Problem with Lee six cavity

[Cloudpeak]

I've cast a few thousand bullets from my Lee 6 cavity TL401-175-SWC mold and have had good luck. I cast around 800 bullets yesterday and I think the sprue plate might be warped. Instead of a nice bevel on the base of the bullet which makes seating in the brass easy, I have a bunch of bullets with extra material on the base that is leaving a fine edge. When I hold the mold up to the light, I can see light between the mold blocks and the sprue cutter. I have not changed anything from previous casting sessions except that I laid the mold on a small hot plate to pre-heat the mold so I can get "up to speed" in my casting. I can't imagine this would cause any problems. The extra material hangs the bullets up in the mold and the mold requires more tapping to release the bullets. (Yes, the mold has been smoked with wood matches.)

The mold is getting scratched up a bit where the sprue cutter contacts it but I try to keep this cleaned off with "Scotch Brite" which does a pretty good job of cleaning off "lead smears." I can't see how this would have any effect, either.

How many bullets can you expect out of these molds? Do I need to send the mold back to Lee to have it re-furbished?

While I was casting 40 caliber bullets, I got out my old Lyman 4 cavity 44 cal. mold and cast 70 or so bullets. I'd forgotten how nice this mold is and what nice bullets it drops. Being all steel, there are no scars, wear, dings, grooves like I get on my Lee. I suppose you just have to figure on some wear and tear with aluminum molds. Over the years I've cast several thousand bullets with the Lyman mold and it looks as good today as when it was new.

Thanks, Cloudpeak

[imashooter2]

Scotch Brite will remove aluminum. How often have you "cleaned" aluminum off the top of it?

[Cloudpeak]

Scotch Brite will remove aluminum. How often have you "cleaned" aluminum off the top of it?

I don't think too much. I do have way too much experience with Scotch Brite and aluminum. I used to build aluminum airplanes and used S.B. to surface prep before applying corrosion protection. This was done just enough to "rough up" the Alclad (soft surface coating on the aluminum) to give some "tooth" to the surface so the anti-corrosion primer would stick well.

I used, used gray S.B. I had just enough tooth to pick up bits of lead. I don't think there is any way I could have removed enough to produce a gap between the sprue cutter and mold blocks but I could be wrong.

Thanks, Cloudpeak

[Bass Ackward]

I have not changed anything from previous casting sessions except that I laid the mold on a small hot plate to pre-heat the mold so I can get "up to speed" in my casting. I can't imagine this would cause any problems.



Cloudspeak,

All metal can warp if it reaches the right temperature. One batch of brass or aluminum or steel won't warp at a certain temp. And then the next batch will. Depends on the stress in the metal and whether it was heat treated and relieved before machining or not.

But heating a mold up or .... cooling one down quickly is like ringing a chamber. It doesn't happen very often, but it can and does happen.

The question is, did the plate or the block warp or both? Find a glass surface to lay some fine (320) emery paper on and see. That's about your only option at this point if it is bad enough to need corrected. Do this when you are fully relaxed and patient.

[Willbird]

I am told that lee 6 cavity blocks are NOT flat on top when they are new, Lee claims this is by design, or it could be that their machine isnt the greatest. I have not checked any yet.

Bill

[44man]

This is a problem even with my home made molds with very thick sprue cutters. I don't get any warpage but just fitting a new plate to new blocks is very hard. I won't use any type of sandpaper because the cutting leads the edge that goes against the paper, even if the paper is glued to the glass. I have tried figure eights and circular motions with no luck. Even using grinding compound on thick glass, it is hard to get them flat. It seems that the edges always get cut more then the centers. I have lapped them and the top of the moulds as perfect as I could and when setting the cutter on top of the mould, I see no light but as soon as I put the screw in, it tips the plate up and I see light. It will drive anyone nuts.
Sometimes I give up and put the blocks and the sprue cutter back under the mill and that fixes it. It is VERY hard to lap them for a perfect fit. I only lap a new plate now to remove any burrs, the milled surface is flatter then any lapped surface.
I don't have a six cavity and don't know how thick the plates are. But I detest the plates on the single and double cavity moulds. I don't like the old, thin Lyman plates either. They are hard to cast with.
Those thin plates can warp fast and those that put the cutter on a cold rag can really mess them up. I can picture the plate twisting and cupping each time it is cooled fast on one side. No thanks, I will cast slow and protect my moulds.
I pre-heat my moulds in a little mould oven on a hot plate and have never warped anything. My first boolit is always perfect. I take the blocks to 500 degrees. For years, I set the blocks on the pot edge and then finished heating with a propane torch by passing it quickly all over the mould without ever harming one.

[castalott]

I had the same condition on 2 or 3 Lee molds. It was caused by the sprue plate warping. Close the plate and look under it at light (no, not the sun). All of mine have warped up in the middle...that is...the ends touch and the middle is flying high like a bridge. One is warped a fantastic amount. When the plate is warped, it allows 'extra' metal to stay on top of some of the bullets after shearing. If the distance is 'just' right, it makes a thin disc as you describe. Sometimes it makes a large chunky looking thing that won't even allow the bullet to be sized..Anything other than a flat bullet base has to degrade accuracy....

