Stripped threads on Lyman 4-Cavity.

[fourarmed]

I was casting with my Lyman 4-cav. 410459 Sunday, when the sprue plate pivot screw came out. The screw threads are partially stripped, and the threads in the hole are completely gone for about 1/3 of the circumference and full-depth of the hole. The portion where the threads are gone is dark, so maybe it's been this way for a while.

I took off the lock washer and ground off the same thickness from the end of the screw. I put it back in and marked the setscrew position, then ground a good flat for it. It seems to be holding, and I am going to try casting with it tonight. This is only a temporary fix, though.

Is there a simple permanent fix for this? How is Lyman's customer service on these?
I read the thread on similar problems with the Lee 6-cav.

[454PB]

I think you will either have to drill and tap for the next larger size or install a helicoil. The set screw will be a problem with a helicoil, so I think I'd go the larger screw route.

[45 2.1]

The next larger thread size will tap easily. I use allen headed cap screws to do this.

[Newtire]

If you go the rethread route, try a "Time-Sert". You can just buy the insert and use a Heli-coil brand tap (same threads). To install it, you have to counterbore the hole to allow the "hat" to go flush. Install using a good hard bolt. Then you can just drill thru the side to allow the setscrew to fit. Chase out the threads and you are done. Puts Heli-coils to shame.

[MT Gianni]

I have a ly 4 cavity that I bought for cheap because it had a nonstandard, unknown size thread on the sprue plate screw. It turned out to be 1/4 x 20, one of the most common thread sizes anywhere. Gianni

[crabo]

I use the E-Z LOK carbon steel inserts. Your drill and tap to a larger size, then clean your threads and screw in an insert. There is an adhesive on the threads to hold it in place.

I have also used this to repair a 10/22 action hold down screw in the reciever that has been stripped out.


http://www1.mscdirect.com/CGI/NNSRIT?PMAKA=96310412

Crabo

[Newtire]

I use the E-Z LOK carbon steel inserts. Your drill and tap to a larger size, then clean your threads and screw in an insert. There is an adhesive on the threads to hold it in place.

I have also used this to repair a 10/22 action hold down screw in the reciever that has been stripped out.


http://www1.mscdirect.com/CGI/NNSRIT?PMAKA=96310412

Crabo

That looks like it might be easier. Do you need the tool kit to hold it in place while you insert the new bolt to expand it?

[crabo]

No, it is as simple as, drill, tap, clean, screw in insert, screw in new bolt. The insert has a slotted head for the screwdriver. A lot of the nut and bolt places carry the E-Z LOK.

[fourarmed]

Thanks for the replies, guys. My temporary fix was still holding after about 400 boolits last night.

If I understand you correctly, the advantage of the inserts is that it allows me to use the original screw or one like it. Is that right? How many sizes larger do you have to go to install the inserts? What is the advantage over tapping the hole to the next larger screw?

[crabo]

Tapping to the next size screw is the easiest way out. I was just showing the metal insert which I believe is superior to an aluminum insert. And I wanted to brag about the easy fix for a stripped out 10/22 hold down screw.