Stripped Sprue Plate Bolt/Hole??

[nicholst55]

I decided I needed some .38 boolits, so I fired up the Lee bottom-drip and dragged out a used double cavity Lyman 358477 that I bought (cheap) on Fleabay (Yuck! Wash my mouth out with soap!) some time ago (before I started boycotting them). I tightened the sprue cutter bolt and setscrew before I began casting. The mold got up to temp quickly and was casting 'keepers' almost immediately. After just a few minutes I noticed that the sprue plate was swinging awfully easily - too easily. So, I re-tightened things, making certain that the setscrew was tight. No joy - the front cavity was casting boolits with finned bases almost immediately, and the sprue plate was coming loose again.

I've never been accused of being the sharpest tool in the shed, but by now even I have decided that something is seriously wrong. The sprue plate has a definite gap at the front of the mold blocks, the bolt won't stay tight, and finned boolits suck!

So, the way I see it the most likely problems are that the sprue plate is possibly warped, and that either the bolt or the hole (or both) are stripped. I know Lyman sells sprue plates and replacement bolts, but what to do if the hole in the mold block is stripped? I only paid $20 for the mold and handles, so I don't know if it's worth sinking a lot of money into to repair. Then again, a new set of mold blocks are going to cost me $60-70.

Suggestions? :(

[10-x]

Would a heli-coil work? If not then maybe an oversize replacement screw. Is it a 1/4"X 20 TPI screw?[smilie=1:

[crabo]

I would tap to the next larger size hole and use a bigger bolt. I would also drill and tap the blocks for a set screw to keep the bolt from backing off.

Crabo

[wiljen]

I drill em all the way through then use a 1/4 x 20 tap and a 1 inch screw - helps to put a washer between the screw head and the sprue plate too.

[44man]

I can't picture the hole in iron blocks being stripped. Have you checked the screw itself? Some guys ruin it by trying to turn it with the setscrew still tight.
Take the thing apart and tell us what you find.

[WHITETAIL]

Nicholst55, Please if you can take the screws out.
Then let us know what you find.:coffee:
I might be able to help you if I know what is realy wrong.

[nicholst55]

I neglected to mention that I was waiting for the mold to cool off before I took it apart. It was still pretty warm when I wrote the initial post. ;)

I had to finish casting with a single cavity mold, and what a PITA that is! I decided to quit before it got too late, though - gotta work tomorrow. I'll take that mold apart tomorrow and see what's cooking with it. Maybe I got lucky and the previous owner tried to loosen the bolt with the setscrew still tight, and all it needs is a new bolt.

[floodgate]

The sprueplate pivot screw on a Lyman mould has a shoulder under the head that is an easy fit in the hole in the sprueplate, and long enough to reach through the spring washer and the plate; then a threaded section a bit smaller in diameter, and below that a straight section smaller than the threads that the setscrew bears on. If yours doesn't look like this, someone may have substituted an incorrect one. You can get a replacement from Lyman - or several of us here have extras we can send you.

floodgate

[Bad Water Bill]

When you have the sprue plate down correctly BUT before you put the locking set screw back in place insert a short length of copper wire first. The copper will compress against the sprue plate screw creating a friction lock without damaging any threads.bwb:castmine:

[JIMinPHX]

Taping the hole deeper & using a longer screw is one option. A heli-coil or better yet a thread inset collar with locking pins is another option.

[Red River Rick]

FYI. The thread pitch on a Lyman's sprue cutter bolt is 34 TPI, and not 32 TPI as some think. If you choose to go the Heli-Coil or other insert method, you won't be able to use the factory screw. I would just redrill and tap the hole and use a 1/4" x 28 Button Head Cap Screw.

RRR

[w30wcf]

nicholst55,
Lots of good advice from the pards.

Personally, I like a sprue plate that is free enough that a flick of the wrist will return it back to the stop pin after cutting the sprue. 1/4 turn of the screw back from being tight works just fine.

A friend once bought a mold which had a noticable gap from the bottom of the forward edge of the sprue plate and the top of the mold. Closer examination revealed that, in use, the sprue plate was so tight, it wore away the corner of the mold behind the screw.

The easy fix was to take the lock washer and bend it even so that became a flat washer and then back off the screw until the plate sat flush with the top of the mold and would swing freely. That mold made good bullets after that.

Even if the screw is stripped, the locking set screw will hold the screw in place when setting up the sprue plate to swing somewhat freely.

Good luck,
w30wcf

[44man]

I pulled the setscrews from my Lyman molds and that is correct, the screw has the threads removed where the setscrew is. That makes it even more a mystery if the threads are boogered. Just can't happen under any normal circumstances. I can make the sprue plate scew too tight just with my fingers, no need for a screwdriver at all.
I can't wait to see what he finds.:confused:

[nicholst55]

I took the sprue plate off tonight when I got home from work; nothing is stripped. I experimented with different amounts of 'tight' on the screw, and found that the sprue plate is cocked slightly upwards at the front right edge (when viewed from the caster's position) when the screw is completely snug. I backed off on the screw just a bit and the sprue plate lays down flat on the top of the blocks. I installed a longer setscrew, and I'm going to try casting a bit with it like this to see how it works out.

I checked the sprue plate on a level surface, and it is not visibly bent or warped.

I'm confused. :confused:

[nicholst55]

I just finished casting a few boolits and experienced pretty much the same problem as last night. After the mold gets good and warm, the front cavity begins to cast a boolit with lead smeared from the base onto the top of the blocks - not really 'finned,' but with an extra bit of lead slightly larger than the boolit diameter. The sprue plate is cocked again, and adjusting the tightness of the screw doesn't seem to help.

I'm perplexed, because this mold throws some really nice boolits - it starts casting keepers almost immediately. Too bad that doesn't last.

I'll take some pix of the mold and the boolits tomorrow and post them, so you guys can see what's happening. I'd sure like to get this thing to where I can use it for more than five minutes at a time! :roll:

[44man]

Sprue plates are a pain. I make my own molds but even factory molds can have the problem of the front tipping up or even sideways. I mill my plates and the tops of the molds and still have it happen on a few. I had to leave the wave washer off some.
Some molds want the plate tight to lay flat and others need to be loose. This has driven me nuts for years and I think the plate needs a hold down in front to slide under. Someday I will work on this idea.
The main problem is the pivot way in the corner but nothing can be done about that.

[WHITETAIL]

nicholst55, If you want you could send it to me.
I think a trip to the mould hospital is in order.[smilie=6:

[nicholst55]

nicholst55, If you want you could send it to me.
I think a trip to the mould hospital is in order.[smilie=6:

Gee, Whitetail, what a guy you are! I think I'll keep this one and see what I can do with it. I'll bet I can figure out some way to make it useful... maybe as a trotline sinker, or something. :kidding:

[WHITETAIL]

:lovebooliOK, but I offered!

[higgins]

I had a mold I bought used that someone had used a split lock washer between the sprue plate and screw. It caused the sprue plate to be cocked and look like it was warped. If it has a lock washer in place, remove it until you can get the correct Belleville washer.

[Wayne Smith]

I had a mold I bought used that someone had used a split lock washer between the sprue plate and screw. It caused the sprue plate to be cocked and look like it was warped. If it has a lock washer in place, remove it until you can get the correct Belleville washer.

Ditto, exactly my thought.