High temp. thread locker

Does loctite make a thread locker that will endure the high temp. of a steam engine piston? I have a 5BA thread and nut holding the piston to the piston rod. Would a lock washer be better? Thanks, John.

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.

It all depends on

a) the pressure and superheat you are using (if any)

b) the materials of the piston, rod, and thread

c) the sizes

d) is the locked part in the steam or just nearby?

Or are we expected to guess?

Tim

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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

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I would have though the terms 'steam engine' and 'piston' were a good clue.

Nick

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

Loctite 272 is rated to 200°C

Higher rated products are available.

MichaelG.

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P.S. ... This may be of general interest.

Edited By Michael Gilligan on 11/02/2016 14:51:26

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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

No need to guess a & b

a, unlikely to excees 100psi and unlikely to be superheated

b, stainless 5BA threaded piston rod, brass nut

As John has already been asking aboyt Stuart Beam pistons you don't have to be telly Pathetic to work out what the piston rod in question is.

J

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

I would like to thank everyone for all of the generous and expert advice. You can't get this from reading a book.

I realize that I should be more specific in future posts to take better advantage of the professional knowledge that is out there. It will happen. Thanks again, John.

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