Making moulds

[Blammer]

If one were to buy the equipment necessary to make your own bullet moulds and also make them to sell.

WHAT equipment would be "good enough" to start.

Meaning not the top of the line with all the extra fancy stuff, but what would be the good one that will allow for repeated cuts to the exact dimensions needed for making moulds, have the least troubles with and last, along with possibly fix or repair that is easy to obtain if necessary.

Thanks.

[leftiye]

Finally, an interesting thread! (Are my biases showing?)

Believe it or not, the making of the mold is not the hard part - it is making the cherries. Because of that, there is the CNC lathe (can be an engine lathe with a CNC add on) method like Mountain Molds does. He has the cheapest custom molds to be had. He programs the lathe to cut the shape in the cavity, bores the rough hole, and lets the lathe finish the cavity. This is very good for one off molds, though except for tool wear it would be fine for making multiple copies.

Back to the cherries, they're basically specialized reamers, and you therefore must get set up to make reamers. Milling machine, dovetail cutter to rough cut flutes. Lathe to form blank(this comes before flutes) - blank looks like finished bullet, a hair oversized. Heat source (can be heat treating furnace, might get by with acetylene torch and Keep Bryte (anti scale) for hardening, and drawing (tempering). Then you need to grind the flutes (toolpost grinder) and shape to finish size. Next is grinding the back clearance (not that easy!), and sharpening.

You'll need a precision double acting vise. and your cherry, and your milling machine to do the actual cutting of the cavity. Find center of blocks/parting line then drill main cavity with drill shaped to ogive first. Also to mill your blocks to shape and size, and drill and tap the necessary holes too (need drills, taps, endmills, surface mills-can do without,etc) a centering scope (finds edges too) would be very nice if you want precision LOL. You'll have to make modified jaws for the vise to hold the mold blocks. The vise jaws articulate apart and back together to close the mold blocks on the cherry.

As you can see it might cost a bit to get set up from scratch. Someone with a lathe and a milling machine should be within reach without too much trouble. Hope this has helped. Ted

[Linstrum]

Leftiye has got it all covered.

The one very minor addition I would suggest, and it is just a matter of the choice of equipment available or personal choice, is to use a two jaw lathe chuck in place of the articulated-jaw vice. The two tools are basically the same thing with the two jawed lathe chuck being an articulated vice (with a through hole for long bars) mounted on a lathe headstock backing plate. I have never owned a two jawed articulated vice so I don't know what range of repeatable accuracy they afford the user, but I would imagine that like anything else there are good ones and there are not so good ones. The only reason why I even mention the use of the two jaw lathe chuck is the possibility that it may afford slightly better repeatability of getting the mould block halves closed on-center every time the jaws are moved in or out.

I just bought a large two jawed lathe chuck for the exact purpose leftiye talks about here but I haven't had time to even get it out of the box yet (I recently moved half-way across the continent and I've got my machine shop building to build first).

[Blammer]

so you're recommending that you go the way of cherry making then to mould block cutting making, versus just using a CNC Lathe to do it.

Am I correct in this?

[Blammer]

I guess I also need to back up a bit and learn some terminology.

a two jaw lathe chuck, what does it look like?

an articulated-jaw vice what is that?

more questions to follow I'm sure.

maybe a place I can read about the "basics" of a lathe and operation?

yea I'm getting in deep but don't know where to start.

[Blammer]

and what kind of cash layout am I looking at?

[leftiye]

Blammer,

I'm afraid to answer your question about overall cost (taint cheap!). My lathe and mill both were used and cost me about 4000 dollars each. Tooling is pricey. Grizzly Machine Tool has a precision double acting vise for about $90, and there's a CNC (very accurate version) on evilbay for $114 (shipping will kill you). My take is that a double acting vise (especially for CNC) would be more accurate than a 2 jaw JMHO. Thing to look out for is repeatability. MUST close at the same place in relation th Milling machine quill every time or else! No end play on feed screw! I'd say that a lathe converted to CNC might be the cheap way to go, but once you get it you'll be sucked in to getting more equipment so you can do more stuff. I started out wanting a lathe, and I've probly got $50,000 worth of stuff now. I didn't go top drawer either. As I said - pricey!

[Dennis Eugene]

Sure makes the 120 dollar custom molds sound a lot cheaper don't it. ;) Dennis

[crabo]

You might check into some of the community colleges to see if they offer any basic machine shop classes.

Crabo

[Blammer]

I think I might, thanks!

[Buckshot]

.................The cheapest and fastest way to go (not fastest production, but fastest to start) would be a lathe with a DRO (Digital Read Out) and a face plate. Once the face plate is mounted for the first time, you take a skim cut of a few thousandths depth across it with the lathe's crossfeed. The surface of the faceplate is now running exactly perpendicular to the spindle axis.

