Golf Ball Mortar

[jimwaits]

I have constructed a golf ball mortar. It has a five inch total length bbl.
I have been working up loads. Reading the safety rules here they say no wadding. I can't get any bang at all using no wadding.
   My largest load has been 360 grains of FFG Pyrodex. It only causes the flat mount to move back 6 inches when firing at about 45 degrees but it makes a real good bang!   I sure would like some advise from some of you fellows who have already been down this road.
     I hope the word "Pyrodex" is okay to use here. I cannot get any black
powder locally.


Here is an overall shot of my little golf ball mortar on oak carriage.



I started out with a five inch piece of steel with a one inch hole in it.



Here is the breech plug press fit and veed out before welding.



Here you can see the flat spot I milled on the trunion to mate with
the breech. After welding in the plug I machined the breech flat
and then mated the trunion flat spot and welded it all up to a
nice rounded breech.

[Double D]

You shouldn't get a bang you should get a boom.

I haven't had any luck with Pyrodex in cannons.  

I'll let CW speak to loads, he is the golf mortar whiz.

Post you pictrues. One thing we ask is that you no picures large than 7 inches wide.  Some guys with older computers won't be able see the picture full screen if you make them wider.

[jimwaits]

Well, I put some picture up by editing my original post. I am anxious to
hear from some more guys. I gather from what you said I can expect much better results from black powder than the Pyrodex I am using now.

I am figuring to order some black powder but I have to get a clarification from the BATF. I am a dealer and have an FFL but don't intend to buy black powder for resale.  The form I have to sign says "I am not a
dealer" so I can't really say that.

[Double D]

Are you buying the black powder for resale or personal use?

Just because you have an FFL doesn't mean you can't buy for personal use.  Call the seller and ask them.  They will tell you. Don't expect a quick or straight answer from the ATF.


Why a breech blug in that little gun.  Why don't you just bore a hole to depth with chamber.  You must have a reason.  just seem to me the breech plug is unneeded.

The finished result is pretty nice looking.

[jimwaits]

I was looking at their catalog and they said I had to sign a statement saying I was not a dealer. However, since then I looked at their form and it just says I am buying it for personal use which is exactly what
I am buying it for.

About the breech plug. I did not have anything to use for a barrel except this five inch piece of stock which had a one inch hole thru it. To bore that hole out to golf ball size is a big job since I cannot support the outer end and can only hold it in a three jaw chuck.
   To drill out and bore a solid piece would have been harder for me since I don't have any large drills and no big shaft material for a barrel and no way to support the outer end.
   I have obtained a fourteen inch piece of seamless heavy pipe with one inch thick walls. The bore is about the size of the larger dog food cans. It appears I am going to have to make a plug for it too. I plan to pin this larger plug as well as welding it. Also I will put the trunion further up the barrel. I expect to mill a shallow spot on either side of the barrel and weld the trunions on.
   Please, the instructions I read about BP safety said use no wadding. I could not do anything without wads using this Pyrodex. The more wads the more noise. Can I really expect to use no wadding and get good results when I go to the black stuff?

[Double D]

Well, now the breech plug makes sense.

Sounds like you could make a dandy mortar out of the piece of seamlessl

Suggestion.  Look at the post here on the forum about the book The More Complete Cannoneer. Get a copy of that book before you cut your first chip.  Also look for posting here on Anitique Ordnance Publishers.  I have their list of cannon plans.  Look that list over and find a cannon design you like an build a replica gun.  You will get more satisfaction out of a gun that looks like the real thing.  They have several mortars.  That piece of steel might make a nice howitzer.

I have some other plans I can send you also.  Drop me an email.

[Hermit]

Well, I put some picture up by editing my original post. I am anxious to
hear from some more guys. I gather from what you said I can expect much better results from black powder than the Pyrodex I am using now.

I am figuring to order some black powder but I have to get a clarification from the BATF. I am a dealer and have an FFL but don't intend to buy black powder for resale.  The form I have to sign says "I am not a
dealer" so I can't really say that.

Jim.. That's a real nice looking mortar. I am also an FFL, not a prob having 25# BP for your own "consumption". While I do not store powder in my safe,,, for fun I keep a sign on my rifle safe in case someone wants to cut in with a torch. "25 pounds of black powder within, do you know where it is" :twisted: . I have been looking for used/inexpensive hydraulic cylinders off heavy equipment to experiment with. Anyone tried this before? One end is sealed, they handle high pressures.  :roll:  Hermit

[jimwaits]

Two great ideas from the Hermit!! I never thought of the sign about having black powder in the safe.
   Also the hydraulic cylinder idea. I have two or three of them in my junk but I don't remember how well they are plugged up at the end. Usually they operate around 3000 pound pressure and I am not sure if this will stand up to BP pressures. I will give them a looksee tomorrow.
   Seems like they have a hole in the side.
   I have a friend who has mucho junk and I have been walking over a couple of cylinders at least ten feet long and pretty big. He said they were elevator cylinders. I didn't look at the plugged end but will make a trip over there soon.
   Thanks for the great input!

[Hermit]

Jim.. Yup, they have a hole at each end for the hydraulic fluid to move the ram in both directions. With the right cylinder one can be cut off and crowned just behind it and the other sleeved with a custom touchhole. The end should have to hold the same pressure as the rest of the cylinder. I think they have potential. Elevator cylinder sounds interesting :twisted:  I also have a piece of what looks like a large lathe leadscrew. It's acme threaded, about 3" dia and has approx a 1" hole. May just have to reshape, bore and make a golfball cannon from that one. Scrapyards are goldmines.  :-D  Hermit

[SamMiller]

That is a fine looking golf ball mortar Jim. Will send the CD with the pictures tomorrow as scheduled. They are in the envelope ready to go.

