Drilling and tapping new Sprue plate screw

[unknownhavoc]

I just got a nice old Ideal SC 358429 off the eBay. The pictures made it look good, and I got it for a phenomenal price, so I'm not complaining. I actually got to cast with it or a little bit and it drops gorgeous boolits from drop one.

While casting I had noticed the base wasn't coming out 100% even, even after applying lube. I pulled the plate sprue plate off and noticed it was slightly bent, I put it in my bench wise and bent it back (safety jaws installed). When I went to put the plate back on, I noticed the screw wasn't catching maybe more than two threads.

It appears as though the original owner really buggered up the hole, and all but stripped out the threads.

So, I was thinking I could drill out the hole, tap it, and replace with a suitable screw.

Ideally I would really love to keep the original screw/hardware, but don't have a heli-coil set. So what size and TPI would anyone suggest for replacing the sprue plate screw?

[Ben]

They made 2 different lengths of screws.
Someone may have put a short screw into your mold ? ?

[beagle]

A helicoil would probably drift out under heat and vibration from my experiences with them./beagle

[Buckshot]

................Lyman uses a #10-32 thread for the screw, and you're undoubtedly aware it has a 1/4" shoulder for the SP to pivot on. I'd first try chasing the original threads with a bottoming tap. Failing that you can drill the hole on through into the handle slot and then re-tap. Cut the screw off so it doesn't interfere with the handles. You'll have to fab up a 1/4" OD ring for the screw to pass through to carry the SP.

You CAN d&t the hole to accept a 1/4" bolt. I'd suggest 1/4-28. You'd have to accept the SP rotating on the threads, or you 'may' be able to find a bolt with a short full OD shank of suitable length. Major negative of a 1/4" bolt is that the binder setscrew will only have 2-3 threads of engagement. You could also follow the Saeco method for the binder setscrew and drill all the way through the block half and then tap it.

...............Buckshot

[unknownhavoc]

................Lyman uses a #10-32 thread for the screw, and you're undoubtedly aware it has a 1/4" shoulder for the SP to pivot on. I'd first try chasing the original threads with a bottoming tap. Failing that you can drill the hole on through into the handle slot and then re-tap. Cut the screw off so it doesn't interfere with the handles. You'll have to fab up a 1/4" OD ring for the screw to pass through to carry the SP.

You CAN d&t the hole to accept a 1/4" bolt. I'd suggest 1/4-28. You'd have to accept the SP rotating on the threads, or you 'may' be able to find a bolt with a short full OD shank of suitable length. Major negative of a 1/4" bolt is that the binder setscrew will only have 2-3 threads of engagement. You could also follow the Saeco method for the binder setscrew and drill all the way through the block half and then tap it.

...............Buckshot

I've already chased the threads with a 10-32 tap. The problem is that the top of the hole is completely stripped out, with threads only near the bottom around where the binder set screw is. Without the split washer I can catch 3-4 threads, with the split washer I can get maybe one, and of course that won't hold.

I'm thinking I will first try a longer 10-32 screw to see if I might have the wrong piece. If that fails I'll drill and tap down to the handle slot, and rely on the threads in that area.

Thanks all for the help, especially you Buckshot. I will update when I get the work done.

[Catshooter]

The old small block Ideal moulds used a 10 x 36 thread, not 32.

Now that the hole has been chased with a 32 tap the original 36 threads have tried to combine with the new threads. A very weak thread set up.

If it were mine, I'd drill and tap all the way through the block with 10 x 36 and install a locking set screw in the lower half of the block. If I didn't have a 36 tap I'd do it with a 32.


Cat

[unknownhavoc]

The old small block Ideal moulds used a 10 x 36 thread, not 32.

Now that the hole has been chased with a 32 tap the original 36 threads have tried to combine with the new threads. A very weak thread set up.

If it were mine, I'd drill and tap all the way through the block with 10 x 36 and install a locking set screw in the lower half of the block. If I didn't have a 36 tap I'd do it with a 32.


Cat


You are correct that the original threads were 10-36, however the screw that came with it was a 10-32. I'm guessing this contributed to the stripping action. I had tried a 10-36 sprue plate screw I have from another Ideal SC, but it didn't bite either.

It goes to mention the split washer was not with the mold, and the screw provided was screwed all the way in, I'm guessing the previous owner had buggered up the original thread, tapped with a 10-32 and then got a replacement screw. When I pulled it off, that probably spelled soon for whatever poor condition threads were left.

Luckily it is salvageable, and will hopefully turn into a nice mold.