Assembling/casting with MP hollow point molds

[Jtarm]

I tried to assemble a 4-cavity Mihec HBWC mold for the first time today. This was my first multi-cavity HP or HB mold and it was a nightmare for me.

Does anyone have a guide or tutorial for assembling & casting with these type of molds ?

I found it impossible to get all 16 of the pin screws attached and aligned in the blocks. The best I could do was four on each block.

In fact I'm going to have to get some new ones from Miha since some of the threads got damaged.

[DerekP Houston]

I just recently set up mine as well, I'll give you the run down though mine were not HB.

Should be multiple sets of the pins, mine was a 4 cavity mold, came with 4 flat pins, 4 hp pins, and 4 penta-hp pins.

Place the matching pins in to the mold and close it, make sure the holes line up on the side. Should be 2 screws for each pin, total 8 pins installed on 1 side. I screwed them all the way in and backed out a half turn. The c-clip looking things will slide on to the screws at the end, there is a small slit in the metal.

When you open the mold, the pins should all be attached on the same side, that way the bullets slide out away from the mold and you can shake them off. I'll take some pictures of it assembled.

[Southern Son]

I tried to assemble a 4-cavity Mihec HBWC mold for the first time today. This was my first multi-cavity HP or HB mold and it was a nightmare for me.

Does anyone have a guide or tutorial for assembling & casting with these type of molds ?

I found it impossible to get all 16 of the pin screws attached and aligned in the blocks. The best I could do was four on each block.

In fact I'm going to have to get some new ones from Miha since some of the threads got damaged.

There is something wrong there? Four cavities, means FOUR hollow base plugs, and each of the plugs should only be attached to ONE side (Half) of the mould, and it should be attached with TWO of the screws. This should be a total of EIGHT screws? Are you trying to attach the plugs to BOTH halves of the mould? Or just the one?

[dragon813gt]

How did you damage the threads? They are self explanatory to put together. The pin itself has one end that's slightly recessed for the guide rods to screw into. Don't torque them all the way down. You want them loose so there is some play in them. This allows to them to be inserted into the blocks w/ no resistance. After they are inserted you want to tighten/loosen the pins up so they fall free under their own weight. The guide rods are allen head and the small Allen key that came w/ the mold is for them.

[Jtarm]

I was trying to attach the pins to both blocks, which is nearly possible.

I watched the video on MPs Facebook page & got it now.

[MiHec]

Here is the link

https://www.facebook.com/MPmolds/vid...9639013933533/

[gtgeorge]

Nice 3D rendering Mia.

As an extra note look for the recess in the bullet pins where the side pins screw in. You will want to start the little pins on the side with the recesses. Do not tighten them all the way if the pins drag a little back off some. I personally like to polish all the pins up a little with some 400 grit wet paper spinning them in a lathe but a drill would work nice too. They just work smoother from the start. Don't forget to lube the pins that slid in and out ever so slightly with the supplied lube or your favorite mold lube.

[Smoke4320]

beautiful rendering .. if you cant get it after that ..theres something majorly wrong

[Boolit_Head]

Do check both sides of the mold. I found one side the pins worked better than the other.

[DerekP Houston]

Do check both sides of the mold. I found one side the pins worked better than the other.

I assumed it was for lefty vs righty.

[Jtarm]

Thanks to Mihas rendering, blind hog finds the acorn:

[Cord]

Brass or aluminum, I always take the sprue plate off a new mould before I even open it.
If there is a tiny piece of scarf under there, it can permanently scratch the top of the blocks
the first time the plate is swung aside. I know this from past experience.
Then I thoroughly scrub the blocks with a toothbrush using Dawn and very hot water.

I screw a single slider pin into the rebated top hole of one of the HP/HB pins from the back side,
only finger tight, and then see which cavity it fits best in by closing the blocks on it by hand,
holding it up to the light and looking for tiny gaps where light comes through.

I only screw the pins in from the back side of the blocks, and never force them through the bore.
I sort all the HP/HB pins, each one to its own best fitting cavity, in this way.

Then choose one HP pin, put a slider in the bottom hole, also finger tight, see if it slides freely.
I keep trying one bottom pin after another, until I get a nice sliding action with both pins installed.
If I try all available pins and don’t get a good pair, I replace the top pin and try all the others again.
I do this for all the cavities, one by one, until I get the best sliding action possible for each set.

I never polish or sand any pins; after I get them fitting and sliding as close as possible,
they will wear in to a truly perfect fit by themselves during use.
In my opinion, if you remove even a tiny bit of metal you are wearing them out, not in.

I keep a small torx driver handy while casting, and if the sliders loosen up I just
tighten them back to finger tight. Eventually they stay put.

Yes, this takes some time to do it right. Some may consider this tedious or OCD,
but this is exactly the type of hand fitting of parts that gun makers and others
used to do in days long gone by.

Miha and others can make fine precision moulds, but they can’t spend the time
to carefully test fit each part or we would not be able to afford their products.
You have to take the final steps yourself to have a truly custom, hand fitted mould.

My latest MP 4 cavity mould went together very well using this method, and when
I open the handles with the mould dry, no lube whatsoever, and tilt it to the left,
all the HP pins slide right out under their own weight. That makes me smile.

My current project is putting a patina on the brass to keep it from tinning,
and I want to try a new dry lube for the sprue plate pivot.

Eventually, I will almost know what I'm doing - if I live that long.
.