The mould blocks would require a fixture on the faceplate to hold repeat blocks the same, over, and over , and over et'c & et'c. The least expensive fixture would be a vise.

http://www.fototime.com/EC6E32186093ED1/standard.jpg

This is a tool & diemaker's vise. It is accurate to .0002". It's sitting on a 'T' slotted faceplate vs a simple slotted one. This setup will require counterbalance weight to offset the vise's offcenter weight if it's to be spun at any speed at all.

http://www.fototime.com/82E06994EA0F27E/standard.jpghttp://www.fototime.com/B01F3C3697B6AE7/standard.jpg
http://www.fototime.com/025DBFFE3B48D69/standard.jpghttp://www.fototime.com/1E69FACFF7FA727/standard.jpg

The above 3 cavity core mould was made using a faceplate and ground angle plates. It could have as easily been a boolit mould. I will not kid you that using simple dial indicators for long and crossfeed will net you superb moulds. However it will generate useable moulds. I would NOT consider using this method for production at all.

On the other end of the scale, for quality, and quantity production of close repeatable dimensions, you would want to use CNC equipment. You would also want that equipment to have precision ballscrews for movement vs ACME screws in nuts, whether you planned on using a cherry or ground tools to create the cavity. An ACME leadescrew HAS to have play in order to be moveable. A ballscrew doesn't, ergo no lash and no backing up then reversing to recapture your zero.

If you were to use a milling machine you could use a cherry, a form tool and also ground tools. If you went that route my suggestion would be that you hook up with someone who could make and also maintain the cherry. A form tool is like a cherry as it has a full profile of the design but is really a specialized cutter having only one flute. These can be used for many boolit OD's via moving the blocks in a circular motion around it as it spins.

The possibilites, permutations, accesories (required and nice to have) plus the training to use the tools would require several books. Even listing possible options in detail is way beyond what would logicly be posted as a reply. Do searches for CNC lathes, CNC milling machines, engine lathes, toolroom lathes (about the same thing) second operation lathes, chuckers, and turret lathes.

Get on U-Tube and search for CNC. There is a lot.

..................Buckshot

[Linstrum]

I have never really sat down and analyzed the different start-up costs for each of the several ways of making a boolit mould, I already had a lathe when I started making my moulds, so having to buy a lathe and later on a milling machine were not part of my start-up costs. Leftiye has a good dissertation on CNC vs. the other ways, he is right that if one already has a CNC lathe then that is the fastest, cheapest, easiest way of making one-of-a-kind molds.

Probably the easiest way to make boolit moulds is to use the cherry method already described above. A small lathe and a stout drill press, plus an accurate articulated milling vice to feed the mould block halves together are the minimum equipment necessary. The machinists of antiquity by hand with files and hacksaws cut the flutes and relief angles on their drills, mill cutters, reamers, etc, as have I, and it is not that difficult if the principles are understood. Heat treating is also not that hard and can be done with a MAPP torch for probably all cherries. The older 1940s - 1970s editions of Machinery's Handbook I own have drawings and diagrams for making reamers and milling cutters.

CNC is probably the cheapest way for commercial mould production, too, since Lee Precision has the lowest prices for what I consider to be extremely accurately formed cavities and they switched over to using CNC lathes to cut the mould cavities from using a proprietary coining process they (Lee) developed several years ago for precision forging the cavities, which is another good way of mould making if you have access to a high tonnage press. Using cherries to cut mould cavities is fast, but cherries do not last long for making hundreds and thousands of moulds unless made from tungsten/molybdenum carbide and making those is expensive. The Lee Coining process used a tungsten carbide template the exact size and shape of the bullet and was used to make the cavity by being pressed sandwich-fashion into the two halves of the mould block in a 100-ton press. One tungsten carbide template would last for tens of thousands of moulds! The process required the rough cutting of the cavities into the mould halves first before the pressing operation and it was a logical step upward from that to simply go to CNC-cutting the cavities accurately into the mould block and skipping the template pressing operation. The majority of the Lee moulds I own were made by the 100-ton pressing-coining Lee method, including the Lee .309” by 180 grain boolit that delivers ½-inch five shot groups at 100 yards with my 7.5x54 French MAS 36 rifle. My Lee .312” by 185 grain boolit mould is CNC lathe cut and delivers the same degree of accuracy in my 7.62x54R Finland Mosin-Nagant 91/30.

