oversize on length? Sprue plate problem?

[.44rich]

I've been researching this problem and keep coming up with nothing. I have a lyman 225438 mold that just seems to be the devil. I cant get it to cast right at all. First it was casting undersize, then after reading up on "beagling" I turned out a brass blank and lapped the drive bands to the size I had hoped for. Then I was having problems with boolits sticking in the mold, to the point a pair of pliers and careful pulling was required. I found a few threads on deburring and polishing the mold. That was my next step. Now she shines and drops great! But then another plague hits. My question and point to this post is this: Has anyone ever experienced boolits casting oversize on length. I tightened down my sprue plate and I still get some overflow up and boolits started sticking again. It seems the lead is flowing under the plate ever so little, just enough give a tiny lip and stick the boolit hard in the mold. I had purposefully cast for rounded bases and they drop right out. Then when I cast for full fill out they stick. I've tried hotter mold cooler alloy and hotter alloy cooler mold and just about every combination. This is my first small diameter cast, everything else has been larger pistol and some 30 cal stuff. Never ran into this problem before, has anyone else? I'm using lyman #2 from rotometals and currently trying to keep mold around 300 and alloy under 700. This gives me great fill out, but sticky boolits.

[RU shooter]

Hold it up to the light . Can you see light between the top of the block and the bottom of the plate ? You may have a bowed/warped sprue plate ?

[.22-10-45]

When you lapped that mould..are you sure you didn't bell the bottom edge of bullet? If thats Ok..check plate for flatness..I use a surface plate..or thick glass plate with wet-dry 320 paper in fiqure 8 pattern to clean up bottom of plate.

[Geezer in NH]

Length? Problem how? Not judging just asking, when I cast a boolit and the weight is near and size is big enough to work on diameter I can say I have never once measured the OAL of it.

[runfiverun]

if you tighten the sprue plate down it will raise the end away from the screw.

one more thing to look at is if the plate itself is flat, if it's bowed you can have the ridge too.

[gwpercle]

The underside of the sprue plate and the top of the blocks must both be flat , no day light should be seen between them . Do the plate glass, wet-or-dry with oil , figure 8 pattern on the underside of S plate.
Make sure the there is nothing , lead smear, small burr , etc. , on the underside of the plate or on block top.
Ther's a fine line between too tight a plate screw and just right. Too tight will cause lifting. When everything heats up you may need to stop and readjust the screww tightness...heat causes the metal to expand and change.
Gary

[.44rich]

I know the plate and mold are both perfectly flat, they have both been on my surface grinder and checked on my surface plate. But the fine line between right a tight, that rings a bell for me. How tight should they be? I was worried when I had it to tight I was getting smearing.

[popper]

Beville washer should only be deformed 0.020" or so. It's purpose is to take the slack out of the screw/hole, the plate and alloy should hold the plate down. Old moulds don't even use them.

[catskinner]

If using a bottom pour pot try adjusting the flow rate and also try varying the gap between the nozzle and sprue plate.

[Shiloh]

Is it warped?? I have a molds that I can see a hint of light through. Casts perfect boolits. It isn't warped though.

SHiloh

[KYCaster]

Start with the sprue plate closed....tilt the mold. Does the sprue plate fall open from its own weight?

Yes = too loose.

Hold the handles like you're ready to pour. Give it a flip with your wrist (like dealing cards). Does the sprue plate open from the centrifugal force?

No = too tight.

This works for most of my molds.

Jerry

[Echo]

Start with the sprue plate closed....tilt the mold. Does the sprue plate fall open from its own weight?

Yes = too loose.

Hold the handles like you're ready to pour. Give it a flip with your wrist (like dealing cards). Does the sprue plate open from the centrifugal force?

No = too tight.

This works for most of my molds.

Jerry

Plus One...

[.44rich]

So I tightened the sprue plate down like kycaster posted. I notice the plate won't open all the way off. I take it off and check if it's flat...it is. I put it back together and am looking at it for light, fully closed there's light, once I start to open it, it tightens up. Now I'm ***ing this thing bad. Then it hits me, my sprue plate isn't bent, my screw was! I took it out and changed it from a spare mold. Much better. I will cast tonight and see how it works. Thank you everyone for the great info!

[mdi]

When you lapped that mould..are you sure you didn't bell the bottom edge of bullet? If thats Ok..check plate for flatness..I use a surface plate..or thick glass plate with wet-dry 320 paper in fiqure 8 pattern to clean up bottom of plate. This is the same thing I was thinking...

[.44rich]

At last the phenomenon has stopped. It was the bent screw. The plate would tighten when trying to swing off but would be loose on closing. I replaced the screw and hit the plate on some paper again. Now everything is operating smoothly. Some of the other posts about tricky small diameter molds hit the nail right on the head. I still get some sticking, about 30% stick in the mold. But I think that's mostly my pouring technique and i'm still finding the sweet spot for temps on this mold. I picked up some synthetic 2-stroke oil and use that on the bottom on the plate and it really helps! Thank you guys for the great help!

[44man]

I mill my mold tops before the cherry and mill plates. Still have to adjust right or a plate will tip. I never thought of a bent bolt but I use aircraft stainless bolts. My plates are THICK and I hate lee and Lyman plates. Lee has a self tapping screw for the plate---CHEAP so I replace and put a set screw in.
So happy you fixed it.