Lee 225-55-FN Sprue Problems

[rsterne]

I contacted Lee about the diameter of the holes in the sprue plate on their .22 cal mould…. No matter what I do, it rounds off the corner of the base on the tension side.... They got back to me and asked for photos, and I sent them these....



Both bullets are rounded on one side of the base, but I mounted them so that the photos would show a good (compression side) and bad (tension side) of the base....



The holes in the sprue plate are 0.155", which is HUGE on a .211" base on the gas check shank.... Most mould makers use a hole in the sprue plate not larger than 50% of the caliber.... I have a replacement plate with 0.109" holes, but haven't tried it yet....

Anyways, I'll let you know what happens when I hear back from Lee....

Bob

[K.O.]

It is not just a 6 cavity problem... and even when I let my 2 cavity's cool for a full min and have torn bases it still pulls the one side... It is a problem on my .225-55-rf Bator mold also... I think even having the sprue hole at .125" would fix it...

Mine one(Bator) measures ~.142 the other two ~.147...

[K.O.]

also it may be a shrink problem on top of the pulling problem the sprue plate will hold more heat than the mold so the base is the last part to cool... I can at times watch the sprue puddle sink as it flashes... that can pull from the edges resulting in rounded/ partially rounded base edges...

[KnifeMaker]

Yes, smaller spru holes with help, as will more heat in the plate itself. You have to play with the heat to see what it likes in the plate, and also the tightness of the plate.


Higher heat overall, and slightly tighter plate to blocks will help, but you MUST keep the bottom of the plate clean and lubed or otherwise it will cause galling of the blocks. Especially int he soft, low quality Lee alu. 


Open too soon, an you will get tear out. Let cool too long before opening, you will get a half moon on the tension side.


It's all a balancing act. LOL Comes with experience. And no matter how long you have been casting, these small pills require much closer attention to the fine details.  

[rsterne]

Mike, I tried everything, and I could not avoid that problem.... I could sure make it worse, though.... From previous experience with Lee .22 and .25 cal moulds I know the holes should be smaller.... I hope they will listen.... The sprue holes in a .22 cal NOE mould are only 0.109".... The ones in this Lee mould are 0.155".... Twice the area means twice the force to shear the sprue....

Bob

[K.O.]

and even when I let my 2 cavity's cool for a full min and have torn bases

concentration probs again...was supposed to read...

and even when I let my 2 cavity's cool for a full min and when I have torn bases 

was trying to express it happens no matter what I do...

The reason I think it is also shrink is the rounding... when it is just pulling it is not so rounded of an edge imo...

Had the prob with my .250 40 BBT and Al sent me a .125 spru plate... fixxed it right up...

[KnifeMaker]

LOL! Kirby, I'm following now. ;<)


Mr. Bob, Swede sent me a smaller hole plate for one of the .257's and it worked very well. He sent a blankj one some time back, aand I need to get of my rear and do it as well.


Cedric sent me a Lyman some time back, and I made new spru plated with much smallr hles for both of them. It really helped.


Another thing that truly helps is sharpening the spru cutting hole. I use a very sharp carbide counter sink make for the milling of steel, and follow up with a diamond sharpening hone. Much finer than any of the diamond burr's that I have seen. Around 1000 grit then a ceramic cone. Finishing with a hard felt cone bob loaded with White Chrome mirror polishing compound for hardened steel in the Foredom Tool. This leaves a full mirror polish in the spru holes and spru cavity, and once heated, are a good looking blue chrome color. Lead doesn't stick to them, just falls away with no effort. Using this and spru plate oil, I never have to tap the mold handle hinge with a mallet. Just turn the mold upside down and the spru simply falls away like magic.
(Thinking of doing the same to the top surface of a spru plate to see if it gains further improvements).




Finally, to remove the bur left on the bottom of the plate, I re-hone it flat on an 1800 grit diamond hone, and finish on a pure hard Arkansas Stone. this leaves a true razors edge. Dead smooth, nothing to catch and hold the lead.   
I use no mallet to open the spru plate, as the plates so treated, cut thru the spru like butter with a gloved hand.  I enjoy how smooth they cut.


Mike