Converting Lee mold to hollow point?

[GaryM]

I have been reading on how to convert a regular mold design to a hollowpoint type. I would like to try this with a 175gr 10mm SWC mold. Has anyone ever done this with an aluminum mold? I would be using the "B" method listed on the LASC website.
Thanks!

[W.R.Buchanan]

Gary: the biggest challenge will be accurately locating the center of the bullet cavity.

I would take very close measurements (Optical Comparator) to determine the exact position of the cavity in the mould blocks, and then locate the mould in a milling machine to do the actual drilling.

As a Machinst/Toolmaker I don't see getting it right on a drill press unless you are a very lucky person. [smilie=w:

If the hole is not in the exact center of the bullet then it will not fly strait. :holysheep

Randy

[GaryM]

I would be drilling the hole in a lathe. The method is to make a shaft that fits the mold cavity then clamp the mold over it. Place the shaft in the chuck and use a drill in the tail stock. Turn at low speed of course. This should give a nicely centered hole for the hollowpoint stud to go into.
I would also turn the hollowpoint stud. A collar would keep it at the correct depth and of course some sort of handle so it could be inserted/removed while still hot.
I am not a machinist so my terminology is off but I hope this explains what I am thinking. My worries are will an aluminum mold block be capable of handling this modifications and would a steel stud work with the aluminum block.

[mooman76]

Lee used to make them. They had a button that had a steel pin in it. The button made a aluminum was a made to fit in a space cut out of the mould. Similar to their hollow base moulds. Might be easier to make something to drill the hollow point after the fact.

[Beerd]

this fellow did a .45 Lee mould
http://castboolits.gunloads.com/showthread.php?t=106303
..

[Rangefinder]

http://i98.photobucket.com/albums/l259/hillsjim/hpmold002.jpg

You mean like this? It's a .357 SWC. One thing you MUST do with a Lee mold is tap the alignment pin out of the way. Any attempt to drill through it will prove disastrous to the mold---ask me how I know. Center your hole extremely well, and bore it slightly smaller than the pin you intend to use. Any micro-adjustment to center can then be made through lapping the pin hole out to the proper size.

http://i98.photobucket.com/albums/l259/hillsjim/357HPjpg.jpg

Finished product. The angle you see on the cavity mouth is from a quick spin with a deburring tool. I like a nice, clean cavity. The added bonus I've found is it helps begin expansion at lower velocities.

[GaryM]

That is exactly what I am talking about.
Pardon me fellers, I am off to the shop now. :)\\:mrgreen:

Proof of concept die works! No pictures since I was in a hurry and, well, it doesn't look very pretty but the hollowpoint is centered and it looks good. Too bad I can't test these samples but I used a .41 cal mold and I don't have anything in that caliber.

[Donor8x56r]

Is anyone hollow pointing Lee moulds commercially?

I know some places that do steel moulds ,but no aluminum is mentioned there.

I have a couple of mouls I wish where HP...

[Buckshot]

................As far as I'm concerned, the best way to HP a mould is to indicate the cavity with a TI while the blocks are in a 4 jaw chuck, below:

http://www.fototime.com/2235C21F3A083BE/standard.jpghttp://www.fototime.com/4E82C710D2AEAC9/standard.jpg

Another mentioned indicating off a pin held in the cavity. Again it'd have to be held in a 4 jaw. A -.0002" pin gage is being used, below:

http://www.fototime.com/DCB35A804CC78CC/standard.jpg

The problem with the above is that there have to be 2 lube grooves or other feature to grip the pin. Add in that you have to be able to remove the pin from the cavity.

You can also set the blocks up on a faceplate, below. Nice to be able to have a clear area under the cavity as a place for the bit to go once it breaks thorugh!

http://www.fototime.com/EC6E32186093ED1/standard.jpg

An educational excersize is to place a set of blocks on a surface plate and then check various places within the cavity to it's mating half. Also interesting is to check a few places in the cavity against the face of the block, then check the other block half in the same places :-)

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

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

[GaryM]

Wow, that is a nice setup there. I just turned a pin that fit snugly in the mold cavity. I knew it was true since I never dismounted it. I then clamped the mold block over the pin and drilled it from the tailstock. The only real problem I have is the face of the bullet being a bit wonky since the drill did not break through cleanly. When I do the next one I will just place the drilled mold half under a magnifier and gently clean it up with a knife blade.

[Beerd]

A question for them that have done it, do you use an aluminum or steel rod to make the hollow point pin? Is there any advantage of one material over the other?
Thanks.
..

[Buckshot]

A question for them that have done it, do you use an aluminum or steel rod to make the hollow point pin? Is there any advantage of one material over the other?
Thanks.
..

............Of the two steel would be best. It'd be more durable and while it takes a bit longer to heat up, conversely it holds it's heat better not radiateing it as fast as aluminum.

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

[Rangefinder]

Definitely a nice set-up Buckshot--a bit pricey for me though. I'd LOVE to play with it! But since I can't...

The next mold I HP I plan to do a little more easily than previous ones. It'll need my drill press, a drill bushing with the OD spun down to the diameter of the cavity to ride the grooves snug, and the right bit for the bushing. If all follows plan, it should be almost a no-fuss job (for a change). Set-up is easy once the bushing is fitted--Chuck the mold in the drill vice with the bushing in place and bore the hole. If the bushing is sized to cavity correctly, the guide hole is going to be centered and in line, so I should be able to drill away without much worry. I'm curious how this little thought is gonna pan out.

[jlmomaha]

I did precision machining in college for gumsmithing purposes, ive been thinking hard bout offering to convert lee 6cav molds to hollow points "noe style" for bout $120 for all 6cavs, but dont know if thered even be a demand, I do know it wouldnt be to hard to do, finding center on a hole is easy. And I have the tools to do it already lol...

[nanuk]

Definitely a nice set-up Buckshot--a bit pricey for me though. I'd LOVE to play with it! But since I can't...

The next mold I HP I plan to do a little more easily than previous ones. It'll need my drill press, a drill bushing with the OD spun down to the diameter of the cavity to ride the grooves snug, and the right bit for the bushing. If all follows plan, it should be almost a no-fuss job (for a change). Set-up is easy once the bushing is fitted--Chuck the mold in the drill vice with the bushing in place and bore the hole. If the bushing is sized to cavity correctly, the guide hole is going to be centered and in line, so I should be able to drill away without much worry. I'm curious how this little thought is gonna pan out.


RF: I was wondering if one could just size down a drill rod, to the proper diameter to center the cavity, then once centered, swap it out for drill bit, and drilll straight down.

[Rangefinder]

Nanuk>> That could probably work for centering the cavity under the press, but the purpose of the bushing is to keep the bit centered all the way through. Also, here is the link to the write-up on the above-mentioned idea with photos.

http://www.castboolits.gunloads.com/showthread.php?t=123677

[jlmomaha]

nanuk, thatl prob work just go slow n use alotta oil, then ream n hone hole to get that mirror finish. Id suggest tryn it on a mold u dont care about first. Also alum should be a lil easier to drill being that its a softer metal.

[white eagle]

surface plate and everything
that aint no regular guy set up there

[nanuk]

Rangefinder

I have read your linked thread a few times.

I now remember about the bushing. I seem to remember also, someone using a lead bushing, poured into place around a bit.... was it Ben?

I have to look around for some bushings... I am not sure where to start.