New mod for new Lee moulds

Ian

Notorious member
I had the blocks off to do some work to them, including drill/tap for an 8-32 set screw, and decided to reverse the blocks when reinstalling them. I like it much better on these little two-cavity jobbies.

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Ian

Notorious member
Sure am, but I hold the mould in my left hand like I think most people do.

This works great, just flick the sprue plate with my gloved thumb (rh) while applying a little downpressure to make nice flat bases. One reason I wanted to try this is I tend to get out of round bullets from the Lee moulds and after studying the problem a bit I came to the conclusion that I'm torquing the blocks when I push the sprue plate open. With the blocks mounted backwards, I can more easily apply the sprue cutting force at an angle that doesn't tend to slide the blocks in opposite directions and imprint the soft castings with the edges of opposite cavities.
 
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Ian

Notorious member
The pins that hold the blocks on the handles? Get them started back in their splines, push and twist in place with an Allen wrench. The trick is getting them OUT. Crank on them without pushing down, they crack loose and spiral out right before the heads strip. Usually.
 

JonB

Halcyon member
SNIP...

I tend to get out of round bullets from the Lee moulds and after studying the problem a bit I came to the conclusion that I'm torquing the blocks when I push the sprue plate open. With the blocks mounted backwards, I can more easily apply the sprue cutting force at an angle that doesn't tend to slide the blocks in opposite directions and imprint the soft castings with the edges of opposite cavities.

I've been wondering for a while, if there is some influence I have in my technique that creates a .001 out-of-round condition. I get it with a number of molds, including NOE molds...but not all molds. For the longest time, I was certain it was the mold. But about a year ago, I bought a 41 cal Lyman mold, it came with 2 sample bullets in the cavities. Those two bullets measured near perfect. I cast with that mold and get .001 Out-of-round. My first thought was I wasn't holding the mold plumb while filling/freezing.
BUT, now I need to analyze my gloved hand sprue open technique.
Thanks !
 

Rcmaveric

Active Member
Now you just need to make a cam lever for the sprue. To assist in cutting the sprue till the blocks warm up. Make it adjustable so you can use it with the NOE molds also. I hate beating on my blocks. Some molds i swear the blocks over heat before the steel sprue gets hot.
 

Ian

Notorious member
I preheat mine and never, ever beat on them.

Jon, I think it's likely. It took me 25 years to realize it, but I get lazy with my grip hand while cutting the sprue and that can let the blocks shift a thousandth or so, which is usually about how much my bullets are out of round with anyone's mould. I mount all mine the same way typically, with the sprue plate pivot on the left block close to the handle hinge, and I tend to hook my middle and ring fingertips around the front corner of the left block to brace my hand while I push the sprue plate open with my thumb. Putting force on it that way pulls the sprues...and bullets....forward slightly in the cavities of the left block and if I don't have the handles squeezed tight, or turn the mould crosswise to my body and make a deliberate push straight across the left block with the sprue plate, this out of round thing happens.

Reversing the blocks enables me to put angular force on the sprue plate, actually pushing toward the pivot screw as much as straight across the blocks, to counteract the swing arc and direct the cutting stress at 90° to the block where the sprue plate is hinged.

I'm starting to understand why some mould makers mount their sprue plate pivots in the middle.
 

JonB

Halcyon member
I'm not sure when my next casting session will be?
For some reason, I can't conjer up the exact details in my brain of exactly how I open the mold...So I'll have to watch myself during the next session.

ALSO, 18+ months ago, I changed how I hold the mold handles during pouring, due to a case of tendentious..which still lingers. I use to hold the handles with left hand for entire process, but now I hold the handles with my gloved right hand during pour and then change hands so handles are held with left hand, just before I cut the sprue with gloved right hand. Tap if necessary(tapper in right hand).
 

JonB

Halcyon member
the tendentious is in my left wrist, weak grip. So Maybe I need to think about changing my technique to hold handles with right hand the entire time, and wear the glove on left hand to open sprue? If that is possible? LOL o_O
 

Kevin Stenberg

Well-Known Member
Ian the 2 tips you gave in post 1 of this thread helped me tremendously. Today i tried a new to me mold. Keeping in mind tip 1 cut the sprue early. Tip 2 press down on the sprue plate during the cut.
I made 3 correction in timing. My first group had a weight variation of 2 grains. My last group had a max weight variation of .8 gr ,but 80 % of the bullets in the group were in a spread of .3 gr. And of all the bullets cast i only had 3 rejects because of a sprue cut bump.
So your lesson was put to good use!! Kevin
 
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fiver

Well-Known Member
I turn my mold blocks sideways when opening them.
this drops the sprue right in the palm of my hand.

all 2 of my LEE molds are mounted like shown in the picture.
I figured there was just someone at the factory that didn't know which way to put a mold on the handles.