Can a sprue plate be sharpened????

[kevmc]

Older mold, sprue plate not cutting clean.
Boolit bases show sprue not clean cut.
Sharpening or adjustment issue?????? Mold temp???? timing of sprue cut???
Your thoughts????/

[supv26]

I'd say you have a temp issue if the sprue is not cutting clean. On any of my molds I want the sprue to cut easily and smooth. If the mold and melt is too hot it'll smear the cut. If it's too cold then it will break a piece out of the base of the boolit. Pure lead cuts the best and wheel weight needs to be just right or it doesn't cut pretty.

[kevmc]

Yep, it's breaking a piece from the base.
Alloy is 50/50 Lyman #2 and PB, cast at 700*
Mold preheated, and still does it at the end of the pot..molding quickly----4 times/min.
Cutting sprue when it frosts...cuts easily enough..

[supv26]

On my 2 bangers I want to be able to break the sprue with my thumb, gloves on of course. Once I get a rhythm going and can maintain the heat the sprue cuts very nicely. I have to experiment with the molds on the start of each casting session.

[kevmc]

Sounds like the right direction to look.....
Mine's a 4 cav, might just need to experiment with it.

[David2011]

Sorry guys but I'm like a broken record tonight- third post this evening mentioning Bullshop's lube. A smidge of Sprue Plate Lube from Bullshop lets you open the sprue plate before the sprue is frozen hard. Just wait for the cooling boolits to suck a little depression in the sprue and push it open with your gloved hand- easy cutting and no smearing!

David

[longbow]

Sharpening or adjustment issue?????? Could be. If the edge is visibly "dull" you can use a countersink to touch it up. They don't cost much and you can do it by hand... slowly and carefully. Also once done, you want to stone the bottom of the sprue plate to remove any burrs. I would only do this as a last resort.

Mold temp???? timing of sprue cut??? I'd start here first and play around a bit to see if things get better.

Another thing is sprue plate tightness. I like to run my sprue plates fairly loose but it too loose they sometimes jump up a bit and leave a nub. You might check that because again, it is an easy fix.

My $0.02 (and Canadian no less!)

Longbow

[kevmc]

Sorry guys but I'm like a broken record tonight- third post this evening mentioning Bullshop's lube. A smidge of Sprue Plate Lube from Bullshop lets you open the sprue plate before the sprue is frozen hard. Just wait for the cooling boolits to suck a little depression in the sprue and push it open with your gloved hand- easy cutting and no smearing!
David


Makes me think I'm waiting too long to cut sprue...I'll try it as soon as the boolit sucks.
I've been using 2-stroke to lube,

[prs]

Makes me think I'm waiting too long to cut sprue...I'll try it as soon as the boolit sucks.
I've been using 2-stroke to lube,


Is Bullshops's BullPlate better or same or similar to air cooled 2 cycle fuel mix oil? I use NRA boolit lube, but would not mind having something better or that lasts longer.

prs

[mdi]

Yes, you can sharpen the cutting edges of your sprue plate (wonder why others went directly to temp. recommendations?). I have removed the plate and "honed" it on a flat knife sharpening stone; a bit of oil and holding the plate flat on the stone, rubbing the plate back and forth will flatten the plate and sharpen the sprue hole edges. The plates I have are a but too hard to use a regular countersink to sharpen the holes so I think a tapered stone in a Dremel would work too...

[kevmc]

After another casting session this morning.....
I cast boolits from cav 1 & 3
then from cavs 2&4
cav #1 throw 245.5 to about 247.5
cav #2 throws about the same
Cav #3 throws 247 - 249.5
cav #4 throws about 249.5 to about 251.5

So, low to high 245.5-251.5 = 6gr. diff
all cav throw same dia boolits.....
alloy temp steady at 725*, mold hot.....

different cavs...diff weights.....varyance within each cav not to bad..
used mold from ebay.....oops!

[Shiloh]

Can it be replaced?? I am also a fan ot Bullplate on the sprue plate.

Shiloh

[Springfield]

2 stroke synthetic oil works OK, but I still feel the Bullplate works better. I have only tried 5 different other oils so far, so that is not carved in stone. But I'm glad I still have 10 bottles of Bullplate left.

[detox]

Older mold, sprue plate not cutting clean.
Boolit bases show sprue not clean cut.
Sharpening or adjustment issue?????? Mold temp???? timing of sprue cut???
Your thoughts????/

Boollits with antimony in mix will not cut as cleanly as a pure lead/tin alloy. The antimony sprue breaks off insted of being cut.

It is best to sharpen sprue hole from top using a tapered tool.

[Kansas Ed]

I'm certainly a nube to this game, but my molds I've found especially with the larger calibers seem to rip a chuck out of the base if I don't wait long enough between casts and the bullet is yet soft....never had it happen the other way round personally.

Ed

[Le Loup Solitaire]

Sprue plates can be and have been sharpened successfully. The approach from the top would use a conical shaped piece of wood that is coated with fine valve grinding compound. A countersink could also be used but with great care and slowly so as to get the job done with a minimum of metal removed; just enough to sharpen the edges of the sprue hole. The hole is sometimes enlarged on purpose by casters seeking to improve the pouring process, but if overdone it can result in the need for a new sprue cutter. The approach from underneath side is to lap the entire underside of the sprue-cutter on a section of 400 grit or 600 grit sandpaper/black abrasive paper placed dead flat on a piece of glass. An extremely flat (new) Arkansas stone with some cutting oil will also work. A used stone if it has been used (already) to sharpen tools may be "dished" and won't!!. The back of a plane iron with some fine valve grinding compound will also do the job. However you choose to do it, go slow and check the sharpness of the cutting edge as you go. Usually sprue cutters hold their hole-edge for quite some time so its not a job that has to be done often. The worst scenario is that you may/ultimately have to buy a new one or make your own; its not a hard job to fabricate one either out of steel plate or aluminum, if you have a few tools around. sounds scary, but it really isn't. LLS

[GaryN]

I had one hole in my sprue plate that was not drilled deep enough. It was a Lyman. You could easily see that they didn't run the tool deep enough. I bought a countersink that fit it and drilled it deeper. Works good now.

[rintinglen]

After another casting session this morning.....
I cast boolits from cav 1 & 3
then from cavs 2&4
cav #1 throw 245.5 to about 247.5
cav #2 throws about the same
Cav #3 throws 247 - 249.5
cav #4 throws about 249.5 to about 251.5

So, low to high 245.5-251.5 = 6gr. diff
all cav throw same dia boolits.....
alloy temp steady at 725*, mold hot.....

different cavs...diff weights.....varyance within each cav not to bad..
used mold from ebay.....oops!

Are both ends of the mold fully closed? If the pins are holding the "3&4" end of the mold slightly open, you get that inadvertent Beagle Effect. Tap the pins on that end back in slightly, and carefully check for burrs on the alignment pin holes. Also, carefully inspect the mold for any spots of lead, dimples or dings that could be keeping the mold halfs from fully closing. I had a two banger 311-644 that went from dropping one cavity about 2 grains heavier, to pretty much even stevens when I adjusted the pins to allow easier closing.