Golf ball size Thunder Mug

[Double D]

When Tim mentioned Golf Ball thunder mugs the other day, I got this idea.  Out in the scrap buckets is the remains of a reject idea I had during the Golf ball Mortar contest several years ago.  For the past couple of days I have been working on it. It's built like my entry in the contest except instead of a piece of 1 inch round stock bolted to the base for a trunnion, I bolted on a piece of 1 inch plate scrap plate for a base.



You can see it sitting under this pile of projects.  Last night I turned the base round.  That was fun, turning a sheared of on three sides, ragged off cutting torch on the 4th side squarish piece round.  Go it done how ever.  Started a full diameter face cut then worked out.  The shock of the interrupted portion of the cut was a whole lot less stressful than a side turning cut.  Once I had a round bottom with flat sides it looked pretty good and the wife called me into the house for a bowl of ice and that finished me for the night.

This morning I got up and decide the wide 1 inch base was begging for some decoration and perfect place to try the Incremental cut method for making balls.  Friend Wes Pilley- Powder Keg who use to be around here some years ago used the technique to make moulds that a lot of use bought from him...I have a few myself.   Wes said he got a copy of Guy Lautard's book Tables and Instructions for Ball and Radius Generation.  I have had a copy since shortly after Wes Told us about the book.

Basically with a parting tool you make a progress set of cuts roughing out steps for the  ball-round shape. The book clearly describes the process.    

I decided to just start small on this bas and and make a simple 3/8" radius.  Here's my set up on the lathe.



I used a dial indicator to measure carriage travel Z axis or as Lautard calls it North-South travel.  North being the tail stock, south the headstock.  North an south is use to indicate which side of the ball you are working on.

In and out of the tool, is the Y axis.  Lautard's book has charts for established base radius as well as instructions for computing larger radii.



To start the cut, I set the south side of the parting tool blade 3/8" from my north edge of the work.



Now starting at the bottom of the chart, to make may first cut I come South towards the head stock 0.026" and feed in 0.001".  Second cut is South 0.051" and in 0.003" and so on up the chart to the last cut of .375 S and in .375.



Next I painted cut with dykem and the started filing the high points away.



I kept filing until all the dykem was gone.



So this is where I am on this project.  



Now out to the garage for to finish up the Elevator on the SAMCC gun.

[seacoastartillery]

     Looks real good, Double D.  Glad to see we are not the only ones who cut a radius using that method.  It works and if you divide the distances by 4, you make more cuts, but reduce the time filing by quite a bit.  The same technique works well on the mill too, using the -X- and -Z- axis dials.  Used rotary tables are cheap.  Although we use the Excel spreadsheet program on the computer to get our pages of numbers, Guy Lautard's book looks excellent and probably would save some time on figuring out the numbers for many jobs.

Nice clear photos.  Thanks.

Mike and Tracy

[Double D]

Pictures fixed!!!

[Cannoneer]

I like it DD; but do you now have to weld the tube to the base, or was it made from a solid piece?

[Double D]

The base is attached with socket head cap screws just like the trunnion on my K.I.S.S. Golfball mortar.

[Cat Whisperer]

SO, are you going to BRING it to the NRV shoot in July?   

[Double D]

I wish....but no.   

[Ex 49'er]

I wish....but no.   

DD,  No you're not bringing it or No, that you're not going.  If you're not going; don't worry. I'm not going either.
It's kind of far from the west coast.

[Double D]

Test fired the Golf Ball thunder mug to day.

First shot was with a powder charge and a single card wad.



Movie below, click to view.

[Double D]

Here's the test using barley as a filler.



Movie below, click to view.

[Double D]

Some one the other day suggested creamora as a filler.



Video below.

[Double D]

We also fired projectiles.

Golf ball





Steel ball








It takes the golf ball 3 frames to clear the camera.  The steel ball takes 6 frames. 

[RocklockI]

HELLO !!!!!!!!  D D  BARLEY   as a ...filler is this the same barley slated to become beer ? HUMMM ?

The very day of St Patricks Day ...     ?  You are not on the snakes side are you .... hummm? It could explain somethings

Blowing up barley is bbaaaddd . (mr garrison southpark)

ETA Cool pics BTW

[Double D]

Barley as a filler is eco-friendly and feeds the Pheasants that come in  the yard

[Double D]

Oh and based on the experiments, thunder mugs are not good projectile launchers. Tilted about 5 degrees the golf ball went about 40 yards. The steel ball went 20 yards and threw gravel at impact.  Never again.

The best bang came from putting a card wad over the powder chamber, filling the bore with powdered filler and then putting  a card wad on top.

[Cannoneer]

DD,
Why did you make the t-mug with a powder chamber?

[1Southpaw]

Great test . Love the single frame of the movie stop action .
I actually did not see fire when I observed the real life firing , just the big smoke cloud .

Will have to get up early to get the ring in spring stuff in place for the firing .

[BoomLover]

Ready for the "Ring in the Spring" fling thing...  .69 cal, .75 cal., G.B. Mortar/ThunderCup, maybe even the C.S.A. Mortar in #15 Tomato Sauce can size! LOL And good weather for a change! No rain predicted...been a cold, wet winter here!

[Double D]

DD,
Why did you make the t-mug with a powder chamber?

Good question John.  As you may recall I pulled this out of the scrap bucket.  It was a reject prototype of my original golf mortar for the contest a few years ago.  It was already there.

I would need a 5 1/4" piece of stock for a cylinder bore of golf ball dimensions. 

[Cannoneer]

Thanks, Douglas! Sometimes my light bulb dims, all I had to do was reread your opening post for the answer to my question.

[grymster]

Good job DD! I haven't cut a radius like that since the advent of CNC. But in preparation for retirement (when I'll be regulated to manual machines) I dusted off an old spreadsheet calculator and (hopefully) improved it. I plan to use tools with a nose radius for smoother finishes and less hand work. The calculator has provisions for tool nose radius, desired stepover as a percentage of tool radius (so you can pick your finish) and provisions for cutting the radius anywhere on the part (the origin, or "zero" points for the axes can be set say at the end of the part and radii cut elsewhere on the part). I don't have a lathe yet, but my brother just bought an old Logan and we're going to make a cannon as one of the first projects. Kinda excited to try out my calculator!

[JeffG]

The steel ball takes 6 frames

The whaaaa??? What kind of helmet do you wear?  Where do you park your truck???