Making bullet molds

[acoilfld]

Found this link on Google. It is a 66 page word document describing how to make bullet molds. Lots of good pictures in it also.
http://www.usi.edu/Science/engineering/moldfixture/MakingBulletMolds.doc

The link gives you the option to either open or save the document.
I found it interesting and thought that I would share it.

AC

[shdwlkr]

acoilfld
thanks for putting it up for us to see. Very interesting reading

[deltaenterprizes]

I think that was written by our member "The Professor"

[No_1]

I believe that article was authored by fellow forum member "theperfessor". I am sure if you have any question he would be more than happy to answer them.

Robert

[Shiloh]

I have admiration for machine tools and those with the knowledge to achieve the most out of them.

Wonderful article !!

SHiloh

[acoilfld]

I assumed that it was OK to link to this since it was posted on Google.
If I would have known how to contact him first I would have.
As it is - I would like to thank him for the article that he wrote, It answered a lot of questions that I had about the process.

AC


EDIT:

I tried searching for "The Professor" on this site (to let him know that I linked to his site) - but could not find him listed. :(

[theperfessor]

No problem with the link. I think the original thread is in the Classics and Stickies section now. Glad to hear you enjoyed it.

I'm still improving tooling and developing knowledge base to make custom multi-cavity bullet molds to my standards.

[robroy]

acoilfld and Professor, ThanksI coppied the document and saved it to my desk top. Professor If I ever get a lathe and a mill I'm gonna steal your fixture design. By then you'll have the bugs workedm out and I'll still have the old design.

[tommygirlMT]

In order to have better control of as-cast bullet diameter, I plan to make two five-cavity molds, one each of 7075 and 2024 aluminum, with drilled and reamed cylindrical cavities with diameters of ¼" (0.250"), 5/16" (0.3125"), 3/8" (0.375"), 7/16" (0.4375"), and ½" (0.500"). This covers the range of possible mold diameters I am interested in. I will get the molds up to proper casting temperature and use pure lead, recycled wheelweights, linotype, and other alloys of interest to cast slugs that I can measure and compare to the cavity size to get empirical data on the amount of actual shrinkage with each alloy in a mold of a certain composition.

I would like to ask the author of that article, theperfessor, if he ever completed this and what his results were. I would be very interested in them. I would especially like to know if shrink ratios were also effected by the depth of the cavity.

[theperfessor]

I'm using my iPhone right now so I will keep this short and simply say that I will give update on this tonight when I get off work.

[deltaenterprizes]

No problem with the link. I think the original thread is in the Classics and Stickies section now. Glad to hear you enjoyed it.

I'm still improving tooling and developing knowledge base to make custom multi-cavity bullet molds to my standards.

A DRO would be a big help, you have a big challenge with manual machines even if it is a Monarch 10EE.
The biggest problem I see is measuring the ID of the cavities.

Has any members checked the variations of the weights between the cavities on LEE molds? They are lathe bored on CNC machinery. CNC machines are supposed to be able to hold .0001" accuracy or more given the right environment.

[machinisttx]

A DRO would be a big help, you have a big challenge with manual machines even if it is a Monarch 10EE.
The biggest problem I see is measuring the ID of the cavities.

Has any members checked the variations of the weights between the cavities on LEE molds? They are lathe bored on CNC machinery. CNC machines are supposed to be able to hold .0001" accuracy or more given the right environment.

A manual lathe with old fashioned dials will hold .0001" if the right person is running it. CNC eliminates most of the human factor.

If coolant temperature changes, or machine temperature varies, it's pretty easy to go over a .0001" tolerance. It can change that much between parts due to cutter wear. .001" is much more realistic outside a highly controlled environment and other factors.

[DLCTEX]

Enjoyed that! Thanks Perfessor.

[deltaenterprizes]

A manual lathe with old fashioned dials will hold .0001" if the right person is running it. CNC eliminates most of the human factor.

If coolant temperature changes, or machine temperature varies, it's pretty easy to go over a .0001" tolerance. It can change that much between parts due to cutter wear. .001" is much more realistic outside a highly controlled environment and other factors.

The manual machine may be able to hold .0001'' but .001'' to .0005'' about the best I can do on a good day!

[JIMinPHX]

Tolerances vary with the machine, the machinist, the tooling, the operating environment & the time available. There are a lot of places that you can loose more than a tenth.