As far as the old fashioned methods of mould making that go back about 170 years to the time when conical projectiles with lube grooves and powder residue scrapers were first invented (like the original French Minnie Ball), there are two ways used for cutting those complicated mould cavities. One is by using the cherries in a machine like a heavy duty drill press or milling machine with an articulated vice that feeds the mould block halves together like leftiye just discussed above, and the other way is by hand in a lathe using the cross-feed micrometer and a test dial indicator on the carriage in conjunction with special shaped tool bits. In another thread Buckshot has photos and discussed how he has formed ogives and lube grooves in mould cavities using hand ground shaped tool bits in his lathe, guided by a test dial indicator and the lathe cross-feed micrometer.

Buckshot’s lathe cutting methods are also the same as what I have used since 1964 for making most of my moulds. It takes some getting used to making mould cavities this way since the cutting action is out of sight down inside a hole, and running blind like that requires a bit of faith in the one’s own skill as well as the accuracy of the lathe carriage cross-feed micrometer dial and test dial indicator to position the lathe carriage! To learn the necessary moves required to blind-cut mold cavities like that in a lathe, I first cut an inverse or external practice piece on a bar of soft steel or scrap aluminum to make sure that the tool bit is actually going to where I want it to according to the test dial indicator and micrometer feed. I do this on the back side of the work piece (with the rotation backwards) to simulate the same tool bit and parts motions and manipulations as are encountered down inside a hole on an internal cut. Long-time machinists usually have a good sense of what the cutting tool is doing, but we aren’t perfect! Hence doing the practice pieces first since mould blocks take A LOT OF WORK to prepare before the boolit cavities are ever ready to be cut and anything that will destroy hours and even days of work is to be carefully avoided! I can’t emphasize this enough!

A final way to make one or just a few-of-a-kind test boolits is to use the cheap cuttlebones that are sold by the bucketful in big pet stores as well as some jewelry making supply businesses (parrots love to chew on cuttlebone to keep their beaks in shape and cuttlebone is also used to make inexpensive jeweler’s sterling silver casting moulds). Cuttlefish and squid have a big shield-shaped bone in their body made from mineral lime that is sponge-like and takes good impressions by pressing the part to be copied into the cuttlebone. It has to be prepared first by baking in the kitchen oven at maybe 300°F for an hour or so to get all the moisture out of it to prevent a steam explosion when the lead is poured in. In times past I have made a test boolit or two by lathe turning a piece of hard plastic or soft metal like aluminum to the size and shape of the boolit I want including a sprue piece with funnel shape and then pressing it between two pieces of cuttlebone to form the boolit casting cavity and pouring hole with funnel. Before removing the boolit template from the cuttlebone sandwich, take six or eight 8d or 10d nails and run through the sandwich to act as alignment pins and then pull the sandwich apart being REAL CAREFUL not to wiggle the nails so they lose their tight alignment. Pull the boolit template out and carefully put the halves of the cuttlebone mould back together, tie with twine to keep the halves together tightly, and cast your test boolit. I haven’t made more than a few test boolits this way myself so I can’t say how really effective it is as far as keeping critical dimensions goes but a few can be made before the cuttlebone comes apart. Just to warn you, the cuttlebone will stink to the high heavens with the hot lead in it. Of course the cuttlebone mould has no sprue cutter so you will have to carefully remove the sprue piece from your boolit plus your boolit will not exactly be like the nice-looking smooth silvery gray objects of The Silver Stream you are used to getting from your commercial metal moulds.

Have fun!

[44man]

I went to a foundry and bought two risers for $45. They said it was the highest quality iron and it was true, the stuff ate cutters. I used an angle grinder to form rectangles outside first and a cut off wheel to trim them. Once ground to where I could fit them on my cheap Smithy, I milled them to shape. This is a double action vice that slips onto the gibs of my milling table after I remove the top platform.
It took me two weeks to cut it but it works like a charm.
I bought a cheap index tool from Enco for $30 for cutting flutes on my cherries with just end mills. I then file the cutters to the nose by hand and hone them.
I have a total of $75 tied up in the tools plus a few cutters for the cast iron. Less then $100 though.

[44man]

You can see the bolts coming into the sides of the cavities. The blocks are clamped between the jaws and I put thick pieces of aluminum between the blocks and the bolts. Tightening the bolts locks the blocks into the vice jaws so I can open and close them without losing position. I never remove the blocks until they are finished. I de-burr by opening the jaws and going in with fine emory paper taped to a thin stick.
This is the only use I have for WD-40! :mrgreen: I lube the cherry with it.
You just can't get any cheaper, just need some time and labor! :drinks:

[JIMinPHX]

I would think that you would basically need a mill & a lathe. Of course, you will need a little tooling for each.

I don’t think that the two-jaw lathe chuck idea will work very well with a cherry, because I have never seen a 2-jaw chuck that you could close as the chuck was spinning, except for a 10” Kitagawa hydraulic chuck that was worth over $5k. Even that didn’t have variable closing rate.

