Mold problems

[Archeryrob]

I have the MP 9/38-147 mold in .359 hollow point. It’s been pretty flawless until today. Started good then half way through it start leaving shears, not smears on the last one sometimes two farthest of the four casts. There is a gap on the spruce plate and my other molds don’t have this. I was having lead or other collecting on the sprue underneath.

I was loosing 1 to 2 casts per cycle and it’s getting really annoying. Had another piece of metal stuck to the sprue when finished and took the propane torch to it and it took a lot to melt it to wipe with a shirt. Didn’t seem like lead. The alloy is 1/2 pure lead and have wheel weight. Never had trouble before with the allow or mold and today was a fit

 

[85MikeTPI]

Have you tried tightening the sprue plate screw? IIRC there’s a locking set screw on the side, then the sprue screw can be tightened after the set screw is loosened

 

[Archeryrob]

the set screw was in the box and fell out. The sprue plate lays flat until I tightened it and it compresses the washer

Not seeing any foreign stuff in there. Wear on it and brass on the sprue plate

 

[John from MD]

Have you tried tightening the sprue plate screw? IIRC there’s a locking set screw on the side, then the sprue screw can be tightened after the set screw is loosened

I too would look at the Sprue plate first. Additionally, you may have let the sprue plate get too hot. I usually keep a wet sponge on my bullet making table so, if the sprue plate gets too hot, I just lay it on the sponge for 10 seconds or so to cool it down.

 

[Archeryrob]

you think the sprue plate warped? Its cooled down and I can't get the sprue plate to lay flat with the screw tight. Loosen it and it lays flat and no gap.

 

[John from MD]

you think the sprue plate warped? Its cooled down and I can't get the sprue plate to lay flat with the screw tight. Loosen it and it lays flat and no gap.

Not necessarily. My MP sprue plates need to be adjusted so you can't see light through the gap via the sprue bolts. While MP molds are machined well, and are inexpensive for what you get, they do have small quality issues.

 

[Archeryrob]

So adjust it how? Please teach me/us what needs to be done to adjust it to lay flat.

Thank you in advance

 

[85MikeTPI]

So adjust it how? Please teach me/us what needs to be done to adjust it to lay flat.

Thank you in advance

I believe I had to remove the washer under the sprue plate on one of mine, but still needed one on top of plate to keep tension because the screw bottoms out. I use bees wax to keep it lubed

 

[John from MD]

So adjust it how? Please teach me/us what needs to be done to adjust it to lay flat.

Thank you in advance

Hold the mold up to a light and gaze at the joint between the sprue plate and the mold body. Adjust the hold down screw(s) as needed to get the least amount of light shinning through.

 

[Archeryrob]

Mine did not have a washer under the sprue plate. There is sleeve that the sprue plate pivots on, the screw goes through, and it sits right on the mold.

When I loosen the screw it sits flat. As soon as pressure is applied by the screw to the sprue plate it lifts up.

 

[John from MD]

Mine did not have a washer under the sprue plate. There is sleeve that the sprue plate pivots on, the screw goes through, and it sits right on the mold.

When I loosen the screw it sits flat. As soon as pressure is applied by the screw to the sprue plate it lifts up.

Then leave it loose. As it heats up, it will tighten up some anyway. Don't forget to use a high temp lube for the pivot.

This is the closest to the original Bullplate lube that I have found. It isn't cheap but you don't need much.

Sprue Plate Lube | NOE Bullet Moulds

noebulletmolds.com