[leadman]

Lee molds are no longer bored on a lathe. Pat told me last week that they are using a milling machine now. The molds halves are not closed and are cut seperately. Must be something like MiHec is doing.

[theperfessor]

Let me answer some specific questions and issues raised in some of the posts here.

deltae-
Just as you mentioned, I realized I needed to improve the positional accuracy of my lathe, and I needed better inside measuring tools. I had the local guy that I buy all my tooling from install a DRO on my 15 x 48 Clausing Colchester lathe. I really love the Newall unit. (Picture 1) The axes readers are hollow aluminum tubes filled with steel balls. They're completely sealed, no gears or glass scales. The pickup unit just slides over a smooth tube and reads position by magnetic induction through pickup coils.

The new units have all the mill and lathe functions built in, so the same display/control unit can be used on mills or lathes. It will store offset values for up to 99 tools, so I can program in a unique position for each tool. It lets you use built in functions, such as locating points on a line or an arc, to generate coordinates to "step cut" curves and arcs. I can hold 0.0005" to 0.001" on diameters between tool changes fairly easily with this.

I have always used small holes gauges with an outside micrometer to measure small holes. (Picture 2, 3, and 4) These things come in sets that typically run from 0.125" to 0.500". They have a reverse taper plug on a threaded stem that spreads the leaves apart when the knurled handle on the end is turned. Put the gage in a hole, turn the handle until you get a light feel, pull out the gage and measure across the leaves with the same feel on your mike. I can easily fit things together to 0.0005" accuracy this way, since the same mike is used for both measurements, canceling out any calibration errors.

I also use inside micrometers. (Picture 5 through 8). The two shown here cover a range of 0.200" to 1.000" and 1.000" to 2.000" They come with a ring gage as a calibration standard.

The trouble with both of these methods is the inability to measure the diameter of a hole that is larger than the hole connecting it to the side accessible to a measuring tool. I bought a special tool designed primarily to measure the diameter of snap ring and O-ring grooves. Its a digital spring caliper. (Picture 9) It can be calibrated to a specific size with a mike or ring gage to read absolute size (say 0.358"), or it can bet set to zero at a certain size, and it will then read the tolerance, or how much bigger or smaller the hole is (+/-) from the perfect size. Both modes can be useful. The tips are small enough to read a narrow groove, and the diameter and length range cover any bullet size I would make a mold for.

robroy-
Don't mind you copying design. But don't just take it, improve it. Make it work for you. I have moved a couple of pieces so now I can make 5 cavity molds for anything .40 to .50 caliber and 6 cavity molds for .30 to .40 caliber.

tommygirlMT-
I wanted to determine shrinkage characteristics of various mold materials and alloys. I knew that I would have to be able to measure and control the temperature of my lead pot and bullet molds, so over the Christmas break I built a dual PID controller. Here is the thread on that:

http://www.castboolits.gunloads.com/showthread.php?t=71208

I have prepared a batch of 12 bullet molds that are ready to have the cavities cut. Five of them are 7075 aluminum, five are 2024 aluminum, and two are Dura Bar malleable iron. Now that I have the equipment and tooling issues under control, and a way to accurately measure things, I am ready to cut my five cavity test molds using one of each material type. It will probably be a while before I can get to them , because I am heavily involved with a number of student and other personal projects right now, but it will happen and I will report the results on this site.

Along the way, a topic was raised in another thread concerning the observation that too-hot molds cast smaller bullets. My original objective was simply to determine the proper minimum melt temperature to use to get good fillout, but I realized that I could address this issue as well by broadening the test parameters (temperature range), so I plan to address this also. In any case, it will generate enough empirical data that I can use to determine the recommended "best" melt temperature to use with my molds.

machinisttx-
I'll go with your 0.001" as a practical figure. Anything closer than that I sneak up on, hand fit, or find a better process!

Thanks again to all for your interest and kind words.

[Willbird]

I keep turning the idea over about making a set of mold blocks from EDM graphite

[theperfessor]

Other than high temperature resistance, what qualities does EDM graphite have that would make it better than what is being used now?

I'm surprised that somebody hasn't tried making bullet molds using powdered metal/sintering technology.

[Willbird]

Well it machines pretty easily was what brought it to mind. The mental wandering went to things that have a lower coefficient of expansion (like TI) but are difficult to machine. The cats meow might be a set of "master" blocks that can have some slabs of the graphite bolted to them, the master blocks would have the machining for the handles, and maybe even the sprue plate. Then all the graphite is doing basically is providing the cavity.

