4 cavity spur plates

[hornady]

Yesterday I cast three 20 pound pots of bullets with two of my 3 Lyman 4 cavity molds. As usual I spent a lot of time tightening the spur plates down. 2 of the molds are about ten years old the 1 is less than a year. I have tried rebuilding the old molds with Lyman rebuild kits, and no luck. And the new mold is as bad as the older ones. Dose anyone have a fix for this. Or is it just the nature of the beast. It’s kind of a pain tightening the screw every 4th or 5th time.

[stocker]

Try cutting a small section of bronze brazing rod and putting it under the set screw. If you don't have Allan head screws and have slotted screws replace them and tighten like crazy. A new set screw might help or a bit of rosin dusted on the threads.

[hornady]

Do you think a couple pieces of shotgun shot under the screw would work. I was thinking of this but did not know if it would work. With the heat, and once in there it would be a bear to get out if it did not

[theperfessor]

The main problem I have with Lyman molds is the horrid "spring" used under the pivot screw head. This is really a split-type lockwasher and not a spring. A lockwasher is designed to prevent rotation, in this case by digging into the pieces on either side of it which is the bottom of the screw head and the top of the sprue plate. When you force the sprue plate open it will turn the screw and loosen it. Look and see if your parts aren't scarred up in this area.

I used to grind off the sharp corners of the lockwasher but now I simply toss the piece in the trash and replace it with two stainless steel flatwashers. In another similar thread one of the well respected members here commented that he used a wave-type washer as a replacement, which is also a good solution.

In either case you need to ditch the Lyman-supplied lockwasher or you will have a hard time keeping the pivot screw from coming loose!

[Texasflyboy]

Back when I first started casting I had the same problem with my Lyman 4 cavity moulds.

What I did to "cure" the problem was to get three or four sprue plate bolts (new) and install them one at a time. With a special allen set screw that had a hard point on it, I drove the allen set screw into the new sprue plate bolt to make a mark where the plate worked best. Once I had that mark, I used a dremel cone shaped tungsten bit to carve a matching cone into the sprue plate screw. This allowed the set screw to drive deeper.

The set screw would loosen after awhile, but I did manage to make it work much better than before.

[Texasflyboy]

... he used a wave-type washer as a replacement, which is also a good solution.

I think Lyman calls that part a "Belleview Washer" (http://en.wikipedia.org/wiki/Belleville_washer)

[hornady]

The older molds have the lock washer I believe .and the newer with the wave washer. This must be a problem Lyman has been dealing with. All three molds have slotted screws. I will try the stainless washers. The price of new 4 cavity molds I don’t want to do anything to mess them up, thanks for the advice

[theperfessor]

A wave washer and a Belleview washer are different types of short profile springs. Either should work fine for holding down sprue plate. I don't use them simply because I have a whole box of SS flat washers in my parts drawer, and I haven't found any need to hold down a sprue plate that tightly anyway. A little bit of clearance lets the air out the top and gives me nice sharp bases with no finning if adjusted properly. But that's just me, YMMV.

[hornady]

The above is true and I do not want it too tight. But the screws will back out to the point the spur plate wobbles. And need a turn to a turn and a half to snug it back up. I will try the ss washers. I have tried both lock and spring type lock washers to no avail. I do not think the spring washer can take the heat and fails.

[mtgrs737]

I have a bunch of Lyman four cavity molds and only had a problem with one of them. I ground the sharp edge off the lock washer and the problem was solved. I run my spru plate loose enough that just flipping the mould will swing it back in place so I don't need much tension anyway. I also noticed in the latest American Handgunner article that Mike Venturino whom I believe is a member here has a brass flat washer under the screw head of his Lyman 4 banger mould. I love the production those 4 and 6 cavity moulds can crank out!

[testhop]

thanks guys you solve a probllum i didnt think about .i alwaye thought it was something you had to put up with . now i know better thanks again

[hornady]

Yes thanks everyone, you through out some great ideas, this was not a major malfunction. More of an annoyance. But when you sit down to cast 60 pounds of lead or more. It cuts into casting time.

[montana_charlie]

Do you think a couple pieces of shotgun shot under the screw would work. I was thinking of this but did not know if it would work. With the heat, and once in there it would be a bear to get out if it did not
If the shotgun pellets don't melt, you are running your mould too cold.
If you need to get them out (assuming you go ahead and use them) you just melt them out.

Brazing rod, brass, copper, or aluminum beads, or heavy gauge copper wire all seem like better choices...

CM

[Echo]

Well, Duh! Snipping a little bit of Romex - what a concept.

Why didn't I think of that?

[MtGun44]

The top, movable part of the mold is the

SPRUE plate, not "spur plate". I thought this was a typo until I saw it in the second post.

Bill

[hornady]

Well I finally found the problem. On the Lyman mold you have an Allen screw on the side of the mold to hold tension on the spur plate screw. I removed the Allen and the spur plate and ran a tap through the set screw hole. There must have been a burr or bad spot on the treads. I would snug the set screw up but it must not have been locking the spur plate screw in. I ran about 5 pounds of lead through the mold without any more trouble. Funny how something so simple can give you so much trouble.

[Glen]

Hornady -- There aren't any spurs on a bullet mould, spurs go on boots. As MtGun44, that part is called a SPRUE plate since during the pouring process a puddle of lead (aka the sprue) collects there and it cut off by striking the sprue plate, thereby giving the bullet a flat and square base.

[anachronism]

Now that you know where the screw should be set, remove the sprue plate screw & file a little flat on it where the setscrew engages it, and it'll never move again.

[hornady]

Wow no help with the mold problem, and right there to nit pick about a mispronunciation of a word. Good job, I could tell the guys that were actually trying to help were having trouble understanding me. But I do want to thank all the guys that truly looked at the problem and tried to help.

[jameslovesjammie]

Hornady,

Please don't take offense to the posts about pronunciation. You have to remember that the guys on this site are incredibly technical. The posts were trying to educate, not to put you down. They were just trying to make sure everyone is on the same page.

It also looks like there are several posts trying to help. Try their suggestions and if they don't work let us know.