My first set of home made blocks

[JIMinPHX]

I finally got around to getting myself set up to give mold making a whirl. The blocks with roughed out cavities in the picture below are my first set.

[JIMinPHX]

I had intended to make a rather heavy .22 boolit with a big meplat for use in a .223. The basic design that I had in mind is below. It's basically a Bator design with the forward lube groove omitted & the front end pushed out a little further. At first, it seemed so simple, then I started wondering about how wide I should make the driving band, how deep I should make the lube groove, etc., etc., etc. The bator is a very good general purpose boolit, but what I want to go for is a heavier, harder hitting boolit with top accuracy. Can anybody chime in with comments on my basic drawing?

[45&30-30]

Wow, very nice Jim. What caliber/style are ya going to end up with? Lube grooves?

Edit: Ya answered my questions while I was typing. Looks good.

[JIMinPHX]

I started the blocks out using the basic size & hole spacing of a Lee mold so that I could just use Lee handles, a Lee sprew plate & Lee hardware. I substituted long set screws for the handle pins so that I could change handles easily. I used standard dowel pins for alignment because the Lee alignment system would be too much work to duplicate. My basic drawing is below.

[JIMinPHX]

Those shallow 1/4" holes in the bottom are for locating the blocks on my cavity making fixture. I set it up so that I can get back on center again with the cavities if I ever want to bore them over to something else.

[JIMinPHX]

A "C"-shaped pinch down clamp holds the two mold halves together & on top of the 1/4" diameter locating nub. Two #10 screws hold the whole mess together.

[JIMinPHX]

A hole in the center of the clamp allows access to the cavities.

The real beauty of this system is that once you make up the fixtures, you can set back up to work on a bore again in a matter of seconds. Also, If your chuck is less than perfectly centered or is a little off true, it doesn't matter. Once you skim the surface of the mounting base & cut a fresh 1/4" nub, everything is back to dead nuts again.

[opentop]

impressive! Great work there!

[copdills]

very impressive, great JOB

[JIMinPHX]

Thanks for the compliments guys.

Has anybody got any advice on boolit dimensions? Maybe some way of calculating the proper driving band size or lube grove depth or something like that?

[Wayne Smith]

Jim, first I'm not capable of machining anything! However, you have not told us about your barrel and it's internal dimensions. Or your throat and it's dimensions.

Remember that fit is king, and to answer your question about design we need to know what it is supposed to fit.

[Glen]

Very clever mounting clamp! So, you lathe-bored a .22 caliber mould cavity? Wow! I'm impressed!

[JIMinPHX]

Wayne,
Thanks for the reply. I was planning to adjust the OD of the boolit to be .002" over the groove diameter of my barrel & then size down to +.001". That much I think I think I have a handle on. I think that I need to cut my cavities .002" over the diameter of the raw boolit that I want it to throw. I was going to cut it just .001" over at first, since it is easy for me to skim it a little larger later if needed. After that, the whole design of the boolit gets more murky.

I got rid of the front lube groove that the Bator had, because that part of the boolit stuck out of my cases & I wasn't putting lube in it anyway. I was under the impression that more bearing surface was better for accuracy, but I don't know if there is a limit, after which more is no longer better & instead more starts to cause problems. That is one question. If what I drew is too much, then maybe I should cut the front nose diameter down to the bore diameter of the barrel for the first 1/4" or so.

Another question is how much driving band width do I need? Do higher pressures require a wider band? Do lower pressures work better with a narrow band that deforms more easily? Does a deforming driving band squeeze lube out into the barrel? Does it not matter because I am using a gas check?

I drew up the front edge of the lube groove 0.190" from the heal of the boolit. This gives the neck of the .223 just enough room to cover the lube groove without the gas check sticking out the back of the neck, inside the case. That seemed to make sense. I kind of guessed at how wide & how deep to make the lube groove. I wonder if I am going to need more lube capacity or not.

Any advice or even wild thoughts are appreciated. I'd love to get a dialog going on boolit design in general & the advantages/disadvantages of altering various features.

Thanks,
Jim

[JIMinPHX]

Glen, that bore is just roughed. Don't be too impressed just yet. I figured that I would start with a .22 & if I messed it up, I could always make it into a .30 or a .38.

[Buckshot]

..............Pretty cool Jim. From what I understand you're supposed to wreak your first few mould attempts while learning:-) So now you can make a single flute full form tool, and then try boring it with a couple individual form tools. Regardless they'll both be kinda on the teensy weensy side, ha!

