how do I trim off[\\'shorten' a mold?

[rdlange]

I want to trim off the top of a 90274 lee mold to make a shorter, lighter 32-20 flat base bullet to use in a Martini Cadet with a .323 bore. Couldn't find a thread about this. Any assistance would be appreciated?

I don't have a mill or lathe. And yes, I do know a smith that could do it for money when he has the time.

thanks.

[country gent]

Need more information as to how much you want to reduce the mould. A gas checks length, a driving abnd and grease groove? alot depends on how much metal need to be removed?

[rdlange]

OK, 1/4 to 1/2 inch. Starting with the 90274, 175gr. If you look at the bullet I'd be taking off the GC, the lower band, leaving one band, one lube and the crimp grooves. so then I powder coat it for lube. does that help? I could just attack it with a hack saw, file it flat and drill the sprue plate screw hole deeper.

so what else do I need to do or consider? anyone else done this successfully? tks.

[country gent]

DO some additional measuring first. Check and see that there will be sufficent blocks left for solid sprue plate screw threads above handle slot. Is this a "new " mould with alighnment pins? If so make sure you wont be cutting a alighnment pin away also. "Attacking it with a hacksaw" with out checking can quickly destroy a mould. If all is good on depths and pins then here is what I would recomend. With Dykem lay out fluid and a dividers layout the cut line completely around mould. Do thus from finish and then .030 steps up for 4 or so lines. This gives lines to follow besides the one your cutting. Use a medium blade in 18-20 teeth per inch. cut at least .030 above finish point. Cut slow and even cutting on the forward stroke only follow lines and stay as square as you can. With a good coarse file filled with chalk slowly clean up surface. Once close draw file to flat surface and switch to a fine chalk filled fie draw file in diffrent directions corner to corner to finish. On a flat surface bring final finish with sand paper.I would deepen the sprue plate screw hole before cutting as this gives more alighnment for the drill. Its not going to be easy or fast. I would really recomend talking to a local gunsmith or machine shop about cutting it down. 10-15 mins in the mill and its done. no muss no fuss.

[Yodogsandman]

If that's a new mold, does it have the "left hand" threads? Also, check the height of the pins that attach the mold to the handles.

I recently cut a Lee mold down the way country gent describes and it can be done but, take your time.

Another source for machining it is a high school machine shop or some auto parts stores that mills engine cylinder heads.

[cajun shooter]

You may be surprised at how little a small machine shop would do it for you. If they are real big and loaded with work, they will give you a high price so that you will walk with your project. A small shop may have the time to assist you. Best of Luck, David

[dubber123]

Be aware on at least the older LEE 2 cavity molds, the pins that hold the handles to the blocks come pretty close to the top of the blocks, and end mills don't like running into these VERY hard pins unexpectedly. Remove the pins first before machining.

[Kraschenbirn]

You might also get in touch with Buckshot here on Cast Boolits. He's sort of our resident 'moldsmith' and does excellent work at reasonable prices. He did pretty much the same operation you've described on an old NEI mold that's now casts my 'go to' boolit for the .38-55.

Bill

[Yodogsandman]

Before you cut that mold back and maybe finding out that you don't like the shorter boolit, how about taking some boolits and cutting them/filing them/ sanding them to the length that you want and trying them out first? Before I cut mine, I did this and found that I did indeed like my boolits shorter.

[Thin Man]

I have had a few Lee molds decked off at a local machine shop. I prepare the mold by removing all possible pins, screws, etc., also provide them an accurate measurement of the height of the mold before being cut with a target length for the finished cut mold. Don't know if cutting aluminum is lower cost and less work than steel, but the charges have been $15 for some work and $20 for other. All of these have come back exactly as requested, short time, top surfaces perfectly square with the sides. Then I would reset any pins, sprue plate, etc. to get finished.

Thin Man

[bhn22]

You can do it yourself if you have the time, but look at the situation. This would require you to file/cut the mould blocks exactly level down to your desired height, then redrill the necessary holes, tap some of them as required.

[sawzall]

I milled the gas check shank off a Lee C285-130-2R. I used a cross slide vise on my drill press with an end mill chucked up. Just make sure you get the top of the mold level so the base of the boolit is flat and true. Go slow and take small cuts. It's easy for the cutter to dig in and make the table shake producing a very poor, rough finish and maybe go too deep. After "rough machining" I wet sand it with 400 grit paper on a perfectly flat piece of steel. The end mill will chew through the handle pins without a problem. I also found the hole for the sprue plate screw in the new lee molds is drilled plenty deep enough to accommodate the reduction in height of removing the gas check shank. I just rammed it in with a screwdriver, cutting new threads as it went There was one other issue but I don't remember what it was...whatever it was, it was easily overcome anyway.

Cross slide vise. As cheap as $50 but can get very expensive. Mine is a cheapy from Princess Auto, kinda like Harbour Freight in Canada. I believe mine is a 6" but it's maybe a little too big. 4 or 5 would do fine.


3/8" carbide end mill. I used lots of lube and was very satisfied with the result.