Carbide would be a good material too, it can be machined in the "green" state, then it gets some kind of final process (involving high heat I'm sure) that makes it into what we know as carbide. I have never machined it but heard from more than one person that they had done so. I have ground a lot of carbide, and it is very nice to grind using the proper equip and wheels, you can rip it off as fast as you want and it never heats up and swells like steel does when you try that.

I'm interested in paper patch molds lately, and those especially would be readily done in carbide because there are no grease grooves, it is all ID grinding. I wish I still worked in the shop where I learned all that stuff :-).

Plain old 12L14 might make good mold blocks.

Bill

[45nut]

We have some very skilled machinists aboard, tis a pleasure to read about it.

[JIMinPHX]

Carbide would be a good material too, it can be machined in the "green" state, then it gets some kind of final process (involving high heat I'm sure) that makes it into what we know as carbide. I have never machined it but heard from more than one person that they had done so. I have ground a lot of carbide, and it is very nice to grind using the proper equip and wheels, you can rip it off as fast as you want and it never heats up and swells like steel does when you try that.

...Plain old 12L14 might make good mold blocks.


It might also be useful to cast some cemented carbide into the shape of a mold. Something similar to the lost wax method may work for that. I haven't cast carbide myself, but I know that it does get done. I've used some unground cast carbide inserts on my lathe before & gotten surprisingly good results.

I have some blank mold blocks made from 12L14 that a board member gave me an embarrassingly long time ago, that I haven't cut cavities into yet. I really need to make the time to get that project back out & finish it. The gentleman who gave me the blocks told me that 12L14 worked quite well for molds.

[Willbird]

12L14 is a material that is made to be machined, and man does it machine nice, the only down side to it is that it cannot be used to make things that get welded together. The lead prevents full weld strength, or so I was told anyway. But 12L14 mostly comes in rounds, squares, and hexes. there are other leaded materials too like 41L40.

Bill

[JIMinPHX]

12L14 ... the only down side to it is that it cannot be used to make things that get welded together. The lead prevents full weld strength, or so I was told anyway.

I can confirm that from personal experience. Leadloy does not weld well at all, especially if you try to weld it to something like cold roll.

[machinisttx]

It might also be useful to cast some cemented carbide into the shape of a mold. Something similar to the lost wax method may work for that. I haven't cast carbide myself, but I know that it does get done. I've used some unground cast carbide inserts on my lathe before & gotten surprisingly good results.

I have some blank mold blocks made from 12L14 that a board member gave me an embarrassingly long time ago, that I haven't cut cavities into yet. I really need to make the time to get that project back out & finish it. The gentleman who gave me the blocks told me that 12L14 worked quite well for molds.

Carbide isn't "cast", at least not any that I'm familiar with. It originates as a powder which is then pressed into a rough shape, and then is put into an atmosphere controlled oven at some pretty extreme temperatures for sintering.:confused:

[deltaenterprizes]

Professor,
That digital groove caliper is just the tool for the measurements I referred to. Combined with the DRO it looks like you are heading down the path to success.

The path I have chosen is to try to achieve the level of quality of Eagan and H&G and others with cherries made with my own hands, sharpened in a jig made by me, using tooling available to the masters in their time.
I started this venture long ago when I was doing commercial casting and 2 cavity bullet molds were the sky high price of $40. I wanted to be able to take worn or damaged blocks and recut them. Now my goal is to be able to make molds close the ones I lost for my personal use and if I get proficient, sell a couple!

Willbird,

There was an article about a jeweler that made a mold using graphite to be used to cast silver bullets. He made a 3 fluted cherry and hand sharpened it, He reported that the graphite machined easily. I think I found it doing a search for "making bullet molds" or "making cherries for bullet molds".

[theperfessor]

deltae -

You have set an admirable goal for yourself. I hope you are successful and I wish the best for you.

I and many other members would enjoy seeing some photos of your work. I am especially interested in your sharpening fixture. How about some pictures?

Cutting accurate form tools is still one of the problems I am working to conquer. Part of the reasons I opted for lathe boring versus the more traditional cherry-and-double-acting-vise method is I figured it would be easier to cut ONE accurate edge instead of the three or more that a conventional cherry requires.

