Sharpen the Sprue Plate Hole - It Makes a Difference

[John Boy]

Was reading the 1958 Lyman Handbook on the subject and gave it a try casting a couple hundred 454190's today. Best bases I have ever had - perfectly flat! And the sprue puddles dropped each time

* About a 4" dowel rod - 3/8" dia
* Turn the end down to a rounded point to fit the sprue hole and chuck in a hand drill
* Coat a patch with valve grinding compound
* Run the patch on the end of the dowel in the hole
Bluing will disappear and the bottom of the hole will start to sharpen
* Then take a drill bit, I used a Letter bit (don't remember which one) and turned it by hand in the sprue hole

Felt the hole from the bottom of the plate and it was sharp as a knife

[geargnasher]

Roger that, JB. I use a conical stone in the drill press with sprueplate removed, just hold the plate up against the stone and rotate like a swashplate until machining marks are gone and hole is sharp. Finish with 320-grit paper and fingertip. Dress back side of plate with wet 400 grit on a piece of thick glass or machined steel block. Cut sprues jump out, even when cutting them with a flick of a gloved thumb, I have been trying lately to get all my moulds to work entirely without having to beat them with the wooden club, and sharp, clean sprueplates are essential.

Gear

[shotman]

A standard counter sink will work as good . set on block of soft wood [pine] and use oil and it wil do it in a couple seconds. drill press is a must to keep it centered

[Bret4207]

I've recommended a simple Dremel tool stone of the appropriate size for years. Turn it in the hole with the fingers, NOT A DREMEL, and when a ridge appears on the bottom then flatten the plate with something like 320 paper on a piece of heavy glass or surface plate. Makes a big difference to me.

[madcaster]

Great tip,thank you Sir!

[waco]

+1 shotman!
i just take my molds to work
clamp in drill press and kiss with a 60degree countersink
easy fix