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

[44man]

That is an impressive setup, my hat is off to you. :drinks:
I don't have the guts to lathe bore with my cheap Smithy, I would need 20 dial indicators! :mrgreen:
I can't help with the boolit, I just draw them up with a pencil on paper, then make a cherry. I only worry about getting GG's and drive bands to fit. I found it is not rocket science and almost all of my boolits shoot better then from any store bought mold. Besides, math scares me at my age! [smilie=1: I would start with a boolit that "looks" right.
I kept reading about making the base band wide and screwed up my WFN .475 mold, wound up with a base band of .080", smaller then the rest. It has turned out to be the most accurate .475 boolit I have, able to hit a pop can at 200 yd's. 5 shots in less then 5/8" at 50 yd's. Even Jack Huntington says I made the perfect boolit.
Boolits are more voodoo then thinking! Bless with a dead chicken and eye of newt! :Fire:
All of my friends use my boolits only, use my molds only and outshoot me. Did I do something right? Who the heck knows? I sure don't.

[felix]

Yeah, you do 44Man! You know the relationships. The base band being small is an indication that your load is expanding the base to meet specs. If your base was larger, then the boolit would need to be harder for the same accuracy. Remember? Really, it is not voodoo, but just plain statistical luck in getting things to match-merge just perfectly in practice. This match-merging stuff is called "fine-tuning" and is left up to the technician working from the engineering design, which follows the principals provided by the scientist. All three professions taken together is needed to bring forth a viable product. ... felix

We have all heard about the phrase: "how, what, when, where". How = engineer; what = marketer; when = technician, where = God, who provides for the talents required of each profession. ... felix

[Wayne Smith]

Jim, the next question is the hardness of your alloy. The harder the alloy, the smaller the base band has to be, and Felix said. You need enough band, hard enough, to engage the rifling without skidding. This is true of all the bands. That's why they are there. Fitting your boolit to your case neck on one end and to your throat on the other does make sense.

When you start talking about lubes you open up whole nother case of worms! Get your boolit design down and then find a lube that works. Give yourself ample lube room and consider the length of your barrel as well.

[44man]

My alloy is 22 BHN. Boolit diameter sized after casting is .476 but after aging will reach .477 to .478.
Naw, Felix, it is just LUCK! [smilie=1:[smilie=1: But then again, I use Felix lube.
I did no thinking at all making this mold. I just kept moving cutters by eye on the cherry.

[JIMinPHX]

with my cheap Smithy, I would need 20 dial indicators!

Actually, that's the whole reason behind the setup that I used. It doesn't matter if the concentricity on your chuck is out of whack or not. You chuck a piece of stock, then turn a flat face & leave a 1/4" nub in the center. You now have a flat, true surface & a centered locating nub regardless of what your chuck is doing in the background. I started up doing it this way with a half a thought towards later maybe selling blanks to guys that had cheap lathes & no mill. This would allow them to make their own molds with little extra effort.

Thanks to you guys for all the good information that has started pouring in. I'm interested in what you have to say. I still haven't decided how I'm going to cut my cavities yet. I'm still pondering the details of what I want to try. Your comments are good food for thought.

[JIMinPHX]

This match-merging stuff is called "fine-tuning" and is left up to the technician working from the engineering design, which follows the principals provided by the scientist. All three professions taken together is needed to bring forth a viable product. ... felix

We have all heard about the phrase: "how, what, when, where". How = engineer; what = marketer; when = technician, where = God, who provides for the talents required of each profession. ... felix

You sound like you've been through this a few times before Felix...

My take on it was always more like -

Engineering - the fine art of learning by observing the unexpected, after engaging in lengthy & painstaking calculations to predict was was apparently obvious, but was actually wrong. :mrgreen:

[runfiverun]

jim, i see you have no venting set-up......

[JIMinPHX]

jim, i see you have no venting set-up......

Not yet, I will add that.

[Greg]

Jim-

I shoot the NEI 22-55 GC boolit that I had Walt cut for my barrel about 8-9 years ago. I had Walt cut it to .228 / .220

I have shot this boolit in three rifles: BRNO 22 k-Hornet ~ 1-14 twist; Rem 788 222 ~ 1-14 twist; Win M70 Heavy Varmint 223 ~ 1-10 twist.

This boolit has 2 driving bands and 1 lube grove. my best efforts at measuring a random sample cast of 92-6-2 alloy is thus;

driving band dia. - .228

bore ride dia. - .218 ~~ should be closer to .220

gas check shank dia. - .215

length - .632

gas check shank length - .065

1st driving band width - .060

lube grove width - .035

2nd driving band width - .060

.158 measured from the base to the leading edge of the lower driving band.