I have my eye on a used KO LEE universal tool grinder that might come up for sale here locally. If I can get this I think it will go a long way toward helping me make accurate cutters. If I can grind accurate multi-flute cutters I may in the future get a double-acting vise and try the traditional method, especially for longer, skinnier (rifle) bullets.

[deltaenterprizes]

The jig is a smaller version of one described in "The Machinist Bedside Reader" Vol 3. by Guy Lautard. If you do a search for his site there is a version pictured. The jig, according to the book, if I remember correctly(rare occurrence these days) is that it was designed to make match reamers from standard rifle chamber reamers.
I missed a small tool and cutter grinder not far from me at a good price and also a small surface grinder.
I wish for some warm weather ( not hot) and motivation so I can go work in the shop and finish some projects!

[deltaenterprizes]

I can email them to you,I tried to post them and it did not work.

[theperfessor]

deltae -

email sent. It's been pretty cold here too. My shop is a 24' x 30'-4"cement block building with 2" of hard foam insulation and has an electric heater. When its in the twenties it takes an hour to warm things up to get comfy and even longer to get machines warmed up to cut accurately.

If I only have an hour or two to work I can't get much done, so I usually work on the weekends. Hard to get motivated, so I do a lot of design/project planning/material acquisition to prepare for later projects. But I do love the machining and fabricating. Unlike a slightly younger generation, I understand the difference between reality and an electronic representation of reality.

And with my Colts making it through the playoffs I've been down to half a day on Sundays. Go Colts! :grin:

[JIMinPHX]

Carbide isn't "cast", at least not any that I'm familiar with. It originates as a powder which is then pressed into a rough shape, and then is put into an atmosphere controlled oven at some pretty extreme temperatures for sintering.:confused:

I've bought TGU322 inserts from places like Henley Tool who advertised them as unground cast inserts. Based on that, I believed that cemented carbide could be formed by casting it. I have also seen references to sintered carbide in other places. Since I have not manufactured carbide myself, I am not personally familiar with the exact process(es) used to form it. Perhaps the paperwork I saw had a misprint. Perhaps sintering was mistakenly being referred to as cast. Perhaps there is more than one process by which carbide is formed. I don't know for sure.

Do any of the board members here have a background in carbide production?

[machinisttx]

Jim, I have only limited knowledge of it based on a trip to a company that manufactured some stamping dies and tooling for the company I was employed by....so it's entirely possible that there is more than one process. I'm interested in knowing the answer myself. :grin:

The way that they got the basic material was in five gallon buckets as powder(and there were a lot of them). They obviously didn't tell us a whole lot of the details, but the basic process was explained and we saw the operation start to finish.

[theperfessor]

I think there is a vocabulary difference between how we use the word "cast" here on this site and how other trades use the word. In general, a "cast" product is one which is formed to a specific shape in a mold or cavity as a discrete item and a "wrought" item is one produced in a continuous length.

Let's also be clear about our definition of a carbide. A carbide is a form of a ceramic, and a ceramic is a material where one or more metal atoms forms a compound with strong ionic bonds with one or more non-metal atoms. The ratio of atoms also allows the molecules to form strong bonds in a crystalline structure of some sort. The end result is typically a hard, brittle material with no real liquid phase.

The typical carbide used for cutting tools is tungsten carbide powder coated with a cobalt binder that is pressed into molds to form billets or parts under high pressure and then heated to allow the cobalt binder to melt and bond the particles together. Both processes are sometimes used together to reduce inter-granular porosity.

Oxides are also ceramics. One of the most widely used is Al2O3, or aluminum oxide. This what is used on many abrasive papers. A few years ago a process was developed that is called the sol-gel process. A chemical mixture that forms a gel is cast in a mold and allowed to react and dry, followed by heating/sintering phase. This allows casting of ceramics into shapes by starting with a liquid vs solid/powder material.

Machinable ceramics usually have a vitreous (glass) binder. Cemented carbides have to be ground with diamond grit abrasive.

The main problem as I see it with using ceramic materials for low temperature (bullet) molds is the shrinkage that takes place during the drying/sintering phase (up to 30%), the brittleness of the resulting material, and the exorbitent expense of the whole process.

My personal evaluation of using ceramics for bullet molds at the current time is that it is not a cost effective method for low volume production and offers no area of superiority over good quality aluminum, steel/iron, or brass molds.

