Bent threepence

[nealeffendi]

There is no crease but a gentle curve, had there been a crease I wouldn't even consider trying to level it

The crease comes after you apply pressure to straighten the Coin,i forget which side the crease forms on but i guess it varies depending on the curve and the amount of metal that has to reform and the pressure used.

I'll try it on a couple of bullion grade threepences to see if it is go or no-go to attempt to level. The curve is under 1mm.

[robbiegal]

maybe pop them in the oven first - just just after you've made a great pizza

warm metal moves better

then cool them in hot water

i used to watch the copper being smelted when I was a kid

piping hot metal
then poured into molds

then I think they were cooled in some sort of water

something like that

[Fulvio]

maybe pop them in the oven first

I don't think I've be keen to do that with silver. Sure, it won't melt, but still...

[trout]

Maybe it would be better if you could return the coin and wait until a decent problem free coin becomes available :angel:

[nealeffendi]

Maybe it would be better if you could return the coin and wait until a decent problem free coin becomes available :angel:

No, I knew it had a slight bend and I bid accordingly. Even if I don't attempt to unbend it it is still a nice coin for my "nice but not slab-able" Purple Penny folder.

[ausjack]

I wonder if you put it in between a couple of bits of cloth Neal and run a rolling pin over it, maybe a vice might be better though.

[nealeffendi]

I wonder if you put it in between a couple of bits of cloth Neal and run a rolling pin over it, maybe a vice might be better though.

I'm going to try a few different methods on a few bullion grade threepences. I think the first method I'll try is to sandwich a coin between 2 sheets of plastic and then put in a vice with multiple steps of tightening then loosening (to inspect for both good things like straightening and bad things like creasing, rim damage etc) and each time tighten just a bit more.

[JeffH]

And some pine offcuts either side to protect from the jaws?

[ausjack]

Yes you have to watch for marks from the jaws, even putting a bit of light weight sheet to cover them. Good luck with it Neal and please keep us informed on how it all goes :good:

[nealeffendi]

And some pine offcuts either side to protect from the jaws?

Something like that but perhaps hardwood so the coin doesn't just get buried in the wood. The plastic I'm thinking of either side of the coin is an ice cream container lid, thick enough to absorb the coins rims and details but not so thick that it prevents the force from the vice getting to the coin. So 2 thin bits of hardwood, 2 bits of plastic and 1 threepence in the sandwich (plus a vice to provide the force).

[ausjack]

Here ya go Neal, we used these sort at school and at tafe and they're cheap and easy, we used sheet tin. Hope it helps
https://www.youtube.com/watch?v=hSaAqlbO82U

[autocoupler]

Yeah, they're simple and work great. Believe it or not I've had the same pair of brass angle plate protectors since I was an apprentice, and still in use on my bench in the back shed today.

Getting back to straightening bent planchets, the problem with straightening a disc that exhibits a raised outer rim is that you can't apply equal or even pressure to all surfaces at the same time without a stepped tool that allows this to happen. So the logical solution is to turn up two stepped blank dies  in a lathe and use these to apply pressure to both sides of the planchet at the same time with the use of a press or vice.

Not everyone has access to the equipment necessary, so what if two short lengths of soft rod made from aluminium, each being a tad smaller in diameter than the inside rim, was used in conjunction with a vice to provide the same effect on the central planchet area. A thin disc of plastic cut to the same diameter and glued to each rod end (I'm thinking .020" styrene, available at any good hobby shop) would provide added protection to the surfaces.

Following on from this, it would be a pretty simple process to then apply pressure to the outer rim in a similar manner. Maybe then repeat the process a few times till satisfied.

When in doubt......just do it :yahoo:

[Basil]

Getting back to straightening bent planchets, the problem with straightening a disc that exhibits a raised outer rim is that you can't apply equal or even pressure to all surfaces at the same time without a stepped tool that allows this to happen.

Exactly,but even if you manage to do it small silver coins crease when force is applied to flatten it,or at least that's what i found.
As a kid i used dowling and then broom handles to flatten pennies(Tram tracks) enough to get them wedged between wood in a vice to complete the job.They were stuffed but capable of being spent in some cases.:grin:

[Nevol]

I think all the suggestions will result in a damaged coin. Best to leave it as is, so then, no regrets.

[ausjack]

Yes probably best to leave well enough alone.