what happened here?

[nueces5]

I started to take advantage of the autumn in Argentina and I find that as I produce more boolits, they begin to come out with this notch at the base
I use an alloy half lead, half linotype, at 685°F, the mold is 314299.
It happens to me very often that I need to adjust the sprue plate screw.
I listen to opinions, this had never happened to me.

Thanks

[Wheelguns 1961]

It looks like your sprue plate is not getting completely closed. You can tell because your sprue cut is not centered on the base of the bullet. I am not sure if this could cause your problem, but it is a good place to start.

[Walter Laich]

is 685°F your normal casting temp?

mine is 710°

yours look like it might be hardening before completely filling the cavity


A couple of thoughts:
do you have a large enough puddle of lead on the top of the sprue plate when casting? could be not enough lead to be drawn down into mold as lead cools

guessing Lyman mold?

iron mold that does take a bit of time to heat up to operating temp.

a simple and cheap suggestion is to cast as fast as you can and let mold get really warm--see if that helps--and doesn't cost anything to try this

keep us posted

[Bazoo]

Looks like too cold sprue plate temperature at first, but the way its always in the same orientation, makes me think you have oil wicking from the sprue plate pivot. If you're lubing with 2 stroke oil, then I think that's it.

[nueces5]

Well, I have things to start checking all these things.
Yes, it is a lyman mold, I leave a small puddle of lead that joins both holes.

She lightly lubricated the sprue plate with 2t oil, wetted a little bit of tissue paper with a few drops and passed it on before starting to heat the mold on the underside of the sprue plate. I leave the latter more or less tight so that it closes with a very small effort. You should make a film to understand.
I'll raise the temperature to 700°F and comment again

Thanks

[405grain]

I second all the things that are being said here. It looks like the sprue plate isn't getting hot enough (which is odd because it looks like the mold blocks are). If there's any lubricant wicking from the sprue plate pivot screw it could be flashing to smoke, and that might be causing the cavitation. An interesting point that you made was that you've been needing to readjust the sprue pivot screw. There's a bevel washer that is used beneath the head of this screw which acts like a spring and puts a slight tension on the sprue plate. If that washer has been crushed by really cranking down on the pivot screw, it will no longer be able to apply tension to the plate, and the sprue plate will just flop around after that.

First clean up everything to make sure that there isn't excessive oil on the mold. Then check to find out why the sprue plate isn't closing all the way over the mold cavity. Loosen the set screw, then remove the pivot screw, and see if the bevel washer has been damaged. It it has, cranking down the pivot screw to "tighten" the sprue plate will just cause scoring and wear on the mold block around the pivot screw hole. If that wear gets bad enough, the sprue plate won't fit squarely on the mold blocks, and a few thousandths will have to be machined off the top of the blocks for the wear to be removed, and the sprue plate to sit square. If the bevel washer has been damaged, Lyman sells mold repair kits for all of their bullet molds. Here's an example for a single cavity mold: https://www.lymanproducts.com/bullet...lacement-parts

Lyman mold repair kits are available from several different vendors (almost anywhere that you can buy molds) If you live in a country where importation of these items may be a problem, see if an industrial bevel washer that's nearly the same size can be acquired from a nuts and bolts supplier. All this is assuming that the washer has been damaged - it may be just fine.

I just read your post above - It sounds like you're using too much oil. Try using just one drop of 2 cycle oil on a Q-tip, then just touching the tip of that to the part that you want to lubricate.

[243winxb]

More heat. I never lube my Lyman molds. The alloy the mold is made from, needs no lube.

The spur plate does not need to be overly tight.

[brstevns]

OK just me, but besides oil getting in it looks like a loose spur plate .

[stubshaft]

It is the lead splashing in the mold and hitting a cold sprue plate, freezing BEFORE the mold is filled.

[paul edward]

1. Thoroughly clean bottom of sprue plate and top of mold blocks.
2. Figure out why the sprue is not centered.
3. Increase casting temperature.
4. Let us know what fix works for you.

I have been casting 311299 since 1963 for 1891 & 1909 Argentine Mausers as well as 303 British.

[Bazoo]

I'm interested to know what you find out. It's always interesting to see a casting problem that I've not encountered before.

[nueces5]

I have been casting 311299 since 1963 for 1891 & 1909 Argentine Mausers as well as 303 British.

Today I will be busy, I hope tomorrow I can cast.
But I want to know if it's the same mould since 1963 or have you bought more than one in these 60 years of casting?
I was born in 1974, he has cast more time than me in life, hahahaha

[Cap'n Morgan]

The edge of the base is not fully formed and sharp. From the look of it, the defect seems to be located at the same place compared to the sprue. My guess is that you're canting the mold slightly and air is trapped at the topmost point. Combined with low lead temperature, the base solidify before the air can escape.

[Green Frog]

Ahoy, Cap’n! I think you’ve got it. Get the lead hotter and drop a little faster. That sprue is breaking off rather than shearing as it should.
Froggie