Cutting vent lines in iron moulds...depth?

[WallyM3]

I'm cleaning up a vent-lineless mould and I'd like to cut a few vent lines. Rather than guess, would someone be willing to recommend a down feed?

[marvelshooter]

I added some vents to a Lee mold recently. I went .005 deep with a fly cutter ground to a 120 degree included angle. This gave me a groove about .015 wide. The hard part was getting a spacing I liked. I ended up at 60 rpm and 9 ipm feed giving me around a 1/16" between grooves. Hope this helps.

[MT Gianni]

I would see how it casts first. I have a few I have kept ventless.

[WallyM3]

I would see how it casts first. I have a few I have kept ventless.

That would be the sensible thing to do. Someone tried tofile a few grooves, so I suspected that maybe the mould was giving trouble. It's an Ideal 360302 (Himmelwright form) that might need help at the leading edge. But, I'll see what it drops first.

And thanks to "marvelshooter", I have a set-up.

Thank you both.

[WallyM3]

Best 4 of the first 12 drops. Mould still a little cool. I don't see a vent line related problem (BTW, this is a single cav. mould), but have a bent sprue plate.

At least that's simple to fix.

86593

86594

[John Boy]

Nearly all of my old Ideal flat sides in my collection cast the best bullets. Why try to re-invent the wheel?

[WallyM3]

Because moulds all are made with vents now. I thought there might be something behind it.

And the seller advised that sometimes the "noses" didn't want to fill. I don't see that now that I have dropped a few.

Besides, I abandoned the idea as a result of casting with it, anyway.

[Moonie]

I have an old Ideal, no vent lines, casts a beautiful 134gr rn .270/6.8 caliber boolit. (it is a .270 mold but I use it in my 6.8 SPC upper). If it casts well leave it ventless.

[beagle]

Bevel the top edges slightly with a stone if they give problems. This normally vents enough. I have half a dozen ventless moulds and they cast great./beagle

[WallyM3]

Funny you should mention the edge bevel. During the initial stages of cleaning up this mould, I stoned a chamfer into the top seam with a hard Arkansas, both halves. Looks to be 0.007" to 0.010".

I cast about 50 more today and the thing is dropping marvelously (compared with expectations). I'll be dragging out all my .38s to find those with the shortest forcing cones and do some shootin' next week.

I's dearly love to acquire the 44 version, the 429220, for my 24. They may not be as accurate as more recent wad cutter designs, but it's sure fun.

[paul h]

Hard not to like bullets with boobies ;)

[WallyM3]

Ah....you know me so well.

[country gent]

I have a small tool makers square ( 2 1/2") I lay accross the blocks and scribe a light line with a sharp carbide scribe when vent lines are needed. I just count the number of passes made and do the same each time. I normally start at 3 passes on each block try and go from there.

[WallyM3]

I have a small tool makers square ( 2 1/2") I lay accross the blocks and scribe a light line with a sharp carbide scribe when vent lines are needed. I just count the number of passes made and do the same each time. I normally start at 3 passes on each block try and go from there.

Intuitively, the method that you suggest was the first that came to mind. It certainly would be far less tedious than setting up the Bridgeport for accurately spaced shallow cuts on a 45 deg. piece.