Why do Lee sprue plates warp?...

[GRid.1569]

I've two 6 cav Molds, little used, and I've got base finning... on a .358-158 RNFP near to the pivot screw... and a 148 TL Wc its mid plate....

Are alu. sprue plate temp sensitive? Yet every body says.. "run 'em hot" I've use 2 stroke oil as a spure lube...

Even cold I see daylight between the SP & molds blocks.... This is pee'ing me off.....

It takes so long to get good boolits then this "finning" jumps in to screw things up... Ahhh.... HELP..... please.....

[Springfield]

Even with a touch of daylight the bases shouldn't fin. Make sure the sprueplate screw is tight. Also put some lube on the bottom of the plate and th top of the mould, helps kep the finning down. If you are using a bottom pour pot sometimes either moving the mould farther from the spout or slowing down the spout flow will help also.

[NuJudge]

I've read comments from Lee to the effect that there should be a very slight curve on the bottom of their Sprue plates. It is not noticeable on most of my Lee molds, but I do have a single cavity for the 8x56mm which has a very pronounced bow to it. I do not believe the mold had that much bow to begin with.

One out of more than 25, that's not often.

CDD

[fredj338]

They are probably th e thinnest of any mold I have used. That & the high temps most run their Lee molds, they're gonna warp.

[Bret4207]

I run mine hot and fast and never had a warping issue. I have had to take the sprue plates off some 1,2 and 4 bangers of other brands and flatten them. The most I've had to do with a 6 cav Lee so far is polish the plate bottom.

You aren't twisting it somehow? I've seen a few people that are rather "vigorous" in their treatment of their moulds.

[JIMinPHX]

Usually, when I had a sprue plate that is showing some daylight, it was because the pivot wasn't flat, or there was some galling on the top of the blocks. In either of those two cases, the fix is to resurface the tops of the blocks. The short term fix is to loosen the sprue plate screw & push the sprue plate down with the ladle when pouring.

[geargnasher]

Jim, how the heck do you fill a six-banger with a ladle? You musta meant "shovel":kidding:

Gear

[myg30]

Grid, My lee 230g TL 6 cav did the same thing this week for the first time after casting 900 or so boolits. Remove the spruce plate, clean it, clean the top of the mold blocks. Lube it re assemble it. When it gets hot, you will have to tighten the spruce screw again BEFORE any lead gets under it. If the alunium around the hole is raised up from over tighten, take a flat file to it lightly, make it level again.
The spring washer should hold it tight but most drill and tap a set screw to hold the spruce screw like the lyman and others have.
Good luck sir,

Mike

[qajaq59]

I've bought used molds that were a more expensive brand then Lee. And they were bowed because obvously someone let the sprue get too cold and then beat the tar out of them with a hammer handle. Or maybe the Hammer?

[Maven]

"...how the heck do you fill a six-banger with a ladle? You musta meant "shovel."

Two things: (1) Some of the sprue plates on my 2 cavity Lee molds came "pre-warped,"* so I wouldn't have to worry about them later I suppose. So far, none of my three 6 cav. molds has had a warped sprue plate. (2) I always use a ladle/dipper (Lyman) to fill my 6 cav. molds. You can actually fill all 6 cavs. in 1 pour IF the CB is small, 4 if it's large. I generally pour 3, re-dip and pour the last three.


*Straightening those out-of-plumb plates is fairly easy once you remove it from the mold. (That may be more difficult than straightening it!)

[GRid.1569]

Thanks to everybody for your input... I think it gets worse as the session continues and the mold heats up... Trying to maintain a stabile temp (both the lead & mold) Guess I'll just have to stick at it.... Good thing is i can always recycle the bad ones

[leadman]

My recent 6 hole Lee molds have had the shank portion of the sprue plate bolt too long. You can check this by opening the sprue plate and checking the up and down movement. There should be some but mine would move from 1/2" to 1" at the sprue plate handle.
I used some thin washers I had in my fastener stash to shim the plate so it is a little tighter. Don't get it too tight 'cuz then it will gall the top of the mold.
Two of my recent molds had a steel insert for the sprue plate bolt. It was not flush with the top of the mold block so used a file to correct this.