New Mold

[nighthunter]

The UPS guy dropped off a new mold at my house yesterday. A 4 cavity Lyman 401638 for my Beretta 40 S&W. I cast up about 2000 of them today in a short amount of time. Its a really nice mold. Bullets drop out real nice with very little sticking. The only problem I had was while bringing the mold up to temperature the sprue's are pretty difficult to cut. I'm going to take the sprue plate off and work it on a stone to see if I can maybe sharpen the cutting edge up a little. I tried not letting the melt cool too much but a 4 cavity has a lot of iron in it and the first few casts even with pre warming on top of the pot let the melt set up real quick.
Nighthunter

[David R]

Same problem with my 4 cavity 452560. The first few sprues take a really good whack! to cut them. Once it warms up, no problem.

David

[C1PNR]

nighthunter,

Also think about just a touch of a countersink tool on the top of the sprue plate.

Take a good look at the inside edges to be sure there aren't any flat spots. If there are, then maybe the countersink tool helps. Just be careful not to get too enthusiastic and open the hole up too much!

[nighthunter]

Working the sprue plate on a carberandum stone helped a lot. I worked it with a circular motion to keep everything even. There were a lot of machining marks at first but now they are all gone. The sprues all cut a lot cleaner and there is definately a lot less tear out on the bases of the bullets. Also a lot less lead smearing on the blocks. Definately worth the effort it took.
Nighthunter

[chunkum]

nighthunter,
Ever try pre-warming on a hot plate? It works for me with my four cavity Lyman 44 cal mould. Seems much more effective than warming on top of the pot.
chunkum

[sundog]

Fellers, I've been doing mould tuning for quite awhile. I'm not sure you want to remove all the machining marks. Burrs, yes. Smooth to smooth surface, well maybe not. I am in process of doing a mould right now that has a number of machine marks that will never come out - and prolly shouldn't. That's okay, it's a place for air to pass, a vent. Chamfered edges and deburred surfaces that do not chaffe against one another is what you want. I spent over two hours a few nights ago (and more time since) lightly stoning and burnishing a problem mould. Today, during it's second full session the boolits were beginning to drop without assistance. Caliber? .22. Takes alot of care and patience to make it work. Oh, one of the things I get a little aggressive on is things like alignment holes that were cratered during production. Smooth them puppies out and make the blocks align properly. Also check the holes for the mounting pins. Often the are cratered and the handle grooves need cleaned up in order for the mould to float freely in the handles. Again, that's a cratering problem caused by drilling too agressively during manufacture. Lightly chamferring block edges on mating surfaces also reduces alot of alignment problems. Sometimes it takes several session to get a mould to it full potential - including the Lee aluminium moulds. sundog

[sundog]

Oh, I've thought of another thing. Tune your mould handles. The fellers who trim them up in the machine shop are only trying to make quota. The edges and holes need a little help. Stones, chamferring tools, steel wool, and any other 'aid' you can think of are fair game for getting mould and handles working 'right'. sundog

[Dale53]

Chunkum;
I have been casting bullets for well over fifty years. However, I am always learning new ways to do things. I recently purchased a hot plate for preheating my moulds. Actually, for pre-heating my steel moulds (aluminum ones I just stick the corner of the blocks in the molten lead for 20 seconds).

What setting do you use on your hot plate? I want to pre-heat but I don't wish to overheat.

Dale53

[chunkum]

Dale53.
I just turned 67 a few days ago and have been casting bullets for a good while too. However, after retirement, when I really started paying attention, I was amazed at all the little intricacies of the process that I'd missed/overlooked. I can't remember anyone every telling me about preheating my moulds with hotplates and only started using one over this past year. It has been almost like joining the church. I am admittedly not completely systematic in the hotplate preheat, but I start mine on medium. sometimes I'll have several moulds on it.
http://img489.imageshack.us/img489/3782/hotplatepreheat3da.th.jpg (http://img489.imageshack.us/my.php?image=hotplatepreheat3da.jpg) (click on thumbnail for a better view)
If the sprue doesn't harden normally, then I know I'm running it a little warm. But I've found that it takes a lot less time to let the mold cool off some when starting up than it does to get it running hot enough for good casting by proceeding with conventional "warm-up" methods. A lot less. I have run into no problems with using the hot plate though I"m sure that scorched handles could occur if you are not paying attention. However, I've occasionally gotten that over time without the hot plate anyway. I use mine with my aluminum NEI moulds and my Lees as well as my conventional iron moulds. Getting a new mould nice and hot in the first time casting session has greatly abbreviated the "break in" process. There may be negatives to using the hot plate but I've not run into them. If I have an interruption or have to take a break, my mould stays hot and I can resume casting with good bullets almost immediately. I wish I'd been creative enough to try the hotplate years ago.
Best Regards,
chunkum

[44man]

I have to agree that you do NOT want the bottom of the sprue plate and the top of the mould deads smooth. I make my own moulds and the very best is when the milling cutter marks are left on both surfaces. I just de-burr the surfaces. I cut the tapered hole in the sprue plate with a lathe cutter in a four jaw chuck and get the edges very sharp, then de-burr it. It is like a razor.
The rough surfaces take the mould prep very well and I never get lead smears or galling on the mould tops. All edges of the sprue plate have to be chamfered and smooth before mounting it so there are no sharp edges to rub the mould.
I have NEVER been able to lap a plate or the top of the blocks perfectly flat on a glass plate or any other means. The edges always get cut more with any method of rotating or figure eight movements. When I need to flatten these, I use the mill.

[Dale53]

chunkum;
Thanks for the information. One of the great benefits of the internet is the Special Interest Forum where we can share information and "Hints and Kinks" with each other.

Dale53

[MGySgt]

Chunkum,

Use a piece of steel or aluminum on top of the hot plate. Helps distribute the heat better and if you have something you can use as a rim, the molds will sit flat on the steel.

I like my hot plate to preheat. Just remember to turn it off when done, I have burnt up a few because I forgot to!

Drew