trouble opening

[moto357]

Earlier this week I got in the mail an aluminum T/C maxi mold in 50 cal. Its been used a bit, the cavity looked superb other than a few small marks on the base. I tried casting a few with the mold as-is, and those marks in the base were minor, although with ever cast the mold was xtreemly hard to get open. No banging or anything, just working the handles till it opens and then the bullet drops right out.

Before next casting session I checked the alighnment pins, wich don't seem to be the problem. It seems to be holding together right at the base of the bullet. I lapped gently the bottom band where those dings were, and they are barely noticeable anymore to the eye, and I can no longer feel them. Casted sum more last nite and it was still sticking with no improvement. My last thought is maybe has something to do with the top of the blocks being marked up pretty good. My guess is either the spru was rarely lubed, if ever, or the ol mold has done its share of casting.

Sorry to make this long, just wanted ta give the best picture of what's going on so's maybe one o yall could help.

[Maven]

moto357, There are a couple of things to try, which may improve the mold's functioning. First, remove the sprue cutter and lap/polish the bottom on a perfectly flat surface. Second, do the same with the top of the mold blocks, but be careful as it isn't as easy as lapping the bottom of the sprue cutter. Third, maybe you DO need to look at the alignment pins' protrusion and the holes in the other half of the mold block. To wit, measure their protrusion with a caliper or micrometer and adjust them so that both are equal. Then check the holes for roundness and burrs. If present you can remove them with a case chamfering tool if you are gentle. When you reassemble the mold, put a tiny dab of bullet lube/beeswax in each pin and in each hole. (Use a toothpick, etc. for this.) Hope this helps!

P.S. It is also possible that the pins & holes need to be lapped, but that is a last resort. Btw, I've owned several T/C Maxi- and RB molds, and found them to be of excellent quality.

[montana_charlie]

the mold was xtreemly hard to get open.
When a mould has that little 'hitch' on opening it will sometimes disappear if you try a different brand of handles.

Another workaround is to press lightly against the back end of the right-hand mould half (with your sprue knocker) as you try to spread the handles.
Try pressing above the jaws, below the jaws, and out on the right-rear corner.

If the blocks have that same glitch when the mould is cold, that makes it easier to experiment with different 'cures'. Carefully note the motions the blocks go through when they close. If they have to 'make adjustments' in order to close, try to figure out why.

If a mould only operates smoothly when the blocks are resting on a flat surface, thicker jaws...or holes in the jaws further back from the jaw edge...might fix it.
CM

[mooman76]

Did you lube the mould and with a good high temp lube?

[moto357]

Thanks fer the ideas. I'm thinking what Maven said about the top of the blocks and the spru cutter. Two reasons I'm thinking this, mold works perfectly fine cold or hot with no bullet. Also after reading that I notice that when held up to a light, I can see daylight between the spru cutter and mold blocks, more so with one block than the other. I'll keep yall posted on any progress made.

[jack19512]

First, remove the sprue cutter and lap/polish the bottom on a perfectly flat surface. Second, do the same with the top of the mold blocks, but be careful as it isn't as easy as lapping the bottom of the sprue cutter.







I have found myself doing this to my Lee molds. I have a small piece of window glass that I use just for this purpose. You would not believe how much smoother the sprue plate moves after doing this and from my experience gives you a better looking boolit base. If you think that all of the Lee sprue cutters and molds are flat try lapping one and you will see for yourself.

[moto357]

Haven't casted any recently with the mold, but I THINK I might have found my issue. Not sure till I drop some though. The top of the mold block (the one holding the spru cutter) doesn't appear to be square/flat. This is why the spru plate will not sit flush n tight on top of the blocks. After a little lapping its better, but I'm gunna see how it casts before I remove anymore material.