Making my first 4-cavity mold

[theperfessor]

I will in the future post a link to a website that will be a photo-illustrated story showing all the stages of designing and building a fixture to lathe cut multi-cavity bullet molds, as well as making one or more molds and the resulting output of boolits.

Until then I thought I'd just post a couple of pics showing the end result of the process. I've still got some tooling issues, and they're being worked out. This cavity has some problems - its .459 at the front and .454/,455 at the base. I'll re-indicate my form tool and try again.

I was trying to come up with a short nose button tip wadcutter at 220 to 240 grs with a single deep lube groove and a crimp groove for a light roll crimp for use in my 5" M625.

Comments always welcomed but at this point I am not in the business of making boolit molds for anyone else. My quality isn't good enough yet and I wouldn't want to disappoint anyone and look like a jerk in the process.

More later on this project......

[HeavyMetal]

Interesting design! Looking forward to seeing that link.

[kingstrider]

Wow I'm a bit jealous of all you machinist types. I always wanted to make scale radial aircraft engines but haven't had the time nor inclination for yet another hobby. Best of luck with your project!

[Dale53]

Perfesser:
First of all, I applaud your efforts. I was trained as a machinist and I can see MANY pitfalls to this effort. Congratulations on your progress!

I have never understood the reason for a "button nosed" wad cutter. After the double-ended wadcutter was released to the public (for .38's) I have shot several thousand of those. They shoot just fine (as accurate as any other), are a bit easier to cast and cut a FULL DIAMETER hole in meat. What more could we ask. They surely will be much easier to bore, also.

Just a thought or two...

Keep up the good work and let us know of your progress.

Dale53

[44man]

Very very nice and I am sure you will work out the settings.
I have to use cherries with my equipment.
What I really like are the pins and bushings on your molds. Could you go through the process for me? Include dimensions if you would.

[felix]

Reason for the cap, TC, button is to get a little more range than without with the same, or acceptable accuracy even further. ... felix

[Dale53]

Thanks for the response, Felix.

Dale53

[Cap'n Morgan]

I'll re-indicate my form tool and try again.

Perfesser,

If you don't have a dial indicator to run along your cutting tool edge, you can just take a shim cut on a rod of aluminium or brass on the outer diameter to check for tool alignment.
Just run the lathe in reverse, and cut on the "far" side of the part.

[theperfessor]

Went out to shop today and re-indicated cutting edge of tool. I had over-estimated the amount of deflection on my first attempt. Cutting second cavity took a while as I wanted to "sneak up" on size and not overbore the diameter. Took about an hour and a half to do this. Cavity measures parallel within .001" and has a basic diameter of .454/.455.

Once settings on lathe dials recorded it was an easy matter to cut cavities 3 and 4. All are within .0005" of desired size and each one only took about 20 minutes to cut.

Note that first cavity cut is not only tapered (too big at front as mentioned in first post) it also has flaws in grease groove and crimp groove where aluminum stuck to cutting tool (BUE - built up edge) and gouged cavity. A little polishing of tool face and lots of Mike-O-Cut 87 coupled with light cuts and lots of in-and outs to remove chips was required.

Thought I'd post a few more photos. Four of them are of mold, one shows form tool in lathe. I will post all drawings for fixture and my "standard" mold as well as 3D DXF file for CAD types to download. Will include all dimensions, etc., so anyone else can make/adapt to suit.

Be patient 44man, I'll cover pins when I get a little time.

I also make no claims for efficacy of bullet design, was trying to determine tooling problems (cutter relief angles and such) for a bullet with a nose of some type. Figure if I could do this I could easily make flat nose slug. I have had satisfactory experience with button nose wadcutters in .38s and thought a scaled up version might be worth trying.

This mold made from 6061 aluminum. Its kind of soft. Have acquired some 7075 and 2024 aluminum and will try those next. Form cutter still plenty sharp enough, may try to use to to make wadcutter for .44 Special next.

