HP inset bar

Pistolero

Well-Known Member
Fiver, I am certain that MP makes mold halves separately, with enough precision that
they just go together. How do I know that? Because I have a mold from him with one
cavity half misaligned by about .1" to the one across the way, and the other cavity aligns
perfectly. Clearly both sides of the cavity are not cut at the same time. The workpiece got
moved between first cavity cut (correct) and second (offset). He replaced it, of course.

I am pretty sure he has carbide profile cutters made and then can cut whatever diameter
he chooses, by running the cutter on a circular path, down to the point when the circle
turns into a point and the 'profile cutter' becomes a cherry. I saw some images on his
site that showed a beautiful cutter which was clearly for a Keith design, likely a 429421,
but was too small in diameter for the length......a profile cutter. This is why he can say,
"what diameter would you like for this design?" and make .429, .430, .431 .432, etc
without any extra charge. Just program a slightly different circle diameter for the cutter
path.

Spectacular mold quality, though.

Well done, Brad. I have considered trying this and can't quite work up the urge.
Clearly not easy, and very possible to total a good mold - and Eric has done
a few for me, and they are SO nice. Insufficient curiosity and bravery, together.

Bill
 
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Brad

Benevolent Overlord and site owner
Staff member
Find a mould you no longer care about and have at it Bill. It wasn’t difficult so much as time consuming. I likely spent as much time doing it in my head as I did doing it on the machines.
 

Pistolero

Well-Known Member
Hmm. Then I'd have a mold that I don't care about which I have invested a couple
of days of work into. :headscratch:

Maybe do a Lee new style dbl cav, cheap enough to replace if I screw it up.

Bill
 

Brad

Benevolent Overlord and site owner
Staff member
That would work.
Or see if anyone has a buggered up Lyman.
To me it was more for the experience than anything. With a bit of work to remove the nose flashing from the bullets mine makes a usable bullet but I just don’t shoot that kind of loads?
 

Rick

Moderator
Staff member
I have two MP 311410 4 cavity molds, one of them is plain base and one is gas check, they both have three different sets of pins with two different HP pins and for a flat point bullet. I used these molds to invent the half check bullet. Now my supply of checks last twice as long. o_O

022-9.jpg

When I got them I took both molds apart to do my normal cleaning of a new mold. When I put them together I had placed a gas check half with the plain base half & started casting, looked down at what I had & thought now that just ain't right. :confused: Absolutely amazing though that the blocks from two different molds fit together so well that there isn't even a parting line seam visible on these bullets.
 

Pistolero

Well-Known Member
More proof that MP makes mold halves, not molds.

99.9% they are so darned perfect as to be amazing. Looks like a fine candidate for
de-gas checking....only half, of course.

A half-assed bullet, eh? :rofl:

Bill
 
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F

freebullet

Guest
Rick, that mold must be the Cali edition. They will probably ban it though.
 

fiver

Well-Known Member
when we cut the HM-2 molds each mold half was installed in the fixture in the CNC machine and all of the operations were performed.
it went in as a milled and squared block and come out as half a mold.
then the other side went in and program B was punched up on the controller and started.
it took about 20 minutes per half, plus the cleaning/drying time and the edge break.
the cherry looked nothing like the bullet, and it didn't cut by rotating in a circle, it oscillated and took out little bights as it rotated in the half circle across the mold face.
this meant each cavity was cut by the same cherry, and it could be programmed to nibble another .001 up to a pretty amazing amount.
the only thing stopping you from cutting a 30 cal mold then using the cherry for a 35 cal mold was the deflection on the thinner parts like the nose.
it was certainly possible if you did the cut in 2-3 steps to minimize the side force on the cutter.
 
F

freebullet

Guest
Just the programing for that sounds like an absolute hammer needed nightmare. Makes the molds seem cheaper, thanks.
 

Brad

Benevolent Overlord and site owner
Staff member
I wish HM2 was still making moulds, the one I have is awful nice. It was tough as hell when I got it. I had to file a bevel on the inner top mould surfaces to get good base fill out. Not a flaw in my mind, just a sign of how well the blocks and sprue plate fit.
 

fiver

Well-Known Member
I know all the ones we run when I was there got the top edge break with my Grandpa's old Arkansas whet stone.
I left the stone when I come home with the first mold off the machine.