hold the 5/16-18 cap screw so I could dril the hole in it.
 




Today I drilled the base wood for the crosspiece screws and the trunnion.  Later this evening I'll start the inlet.





I was going to make the base like the base on the 10 inch seacoast  mortar, I was going to cut the cheeks from some 1 inch plate.  That base is just a bit too complex the K.I.S.S. concept. 

A standard wood base ala Confederate 24 PDR fits better. I was going to use a 4"x 4" for the base. 

They are tearing down an old grain elevator in town that was built back in the 1920's.  The wood is being pushed into a hole and burned.  I grabbed up some 6" x 6" beams for a base for the  Junk yard dog.  I also saw a 4" by 12"  x 4'  that I grabbed up and took the the  Hutterites to run through the planer.  I cut 3" x 3 1/2" x 16" pieces out of this cleaned up wood.

Any body else working on winter projects? Update your project posts.

Better hurry, spring is coming.  March 20, will be time to ring in the Spring!!!!!

Now back to the shop and start inletting.  Should be easier with fir than oak.

 

[Double D]

I did the inletting for the barrel this afternoon.  Fours hours of inletting stretches the concept of leisurely recreational retirement activity.  The dogs missed their nap this afternoon and are cranky tonight.



 

[Cat Whisperer]

I'm shocked!     You COULD have roughed it out with an adz so it would be authentically brought to size.  NO, you stooped to modern machinery.   

[Double D]

A wood chisel is not  modern machinery, and I have the blisters to prove it.  That barrel inlet is all hand chiseled out.

[dan610324]

lets see the blisters   

[Double D]

Everything is done.  I will test fire next week while I am down in Idaho.   Then it will be sand and paint time.  Probably do that after I get to  Maryland  I did put on a coat BLO on the wood to protect it.  Makes up into a pretty good looking mortar,  I think.
 


Blisters healed up overnight..

[dan610324]

it sure looks good and authentic , even if thats not the intention with the  K.I.S.S  design

you for sure heal very fast     but thats good

[little seacoast]

Nice job of inletting DD. I like the Can mortar a lot, deserves a Kewpie.  Since you're the only one who can award them you'll have to settle for a heartfelt attaboy!