How to make a round ball bullet mold

longbow

03-15-2012, 12:20 AM

Since you don't mention your level of machine shop/gunsmithing experience or what tools/skills you have I'll guess not much from the questions.

You certainly don't need a CNC mill or even a shop full of power tool to make a round ball mould. The old time gunsmiths made a lot of gear with pretty simple hand tools but they also served long apprenticeships to learn the tricks of the trade.

If you are handy with your hands and know how to work with steel to make a cherry or D bit you should be able to make a serviceable mould from aluminum or brass.

There are different ways to make a mould depending on the type of mould you want to make. Most commercial moulds are made from square/rectangular bar stock as split halves milled to fit commercial handles and have niceties like a sprue cutter. These types of moulds are fairly difficult to make with simple tools... or more correctly are difficult to make accurately with simple tools.

Some of the old style moulds were hinged tongs similar in style to fishing jig head moulds you see in your local sporting good store.

There are a number of internet sites on mould making and what is available as commercial moulds.

Most commercial moulds are of the split block style to fit scissor like handles:

http://www.buffaloarms.com/Products.aspx?CAT=3754

but there are some tong types available as well ~ Track of the Wolf has some and so does Dixie:

http://www.trackofthewolf.com/List/Item.aspx/1195/1
http://www.dixiegunworks.com/advanced_search_result.php?s=1&keywords=mould

Another style:

http://www.jt-bullet-moulds.co.uk/moulds.htm

And another:

http://shaysrebellion.stcc.edu/shaysapp/artifact.do?shortName=bullet_mold

All in all, unless you have pretty good metal working skills and some tools Norbrat summed it up well ~ it is hard to better than a Lee mould for the cost, unless you simply want to do it yourself or you need a size not readily available.

As for hard lead balls, they should be fine in a smoothbore, patched or naked and some use them with good success in rifles as well but patch/ball fit might be a little different with a hard ball as the lead won't give as much.

FWIW

Longbow

I made a RB mold for slingshot use and it casted 5/8 dia lead balls. Squared up 2 blocks and ground them flat. A ball cutter was used to cut the cavities and went slightly deeper than .3125 and ground off the excess and the depth was checked w/ a depth mike. The cavity is just breaking through the edge of the block for a minimum sprue remnant. The cavity finishes were fairly smooth and to aid the ball cutter, a 3/16 dia hole was drilled just short of the depth to compensate for the ball cutter's web.

A .625 ball bearing was tightly clamped between the 2 mold halves in a large vise and the halves were aligned w/ a dial indicator and the 2 pairs of guide pin holes were drilled and reamed for a press fit w/ the guide pins and then 1 cavity block was reamed again to supply a slip fit w/ the guide pins. A sprue cutter plate was then attached and a very minimum sprue remnant was present which we didn't trim off. Both the cavity blocks and sprue cutter plate were made from unhardened tool steel.

Attached the cavity blocks to commercial handles and used the mold for many yrs. A .625 dia. {slightly smaller because of shrinkage} might seem too large for a slingshot projectile, but the slingshots used surgical tubing which was capable of imparting sufficient speed to the large ball for a reasonable trajectory. A side benefit of the large ball was that it was visible in flight which then allowed compensation. Later on tried .490 lead balls but these were not visible in flight, so discontinued their use.

The slingshots using these lead balls killed many cottontails, gray squirrels and a few pheasants sitting on the ground. We hunted wild and park areas in the city and always had to be aware of law enforcement......Fred

So, though I have not done it, the traditional technique is as follows:
Forge a cherry on a shaft and file the ball to rough over size dimensions.
In a steel plate about 1/8” thick and perhaps an inch and a half square drill a hole the desired ball size 1/4” to 1/2” from an edge. Saw and file a wedge shaped channel from the hole to the edge. This cutout is to allow the shaft of the cherry to pass.
Now you have a plate with a cutout the shape you want the cherry to be.
File one face of the plate flat. Flip over and file the backside of the cherry hole to relieve it so the hole is still round and unchanged on the flat face, but now the hole has a sharpened edge. Harden the steel plate by hardening and tempering if spring steel or an old wide file that was annealed. If mild steel, case harden it.
Now chuck up the forged cherry in an egg beater drill. Spin that baby rapidly with the cherry parallel to the face of the plate on the flat side. The neck or stem of the cherry fits into the slot. You are now making the ball on the cherry nearly perfectly round as it settles sideways into the hole.
You might stop, inspect, and hand file high spots to speed things up and use this to direct your efforts and put a final shape on the ball.

Once the ball is made, paint it with dykem and file teeth on it like a ball grinder bit. Now you have the right size cutter for your round ball mold blank.

I've never made one, but the idea of making your own has been around for a long time.

The Pennsylvania Gazette
January 5, 1748
From the GENERAL MAGAZINE.
A New Method of making BULLET MOULDS.
"THE Badness of the Bullet Moulds brought into America for common Sale, and the Difficulty of meeting with one of them, bad as they are, that will fit one's Gun , will render the following Invention, for making (easily) true and exact Bullet Moulds, agreeable to all Lovers of good Shooting. First provide yourself with two Pieces of Lead about an Inch and Half, or two Inches Square, and half as thick, and smooth their Faces, so that when joined they may make near a Cube; then get some Marbles (such as Boys play with) from the smallest to the Size that fits your Gun, oyl or grease the Marbles and Lead well; and with the Assistance of a Smith's Vyce, with two flat Pieces of Iron in the Chaps of it, press the two Pieces of Lead with the smallest Marble between, till the Marble be quite sank in the Lead; then put in the next greater, always remembering to keep the Lead and Marbles well oyl'd do thus successively, till you have brought it to the Size you want: And, to prevent the Bullets having Edges, smooth the Faces of the Mould, and press in the same Marbles several Times, by which Means you may make Moulds of wonderful Exactness. Then cut a Gate and fit the Corner with Pins, to keep the Pieces in a proper Position for casting. When you use it, smoke it well, and take Care the melted Lead be not so hot as to burn Paper."

In an earlier discussion of this idea a TMF member made one, and it worked.

Spence