Need some help with a busted mold

[asmith80]

So I was tightening down the sprue plate hinge screw on my MP mold and I must've not been playing close enough attention to what I was doing and snapped the screw off. I'm so mad at myself for such a stupid thing.

Does anybody have any solutions to getting the stub of the screw out and replacing it, or anywhere I can send it to get it fixed?

https://i.ibb.co/kgscvB6/20200824-153059.jpg (https://ibb.co/PZvC0jz)

[farmbif]

center punch and left hand cobalt drill bit.

[bangerjim]

Use a Screw Extractor. Center punch, drill appropriate hole, and the extractor will do the rest. I do not know if they used case-hardened screws or REAL hardened screws. If fully hardened, you may need a carbide twist drill to make that hole. Standard alloy, cobalt, or TiN coated drills will not cut it.

If you do not have access to those kind of tools like I do, you may need to seek the help of a qualified local machine shop.

banger

[Scrounge]

Clock and watch repairmen use alum to remove small broken steel screws. Might work for you. You can find it in the canning and spice sections of the grocery store, among other places.

[rancher1913]

you did loosen the side set screw correct.

[farmbif]

something new to me. how do you use alum to remove screws.
ive only ever drilled em out, used ez out or just keep drilling and use heli-coil or else welded a nut on and wrenched em out.

[Conditor22]

WARRIOR
Screw Extractor And Left-Hand Drill Bit Combo Set, 10 Pc.
https://www.harborfreight.com/screw-extractor-and-left-hand-drill-bit-combo-set-10-pc-61981.html

[asmith80]

you did loosen the side set screw correct.

I did, but MP molds have a screw I've never seen anywhere else. Its got a collar at the top near the head and it looks like the hole in the block was counter sunk so that it could only go so far before meeting resistance. It looks like the screw snapped right below the collar where the threads started

[asmith80]

Thanks for all the replies, guys. I've got a screw extraction kit and some left hand cobalt bits coming, so we'll see how that goes.

[country gent]

Those bolts can be very hard. I have pivked them out in the past.
first make sure any set screws are loosened even better is to remove and work some penetrating oil in, let work for some time

a small hardened rod. grind a small chisel tip on one end 1/8" or so dia. You want this sharp and fine. close to the edge thru center drive an line as deep as you can use a light hammer and work slow and easy.

Once you get a nice line insert the end and try turning out like a screwdriver bit. If this dosnt work angle and tap around turning with the tapping.

With the head and shoulder off the threads should be under no tension and turn freely.

[Scrounge]

something new to me. how do you use alum to remove screws.
ive only ever drilled em out, used ez out or just keep drilling and use heli-coil or else welded a nut on and wrenched em out.

Dissolve it in water, put the part in that has the broken screw, and wait for it do dissolve the screw. Works for broken taps and drills, too. Can speed it up a bit by heating the solution. https://hackaday.com/2015/08/03/dissolve-steel-drill-bits-in-alum-from-the-grocery/

Note that it doesn't work for steel in steel.

[country gent]

Another old trick is center it and drill 1/8-3/16 hole in it then coat shank og the drill with super glue and insert then when cured back out

[ABJ]

Another neat trick I just learned is, use a Dremel diamond hone, pointed, to get the hole centered and started before drilling the pilot hole. The last one I had to do broke at an angle and I couldn't keep the drill bit from walking off center and it was too far into the hole for a center punch.
It didn't help that it was a #10, not much to work with. Yours looks pretty level so the center punch will probably work.
Tony

[gwpercle]

Clock and watch repairmen use alum to remove small broken steel screws. Might work for you. You can find it in the canning and spice sections of the grocery store, among other places.

Some one has been pulling your leg ... alum is not going to dissolve any broken metal screw .
The reason I don't watch U-Tube is too much fake stuff .
You can't believe evrything posted on the net ...they lie .
Gary

[bangerjim]

Some one has been pulling your leg ... alum is not going to dissolve any broken metal screw .
The reason I don't watch U-Tube is too much fake stuff .
You can't believe evrything posted on the net ...they lie .
Gary

Sorry but it DOES dissolve steel! I belong to the NAWCC (National Association of Watch & Clock Collectors) and here is a thread from their official site, not some whack-o on YouTube:

https://mb.nawcc.org/threads/use-of-alum-to-dissolve-screws.61683/

Just do a net search for "dissolving steel with alum" and read until your heart's content.


Also:

https://hackaday.com/2015/08/03/dissolve-steel-drill-bits-in-alum-from-the-grocery/

Many questions asked on this forum are easily answered just by a simple net search....but I rarely believe YouTube crack-pots. They just like to hear themselves talk. If it is a video posted from a reliable company, that is totally different.

bangerjim

[kevin c]

Once you get the end of the bolt out, let us know if you found a replacement with metric threads. I emailed Miha for replacements, but never heard back.

[DHDeal]

As far as the set screw is concerned, if you really tighten it up, it can flatten a thread or two of the sprue plate retaining bolt. That'll make the bolt somewhat harder to remove. Next time either drop a small piece of 12/2 copper wire in the set screw hole and then install the set screw. Copper will mold itself to the threads, hold the set, and not bugger the sprue plate bolt.

With all but two of my MP Molds I've modified to use a front hold down bolt (think Accurate Molds style) and I can run the sprue plate pretty loose and have also bought brass tipped set screws from McMaster-Carr.

OP, I don't know if you've noticed yet, but the MP Molds have a sleeve that slides onto the bolt. By your description you are either saying this or you're saying that the bolt is a collared bolt. The sleeve can act like it's stuck and will actually appear to be part of the bolt. Maybe those multi gang molds are use different bolts.

