Newbie building golf ball mortar design questions...

[flyfisher]

Gentlemen,

I would like to build my first mortar and have decided on a golf ball mortar.  I have ample skills welding, grinding, fabricating, etc. with steel, so fabrication should be no problem for me.  I have seen several designs/pictures of your golf ball mortars and have several questions pertaining to the safety/materials involved for creating such a mortar.

1)  What would be the best steel to use?  4130? DOM? Stainless 304? Suggestions please!  (I realize that seamless is a must) (I am not looking to make one out of brass, just a "starter" mortar out of steel)

2)  What is a good thickness for the steel?  I believe that an ID of 1.75" should work fine, but what about the OD? 

3)  What is an ideal length for the mortar to possess?  I am leaning toward around 5".  Will this launch a golf ball several hundred yards and still have a decent "boom" factor?

Any input will be greatly appreciated...I just want to build a mortar reasonably inexpensively and safely in order to have a little fun.

P.S. Double D-the mortar in your avatar looks like something I am looking to build.  Would you mind sharing some info. with me about the mortar?

Thanks,
flyfisher

[GGaskill]

I have ample skills welding, grinding, fabricating, etc. with steel, so fabrication should be no problem for me.

Does that include machinist skills such as lathe and mill operation?  Those are typically the skills needed to make barrels. 

The golf ball mortars we made for the contest of a year or two back were about 4.75" overall length with the bore being about 3.75" including the chamber.  I bored mine to 1.70" since a golf ball is supposed to be only 1.68" in diameter.

I doubt you can get several hundred yards from a golf ball mortar using a rational powder charge.  If you must have that kind of range, you should make a howitzer or gun.  Both have longer barrels which will give more velocity from any given amount of powder.

If you have the equipment, I would suggest that you bore your barrel from solid 1018 steel which will be more than adequate for even 1 lb lead shot as long as you conform to the "chamber wall thickness = chamber diameter" rule.  I would recommend a 3/8 scale Mountain Howitzer which can be made from a piece of 3" round stock 14" long.

[Cat Whisperer]

Flyfisher -

George is steering you right on the 1018 and building it strong enough to handle heavier projo's as well.

I've built hand-held golf-ball caliber mortars of 4140 (which is overkill).

Check out our thread on the mortar building contest - I still have some 1144 stress proof I can send you if you want to go to the effort of piecing together a tube of either Confederate or Union style.

[Double D]

If you go to the post at teh top of the board called  Safe Loads and Cannon plans  and scroll down through the post under it you wiill find links to our Golf Ball Mortars plans.  Those were fun and simple to make.

I agree the better way would be to make them from 1018. 

By the way Tim did you ever send me off some more of that 1144?

[flyfisher]

Thank you all for your input.  I now have a good idea of what to do, what to use, and how to do it.  Since posting, I have had a chance to look at the designs that you guys have posted as well as several others.  I originally tried a search on Graybeard for info. but search is not working, at least not for me. 

DD, thanks for the "Safe Loads and Cannon plans"...that led me to numerous plans, info., etc.  and it is much appreciated. 

GGaskill, thanks for the dimensions, steel choice, etc. it is appreciated greatly as well. 

Cat Whisperer, I'd like to take you up on the offer for some 1144.  I will PM you and see if we can work out a deal.

Thanks again for all of your help.
flyfisher