Brass mold hard to open

I just started casting and have 4 casting sessions in. I ordered a brand new NOE Ranch dog 165 gas check 4 cavity mold. After the first 3 sessions the mold started to get much harder to open and I believe its the alignment pins. It casts perfect bullets still but I am concerned if I keep using it the mold will wear out or I will ruin something. Has anyone run into this issue? I inspected it for lead or other debris and didn't see anything. I tried to lube the pins with 2 stroke chainsaw oil and that doesn't seem to help much. Could I have possibly set the alignment pins wrong? I tried the search feature and I didn't see anything on this.

Are you lubing the alignment pins before and at least once during your casting session?

Do you lube the pivot point on your mold handles?

Is the pivot bolt on your handle too loose (too loose will let the mold get out of alignment when opening and closing

Could I have possibly set the alignment pins wrong? What are you doing setting the alignment pins on a new mold?

Try scrubbing the alignment pins with a toothbrush and dish soap.

IF you cant see light between the cavities when the mold is closed and you hold it up to a light, the pins aren't too deep

I tried to lube the pins with 2 stroke chainsaw oil and that doesn't seem to help much. synthetic or regular? needs to be synthetic.

The instructions said to set the pins by heating the mold to 400 3x before casting. I closed the mold and used a hot plate to do so. I lubed before and during but not after. I’ll check with a light when I get home

There is a 1/2" (iirc) nyloc-style nut on the joining bolt in the handle. Loosen that a mite and see if the mold opens smoother. It may not be the mold pins.

If all those suggestions fail, cast your bullets, cut the sprue, invert the mold and tap the pivot nut while giving slight outward pressure on the mold handles. I know...I know....then hop in circles on one leg with your tongue sticking out while scratching your head....:bigsmyl2: Seriously though, the inverting trick works, I have to do it with two Arsenal molds I have and it works like a charm.

I find my NOE 316299 mould acts in similar fashion. The alignment pins have a rather stubby radius on the ends and a bit of cylindrical section that I think is the cause of binding.

I use my sprue mallet to help line the pins up with the holes as I close the mould by gently pushing on the blocks. The pins are a very close fit in the holes and any misalignment of blocks as they close or open causes binding. I also use use my sprue mallet to gently push on the mould blocks as I open the mould so the blocks stay aligned and that does it for me.

Personally I think the pins should have a larger radius on the ends so they enter the holes easier and less cylindrical section to avoid binding but it isn't worth trying to press pins out to fix it and with use they may loosen up.

Other than that the mould casts perfect bullets so not something I worry about much as it is easy to deal with.

The inverting trick mentioned above is something I'll try next casting session too.

Longbow

One byproduct of burning petroleum based oil is residue, tiny particulate matter, both burned and incompletely burned. A tight tolerance cylindrical fit that becomes coated with any foreign contaminant will bind. It takes very little physical substance to reduce that tiny space to zero, or to an interference. Binding is a sign of trouble. Not bad trouble, just an annoyance.

A solution, not saying it is the right solution, is to polish the alignment pin holes (I would) to remove the residue, brighten the surface, and periodically open them up a tiny bit (blasphemy). Polish can be a fine as 100k grit but compounds of 800 and 1050 grit are probably sufficient.

Let me ad, you do not want to reduce the diameter of the pins or make the holes bigger, you only want to polish them so debris won't adhere as easily.

I had a similar issue with my NOE brass mold. One of the mold handle arms had a burr on it keeping one half of the mold from having the same free play as the other. I gently stoned the burr off of the mold handle, carefully cleaned the pins and the holes, lubed very lightly with NOE lube, and after the next casting session the stickiness was gone.

Quote:

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Originally Posted by Frank H

SNIP>>>

I inspected it for lead or other debris and didn't see anything.

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Frank,
Welcome to the forum.

You have been given lots of good advice so far. My first guess would be residue on the pins or in the receptacles, since you said it got worse as time went on. Are you smoking the molds? I recommend you don't do that, but some say to do it, including Lee's manual.

What I would do, because sometimes you can't "see" the problem, is to clean the pins and receptacle with tooth brush, hot water and dish soap. Then with the blocks removed from the handles, check for alignment pin sticking. You can also do this with one block reversed, that way, you can identify which pin or receptacle is causing the problem, then focus your energy cleaning that one part more judiciously...maybe even with a fine polish, like Flitz (on a Q-tip).
Good Luck.

Molds are close tolerance so it doesn't take much to make them "off" a bit. Might try some engineers blue on pins or inside holes to see where it rubs off. That would highlight any potential binding location. Just be sure to clean off before heating after using it. Not sure if it would stain or not if heated. Using blue stain to determine where parts rub is a fairly common technique in some shops or plants.

The pins and sockets have to be close fit to line the mould blocks up so you don't get any misalignment and large seam. It doesn't take much! Opening up the sockets or reducing pin diameter is a bad idea in my view.

A larger radius or tapered end on the pin with reduced cylindrical section would allow easier closing of the mould (more self aligning) and wouldn't bind so much on opening. If you look at Lyman moulds the pins have a hemispherical end on them and almost no cylindrical section. A few thou cylindrical is all that is required when the mould is closed.

That is my only criticism of NOE moulds. They cast virtually perfectly but I don't like the pin set up. Again, easy to deal with as I do so it wouldn't put me off buying another NOE mould since they do cast so well and right to spec. I have trouble finding the mould parting line on my boolits cast in NOE moulds.

My three favourite mould makers in no particular order: Mihec, NOE, Accurate.

Longbow

I have had a couple molds where the alignment pins stuck out too far and needed a little tappy tap to drive them in a fuzz. I have also had to move a couple the other direction to tighten up a sloppy fit.

Happened to me the other day, with a NOE brass four cavity. Alignment pins moved forward, two days in a row, binding up the mould. First day it was the front one, second day it was the back. It probably has to do with the expansion rate of the two dissimilar metals. Coupled with lubing the pins.............a practice that I won't be doing anymore. I reseated the pins, in my bench vise with copper jaw inserts in place.

Winelover

Thank you everyone for your input! Since I have started casting, this is the first week I have not casted any bullets since started two months ago! I will be trying to figure the mold out tonight but I will start with a hot water and dawn dish soap scrubbing followed with Q tips and acetone. I will try not smoking my mold this go around.

I will update with the results!

Standard steel dowel pins are very, very hard so it’ll be difficult to scratch those. The female bushings are probably much softer (dissimilar materials are good for bearings), but they are probably steel - touch them with a magnet to be sure. If steel, a brass brush from you barrel cleaning kit should do. Using the cloth swab would be even more gentle, but maybe not sufficient. Start with the q-tip and work up if needed. You definitely don’t want to scratch those. And be careful when the molds are off the handles, that you don’t scratch the mating surfaces with dirt (ask me how I know that one). Also, I believe those bushings are tapered (my Al NOE mold has tapered bushings), so it may be hard to look inside and see the debris.

Hope you resolved the difficulty in opening your mold. I just "tinned" the heck out of my Mihec 4cav mold and it has taken a LOT of elbow grease to remove the hundreds of particles of tin from the tiny recesses and especially the very small diameter HP and solid boolit pins and their unobservable holes. These bound the mold up tight and until removed the mold was unusable. I am not going that route again...

My first brass mold was from NOE, it started sticking after a pretty long casting session it was too hot slowed down cooled it off back to dropping good boolits without sticking.
Just a thought ymmv

Mold handles bolt is too tight ... loosen it and forget about futzing with the pins. If the pins were the issue, your bullets would be buggered