Hi, I'm looking for advice on removing the outer worm from a dolls head gearbox end cover. So far I've tried bolting the spanner to the nut through the housing to stop the spanner slipping off and a very tight fitting socket and heat on the casing with no success. I have checked and confirmed that the thread is right handed. I'm reluctant to use more force for fear of damaging the worm as the worm works ok even though it is a bit worn. I do have a replacement worm assembly in good condition which I'd like to fit but but still don 't want to damage the original if possible. I have thought about drilling two holes in the front face and using a peg spanner but suspect the worm is in too tight for that. Any ideas out there please ? cheers Stuart
Corrosion ?
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Hi Richard, I have it…
Hi Richard, I have it soaking now in diesel. I plan to screw the cover to a block of wood to be able to hold it firmly in the vice and use heat when actually trying to free the worm, I have a six sided socket which is a tight fit and might even set up on my drill press to hold the socket down while trying to turn it. Ive had success before with diesel soaking and heat alternately so am hopefully. As you say the size of the nut limits how tight it can be.
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Agree…
A good soak in diesel should shift it. Heating should have broken down adhesion from gear oil. I don't think a peg spanner would hold in the brass too well. You may also consider a freezer spray on the brass on your next attempt. Plumbers or electronics suppliers should carry, in aerosol form.
I have had a few very reluctant to move and the hex is not well defined,or damaged by other attempts. A 6 sided socket on an impact hammer has worked in the past (not supported on the mating face but on a block of wood relieved to support the case around the nut).and screwed down to the bench.
Good luck!
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Soaking in diesel now and…
Soaking in diesel now and wood block and good tight fitting socket at the ready, thanks for your input.
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It shouldn't be all that tight. It can only have been tightened using the small hexagon. Has it become corroded ?
If you have the time to leave it, maybe best to soak it in a bath of diesel for a few weeks and try again ?