I really don't understand why sprue plates need to be so big. All they really need is wide enough to cover the bullet cavities. Taller would be a good idea.... More molten sprue weight to push the cavities full.....I've experimented with adding a 'trough' in a Lyman sprue plate. It works just fine. I'd add that to my design too. And the stop for the sprue plate would touch upon the side of the mold that swivels the plate. No matter how hard you push, it would never push the blocks apart. A screw for adjustment would be nice there too.

The Lee 6 cavity molds themselves are rather durable. I have one mold that has made over 28,000 bulets and still looks & works great! I have had to buy a "Helicoil' insert tool to replace the threads that have stripped. I haven't used the new threads enough to have an opinion yet.....

Lyman molds seem to be very durable. They can still be abused , of course. But cast iron and steel wear better. I use that one modified sprue plate ( the one with the trough) on all the 4 cavity molds when running the machine. I have no idea how many bullets it has sheared...250,000? 350,000? A lot... It's still going. It's not perfcect either.....I'd like to have one made out of tool steel so the cutting edges could be sharpened.

If Lyman would do 4 cavity molds to our specs and a reasonable price....I'd be 1st in line

[slughammer]

Instead of a nice bevel on the base of the bullet which makes seating in the brass easy, I have a bunch of bullets with extra material on the base that is leaving a fine edge.

How many bullets can you expect out of these molds?

Is it more obvious at the front cavities? If so, perhaps the sprue plate and mold top are galling around the pivot screw. The galling will push the sprue plate up causing the finned bases.

Without lube, I trashed (2) 6 cavity molds. Got 4000 out of a 2R 356-125 and only 1400 from a TC 40 -180.

Now I take new 6 cavities apart and lube the surfaces to prevent the galling.

[imashooter2]

Is it more obvious at the front cavities? If so, perhaps the sprue plate and mold top are galling around the pivot screw. The galling will push the sprue plate up causing the finned bases.

Without lube, I trashed (2) 6 cavity molds. Got 4000 out of a 2R 356-125 and only 1400 from a TC 40 -180.

Now I take new 6 cavities apart and lube the surfaces to prevent the galling.

Agree with that. I touch a candle stub to the pivot screw once the mold gets hot and refresh that every 50 or so pours. So far no galling for me.

[35remington]

Your mould needs a shot of spray graphite (like Midway "Drop Out") where the sprueplate rubs against the mould.

When casting the first few bullets out of any mould, I give the top of the mould (with sprue plate swung out of the way) a spritz of graphite lubricant. Don't spray it on too thick or it can affect the venting of the mould. This will prevent galling.

Also, in my experience, you don't want Drop Out in the mould cavities, despite what the name implies. So, you spray the top of the mould after you've cut the sprues but before you drop the bullets out of the cavities.

Your six cavity should give good service if it is properly lubricated, and assuming all else is working correctly. Don't forget the alignment pins.

[David R]

I true my 6 cavity with a new sharpening stone. Its flat and fine.

As far as the stub sticking up from the base of the boolit, once I used the brubeB method of cooling the spures, those went away along with lead smeared on the top of the mold or bottom of the sprue plate. Both are a non issiue.

Everybody has their way. This one works for ME.

David

[44man]

Castalott, using tool steel will not help. When the mould reaches casting temperature the steel will soften to a spring steel temper no matter how hard you make it to start with. You might try air hardening tool steel though. I use stainless and it stays sharp for the life of the mould.

[Cloudpeak]

Cloudspeak,
The question is, did the plate or the block warp or both? Find a glass surface to lay some fine (320) emery paper on and see. That's about your only option at this point if it is bad enough to need corrected. Do this when you are fully relaxed and patient.

I believe it's just the sprue cutter. I just ran out of time & have to go to NE for Thanksgiving. I'll be more "relaxed" when I get back :wink:

Cloudpeak

[Cloudpeak]

Is it more obvious at the front cavities? If so, perhaps the sprue plate and mold top are galling around the pivot screw. The galling will push the sprue plate up causing the finned bases.

It is more evident in the middle four corresponding with the warp in the sprue cutter. I do clean up the pivot point, the latch end and keep the mold lubed.

Cloudpeak

[Cloudpeak]

Thanks for all the tips. I'll give them a try the next time I cast.

Cloudpeak

[castalott]

Hi 44 man!

Thanks for the info. How do you think stainless and the Lee aluminium mold would work together? Would they try to destroy each other? Dis-similiar metals seem to be enemies.. Just wondering....I may have my 'perfect' sprue plate built someday.....
Thanks..
Dale

[44man]

All of my moulds that I make are aluminum and I have no problems. I get less galling then I do with Lee moulds. I make sure I clean up all the edges and burrs. Most galling is from specks of lead on the plate. Sometimes I go too fast cutting the sprue and get a smear. I light a kitchen match and blow it right out. Rub the head on the lead and it comes right off.

[waksupi]

If you have a warped spue plate, they can be flattened on a large anvil, with a smooth surface. Get a wood mallet, and cover the face with thick leather. A few raps, and it is flat, without damage to the metal.