help extracting shaft from connecting boss

[lumphammer]

I have taken out the stainless shaft, which I had to do by cutting the shaft. I know have a small stainless stub sticking out of the boss that connects the shaft to the engine. The boss is about 4in long with a keyway machined to lack the shaft in place. Two allen bolts have been removed.

I have tried removing shaft by sitting shaft in a piece of scaffold pole so that boss sits on edge of pole, a small drift is placed on top of the other end of the shaft so that in theory I should be able to know the shaft into the scaffold pole. Lots of heat has been applied, then I hit the drift with a big sledge hammer!

No movement at all on the shaft!!

Any other suggestions as to how I might free this up?

TIA

Richard

 

[alb40]

A bigger hammer!

If its still stuck, you may need to heat it up hotter, and use some penetrating fluid if theres any corrosion between the two components.

You may have more luck with some kind of puller to pull the flange off. Be careful though, they can ping off with amazing velocity!

 

[cliff]

Put the boss (not the flange) on an anvil so as you can roll it along the surface of the anvil and as you roll it slowny along the surface of the anvil hammer on the top of the boss with a 4lb club hammer or engineers hammer. This should shock the shaft loose. Be careful if it is a cast iron boss as you might break it.

Are you sure there is nothing else holding the shaft?

You said you applied a lot of heat. Did you use an oxy-propane or oxy-acetylene torch? You need to apply lots of heat very quickly to one side of the boss to get it to expand before the heat reaches the shaft. If you tried an ordinary DIY gas torch you will not put in enough heat fast enough and as the boss heats up so does the shaft and being stainless steel the shaft has a greater coefficient of expansion so tries to expand more than the boss and so grips even tighter onto the boss than it did when it was cold.

Plan "B", take it down to your local engineering works or garage and ask them to press it out in a hydraulic press.

Or if you have a big puller fit that, tighten it up as tight as you can then hit the end of the central tensioning bolt as hard as you can to "shock" the assembly (used to have to use that trick to remove flywheels from mini engines).

Please do check there is nothing else holding the shaft in place though.
--------------------

"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>