Anaerobic Loctite on interrupted fit

[Martin DowingParticipant @martindowing58466]

I want to apply anaerobic Loctite before hot pressing of matching parts.

It will be medium drive H7s6 fit.

Does it make sense or it is pointless exercise because of lack of gap between parts and interrupted fit is good enough anyway?

Martin

[Martin DowingParticipant @martindowing58466]

[roy entwistleParticipant @royentwistle24699]

Depends what the parts are, what they are being used for. Not enough detail

Roy

[Michael GilliganParticipant @michaelgilligan61133]

Henkel would have you believe that it makes very good sense.

… I have no reason to disagree.

MichaelG.

.

There is a wealth of information on Henkel's site; but it can be difficult to find an answer to a specific question.

This page might get you headed in the right direction:

http://www.henkel-adhesives.co.uk/success-story-increasing-machinery-life-expectancy-8908.htm

 

Edited By Michael Gilligan on 09/12/2017 09:49:30

[Martin DowingParticipant @martindowing58466]

I need to fit adaptor ring into bore of a pulley to adapt it to another diameter of spindle.

Diameter of pulley is 6 inch. 1 1/4 inch bore has to be coverted into 19mm, eg motor spindle diameter.

Pulley is MS, adaptor ring is of cast iron.

Martin.

[JasonBModerator @jasonb]

Would also depend on how hot you get the part, could just boil the Loctite on contact which is likely to make it no use at all.

With all these queries about Loctite why do you not e-mail Henkle's tech departmant and get it from the horses mouth.

[Neil WyattModerator @neilwyatt]

the guides I've read suggest for maximum strength you shoudl make it a light interference fit and press it in cold using loctite.

If heat shrink for a fit you shouldn't need a retainer anyway – I would, say shrink fits and loctite are alternatives.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 09/12/2017 09:45:39:

the guides I've read suggest for maximum strength you shoudl make it a light interference fit and press it in cold using loctite.

If heat shrink for a fit you shouldn't need a retainer anyway – I would, say shrink fits and loctite are alternatives.

.

Here is their very generic guidance: **LINK**

http://www.henkel-adhesives.co.uk/retaining-how-to-apply-instructions-9640.htm

MichaelG.

.

[quote]

For Shrink Fitted Assemblies

• The adhesive should be coated onto the part to produce a smooth, even film of material. If heating the hub for assembly, coat the pin. If the pin is to be cooled for assembly, coat the hub. If both heating and cooling is to be done, apply material to cooled part. Avoid condensation on cooled parts [/quote]

[Neil WyattModerator @neilwyatt]

Wow, well spotted Michael.

Still it completely debunks the 'leave a gap for the adhesive' myth.

Neil

[not done it yetParticipant @notdoneityet]

I would not do it that way. I would insert the bush by shrink fitting and make a drilling (with a milling cutter) and insert a matching pin, secured with loctite. Two pins, if you must, would take little longer to do.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 09/12/2017 10:08:07:

Wow, well spotted Michael.

Still it completely debunks the 'leave a gap for the adhesive' myth.

Neil

 

… Well not completely, Neil

If you delve into the matter of surface finish, you will find that highly polished surfaces are advised against.

There does need to be a gap for the adhesive … but it's much smaller than we were originally advised.

MichaelG.

.

See this 'Design Guide' 

http://na.henkel-adhesives.com/us/content_data/356776_9294_LT5021_Retaining_Brochure_F.pdf

Edited By Michael Gilligan on 09/12/2017 10:52:41

[Michael GilliganParticipant @michaelgilligan61133]

My guess is that the best for Martin's job would be Loctite 648 **LINK**

http://tds.henkel.com/tds5/Studio/ShowPDF/648-EN?pid=648&format=MTR&subformat=REAC&language=EN&plant=WERCS

… it seems to 'tick all the boxes'

MichaelG.

[John HaineParticipant @johnhaine32865]

Martin, back around late 2013 I asked for help here on fitting just such a bush into a pulley to fit the 3ph motor I was fitting to my VMB. The pulley is CI, I made the adapter of BMS. I made the adapter a light push fit; cleaned the CI pulley bore well, applied loctite, and quickly pulled the bush into the pulley using a long bolt driving a socket with my electric drill. It has been running now for 3 years with no sign of any problems.

[Ian S CParticipant @iansc]

Needed a sprocket on a piece of agricultural machinery, it required a keyway in it, and at the time had no means of broaching one, so bored the sprocket out to shaft size plus 2x the key depth. Then made a bush, a push fit in the bore, and cut a slot to key width, then using a high strength retainer(can;t remember the number. Next day assembled the sprocket on the machine, and sent it out of the shop. After around ten years its still going strong.

Ian S C

[JasonBModerator @jasonb]

648 is what I use for press fits and most other things too, mainly as I have a 50mls bottle of it that should last a long time. That's twice we have agreed on something in less than 24hrs Michael, is it a leap year?

[Martin DowingParticipant @martindowing58466]

Many thanks for commets of all of you. They are very helpful.

Regarding Loctite.

My on duty version is 638, not 648 but by technical data chart these are very comparable.

http://tds.loctite.com/tds5/Studio/ShowPDF/638-EN?pid=638&format=MTR&subformat=REAC&language=EN&plant=WERCSHi

@not done it yet.

That is probably most secure fitting discussed in this context. Perhaps will go for it. Maybe it is overkill but seems foolproof.

Martin

Martin

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Martin Dowing on 09/12/2017 13:39:31:

Regarding Loctite.

My on duty version is 638, not 648 but by technical data chart these are very comparable.

.

Likewise, Martin … but I mentioned 648 specifically after Jason's comment about heat.

If I ever run out of 638, I might invest in some 648 simply because it appears to expand the 'envelope' of usefulness.

MichaelG.

.

P.S. … I would happily use the Loctite as described, in preference to the more laborious method described by 'not done it yet' but I'm sure either would work.

[Neil WyattModerator @neilwyatt]

Posted by Michael Gilligan on 09/12/2017 10:23:26:

There does need to be a gap for the adhesive … but it's much smaller than we were originally advised.

I would distinguish between surface finish and a dimensional gap. From my henkel joint design guide.

"The best performance for slip fits is achieved using
clearances between 0.025 mm and 0.075 mm
(0.001 in. and 0.003 in.), or with interference fits.
Performance is reduced as the clearance is increased."

The same document claims a typical interference fit has 30% metal to metal contact which Loctitite brings (close to I assume) 100%.

Neil

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 09/12/2017 16:26:09:

Posted by Michael Gilligan on 09/12/2017 10:23:26:

There does need to be a gap for the adhesive … but it's much smaller than we were originally advised.

I would distinguish between surface finish and a dimensional gap.

.

Feel free, Neil … but we're rapidly descending into semantics.

I know what I mean, and presumably you know what you mean.

There does need to be a gap for the adhesive, but the locking action is at a microscopic level; and imperfections in the surface finish provide a multitude of said microscopic gaps.

MichaelG.

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The gap-filling of an interference fit is illustrated on page 5 of the document I linked earlier:

http://na.henkel-adhesives.com/us/content_data/356776_9294_LT5021_Retaining_Brochure_F.pdf

Edited By Michael Gilligan on 09/12/2017 17:22:15

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