Locktite

[Garry ColesParticipant @garrycoles69390]

Good morning all. I'm going to be fabricating the crankshaft for my 2in D & NY traction engine and was wondering which loctite to use. I've got 290 and 603 on the shelf, but is there a better one for this job. Also if you say to use another number what sort of fit should the parts be for that number.

Thanks Garry

[Garry ColesParticipant @garrycoles69390]

[Michael GilliganParticipant @michaelgilligan61133]

My first choice would probably be Loctite 638
Note there is no ‘k’ in the brand-name

Copious information on this and other Loctite versions is available on the Henkel website.

MichaelG.

[Garry ColesParticipant @garrycoles69390]

Thanks for that, That's the number I was thinking about using, I just wanted confirmation.

[bernard towersParticipant @bernardtowers37738]

If you make your crankshaft a built up version even if you use loctite I would definitely pin it as well which would help if the loctite  was ever to breakdown over time. I machined mine from solid and it’s not too difficult the worst bit is the hacksawing ( no bandsaw)

Edited By bernard towers on 24/08/2020 10:11:40

Edited By bernard towers on 24/08/2020 10:12:09

[JasonBModerator @jasonb]

Although I do loctite some of my smaller crankshafts (with 648) I would never be happy with that method on an engine of that size. Either cut from solid if a casting is not available or silversolder and pin as a lesser option. You don't need to do much sawing if you stitch drill out the waste.

 

Edited By JasonB on 24/08/2020 10:18:52

[derek hall 1Participant @derekhall1]

Hi Jason,

How do you deal with the locked in stress after chain drilling out the crankshaft out of a piece of mild steel?

There are solutions such as use black hot rolled steel or normalise it, but just wondered if you have had issues in this area and if so what do you do to overcome it? I suppose a lot depends on the thickness of material and the size of the cut outs…

Regards

Derek

[Howard LewisParticipant @howardlewis46836]

My guess would be that any distortions from locked in stresses in rolled bar would be out and accommodated by the time that all the turning has been done.

Hopefully, the distortions will be less than the depth of metal that you remove to reach finished size.

Anyone who has had experience of this, like to comment?

Howard

[JasonBModerator @jasonb]

Ideally avoid using bright bar and if you have to use it then leave plenty of material so that when it moves you can still get the part out of what is left.

That one was cut from some unknown steel flame cut from 2" thick material that was cleaned up first.

On that one I could actually see the two ends curling away from me as I drilled the series of holes, the two ends had probably moved a 1/32" to 1mm by the time they were all drilled.

Ideally start with black ( hot rolled) bar which does not seem to move much, this was 50 x 25 stock that was pickled to remove the mill scale first.

In all cases I like to leave them for a couple of weeks after the stitch drilling to settle before roughing out and will then leave for another week or so before finish machining, this is the one above and some of the remaining length of bar.

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