I use 648 where things are likely to get hot but it is more aretainer than locker so not quite so easy if you want to take things apart again, hopefullly you won't on a piston rod if you are skimming to size on te rod.

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c) 5BA thread [stated]

d) "holding the piston to the piston rod" [stated]

… tw down; two to go.

Edited By Michael Gilligan on 11/02/2016 14:34:26

Hi Tim

The answer to c) is 5BA as posted. Although a,b and d are relevant for a complete specification of the required product, John has asked if Loctite make a high temp thread locker.

Like Jason I use Loctite 648 which I believe is good to 180/200 C, perhaps a search would find something better.

Emgee

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When I made my James Coombes engine I made a very slight recess in the top of the piston rod with centre drill at the same time I was doing the treading.

On final assembly after the piston and its locking nut had been tightened I gave the recess a slight whack on a centre punch placed into it while the base of the piston rod was placed onto a firm base. – The idea being that this splayed the top of the threads ever so slightly to keep the nut and thus the piston becoming loose at some later stage.

Nick

I'm sorry, I did not realise that everyone is expected to know what a Stuart Beam is all about.

Or to have read all the other posts to know what had 'already' been happening.

Tim

from experience, Jason's 648 loctite, plus my own experience with same and 601 are perfectly ok for inside a cylinder in my case with superheat and radiant superheaters.

cheers,

julian