Have sprue plate done but need to make handle screws pins and pivot/sprue plate stop screws. Hope to try to make first cast before end of week and will update this post then.

Until then ......

[theperfessor]

Cap'n Morgan -

Thanks for tip.

[Buckshot]

...............Good lookin' stuff there Perfessor!

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

[Southern Son]

I love reading the how to's for this kind of stuff. Please don't forget the link or just post the whole thing here, either way I am hanging out to hear more.

[Lloyd Smale]

Im jealous too. I sure wish i had the knowlege and talent to do that. But then i guess id be so broke buying equiptment that i woudnt have money for buying guns and loading equip. My wife would about shoot me if i got into another expensive hobbie.

[shooter93]

Are you holding the cutter in the headstock and not the mold?...Just curious and the why. Thanks.

[Willbird]

6061 anneals at 675 degrees F, not sure what most aluminum molds run temp wise when they get "working".

7075 anneals at 775 degrees, maybe better for molds ??

Bill

[theperfessor]

Yesterday I turned all pins and screws for handles and sprue plate. Fitted everything up and did final deburring and cleaning. I designed mold to use Lee 6 cavity handles. (Best cheap handles around IMHO.) Spent most of morning cleaning shop and doing necessary machinery maintenance. Finally got reorganized from machining mode to casting mode.

Fired up Lyman 20 lb bottom pour, which was already filled with straight WW alloy of dubious ancestry. Did final acetone cleaning of mold, put silver grade anti-seize on all screws, and a little Bull Plate lube on all the sprue plate washers and other exposed surfaces. Put on handles, adjusted sprue plate, and put in propane grill w/lid down. By the time the Lyman was up to temp the mold was about 300F. A final touch of Bull Plate on top the mold and I started.

The final result is shown below. It didn't take long to start getting good boolits - had to throw away about first 4-5 pours but after that when I did my part I generally got good boolits. They dropped from the three good cavities at .4537/.4547. (One shown below measures .4538) I'm getting about .0013" difference in cavity size to boolit size using this mold material/bullet alloy/operating temperature combination. (This was one of the many things I wanted to learn from this project.)

Weighed a dozen picked at random from pile. Weight ran from 211.9 to to 214.9 grains. When I threw away the heaviest (measurement showed it was from the bad cavity that was oversize at front) and the lightest (which I suspect has a hidden flaw), the rest averaged 214.3 +/- .5 grs.

I can eliminate the first problem by marking bad cavity. I pour it as it keeps mold up to temp uniformly. The second is probably an alloy cleanliness problem which I can also deal with. I plan to make these out of a fairly soft alloy (50%WW/50% pure lead) so I will drain pot and give it a good cleaning before then. Would imagine that the slug might weigh a little over 220 grs with this mix.

In general, casting rate similar to Lyman /Saeco 4 cavity iron/steel molds, no temp problems, good fillout. Boolits sticking a little in one side of mold, so I plan to polish it out a little, but not unusual compared to commercial products.

Final picture shows three .45 bullets between two .45 ACP cases - my 214 gr WC boolit on left, 230 gr TC in middle, and 260 gr Saeco SWC on right.

Plan to size these to .4515 for M625. Will report on range results later.

[theperfessor]

Shooter 93 -

I'm holding tool rigidly in V-groove notch in tool block that fits my quick-change tool holder which is mounted in the compound of my lathe (a 15" x 50" Clausing). Used 5/16 end mill to bore hole .450" deep. Used form tool to aligned to center to plunge in to .550" deep. Then I fed cross-slide out by hand to cut profile of bullet - OD, crimp and grease groove. Had to cut about .030" on ID at a time before dialing cross slide back to center and feeding out to clear out chips. Depth controlled by dial indicator, ID controlled by cross-slide dial. One end result - I'm getting DRO put on lathe in a couple weeks.