I can't help any more than the experienced guys above with getting the mess fixed, but when you do get the bolt out, try using the copper wire trick so you don't bigger up that nice aluminum mold (or brass as the case may be).

[gwpercle]

A simple Alum solution isn't going to dissolve that hardened bolt , stuck in the aluminum mould blocks without damaging the aluminum blocks .

[asmith80]

As far as the set screw is concerned, if you really tighten it up, it can flatten a thread or two of the sprue plate retaining bolt. That'll make the bolt somewhat harder to remove. Next time either drop a small piece of 12/2 copper wire in the set screw hole and then install the set screw. Copper will mold itself to the threads, hold the set, and not bugger the sprue plate bolt.

With all but two of my MP Molds I've modified to use a front hold down bolt (think Accurate Molds style) and I can run the sprue plate pretty loose and have also bought brass tipped set screws from McMaster-Carr.

OP, I don't know if you've noticed yet, but the MP Molds have a sleeve that slides onto the bolt. By your description you are either saying this or you're saying that the bolt is a collared bolt. The sleeve can act like it's stuck and will actually appear to be part of the bolt. Maybe those multi gang molds are use different bolts.

I can't help any more than the experienced guys above with getting the mess fixed, but when you do get the bolt out, try using the copper wire trick so you don't bigger up that nice aluminum mold (or brass as the case may be).

It looks like its the same type of bolt that's on my 4 cav MP molds. It does have a sleeve, i just wasn't sure how best to describe it

https://i.ibb.co/GxZXjm3/20200826-155609.jpg (https://ibb.co/smThr7J)

My screw extractor kit got here today and I managed the get the bolt stub out with no issues and no damage to the aluminum threads. Now I'm in the same boat as Kevin C, I have no idea where I'm going to get a replacement, especially one with a sleeve like this. Maybe I can just use a bolt from one of my other MP molds and swap back and forth, but that seems like too much work

[Winger Ed.]

Maybe I can just use a bolt from one of my other MP molds and swap back and forth,

Could ya get a longer screw/bolt, run it into the hole, back it out a little, and put two nuts jammed together on top,
and trim off the excess sticking out?

Or get a longer screw/bolt, and just trim it to fit?

[asmith80]

Don't see why not, that doesn't seem too difficult and I wouldn't have as hard a time finding a replacement

[FLINTNFIRE]

Contact mihec and see if he has any , He does list some spare parts , take a look and see what he has and contact if it is just the screw , he sent me some mold handle screws when I broke one , he may take a little while to reply .

[Big "D"]

The fastener in question is a shoulder screw/bolt. Check with McMaster Carr, Grainger or other industrial fastener suppliers. I say this as I assume it is a metric thread.

[asmith80]

I'm thinking its metric, too. Found a handy guide at the boltdepot.com that let me measure a couple places on the bolt I have to figure out what I need. It's got an Allen head instead of a hex head, but the sleeve and thread pitch should be right

Metric shoulder bolts (imported), Allen, Class 12.9 alloy steel black oxide finish, 8mm shoulder (6mm x 1.0 thread) x 16mm

I ordered a few so we'll see if they fit when they get here

[asmith80]

Well, That's not going to work

https://i.ibb.co/6Zr05hW/20200831-135101.jpg (https://ibb.co/mBb57sc)

At least I know it's a 6mm thread, so worse comes to worse I'll just get a 6mm bolt from the big box store and some nuts and jury rig my own

[kenton]

Could you pick one from here?
https://www.mcmaster.com/screws/thread-size~m6/shoulder-screws/

I would look at removing the collar from the broke off screw and using a 10.9 or 12.9 grade M6 screw from the local hardware store.

Also another trick if the broke screw is just proud of the surface but you can't grab it with pliers is to use a cut off wheel to make a screw driver slot in the broken screw.

[asmith80]

haha, I just went through McMaster. I think I found it. Everything else about the first one was good except the shoulder length, so I just remeasured it and realized I needed a 6mm shoulder length, not a 16mm like I bought. Just put in for the right size a second ago

So if I'm right, MP uses a bolt with 8mm shoulder diameter, 6mm x 1.0 thread, 6mm shoulder length

It's stuff like this that make me realize why I never became an engineer

[kenton]

If you are measuring with inch calipers the sprue plate should measure .236" for a 6mm thickness. 8mm would be .315"

[asmith80]

Much better

https://i.ibb.co/qgGzhbk/20200901-141135.jpg (https://ibb.co/dp9SXnG)

McMaster Carr has some crazy fast shipping. I ordered these bolts at 2pm yesterday, standard ground, and they got here today. Granted, it's only going from NJ to MD, but that's fast for standard shipping.

I think if you wanted a little more adjustment room to get the tension of the sprue plate just where you want it, a 4mm long shoulder length may be even better. As it is, it's exactly as MP molds had it set up when I got it in the mail, and if I want to adjust any tighter I can always put a washer between the bolt and the sprue plate and give me some room.

[DHDeal]

You probably don't need it tighter, though I like mine to not flop around. It's a Goldilocks thing for me, but I don't stress over it too much.

Drop a tiny piece of copper wire in the locking screw as it'll keep the new sprue plate screw from getting buggered up. Over some short period of time the copper will mold itself to the threads but the 2 hardened screws won't touch. At worst it won't hurt anything and at best you'll not flatten any threads.

I have an account at McMaster-Carr and agree that the only way you can get it quicker is if the local hardware actually has what you need and you have the time available to go uptown to get it. McMaster-Carr may not have everything, but I've always been able to find even the weird stuff there.