[jimwaits]

Hello, My son is visiting me and with his help I ran a test of this golf ball mortar using real FFG black powder. We made a video and I have put it up on Neptune. I just have a temporary account and this link is only good through May 9th.

It is a movie clip. The charge 1 35mm film can full of FFG and a golf ball.
No password necessary, just go to the site and click on the title to see it run. Have your sound turned up to get the audio.
Any comments you can email me direct at:  jimwaits@emcst.com

http://jimwaits.neptune.com

[Calamity Jane]

Hermit: near as I could find, a Blackpowder rifle will run about 30,000 PSI - that's what I used for my 1/3rd scale 6 pounder.

[jimwaits]

HIGH SPEED VIDEO PICTURES...
Well, my son is still here and we made a fabulous photographic session while firing my golf ball mortar. The charge is a 35mm film can of FFG and a golf ball projectile which is clearly visible as it comes out of the mortar.

There is no sound here of course but the fire coming out of the vent hole and all the details of the firing are pretty good. Photographed at a speed of 1000 pictures per second with an exposure time of 129microseconds.

This "High Speed" movie is smaller than the "Mortar" test. You can select either one and it will play. The mortar one has sound with it. No password necessary.

http://jimwaits.neptune.com

This may not work after May 9th.

[jimwaits]

Here is one of the frames from the high speed video taken at 1000 pix per second. Camera info calculates ball speed at 460 feet per second.

[Cat Whisperer]

Jim -

Great pictures!  What range do you get with one film can of ffg?
My hand-held and other golf-ball caliber mortars use from one to two .45acp cases of FFFg for 100-200 yard range.  Bore diameter on the hand-held is 1.70 and 1.75 on the other.  You may find that there is a point afterwhich your adding of more powder just adds more flame and smoke.  Speaking of smoke, some competitors in reenactments mix 50% flour to add to the smoke.

[Cat Whisperer]

I have constructed a golf ball mortar. It has a five inch total length bbl.
I have been working up loads. Reading the safety rules here they say no wadding. I can't get any bang at all using no wadding.
   My largest load has been 360 grains of FFG Pyrodex. It only causes the flat mount to move back 6 inches when firing at about 45 degrees but it makes a real good bang!   I sure would like some advise from some of you fellows who have already been down this road.
     I hope the word "Pyrodex" is okay to use here. I cannot get any black
powder locally.

Short barrels go bang, long barrels go thounk (for the same amount of powder).

Getting the pressure up to ignite black powder is an issue.  How smooth the bore and other factors are the gamble when using wadding.  More mass helps.  It's obvious to see on one of my mortars - sodapop bottle caliber - two cement filled 20oz bottles go much further than one (1-1/2 thick walls of 4140 - so it's still 'safe').

On my first mortar - beer can caliber - 1975 - I tested the can with and without a patch.  Filled the can with WATER.  The patch adds to the pressure, predictably.  When the pressure rose (from adding more powder) the bottom of the can would be pressed in from the explosion.  The pressure was transmitted by the water to the sides.  When the sides would be scraped by the bore I knew the pressure was rising.  Little scrape = lots of pressure; big scrape = lots more; split can = right much high pressure.  At that point I switched to sand filled or concrete filled.

I would not use a patch causing a TIGHT fit, nor a patch that could bunch up and do so when fired.  With cans, I also used seveal layers of masking tape to get the size to fit a little more closely.  Some clearance is necessary for safety and if you don't swab between shots it will fill in fast.

Pyrodex works if you can get it to ignite - more of a problem than with black.  I mixed the last of my pyrodex with the black to get it to burn.

Shooting 2 golf balls - one will always go MUCH further than the other.

[jimwaits]

Cat Whisperer thanks for the kind words. Notice the golf ball appears to be higher than the barrel is pointing. The barrel is just lying on a sandbag and when fired it bucked up a bit causing it to toss the ball a bit higher than the barrel is pointing.

Range is undetermined. As many as five people watching and nobody has ever even seen the ball. Exposure is one frame of the 1000 per second and the exposure time is 129 microseconds. I live in the country on the Choctawhatchee River. I have a fish camp and boat landing and we shoot down there. There is five miles of river swamp in the direction we shoot.
Software calculates the velocity of the ball as 460 feet per second. The shot 2 photo above is part of a movie. The movie is spectacular, showing fire from the vent etc.

I am using FFG Black Powder for all these shots...no more Pyrodex. I do put one .060 wad of vegetable fiber over the tinfoil powder packet. I make the wads with a cutter punch I made from a 1 7/8 inch hole saw. After grinding off the teeth and sharpening it cuts out a wad about 1/32 inch larger than my bore.One of my shots this wad was still in the mortar clinging to the side of the barrel! I have not shot more than a 35mm film can of BP. My golf ball fits the barrel pretty good. It will roll in but only slowly due to air escaping around it. I swab after every shot of course.

Anyone with a question can email me directly at   jimwaits@emcst.com
or check my site at http://www.rooksbluff.com

[jimwaits]

Well the great movies are now up on a site for viewing by all. There are two movies, one with sound and one taken by a high speed camera as the above posts say. There is a few single frame shots of the making of the golf ball mortar and me working on the bowling ball mortar I am making.

These photos can be viewed without password at the site I have them on...     http://www.jimwaits.neptune.com     or you can go to my home page at...      http://www.rooksbluff.com    and follow the mortar line to the photograph site.