Willbird -

Yeah, my next run of blanks will be made from 7075. Don't think mold gets hot enough to hurt 6061, but its a soft, gummy material that nicks and dings way to easy for a klutz like me.

Now that I know my fixture and process are essentially correct, I plan on doing a process review and maybe make some simple fixturing before I run up several hundred dollar in mold blanks - 36" of 2" x .75" 7075 bar stock cost me a little over $120 - which is enough to make five 4-cavity molds and maybe one 3-cavity. By the time I figure in the 3/16" x 1.5" O2 tool steel used in the sprue plate and the 4140 that I make the pins and screws from, I figure it costs about $30 - $35 per 4-cavity blank.

[Buckshot]

.............I used 1.5"x.750" extruded 6061 to make this 3 cav core mould for swaging slugs for the 38-55. I think that it is fine to use for a learning tool (it's cheap) or to make something for yourself, but you're right that it isn't the best for a set of mould blocks.

As Willbird showed, the annealing temp of aluminum is well within casting temps. Fortral is a high tech aerospace alloy, and hardened it shares space with some steels as to strength. However it is really a kind of glorified 7075-T6 and will shortly anneal via casting lead in it as mould blocks. However, having some on hand I thought I might give it a try. It may retain some redeeming property even after casting?

I have heard that 2024 is a fine alloy for mould blocks but have never bothered to check on availability or even on it's specs. Maybe there is a certain TYPE of 2024 that's the bees knees?
Looking at a set of Lee blocks and then a set of NEI or Raphine blocks you can tell that the alloy Lee uses isn't comparable to the other 2, let alone casting with them.

You're lucky getting a DRO for your lathe, but your 15" Clausing probably has room for them. My 11" Logan could handle a scale on the backside of the bed, but the cross slide I think it too shallow to have one fit. Even ball scales which are much less room hogs then glass scales would be a tough fit. I haven't finished wireing my new mill yet, but the Anilam DRO is 110V so I've plugged it in and cranked the table around some to play with it, and it's a wonderous thing to have! Has DI's beat all to heck.

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

[Willbird]

I have often thought with the beagling that can be gotten away with without any visible cast fins on the bullet that a mold could be made that had steel datums to close together, no aluminum/aluminum contact then . And maybe you could even "fly" the sprue plate above the tops of the blocks a few .001 the same way.

Bill

[theperfessor]

Buckshot -

Nice looking core mold you got there buddy! Logan's are nice lathes from all I've heard but I have no experience with one.

Local tool vendor who is quoting price for DRO and installation came up with idea to save me money. A lathe DRO for the full Z travel of my machine is about $3k+, which is more than I can spend right now, so he plans to install a Newell mill DRO with full X (cross slide) travel but only 36" Z axis travel. The Newell unit uses a sealed aluminum tube filled with steel balls, there are no exposed scales, gears, etc. He tells me I can install a plain aluminum rod of similar OD at end should I need to cut a long part. The Z axis indicator would simply not read beyond a certain point but I could still use full carriage travel for long parts w/o problems. Since 99.5% of what I do is close to headstock/chuck this poses no real problems. This gets price down to about $1.2k, which I can afford when I get summer school contract check August 1.

Willbird -

Like your idea of steel-on-steel contact for softer molds but don't know of cost-effective way to do it. Maybe put in some steel pins, grind blocks flat, and acid etch away aluminum by .001 prior to cutting cavities. Worth thinking about but I think I'll try using better aluminum from get-go and see how that works first. Your idea would eliminate need to cut vent lines. I'll file that idea away for future consideration, and thanks.

I might note that at end of first casting session there was no lead sticking to top of blocks or sprue plate and no visible wear on mold or cavities. I attribute this to a) super-smooth surfaces on blocks and surface-ground sprue plate, and b) Bull Plate lube (which is miraculous stuff!).

Have friend that can anodize aluminum - plan to talk to him and maybe try that and see if it changes heat transfer/retention properties, surface hardness, and bullet drop out.