New Accurate Mold

DHD

Active Member
It is a 45-280FG 4 cavity Aluminum with a .448" front band so it will chamber in a Freedom Arms Model 83 (454/45 Colt). The 45 Colt cylinder would not chamber any bullet with a .452" front band, so this mold was ordered with the small front band. I also powder coat and didn't want to deal with any possible oversize issues after the PC.

Anyway, Tom got the order on Sunday and I received the mold on Thursday. He had to have made it on Monday morning and shipped it the same day. Incredible. I still have 2 other 4 gang aluminum molds from him I haven't had a chance to cast with yet. I just needed to get a supply of bullets for this revolver.

I fired everything up on Sunday (29nth) and notice that one cavity leaves a super thin flange on top (bottom of bullet). I've experienced it before on 4 gang molds and played with the tightness of the spruce plate. It's still a new mold so I'll get it, but I'm not ashamed to ask for any short cuts here. FWIW, the cavity with the flange is the furtherest away from the spruce plate screw.
 

Ian

Notorious member
Hmm. Never had that problem with Tom's moulds before, they usually come adjusted perfectly and lock up like Ft. Knox. Check to see if there's a smear of lead under the sprue plate near the pivot, or a smear on top of the blocks or a burr causing the sprue plate to lift on the far end. The sprue plate should not require any pressure to slip under the stop screw head, if it's lifting it will unless the screw is a bit loose. You can loosen the set screw and turn down the stop screw 1/8-1/4 turn to cinch the plate down a little, but beware if you get it too tight you'll have rounded bases from poor venting.
 

fiver

Well-Known Member
there is a little dance with sprue plates especially ones with a hold down screw at the back.
you have to find the balance between what the front screw is doing and holding it in place without changing the pressure on the mold.
some I have set with a definite need for a little lube on the plate where it goes under the rear screw and on others it is merely a stop for the plate to rest against.
I double check not only how it fills but how it cuts too.
 
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DHD

Active Member
I usually have the spruce plate where it will close under it's own weight. Also FWIW, this makes 9 different Accurate Molds I have here. I tend to give them a bath in the ultra sonic cleaner and then heat them on a hot plate while the lead is melting. This mold took 2 pours and great bullets started dropping from it.

No lead under the spruce plate or between the surfaces, and it locks up like a vault as all of his molds do. I like the analogy about it being a dance getting the spruce plate perfect. When I see a mold do the flange thing, I usually loosen the screw a touch.

I'll keep at it as the problem isn't really a problem. When the bullets are being shake and bake PC'd, the thin sliver is getting removed by the BB's and other bullets. After curing and seating the gas checks I cannot tell which bullet came from that particular cavity.

Thanks for the information!

Ian, I reread your post. I will pull the sprue plate off and take a look just in case a small smear is under the plate near the screw.
 

DHD

Active Member
I took a long look at the sprue plate and found my error. I didn't have the sprue plate stop screw tight enough. I would stop the sprue plate, but allowed the front of the sprue plate to lift as the cavities were filled a tiny amount leaving the thin flange on the base of the front bullet. I snugged it down to where the plate would still slide under the screw head but keep the plate down. I cast up about 300 bullets in about 70 minutes (timed it just to see how long it took). Very very few rejects and I learned another lesson about sprue plates.

I knew it was operator error but I just didn't know what I had done. One more thing to watch for on all my multiple gang molds.
 

Ian

Notorious member
Glad you got it figured out.

The MP moulds use a roll pin for a sprue plate stop instead of a pan-head screw, so if you run the sprue plate loose at all it will lift as you were experiencing. I prefer to get that pin out, tap the hole, and put a proper stop screw in there like Tom does.
 

DHD

Active Member
I knew it was something I did, but I thought it was the tightness of the sprue plate itself. I had fiddled with it trying for the "just right" tightness, but that didn't do it.

Sometimes it's time to step back and take a hard look at the whole business and start again. Lesson learned....
 

fiver

Well-Known Member
it's a good one to know.
just like looking at alignment pins and being able to decide how to adjust them when necessary.
 

DHD

Active Member
I agree on sometimes needing to keep the screws looser than I would prefer, but it's hard to argue with perfect bases. I really like how Tom makes the pan headed screws for the sprue plate to slide under. I suspect that I've left some others too loose before also (I have another mold doing the same thing). It won't take but a moment to check them all. Accurate Molds are like Lays potato chips in that you can't stop at one or a dozen.
 
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DHD

Active Member
Got another one in the mail on Monday. I didn't do anything to it other than run it through the ultra sonic for about 15 minutes (scrub with a old toothbrush), lubed the important parts, put it on the hotplate, and started pouring lead when it reached 725°. After the 3rd pour, perfect bullets started raining down.

I made sure the sprue plate stop screw was allowing the sprue plate to close easily and slide underneath. I haven't had anymore issues with a flange on any bases. I love his molds!