Make a mold with a drill bit?

[ThaDoubleJ]

Did some googling, found a little, but not much. I've been sizing Lee's 457 340 boolits down to .457, then .454, then .452 after hi-teking them and using them in my .454 Casull. They go bang and make big holes in stuff, but it's a lot of work. I was thinking about buying one of Lee's blank molds, then just running a 29/64 drill bit into it until the hole is deep enough to drop a ~325gr boolit, then just hi-teking them and sizing if needed.

Good idea? Dumb idea? It's just for fun, banging steel and such.

Guess I could also get a regular .452 Lee mold and run a smaller drill bit in there, just lengthening the nose. I'd just be concerned about getting it centered properly. The TL452-200 looks like it might do ok with a really long nose on it.

Or maybe some sort of weird bore-riding design, like half .452 and half .440 or something.

[RoyEllis]

What's wrong with the Lee 452-300RF? Works well in .45 Colt....454 casull is just a long 45 colt @ higher pressure.......

[Traffer]

It should work if you have rig set up to neither the work or the bit can move at all. Otherwise it will make a bigger hole than you think.

[HangFireW8]

Most drill presses have too much runout for a perfectly round, straight hole of sufficient quality for casting.

To fix that, you can rig up a dremel with a mounted stone pointing up, lower the chuck and bring the jaws down around it and take off the high spots. I did that on a Chinese chuck with some success. Then I replaced it with a Jacobs, and it got even better.

[P Flados]

Flat side molds can be made from Lee blanks.

Good results are usually going to be a little more involved than using a simple drill bit.

My latest flat side did use a Lee blank. It is a 165 gr 30 cal.



My favorite flat side used a Lee handle & spru plate, but the rest was "hand crafted". It is my double cavity 55 gr 0.315



Recommendations are to:

Start with drilling a hole that is at least 0.020" undersized. Use a drill press, or make guide blocks to keep all drilling/reaming straight. Spin a piece of steel rod (average hardness rod will work to cut aluminum) in a drill and use a grinder to shape your "reamer" to the desired shape. Make it at least 0.015" undersized. Grind a big groove in your reamer with a sharp edge for cutting. Run your reamer into the hole with lots of oil for lubrication. Take you time, cutting will be slow. Cast some boolits and find out how undersized they actually are. Either make another finishing reamer just to open up the full diameter portion, and/or use grinding compound to lap the cavity to where you want it. Remember to go slow. You can allways go back and remove a little more, but you can not put any metal back in the cavity if you make it too big.

A drill press and a grinder and possibly a dremmel tool (edge sharpening) are probably the right "minimum" tools for the average do it youself minded guy to have for a reasonable chance. However, I remember hand crafting a 22 cal mold (with lube groove) from scratch with a nothing fancier that a grinder, dremmel tool and an electric hand drill decades ago while I was still in college.

[Good Cheer]

In the seventies I used a Lee 9mm mold and a 3/8" drill bit to create round noses for a 1861 Colt.
For "sizing" had to roll a bevel on the base between two pieces of formica. Swaged and expanded into the chambers at loading. Worked great. Made very accurate bullets.

More recently I'm wondering if something similar could be done with a quarter inch bit to make blunt tipped paper patchers for a 25-35.

[CastingFool]

Make sure you use a brand new drill bit when you drill. A re-sharpened drill bit may have the chisel point slightly off center, especially if hand ground, and this will cause the resulting hole to be slightly larger.

[Ballistics in Scotland]

This is something that would be a lot better done with a lathe or milling machine than a drill press. It might help if you weight the table with something heavy, and prop it with a piece of wood to stop it drooping. The best way of getting a smooth and accurate finish on a hole with a twist drill is to drill first with one a very small amount undersize, then follow it up after rounding the corners of the correct-sized drill with oilstones or a diamond hone.

With blank mould blocks it take only a very small amount off the centre-line to make it reluctant to give up the bullet. In the milling machine I would align it as accurately as possible on a 1/16in. steel rod held in the chuck. Then I would clamp the blocks onto that rod enough to embed it into them. Finally I would insert a shorter length of rod in the hold thus created, and fix another short length in the chuck. Bring them together, and position the blocks with the slides until the to together don't measure over 1/16in. in any direction, and you have a pilot hold to start drilling. Even then I would use a centre drill with a 1/16in. pilot to get a hole the bigger drill would be sure of following.