.220 measured from the base to the leading edge of the upper driving band.


I normally drive this boolit as cast (bhn 12) to 1885fps in the M70; averages about 1⅛" it likes a boolit sized .225 in a most excellent push thru die by our own Buckshot.

Heat-treated 465º for 1 hour (bhn 22) to 2274 in the Rem 788 - it has a rough bore therefor to need for a stronger boolit. averages about 1¾" sometimes I can get to 1½" I size .2265 in a H & I die by Stillwater

I’ve shot it at 2800 in the Rem 788 but accuracy was two minutes of angle.

I plan this Spring to devote lots of time to this boolit and find just what it is capable of

[Springfield]

Just an FYI, when I honcho moulds from LEE they say to cut the mould the size you want the bullet, not over nor under. So far they have been right.

[Greg]

I have left out two minor details

the NEI 22-55 GC cast of 92-6-2 (magnum alloy) weighs 60 grains. I size all boolits to .2265 lube with Apache Blue along with a Gator Check...

for the M70 223 I size to .225 in a push thru die.

[zxcvbob]

Has anyone ever made a cherry and used it to hog out a Lee mold into a larger caliber / different design? Seems to me like a Lee 2-cavity mold in a small caliber would be a great blank for a large-caliber mold.

[Cap'n Morgan]

Has anyone ever made a cherry and used it to hog out a Lee mold into a larger caliber / different design? Seems to me like a Lee 2-cavity mold in a small caliber would be a great blank for a large-caliber mold.

No, but I have a homemade alu mold which started out as a 150 grains 6.5mm, progressed to a 460 grains .465 for my Martini Henry and finally ended as a 600 grains .513 for my Swedish roller :-D

[Salmon-boy]

Jim, Genius. Pure Genius.

It's easy to make something complicated. To make it that simple is just Genius.

[jdgabbard]

So when ya' gonna start taking orders? ;)

[JIMinPHX]

Greg,
Thank you for all that detailed information. Based on what you posted, it sounds like my original design is probably pretty close to being OK as is. I think that I will reduce the diameter of the nose to start off with & make it a bore rider. I can always remove more material from the mold later & turn it into more of a soup can. Putting material back on the mold is not quite as easy.

Springfield,
That is an invaluable little tip you gave me there. You may have saved me from cutting my cavities oversized.

Jdgabbard,
First, I need to actually make some good boolits so that I know that I didn’t do something stupid like accidentally choose an alloy that lead sticks to or something. Then, after that I’ll have to time myself to see how long it takes for me to make a set of blocks from scratch. Then I’ll figure out what I would need to charge. I’ll let you know when I get to that point. Plan “B” would be to take a standard Lee mold, measure the opening in the top of the blocks, & face off my little fixture with a nub that matches the original hole in the top of the mold. You would then mount the mold on the fixture up side down & pop the two little 1/4" locating holes in the bottom of the standard Lee mold. After that, you could flip it back over & recut the cavities to any larger size that you wanted. For me to make this blank as a viable commercial project, I’d probably need to compete with the Lee mold price. I don’t know if that is possible or not. Those guys at Lee run a pretty tight ship on pricing. I suppose that I could just sell the little fixture clamp or something if people needed them.

In the mean time, thank you to everyone else also for the compliments & comments. I’m probably going to try to cut the cavities this weekend, so please keep all the good information flowing until then.

Thanks,
Jim

[SwedeNelson]

Jim

I just read this thread for to forth time.
Your fixture is a great idea.
Was trying to come up with a fixture to
make a hollow point in a mould.
I think your fixture would do it just fine.
Make a pin that is just the size of the
base of the bullet, clamp it in and drill
with the tail stock.
Great Idea!

Swede Nelson

[JIMinPHX]

It turns out that this weekend is a bust for me. A little emergency popped up at work yesterday & now I'm tied up solid until next Friday.

oh well, ...maybe next weekend.

[Buckshot]

Jim

I just read this thread for to forth time.
Your fixture is a great idea.
Was trying to come up with a fixture to
make a hollow point in a mould.
I think your fixture would do it just fine.
Make a pin that is just the size of the
base of the bullet, clamp it in and drill
with the tail stock.
Great Idea!

Swede Nelson

............It IS a great idea so long as the cavity isn't off it's own axes.

http://www.fototime.com/2E52E1F832F7ACF/standard.jpg

Get a few and check them out :-)

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

[SwedeNelson]

Buckshot

Grabbed the first mould in the drawer a RCBS.
2 cavity 37-250 FN.
That was a eye opener.
Would have to make a locating pin that indexed
off the nose of the bullet and let the rest of the
mould run out.
Back to the drawing board.
My hats off to you for what you do with hollow
pointing. Hitting dead center with a drill could
be a challenge.