YMMV

[JIMinPHX]

Thank you Perfessor. That clears it up for me.

[deltaenterprizes]

deltae -



And with my Colts making it through the playoffs I've been down to half a day on Sundays. Go Colts! :grin:

Ah my dear Professor,I lived in the New Orleans area for about 50 years and as sorry as the Saints have been in the past, they have been doing well this year. I will be watching with great anticipation to see Hell freeze over, if the Boys in black and gold don't give the game away with penalties and play a whole game instead of the usual half as has been done in the past!
It is truly a miracle that they have made it this far, they must have stopped hanging out on Bourbon St. the night before the game. LOL!

[Buckshot]

.............Lyman mould blocks are a leaded steel, but I don't know which one. So far as 'tenths' go, I'm generally very happy with .0005". It all depends on what you're doing, and just how accurate does it have to be, anyway?:D One tenth (0.0001) is 1/40th the thickness of a piece of 20# typing paper. Thermal expansion and contraction can eat up a tenth in a heartbeat. Attaining that level of workaday accuracy is for folks a bit better off then me!

So far as mould cavities go, .................

http://www.fototime.com/4E82C710D2AEAC9/standard.jpg

I've probably hollowpointed close to 200 moulds to date. Add in a couple dozen GC shank removals too, and a few have been absolute wonders in concentricity considering the run of the bunch. All will have a 'bump' of some magnitude across the parting line. I use a TI with a 1.25" long probe to reach as far up into the cavity as possible.

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

Checking several particularly recalcitrant moulds has proven that those with truly 'True' cavities (to ANY plane of the blocks) is pretty much something that has yet to happen :lol: So my reasoning for indicating up close to the nose of the cavity is that, that's where the bit is going to enter, and it MUST be as close to on center as possible. I believe that luckily due to the starter bit's small size it's going to follow the block's parting line and then the reamer is going to follow that hole.

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

[theperfessor]

It should be a very exciting Super Bowl. I don't think it will be a one-sided dud like some previous games. And come Monday morning, I still want to be friends with all the Saints fans here, no matter who wins!

[Willbird]

I used to work with .0001 every day all day. I'm sure you can get that at one place in a mold (if recutting) but not all places at once.

One thing to remember with an indicator, a longer tip reduces the sensitivity of the indicator.

Jacket wall thickness runout of .0001 or less is what makes "good" bullets the good ones :-).

As to whether a center drill or any other drill will then hit the center of where you have indicated........I would not bet on that, to get decent accuracy I had to "bore" the hole with an endmill, either plunging straight in, or circle milling (with cnc).

I am going to concentrate on making extremely good 1 cavity molds.......to me they are the holy grail of accuracy anyway. And to start I am going to make it real easy and make only paper patch molds that have no lube grooves...the cavity can then be bored from the rear, or D reamed, or maybe some of each.

I was taught that even a 2 cavity mold where both cavities were cut by the same person, with the same cherry, on the same day, in the same machine....that each bullet was an individual unto itself.

I remember seeing an article where the author shot 2 groups with the bullets from a 2 cavity rifle mold of some kind(30 caliber as I recall). The POI was different enough to create 2 separate distinct groups with the same aim point.

Bill

[deltaenterprizes]

Willbird,
I have read about Schutezen rifle shooters that use single cavity nose pour molds for that same reason.

Professor,
Football is only a game to me, I think the whole lot of professional sports players are over paid.

[BCall]

And with my Colts making it through the playoffs I've been down to half a day on Sundays. Go Colts! :grin:

I knew I liked you! Glad I'm not the only Colts fan on the board.:drinks:

Wish I had the skill and tools to do some mold making for myself. At least I get to watch you guys do some very interesting stuff. Thanks for sharing!

[theperfessor]

I gotta agree with all that's been said about working dimensional tolerances and accuracy by you guys. And I totally agree with the concept that using a single cavity mold increases your chances of getting bullets with the minimum weight and size deviation. This seems to me to be a practical concept for rifle shooter seeking the best possible accuracy in a rifle. But its a tradeoff of production rate vs quality.

I have focused my efforts on producing multi-cavity molds made to achievable dimensional standards that will produce bullets of adequate accuracy for the intended use, intended primarily for handgun level cartridges. (The truth is, I'm trying to make a mold that I would want to buy, own, and use. I'm trying to satisfy ME.)

