Sprue Plate Steel

[thehouseproduct]

I want to make a couple sprue plates. Should I be using A-1 or O-1?

[BattleRife]

I suspect that anything more than 1045 would be unnecessary.

[Lefty SRH]

I made mine out of O-1 but then again it was available.

[thehouseproduct]

I suspect that anything more than 1045 would be unnecessary.
Would you be able to buy the 1045 ground like you can tool steel?

[40Super]

S7 would be another good one. I don't think you can get 1045 or 4140 type steels in ground flat stock normally, but I would think someone will offer it.
The tool steels may be better for a sprue plate for holding the sharp edge in the holes a little better than the softer 1045,otherwise it may not matter.

[theperfessor]

The down side of plain carbon steel is that it begins to lose hardness at any temperature above 400F. Some tool steels retain their hardness to higher temperatures, but all will soften a little bit. Even so, Lee uses aluminum - not the hardest of metals - for their 6 cavity sprue plates, and they seem to do OK for most people.

Either steel the OP mentioned would work fine. I'd probably go with the oil hardening grade as its a little tougher in service and won't accidently harden up from the friction of a dull tool.

Me, I have used 1/4" annealed 4140 plate stock and fly cut one side flat, then lapped it. I didn't harden it.

[Catshooter]

If you're not going to harden them there is no advantage to using tool steel other than the surface finish they come with.

Hardening one would scare me (warping) but then I'm not a machinist.


Cat

[40Super]

If you harden them,they would have to be surface ground flat,but at the casting temps, it would anneal the hardness back out quite a bit so you wouldn't gain much.