Cutting a cavity with a cherry is generally not quite as easy as jamming two blocks together with a spinning cherry in the middle all in one shot. The chips need to have somewhere to go. You need to make a roughing pass first to get rid of the majority of the material & make room for the chips that the finishing cut is going to produce. If those chips get bound up on the cutting tool, you will ruin your finish. One possibility is to make a roughing pass with an undersized drill bit from above a closed pair of blocks. Another possibility is to rigidly mount a block half & move into it sideways with the cherry spinning in a mill. Of course, for your roughing pass, you would not go in to full depth.

If you go with the double acting vice setup, you would only do the close-the-vice-on-the-cherry for your finish pass & that’s only if your cherry is cut on size. Personally, I would prefer to use an undersized cherry, move slightly off center & rotate the work (blocks) to make the final size pass. That way you can adjust your mould cavity diameter by how far off center you move the work when you spin it. You could do that on a face plate in a lathe, as Buckshot has recommended. You could also do that on a turntable that was mounted to the table of a mill. That would be my preference if you were willing to spend the money on a turntable.

For the cheap way out, I would start with a mill & some basic tooling to make the bare blocks & also a lathe to bore the cavity. I would just rough the cavities with a drill bit & then bore them with a few small boring bars that I had hand ground to the shapes of boolit points & lube groves. For limited production volumes, That’s all I would get.

On the used market, you could get into this for about $3-4k. You don't need big machines to make moulds. You do need a rigid machine to pull a cherry or a boring bar with a large contact surface.

If you want to play with cherries, then have one or two ground by a tool & die shop so that you can try them out & see if you actually like to work that way. If you do, then invest in the tooling needed to grind them yourself later.

[JIMinPHX]

44MAN has a pretty serious looking set up there.

I have always found all of Buckshot’s advice to be on the money.

[leftiye]

The offset rotary table is analogous to the orbiting EDM machine on another thread. You wouldn't have to have an actual cherry, but rather a cutter that was the shape of the boolit sans a flat point (narrower by the width of the flat point). As JIMin PHX said , just move the cutter into the side of a preliminary shaped cavity (while spinning), and rotate the table. Measure diameter, and adjust, rotate again. For one offs, just single point it in a lathe (not as easy as it sounds).

[JIMinPHX]

The offset rotary table is analogous to the orbiting EDM machine on another thread.

?????????

[44man]

Chips have not been a problem because I start out cutting dry and hold the shop vac nozzle next to the cutter. I turn the cherry slower then what is normal for aluminum until I get close to finished. The slower speed and the air from the vac keeps the cutter cool. I speed it up a little and start to lube when almost done.
With the blocks clamped, it is no problem to open the blocks a lot to flush chips and deburr.
It takes surprisingly little time to cut the cavities. The cherry must be the right size to start with so a good guess for diameter is needed. I find it best to go a thousandth or two larger. A boolit can be sized.

[44man]

I don't make the prettiest molds but they work. Here are a few.

[Sig shooter]

I have the where with all to make one , maybe a simple single lube groove pistol mold . I figure a ball end mill cutter ( or radius square ) for the hole / tip . Grind up a boring bar to push out the two base bands / lube groove its only .300 deep on a .45 SWC .

I could T.I.G tac weld the blocks together and drive two dowel pins for alignment . A two or three cavity block could be chucked up in a four jaw lathe chuck . My issue would be cavity uniformity , with a few thou - wider - longer ,, they may all shoot differently ,, cavity to cavity .

I would like to try the sharp cone tip ( Spelunker bullet ) I saw in an old book by Grennell / Clapp .

I'm sure all the variations of lube grooves have been done already ,

[Buckshot]

I don't make the prettiest molds but they work. Here are a few.

.................They all look very proffessional to me!

.............Buckshot

[leftiye]

Sig shooter,
I wouldn't weld the blocks together, just my opinion. Not necessary for one thing, could (likely to) cause it to not maintain a zero gap. I make my blocks in one piece to Lyman's dimensions with the thickness dimension plus .100". I drill the guide pin holes next, then saw the halves apart, and then surface the faces.

If you then bore the basic cavity and ogive (maybe with a "D" reamer that you make), after you center the blocks in the lathe and bore out the driving bands without moving the setup, there will be no concentricity problems. You could do an angled cut on the nose end of the front driving band to get a shoulder to your "ogive", or just make a truncated nose design.

This process without boring driving bands etc. makes excellent paper patched boolit molds. Even if they turn out a little rough, It holds the paper in place better.

[Blammer]

Nice pics of your machine and moulds!

[44man]

I am down for a while. I bought an almost new Smithy Granite and it is still in the garage. I took my Smithy CB 1220 apart and got it up and need to sell it. I am making a new bench right now.
I have to figure out how to get the 550# left, after I removed as much weight from the Granite as I could, downstairs.