Modify a Lyman Mould

[Mike W1]

I've been weighing my bullets out of a Lyman DC #452374 in hopes of making better bullets and have been happy enough with the ones out of the rear cavity but not the front one. Suspected that the sprue plate might be part of the problem and another discussion elsewhere got me out in the shop the other day. I drilled out the stop pin and drilled and tapped for a 10:24 screw to replace it along with a 6:32 set screw to hold it in adjustment. I believe this helps the sprue plate stay flat but still allows the plate to swing freely. First test indicated a marked improvement and will be doing some further testing. I understand some moulds are made this way but I've never seen one but wanted to pass along for consideration or comments. Do wonder how those stop pins are put in as I couldn't pull it and had to progressively drill it out which was the worst part.
I bottom pour and have come to prefer aluminum sprue plates so just made another.
http://i.imgur.com/oNmNWib.jpg
http://i.imgur.com/tq8m6eB.jpg
http://i.imgur.com/uy6s51u.jpg

[ascast]

I like your modification. LBT made (makes) molds with a spring hold down. They overheat and need to be replaced after awhile, or may. I firmly do not prescribe the loose sprue cutter school. If it falls of it's own weight; 2 things will happen. 1) it will float when filled causing the far bullet to be a tad bigger 2) you will close it by flipping your wrist. The sprue cutter bangs on the stop. Over time it raises a big burr on the under side of the cutter plate which will lift it up. I like your cutter plates-you makes them for sale?

[Guesser]

I place a wave washer on all my sprue plate pivots and set the pressure to light; Just enough so it will not float when the mold is turned off vertical. maybe they are called "bellville" washers? They seem to stand up to repeated heat/cool cycles very well.

[Mike W1]

I like your modification. LBT made (makes) molds with a spring hold down. They overheat and need to be replaced after awhile, or may. I firmly do not prescribe the loose sprue cutter school. If it falls of it's own weight; 2 things will happen. 1) it will float when filled causing the far bullet to be a tad bigger 2) you will close it by flipping your wrist. The sprue cutter bangs on the stop. Over time it raises a big burr on the under side of the cutter plate which will lift it up. I like your cutter plates-you makes them for sale?

Had just recently learned about the spring dealies LBT uses and didn't have an idea of where or if they were obtainable. Hadn't thought about their overheating either. Anyhow it appears what I've done the plate can be adjusted the regular way and the other screw being adjustable really "locks" it down. The aluminum plate was suggested by Col Harrison in the NRA book and I just copied that with a drill press and a hacksaw. Takes a bit of time I guess but not that hard to do. Only have made them for myself, I'm no professional, just a tinkerer.

[Mike W1]

I place a wave washer on all my sprue plate pivots and set the pressure to light; Just enough so it will not float when the mold is turned off vertical. maybe they are called "bellville" washers? They seem to stand up to repeated heat/cool cycles very well.

I think they're called bellevue but am not sure of the correct spelling either. Use that on the pivot bolt as you do. Looked it up, you were closer than I was. Belleview on google anyhow.

[KenT7021]

Belleville is the correct spelling.Among other uses stacks of large ones on a power drawbar are used to hold tooling in CNC machining centers.

[WALLNUTT]

Noe and Accurate molds are made with the adjustable hold down screw. Your modification looks good to me.