Broken screw on B&M mould: Repair?

[georgerkahn]

Howdy -- I acquired a B&M 452286 mould and the stop-pin at top of mould is apparently sheared off -- flush with the mould top. I haven't used this mould yet, and I assume I can use it as is. BUT, the obsessive genes in me suggest perhaps I remove this sheared screw and replace it. However -- the reason for this post/inquiry -- is to hopefully get a few saged suggestions... "Use as is"? "Drill a wee hole in broken shaft and try an E-Z-out"? "Drill a smaller hole and drive in a roll pin"? ... ???

I have no idea which way to go... again, if any. From what I've read this mould dates back about 85 years and its cavities are almost perfect.

Again, I solicit, and appreciate, your thoughts.
geo

[Ben]

George,

I'd drill out ( with a drill press, not a hand drill ), the broken screw.

Turn a steel pin the appropriate length ( to rest in the bottom of the hole and protrude up above the sprue plate about 20 thousandths.

The pin should be turned the diameter of the hole that you've just drilled + .001" or .002 " and drive the pin into the hole. The dia. of the pin should be tight enough that it needs to be tapped into the hole and be tight. May take a bit of trial and error with the pin being spun in a hand drill using a flat file on it to reach the optimum diameter.

Problem solved.

[georgerkahn]

Thank you, "Ben" -- great suggestion... which I may try. My #1 fear is a difference in metal hardness of mould block and existing screw stub. E.g., if I'm not dead centre on broken piece, it may be too easy for drill bit to wander off. In addition to not being aesthetically pleasing, it would compromise its design. Perhaps if I take my best guess on dead-centre of stub and start with the teeniest (perhaps a number drill in the high 40's?) drill I dare use, drenched with lots of cutting oil, I can drill a starter hole... then progressively redrill larger diameters until I get to something approximating the broken screw's size. Then, if all goes well, I might break the drill (on purpose), and use the shank portion as my new pin. Maybe going one number smaller than the drill number, or, I could chance a drop of mixed J-D weld. I'll sleep on it... perhaps I WILL try this and get lucky. I had been dwelling on "unscrewing" the stub -- but your suggestion sounds better. No doubt a better solution. THANKS again! geo

[country gent]

If it is a screw working along the edge with a fine prick punch at an angle you can sometimes walk it out. Besure to tap work in the right direction so you dont tighten it. I small chiesl or point along the edge tapped lightly will walk a broken screw out. If its a pin then a thru hole drilled and the hole filled with grease the drill shank for a plunger and a few smrat taps with a hammer should hydrolically remove it. You can try the easy out but that small is very brittle. If you have a drill press or mill with reverse a left hand drill bit will remove it also.

[Ben]

Thank you, "Ben" -- great suggestion... which I may try. My #1 fear is a difference in metal hardness of mould block and existing screw stub. E.g., if I'm not dead centre on broken piece, it may be too easy for drill bit to wander off. In addition to not being aesthetically pleasing, it would compromise its design. Perhaps if I take my best guess on dead-centre of stub and start with the teeniest (perhaps a number drill in the high 40's?) drill I dare use, drenched with lots of cutting oil, I can drill a starter hole... then progressively redrill larger diameters until I get to something approximating the broken screw's size. Then, if all goes well, I might break the drill (on purpose), and use the shank portion as my new pin. Maybe going one number smaller than the drill number, or, I could chance a drop of mixed J-D weld. I'll sleep on it... perhaps I WILL try this and get lucky. I had been dwelling on "unscrewing" the stub -- but your suggestion sounds better. No doubt a better solution. THANKS again! geo

I've drilled out the core center of screws like yours , Once you've drilled out 90 % of the screw, you can often times walk them out easy with a small screw driver that fits into the hole you've just drilled.

I had a stubborn one once that didn't respond to the above :

I drilled the screw, it still didn't want to come out. I cleaned the hole, used the shank of the drill bit that I had just used to drill the hole. I cleaned the drill bit shank and the hole with brake cleaner. Put a few drops of J B Weld in the hole that I'd just drilled , lightly coated the drill bit shank with J B Weld also. I tapped it into the hole and walked away.

I let it sit for three days.

At the end of the 3 days, I grabbed the drill bit shank with vice grips and easily backed the broken screw out of the hole.