I think that if I can control the diameter and depth to -0.000 +.001 from hole to hole that will at least be as good as the mass (not custom) produced molds currently available. And by lathe boring I can compensate for tool wear by just moving the cross-slide out a little more, so as long as the tool wears evenly there shouldn't be any change in profile or overall decrease in hole sizes from start to end of a batch. And my experience has been that (a) a lathe bores a lot rounder hole than any milling machine, and (b) by keeping the blocks together during boring you eliminate a lot of the cutter wobble and cavity edge burring that comes from all sorts of places when using the traditional compound-vise-and-cherry method.

I'm sure other people have different needs and standards, but I think that a lot of people would be satisfied to have a five or six cavity handgun bullet mold that would drop all the bullets to the proper minimum size +0.001". But I could be wrong.

(Not a big sports fan, my only fascination with football is that unlike serialized television the outcome isn't really predictable from the start. I seen the same plots rehashed so many times that I can't even get interested in TV anymore unless its the History, Military or similar channel.)

[shdwlkr]

perfessor
Now all I have to do is get my lathe, learn how to use it and start making things. You know that you have done it now don't you, no fair laughing

[theperfessor]

Its as addicting (and frustrating and satisfying) as bullet casting and gun collecting and shooting... :)

[deltaenterprizes]

[QUOTE=theperfessor;801281]The truth is, I'm trying to make a mold that I would want to buy, own, and use. I'm trying to satisfy ME.

Not a big sports fan, my only fascination with football is that unlike serialized television the outcome isn't really predictable from the start. I seen the same plots rehashed so many times that I can't even get interested in TV anymore unless its the History, Military or similar channel.

I see that we agree on a lot of things!

[Willbird]

Willbird,
I have read about Schutezen rifle shooters that use single cavity nose pour molds for that same reason.

.

Some of them even went so far as to shoot the bullets in the order they were cast too.

[theperfessor]

I read in a book called "The Arms of Krupp" (?) that the German engineers calculated the increase in bore size due to thermal expansion and erosion and numbered the rounds used in Big Bertha. You didn't dare shoot them out of order or at the wrong pace of fire! IIRC the barrels were shot out after just a couple of hundred rounds.

[machinisttx]

I'm sure other people have different needs and standards, but I think that a lot of people would be satisfied to have a five or six cavity handgun bullet mold that would drop all the bullets to the proper minimum size +0.001". But I could be wrong.

I agree with this.



And thanks for the info on the carbide. :)

[Chuck_ls]

Great article, Prefessor. I have made both lathe bored and cherry cut molds in the past with satisfactory results. I like your male/female pins for aluminum blocks. I will have to try that if I try again. Thanks for sharing.
Chuck

[deltaenterprizes]

Saints won! Lol!!!!!!!!!!

[theperfessor]

Deltae-

Yeah they did. They played a little better game and took a chance that worked out for them. Can't begrudge them for that. Now you know why I don't bet on sports!

Just to check my assumptions of tolerances for multi-cavity molds for handgun bullets, I did a few calculations. These calculations are based on the density of pure lead and assumes the bullet is a true cylinder of the length and diameter listed in the table. The length was selected to yield a popular bullet weight for the two calibers listed (.38 and .44).

I note that a 0.001" change in length causes less percent change in weight than a 0.001" change in diameter under these assumptions. which makes sense when you think about it. It also indicates to me that diameter is the more sensitive value and maintaining diameter to as close a tolerance as possible is the key to consistent bullets.

(P.S. I got your email w/photos, I'll post them in a new thread when I get unburied here in a few days.)

[theperfessor]

Chuck_Is -

Noticed this was your first post. Welcome to the insanity! It really is a great place to learn and share with other like-minded folks. Appreciate your kind words. I'll be glad to send you CAD file of pins if you want it. I've worked through several designs and have what I think is a good pin design that is both accurate in alignment and easy to manufacture. It is different than that shown in original story. I also have determined proper fit up to prevent pins from loosening due to thermal expansion differences between steel and aluminum.

Post some of your stuff. preferably with photos. The folks here LOVE photos and it helps explain narrative.

[kens]

Any updates on the molds.
Updates on process improvements?
Is Professor still on the forum?

[shdwlkr]

We lost the Professor earlier this year.

[obssd1958]

theperfessor is alive and well and posting actively on another forum. His username there is KeithB

[shdwlkr]

Brain fart it was Recluse we lost not the Professor