Mold out of round

[35isit]

RCBS 357-180 SIL. .360-.361 on high side. .356-357 on low side. measured with a micrometer not a caliper. It had always thrown round boolits at .358/.359. I had a lead deposit on the bottom band of the front cavity. I call myself using just enough heat to remove it with a light scraper. Can I make round boolits again?

[country gent]

Use a magnifying glass and look at the faces for small buildups holding the blocks slightly open. look hard around pins an in pin holes for build ups. A build up in the cavities wont hold blocks open to make an out of round casting. Look for build ups of tin/lea. carbon, soot, burnt lube. Your only talking a .004 build up. Clean faces with a stiff brush and thinner then dish soap an water really working up a lather to float crud off. Use a bamboo skewer or fine awl in the vent lines and clear them also.

[35isit]

Thanks

[Bazoo]

Could be your alignment pins backed out a bit, causing the halves to close off center to the cavity. Might check for play there.

[Conditor22]

After carefully inspecting the mold for any lead buildup on the face,

Removing the handles, I have clamped the mold in a vise to re-set the alignment pins.


Can you see light through the closed mold when you hold it up to a light source?

[beagle]

Easiest way to set pins is to drill holes in a lead ingot and tap in and out with a brass drift of the right size. No stress at all on the blocks that way.

I'd check this first./beagle

[35isit]

I got the mold out last night. There were several places with lead buildup on the face of the mold. I got my son to remove them for me. I have no "eye" for fine detail work. I'm going to try it again this weekend.
You guys on here are the best.

[country gent]

A single edged razor bade laid flat along the blocks works well for shaving the deposits of. Next is a exacto knife. work slow and carefull

[Bazoo]

I use a bronze toothbrush or even a choreboy for heavy stuff. Always scared around the cavity edges of rounding. But I mainly try to remove deposits with a pencil when the mould is hot.

[gwpercle]

I got the mold out last night. There were several places with lead buildup on the face of the mold. I got my son to remove them for me. I have no "eye" for fine detail work. I'm going to try it again this weekend.
You guys on here are the best.

Just a speck of lead on a block face will keep them from closing and hard to see even with young eyes . Sounds like you found the problem ! Now it should do right .
Gary

[onelight]

I use the flattened mouth of a cartridge case filed or belt sanded to the shape I need to scrape lead off iron molds.

[Traffer]

I heat up the mold and use a toothpick or a soft stick like a small diameter dowel to scrape the surface. No chance of scratching that way.

[RickinTN]

Bamboo skewers are great for this. Hard enough to remove what you want but not hard enough to damage a mold.
I save them every time I get the chance from restaurants.
Good Luck,
Rick

[JWFilips]

Out of round bullets get round pretty fast once fired!