Ball mill for round balls?

[Smithy]

I have a fairly large model "noise maker" or so it's often called for liability sake. It's a golf ball bore and it and its carriage are three foot long by two and a half feet wide and about a foot and a half high. The barrel weighs in at 53 pounds with a total weight of just over 100 pounds. So in the small cannon department it's huge, but in the real sized cannon world it's quite dinky.

Besides golf balls, it also is able to chamber/load those 1# fishing round balls. The thing with these sinker molds is not very good alignment. So after casting I wire cut the sprue and any flashing sticking out. The I put the ball on a steel plate and with a hammer, peen the remaining protrusions flat.

I had to do this same treatment with a scissor mold I have for a smaller cannon (.820). I was wondering: Do you folk think that there is some type of media that combined with the rough case round balls, could be placed into the drum of a rotary tumbler to round everything out without causing flat spots around the ball? Interested in hearing what all have to think? Smithy.

[Mk42gunner]

I have read of tumbling buckshot to help make it round(er). The following idea may or may not work; I haven't tried to do this myself.

I think you would need something on the order of a cement mixer to handle enough volume and weight of one pound balls to make it worth while. Tehn you would need to check and or modify the paddles so they wouldn't scar to tumbling round balls.

As for media; I would try tumbling several of the lead balls without anything else first, then use large ball bearings if the lead didn't work.

Robert

[Oreo]

What about having a custom mold made? I mean, by the time you go through the trouble of engineering a jerry-rigged solution you could just fix the source of the problem.

[Smithy]

What about having a custom mold made? I mean, by the time you go through the trouble of engineering a jerry-rigged solution you could just fix the source of the problem.

I was thinking of a solution to all ball size issues not just one. Sure I can get a custom mold and I've gone that way in the past, but it seems like everyone's idea of a one inch bore is not one inch. I've got everywhere from fractions of an inch under sized to one inch and three sixteenths. Not bad if you're just making noise as my wad design takes that into account, but with a lead round ball you'd like to be a little more accurate. I've found a good source for inexpensive odd ball sizes of molds, but they are all of the OLD timey scissor molds. which leave sprue and flashing issues on most if not all of the castings. My concern is not for shooting them as you could always brute force any flashing issue and have the sprue inline with the bore so it wouldn't come into contact with the bore. But I'm truing the balls and painting them to go with my base plates. For one I made a 4 square base and another a 5 square base. Starting with squares and going down a integral square each level you end up with one ball (or 1 squared) at the top of a four sided pyramid. It's a nice addition for a display piece, my last being the Dictator siege mortar. Smithy.

[bumpo628]

Off the top of my head, you could make some sort of 5 gallon bucket tumbler with low-profile bumps glued to the side walls. The small bumps would stop the cannon balls from falling too hard. For media, you could try a bunch of stainless steel BBs.

[NoZombies]

I would suggest that you would probably still want to take away the largest offending bits of flash, but then this would probably work:

Since the stated purpose is to come as close to a round ball as possible, I would start with a large diameter steel tube, (rough guess, at least 4X the diameter of the largest ball you'd want to roll) the smoother the interior, the better. make or get caps for both ends, and set up rollers for it. Power one or both rollers. Put in just enough balls that they will create a straight line down the middle of the pipe. Turn on, and walk away for a good long spell (several hours at least)

You don't want any paddles or anything else disturbing the balls as they roll, and you don't want enough in the tube that they'll tumble over each other. You want them to roll smoothly as the tube rotates. They will likely still not be perfect, but they should be a fair bit better. The softer the lead, the better the results.

Hope that helps!

[Smithy]

Mk42gunner and bumpo628, you both have some really good ideas, but what NoZombies says also makes a lot of sense to not have paddles to overly ding the round balls when they fall and run into other things. Using his idea I can still to my sprue/flashing clipping and a little hammer work on the left over sprue portion and then put them into the roller to smooth things out. I'll let you folks know what ended up working. Smithy.

[imashooter2]

Putting a few into a cookie tin in the trunk of your car for a week would do the same thing.

[bob208]

two heavy steel plates. one with a lip on it the same size of the dia of the balls put b some balls in put the other plate on top and roll the balls arounf till the top plate closes on the stops. in the early days of artillery the projectiles were cut on site by stone cutters.

[masscaster]

Hi Smithy,
Anyway to get pics on here of the mould and ball(s)?

Jeff

[shotman]

I have tried the tumble thing it takes a looong time . you also tend to loose some size. Best way is like they make ball bearings . They use gringing wheels . but a drill press and 2 steel plats on with a ring around it . can weld a stop in it or what I do for may different sizes is get steel ball bearings they size you want . They will stop the plate when it gets to your size.
The Guy in UK makes any size brass ball mold you want and it almost dont have a sprut. about 50 bucks
http://www.jt-bullet-moulds.co.uk/

[Milsurp Junkie]

Has anyone used Durham's rock putty to make a mold for small diameter cannon balls? You could use a suitable size ball bearing (2" or whatever is you bore size) as your positive. Build a two part hinged wooden frame (using 2x4" lumber for the sides and 1" boards for the top and bottom, with screws partruding ~1" into the sides, mix up the rock putty, pour in one half of the mold. Insert alignment pins in the corners, and use the ball bearing (coated with release agent, PAM spray or JPW) to the half way point. Once the rock putty has set up, spray or coat that side with release agent, mix up another batch of rock putty, and place the set half on top of the other half. Wait for it set up. Part the molds, remove the ball bearing positive with a strong magnet. Now cut your fill lines and vent lines.
Clean off the release agent, and thoroughly coat the inside of the mold with graphite powder.
Use as a typical mold (although it is going to take a while for the lead to cool to a solid point.
cut the sprue with diagonal cutters, and run the batches in a rotary tumbler built from a 8 or 10" diameter PVC pipe. rotate it slow (60 rpm or so), and it will smooth out any flashing and sprue marks.

I was going to do this for 1" balls for a ball mill (for gunpowder manufacture).

Anyone have an easier homebuilt idea?