Question about sprue cutter plates

[histed]

I was casting with both my 358-158 TL and 358-125 FN, both 2 hole. This time out both sprue plate screws kept loosening up so that I had to tighten them about every 5th cast. I use a Lyman 10# Big Dipper and run it nearly full temp, but try to keep my molds so the puddle hardens in about 4-5 seconds. So, is this a problem that's common with Lee molds or am I screwing up? Can I use blue Loctite on the screws? Its not a really big deal, just annoying as heck and adds one more genie I don't need into the mix. Thanks for the help.

[multigunner76]

I just put the same mold down. Having the same problem. Curious to see what the answer is

[Maven]

It's not a common problem, but it isn't unheard of either. What you need to do is drill and tap the mold for a set screw so that the sprue plate screw remains as tight as you like. Btw, I had to do this for two Lee 6 cavity molds last week and it really made a difference.

[histed]

Thanks Maven. No Loctite, then? I have no tap and die set, so I'd need to pay to have this done. I could, I guess, but if Loctite will work....

[nitro570]

Loctite won`t help because of the heat.

[462]

Drilling and tapping for a set screw is just part of owning a Lee mould. Since Lee refuses to manufacture their moulds correctly, it becomes necessary for us to complete the job.

[William Yanda]

You don't need a tap & die set. A good Hardware store will have individual drill, tap combos in appropriate sizes, probably for under $10. Working with aluminum and a large amount of care, you can use a small vice grips for a tap handle. Get the set screw at the same time. Good luck. For a small hole in aluminum, you can get away without cutting fluid too. Someone else here suggested making a mark on the screw, facing the side of the die where the set screw will be positioned and filing/grinding a flat spot on the threads for the set screw to hit. Alternatively, a small piece of copper wire or a single shot to cushion the threads of the sprue screw from the end of the set screw are good choices.

[bangerjim]

Just take the screw out, stuff a little steel wool down in the hole so it is over the threads and screw the screw back in. Instant thread tightener.

Just a tiny bit of wool, mind you!

bangerjim

[melloairman]

Just take the screw out, stuff a little steel wool down in the hole so it is over the threads and screw the screw back in. Instant thread tightener.

Just a tiny bit of wool, mind you!

bangerjim

I thought I was the only one that used the wool . But red lock tight will take the heat .Marvin

[histed]

Thanks again. I have steel wool and I should be able to get a tap locally. I get the part about taking the threads off the screw to make a flat spit - How does the single shot work?

[bangerjim]

Thanks again. I have steel wool and I should be able to get a tap locally. I get the part about taking the threads off the screw to make a flat spit - How does the single shot work?

You need some soft metal to go between the end of your new screw and the sprue screw. Otherwise you screw up the threads of the sprue screw and then when you take it out you totally wipe out the threads in the mold block.

I prefer a tiny piece of brass welding rod to lead shot. Anything softer than steel!!!!


banger

[country gent]

To lube the tap when cutting use a small dab of bullet lube in the flutes at the point. A piece of lead shot or copper wire under the set screw saves alot of headaches later on. I also get the set screws long enough to add a jam nut on the back when set. This insures the set screw only loosens when you want it to. WHen tapping break chips every half turn or so. Half turn back up and another 1/4- 1/2 turn till through. This keeps chips small so they dont jam wedge the tap. A little beeswax or bullet lube will help improve the cutting making for a cleaner stronger thread.

[gwpercle]

Thank you Jim, Thank you Marvin, That steel wool thread tightening tip was much needed and appreciated. My older Lee moulds don't have this problem , the new moulds have it in spades.
No tools, no skill, if I took a drill to and aluminum mould it would be ruined for sure.
Gary

[histed]

I,on the other hand, am pretty sure I can handle the drill and tap. Agree with Gary on the moulds, though - I have tow older ones for BP round ball that never cause problems, but the newer ones do. Howsomeever, my thanks to all. Country gent - you are. The tip on bees wax is much appreciated.

[Prospector Howard]

Here is one of the threads about putting a set screw on the sprue plate screw (thanks Ben). It's also the one where I mentioned how I remove the threads in the area where the set screw makes contact with the sprue plate screw. I know alot of people will say that all you need is something softer between the set screw and the sprue plate screw, but the small threads are easily damaged even by the brass or copper that's put in between and then the next time you unscrew the sprue plate screw out of the mold block; the damaged threads will ruin the threads in the mold block.

http://castboolits.gunloads.com/show...odify-Lee-Mold

[bangerjim]

I use the trick of soft brass bar stock in threaded areas where I do not want to damage the threads of surface of the internal piece. I do that on threads as well as sliding tubes and shafts. As long as you don't crank the carp out of the set screw, the little insert will actually become threaded like the screw it is pushing against!

In over 40 years of doing it that way I never ruined either the threads of the screw or the the piece it is pushing against.

Brass is an industry standard "plug" for preventing damage to threads/shafts/tubes that need to be held firmly in place with a set screw.

good luck!

bangerjim

[Prospector Howard]

Let's see here. A piece of solid brass VS the fine threads of a cheap soft steel machine screw on a Lee mold with 10-32 fine threads. Which is going to deform first? I wonder. I guess I didn't know that I'd entered the twighlight zone here.

[bangerjim]

Brass barstock is softer than (even soft) steel. Do NOT use brass welding rod or bronze rod.

And yes the steel will win! It has for many many years.

No twilight zone here. Just metallurgy.

Mohs hardness of common brass is ~3.
Mohs hardness of steel is ~4.5.

If you only think in Bhn, there are numerous conversion charts on the net.

..........added..........just dug out my metallurgy book and found:
SOFT brass....................60 Bhn
MILD steel....................130Bhn



banger

[Prospector Howard]

So quoting you in post 16 you state " as long as you don't crank the carp out of the set screw, the little insert will actually become threaded like the screw it is pushing against"! I guess someone needs to explain the difference betweeen two solid objects pressing against each other and one object even though it may be softer, pressing against an object that has solid points with air space in between (threads) and how that solid object will deform not solid objects such as threads; especially when we're talking about very small threads like 10-32 NF. It would make a difference if the threads were larger and the set screw and piece of brass were smaller (like the brass set screw on RCBS die locking rings on the 7/8-14 threads). Yes if the two objects are solid and pressing hard enough against each other the steel being harder will win out in deforming the brass first. Just quoting the hardness of the two objects doesn't explain it. Try taking a small brass hammer and tapping on the threads of a small 10-32 NF soft steel machine screw and see what deforms first. It's not a perfect comparison but it makes the point. Also in post #11 you state "I prefer a tiny piece of brass welding rod. Anything softer than steel". Now in post #18 you state "Do Not use brass welding rod or bronze rod". Which is it, what do you recommend? This conversation is really getting ridiculous. I try to point out what I believe is a better more permanent fix to a problem, and all I get is (you don't have to do it that way just rig it the easy way because brass is softer than steel). I think I'll just go away now.

[bangerjim]

Whatever. So drop the conversation!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!

Do what you want. Locating WHERE to remove the threads is probably beyond the people on here that say they can't even run a tap into a hole. I have a full extensive machine shop and can make any special screws or anything else I need. Most cannot. That is why I suggested the steel wool fix. Quick, simple, cheap, and effective.

They are your molds and your money. I am not going down a rabbit hole arguing with you on something that is tiny in the scope of things.

I quoted the standards of hardness.......not my numbers.........but scientifically derived industry standards.

Use whatever you desire in the stupid little thread hole. I personally have never had this little problem with any Lee molds anyway.

I consider this thread closed. I have better things to do with my time than reproducing industry specs on material hardnesses. Or arguing with someone.

banger