Thanks
Swede Nelson

[dubber123]

I don't know how the expansion properties of aluminum will affect final cavitiy size, but the iron EDM mould I had done, I had cut to .454" hoping for a .452" boolit. I was close, but it came in .0005" too small. It was a minimal amount to lap out, but if I did it again, I would spec it at .003-.004" over the size I wanted.

Like I said, aluminum may react differently. If it's too small, I guess you could just re-cut it a bit bigger. Very nice work, keep us posted.

[BABore]

I don't know how the expansion properties of aluminum will affect final cavitiy size, but the iron EDM mould I had done, I had cut to .454" hoping for a .452" boolit. I was close, but it came in .0005" too small. It was a minimal amount to lap out, but if I did it again, I would spec it at .003-.004" over the size I wanted.

Like I said, aluminum may react differently. If it's too small, I guess you could just re-cut it a bit bigger. Very nice work, keep us posted.


Nope! It's similar. Boolit diameter, length, and band/groove sizes all affect how much oversize an aluminum mold must be cut. If'in you don't account for it, you will likely be small. You can cut another block set with a reground cherry if you make it too big. It gets real hard to add diameter onto a cherry if your small.

[dubber123]

I see your point if it's a cherried design, for some reason I had it in my head he was just using single point tooling through the end of the cavitiy. Otherwise, you sure are right, adding material to a cherry would be tricky...

[JIMinPHX]

, for some reason I had it in my head he was just using single point tooling through the end of the cavitiy.

That is correct. I am lathe boring through the hole in the end of the C-clamp. It is easy for me to make the cavity bigger later. Making it smaller would be tough.

[Southron Sanders]

Great Job! Next time you make up a mould, consider using 360 Brass. I like brass moulds so much better than aluminum moulds. It just might be a personal quirk, but I have been casting since 1968 and have never got along with aluminum moulds.

[JIMinPHX]

I've been receiving some questions about this recently, so I thought that I'd post a drawing.

[LedShed]

Can someone point me in the direction of how to make a cherry in the first place (a book maybe)? I'm a shooter/machining student that wants to make his own molds. I've found a couple of less than precision based ideas but nothing I'm fond of. Actually they scared me.

[Buckshot]

Can someone point me in the direction of how to make a cherry in the first place (a book maybe)? I'm a shooter/machining student that wants to make his own molds. I've found a couple of less than precision based ideas but nothing I'm fond of. Actually they scared me.

...........Making a cherry is just like making a reamer, because that's basicly what a cherry is. There's a couple differences in operation, one is (and it's a big difference) that the cherry has the mould blocks moved into it, perpendicular to it's rotational axis, so it's cutting full form over it's entire length and creating a hole (cavity). A reamer on the other hand is advanced into a previously bored hole, with their axes in alignment.

Cherrying a set of blank blocks usually requires they be mounted in a centering vise. That's a vise that has both jaws closing together at the same time. Normally the blocks are pre-drilled to remove the bulk of material in the cavity, before the cherry is used. Another method which may be used, especially with a DRO on the X or Y axis or CNC is to move one block into the cherry to allow it to cut 1/2 the cavity, then the opposite block is moved to the cherry for the other half to be cut. With both blocks being formed at the same time, depending on the design of the cherry or how much material has to be removed it may be advisable to open the blocks and flush chips before completion. Cutting one block at a time doesn't require this as chips are readily evacuated.

To make a cherry using high carbon steel, you'd turn the desired form on the lathe. Then the formed piece would be moved to a Spindex or indexing head on the milling machine where the flutes are cut, including main and secondary clearances. After that it's a matter of some cleanup by hand and then hardening. Final stoning is then performed to fully sharpen the flutes.

http://www.fototime.com/B55E2CC4F2DF8E0/standard.jpg

It's also possible to make a simple 'D' reamer, which is basically a reamer with one flute, having half it's width ground/milled away. These above are some I've purchased on E-Bay. Since they're high speed steel they require grinding to produce the desired form. There are a couple positives to D reamers. The main one is they're simple, and they have skads of chip clearance. The major drawback to them is they're nowhere near as rigid as a full OD cherry. They have to be fed slowly or they'll chatter.

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

[44man]

It's not my chuck or alignment. It is the cross feed and depth adjustments at the lead screw. [smilie=f:
Even the mill head can't be trusted. I have a DOR on it and if I hit it right and tighten the friction lock, it all moves up or down a little.