Hollow Pointing - A Universal Option

[JIMinPHX]

Some of you may remember my escapades with hollow pointing boolits on a lathe. That little adventure was documented here - http://www.castboolits.gunloads.com/...ad.php?t=29432

While that method worked out fine for me, not every home brew boolit caster has a lathe kicking around out in the garage, so there is a limited number of people who could take advantage of the info that I posted there. I was bored off my butt, sitting on a plane the other day & I got to thinking about that. What I came up with is pictured below.

[JIMinPHX]

This thing needs to have a real drill bushing added to it & the C-clamp needs to be replaced by something faster & easier to use, like a DeStako clamp, but other than that, this thing is a working unit.

It's easy to change over to different calibers & different size holes. Changing the 2 small blocks on the left side of the aluminum pillar changes the caliber. Changing the top arm & drill bit changes the hole size.

I'm thinking about building these things to sell. What does everybody think about that? Should I go for it?

[JIMinPHX]

Another view

[dragonrider]

Caliber specific??

[JIMinPHX]

Caliber specific??

Changing the two small pinch blocks changes the caliber. 1 Allen screw holds the longer one in place. The shorter one is only held by the clamp.

[southpaw]

Any idea on what the price would be?

Jerry Jr.

[JIMinPHX]

This shows the longer of the two blocks & how it supports the boolit that is being drilled. Everything is adjustable & interchangeable. I designed it to be a universal system.

[JIMinPHX]

Any idea on what the price would be?

Jerry Jr.

Right now, I'm thinking about selling it al-a-carte. That way, each person could put together just the parts that they need & not buy anything that they don't want.

Just off the top of my head, I was thinking -
Main Pillar - $15
Base Plate with screws - $5
Top arm with drill bushing, drill bit, screws & drill collar - $15
Caliber specific clamp blocks - $15

Basically, that would be $50 to get a full rig & then $15 to add another caliber & $15 to add another cavity diameter.

Those are just rough numbers. I need to see how long it actually takes me to make each part & I need to see what the drill bushings will cost me. If I think that I can get 50 people to buy these things, then I can tool up to make them more efficiently & the prices will be lower than if I need to make each part as a 1-off. The clamp blocks were actually the biggest pain in the butt to make, I may redesign them a little bit.

[madcaster]

Good thinking Jim!

[MT Gianni]

Is the top arm hex to fit in a cordless tool or straight to be chucked each time? I like it.

[JIMinPHX]

Is the top arm hex to fit in a cordless tool or straight to be chucked each time? I like it.

That particular drill bit in the picture is a standard 135-degree split-point screw-machine bit that I had handy. I can set this gizmo up with a hex shank bit if you want.

I had made the base so that it would be easy to use this rig in a drill press, but I did my trial tests with a cordless drill. You could probably even turn the bit by hand with a pin vice.

You pick the bit, I'll get a bushing to fit it & make it work. I can't imagine that there would be much of a price difference, if any, for a different style bit.

[thx997303]

Very interesting Jim.

Let me know when you have figured a price.

[geargnasher]

I likes it, Jim!

I've been hollow-pointing finished ammo in a drill press for years using Lee base holders (for the trimmers) to hold and spin the cartridge against a fixed, custom-ground bit. In some calibers I rigged a neck guide, but still have issues with runout.

Your little invention seems to get around that problem.

I think you should go for it, I may well buy one from you.

Gear

[44wcf]

I would be interested in one.

[dragonrider]

Very clever Jim. I'll bet that would sell. Good luck with it.

[jdgabbard]

I would be very interested in one. A poor man's cramer!

[303Guy]

Great thinking!

Do you have a milling machine then?

[chaos]

I'd like one if you do this.

[JIMinPHX]

Well,
Version #2 is now up & running. It’s pretty much the same thing, but I’ve made a few refinements. The drill bit now sits in a tool steel guide bushing. The C-clamp has been replaced by an Allen screw & Allen wrench. Eventually, that Allen screw will be replaced by a hand knob, but I just haven’t gotten to that yet.

I got a little bit of a sticker shock today when I went & looked up drill bushings. The less expensive, headless press fit type started at around $8 for select standard sizes & the prices went up from there. You could spend over $100 on a fancy interchangeable bushing with sleeve. I didn’t really think that was in the budget for this project, so I punted. I made a bushing out of some W-1 tool steel that I had laying around. So far, it seems OK. I’ll have to see how it holds up over time. If I need to, I can always press it out & press in a real drill bushing later.

In this picture, I’m using a simple handle to turn the drill bit. It works, but I would expect that most people would opt for a cordless or a drill press.

Anyway, here it is folks. Any & all comments are appreciated. I hope to have the final design worked out to my satisfaction within the next few days.

[sagacious]

Looks good. A crank handle, as on a manual case trimmer, would be a rapid and effective way to turn the drill bit.