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So the title seems like an obvious duplicate or easy answer. But my question is actually a bit different.

I am trying to get a nut off the shaft of an engine. This is the "master" nut that secures the blower rotor to the engine shaft. It has a lot of (surface?) rust and it does not move. I have successfully managed to snap the almost 1 inch thick steel adapter for my impact in half trying to get it off. I used all sorts of penetrating oils, nothing helps.

I have been in a similar situation recently, I managed to unscrew it with a blow torch because I read in the manual that the nut in that machine was secured using thread lock and I assumed (knew) that heating it up to almost glowing hot would get rid of it.

This is where this question gets interesting. The nut is surrounded by non-removable plastic and that plastic is never further than 5mm away from the nut. So a blow torch is kind of out of the question. Here is a picture:

image of nut

Everything black is plastic. I cant use a blow torch, it will melt off the plastic... What are my options here?

chicks
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Yanick Salzmann
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4 Answers4

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You have not applied enough force in the correct direction. So, good fitting socket and a knuckle bar 18" is usually more than enough (that's the one I have and it either comes undone or breaks...)

But, if you don't succeed, then you can drill down the nut in the middle of the flat sides - choose two opposing ones. Make sure you drill accurately as you don't want to damage the reads on the shaft. Then split with a chisel.

This takes a bit more time but you removed the option of using heat.

Solar Mike
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Step one - are you positive this nut needs to be removed at all? If you can get into the motor from the other side, it may be easiest.

Can you source a replacement plastic fan? If so, the current one is disposable.

Another option might be to carefully cut the plastic in a circle, just outside the washer visible in your photo.

Then once you've removed the nut and done your business, secure the fan between two larger-diameter washers/straddle-plates and clamp with the nut. A good surface-toothing with sandpaper and plenty of quality 2-part epoxy should be enough to hold the fan to the washers, and the clamping action of the nut on the shaft to hold them all together at spinup/down.

We can't see what's on the other side of the nut either - it might have a positive interface with a drive key or pin in the shaft.

Criggie
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Kroil (a quality penetrating oil) and a breaker bar of adequate length (I have three different lengths and cheat with an extension pipe from time to time).

J D
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We can now get [buy!] an induction heater coil which can heat any conductive object e.g. that nut via an kinda transformer effect. https://www.youtube.com/watch?v=psk4wGBX8uI It is very localised, and might get you out of trouble. See also https://www.ebay.com.au/p/2273627200

BigPete
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