I managed to get a longer rod albeit not silver steel(I have one on order but they are 12mm and not 0.5in which the bolt was). Anyway I got it to move a fair bit in that the bulb end is well up the way to getting out but again it has gone tight. So its back in the diesel for another soak. I have tried both directions of rotation as the bulb end had no sign of damage whatsoever and I would rather have it removed than stuck further in. Zoro seem to have parts for these expensive clamps so if I get the old one out I will check to see the price of a new bolt assembley. I wonder what thread it is!
All diesel is going to do is wick its way into badly corroded fixings and ideally lubricate them so that they move. Once the thread has started moving, diesel has done as much to help as it ever will. Chances are there is some physical damage to the thread most likely caused by over tightening. That could mean the thread is twisted, stretched or bent (or a combination thereof!).
Trouble is, you won't know which element of the fixing is the damaged one so winding it out might be doing more harm than good to the female thread.
Had it been me, I would have drilled the thing out by now...
PS what's happening with these smileys?? First my favourite thumbs up disappears, now my next favourite has gone all yellow. Where's the good old green smile gone??
Might just be a lump of weld splatter wedged in there.
If you have got it moving now then clamp the body in a vice, give it a good dosing of whatever penetration lube you have and try turning it in both directions.
Decide which way seems to go easier and commit to that direction and just use brute force to unscrew it.
Failing that, get it to me and I will chuck it in the forge for a couple of minutes..
So today I got the screw out! I found damage to the thread at the bulb end, about 1/3rd up. The lower thread is fine (the first 5)but on screwing it back in it is very tight. The female thread does not look too good. Anybody know what thread it is and size. I measured the female at 16mm at the crown. I think running a tap down and using a die on the pin might save it.
Contacted Carver about the tap size and got a quick reply. M20x2.5p. Good service. I have ordered one or should I say two as that was what the deal was. £27 pound and a bit.
So today I ran the taps down the female thread. First was a "first" tap and the second a full thread. Then tried the male screw in the female and found the fit is sloppy! I measured the outside diameter of the female and it came up with 17mm. I then measured the outside diameter of the male and it read 18.5mm! The damage to the thread on the male was not catastrophic and cleaned up ok so what are your thoughts please.
So I bit the bullet and ordered a new screw assembley. Got it today and alls good! So all in it cost £58 so pleased with that. Doubt I will ever use it. I find the Carvers are awkward to use but I suppose for large engineering they are ideal. What I fettle with is more car related so G clamps do me. So saying I have picked up a few Carvers at auctions!