If you want to make a really bullet-shaped bullet, there are drill, usually carbide, with two straight flutes. The sizes available are limited, but 13/32in. makes a pretty good .40-82 Winchester bullet. The trick here is to make a cast of car body repair paste when you have one flute ground to the ogive you want. Assuming the rear ends of the flutes end in the same place, this will enable you to get them close enough to the same contour. You will probably have to remove a little from each side in turn several times, like the time my mother trimmed our cairn terrier, which ended up smooth and pear-shaped from hips to nose. You can even cut lube grooves in the drill with a Dremel tool and diamond burrs, and mill each block separately.

[nekshot]

yup, thank God for very reasonable aluminum molds you can practice on. Thats how I learned about changing molds from original design!

[mozeppa]

i was going to do that ...only i'd be using a lollipop carbide ball end mill, a drill press and a vise.

but i can't find a .309 bit.

[Ballistics in Scotland]

A lot of carbide burrs, nominally 5/16in. or 8mm., actually cut a bit undersized, but you don't know until you've got them. Those made for aluminium, with unnotched teeth like complete little spiral blades, are most likely to give a smooth surface.

[bangerjim]

Can be done for "seat-o-the-pants" accuracy.

Use NEW high quality drill (not HF!)

Do the drilling in a milling machine and mill vise, not a simple shop drill press!

Step drill up....do not try to do it all in one stroke!!!!!!!! Slow and easy.

Drill undersize and then use reamers to get to perfect size you want.

After all that work, I would just buy the right commercial mold or have it made for me.

Or just shoot what you have!

[Drm50]

I have made a lot of molds on drill press, fishing lures which don't need precision of a bullet. I use
aircfaft Alumilum, pre drill for steel index pins and start with a 3/32" bit. Trying to drill between
the 2 halves with a big bit to start doesn't work to good. With 3/32" I just go 1/8" deep to use
as centering for bigger bits, which I do in steps until I'm up to my final Dia. Then I cut sprew
with a end mill bit in the drill press. Even using new bits this is a PIA. I cut design with die grinder
and spend a lot of time polishing out the cavities with a dremil. On bullet molds I would suggest
buying what you need if possible. Unless you have access to mills and such. I don't make any
fishing lure mold that I can buy. Mine are either new designs or repros of old lures that molds
were never made for.

[Ballistics in Scotland]

If you must use a drill press, you can first drill a piece of metal to use as guide bushing. Stick it to the top of the blocks with epoxy, making sure it is aligned with the split, and then drill through it. It will come off when heated a lot less than a mould will in casting.

[ThaDoubleJ]

This sounds like way more skill and precision (and tools) than I possess. Didn't occur to me that if one side ended up bigger than the other the boolits wouldn't drop, or that drill bits might not be perfect, or that drill presses might be imperfect as well. Good thing you all are here. I look at the .452 300, but it needs a gas check, and I don't feel like gas checking because I'm a cheapo. So maybe I'll try the 452-252 Keithish looking one for now. Would really just like a nice 300gr Keith style. Thanks for all the replies.

[JonB_in_Glencoe]

Removing a GC shank on a lee mold is LOTS easier than drilling a blank mold.
get the correct size drill bit and turn by hand. I'd recommend cutting the base of a boolit off, and put the nose portion of that lead slug in the cavity, to protect it.

Also, I've read others post about removing a GC shank from a Lee mold, with just a X-acto knife.

[country gent]

WHile it can be done with just a good drill press the set up and clamping takes more than simply doing it in the mill. The blocks will need to be alighned square and true to spindle on the desired location of centerline and spacing. Clamp the blocks closed in a solid vise or strapped to a angle plate securely with a piece of paper between the blocks and clamped solidly to the table on location. Drill to the desired depth for the body size of the bullet in several steps. better still is to dril close and finish ream. Then with a form ground drill cut the desired nose form. Its actually more work and set up time doing thedrill press than a mill is.

[Ballistics in Scotland]

You can buy compound tables for drill presses, with left-right and fore-and-aft movement of the workpiece by handwheels. Some of them are quite inexpensive. They are usually described as turning it into a milling machine, which they do rather badly. But they would be extremely useful for this kind of work.

[country gent]

Those tables do help and make it a little easier than tapping the vise around to dead zero on the indicator. They arnt always accurate to the graduations but do allow easier adjustment. one thing to watch is how the locks engage them and lock them in place.

[Traffer]

I have been using dremels and diamond wheels for my machining needs. I have been sharpening and grinding drill bits, end mills and even the occasional reamer with them. Learned how to grind drill bits into end mills and into bullet shapes for cutting swaging dies. After I grind a bullet nose drill bit it goes through steel much easier than a regular drill bit. I was amazed at how well these things work. I can't even feel when they start to cut, I have to watch for the metal springs to peel off to know that I am going in to the work with them. I will make a video and post it for those skeptics who doubt me here.