# Loctite 680 and its use in a press fit application?



## holmes_ca (Oct 7, 2020)

*Loctite is a plastic that fills gaps anywhere from .002-.015 and up, its application is that it expands as it dries, can someone explain why hobbyists and professionals alike use it on press-fitting two parts together under tonnage, surely that defeats the object, it's said it fills up all the faint irregularities in the fit, but surely the press-fit alone does that? for an exaggerated example, the pressing on Locomotive wheels onto axles, Loctite 680  is supposed to work with up to 0 .010 thou gap, 

Edmund...........Alberta*


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## chrsbrbnk (Oct 7, 2020)

I've put in a few thousand bushing using 620 that also is gap filling  with a press fit,  it just works really well


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## Brian Rupnow (Oct 7, 2020)

Locktite markets a product exactly for hard press applications.


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## mcostello (Oct 7, 2020)

I had a chain saw flywheel come loose and wallow out the tapered bore. I used regular grade Locktite and the repair lasted around 10 years until the saw was scrapped.


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## Charles Lamont (Oct 7, 2020)

It is a widely held myth that Loctite retaining compounds require a gap. Mostly, they don't.


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## holmes_ca (Oct 7, 2020)

chrsbrbnk said:


> I've put in a few thousand bushing using 620 that also is gap filling  with a press fit,  it just works really well


But how can you prove that its the loctite working as opposed to the press-fit? surely any loctite applied is squeezed out with the press-fit, yes?


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## holmes_ca (Oct 7, 2020)

Brian Rupnow said:


> Locktite markets a product exactly for hard press applications.


Brian, but I am quoting 620 and 680 specs for this type is a turning motion of the two components and slip fit it doesn't mention press-fit?


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## Asm109 (Oct 7, 2020)

The press fit does not crush out all the small surface asperities. There a still lots of very thin air gaps in a press fit.  Loctite fills them and increases holding strength.  Don't believe, make parts and test with and without.


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## Apprentice707 (Oct 8, 2020)

A close fit is the best starting point, but I always use 620 as a belt and braces. Just habit I guess.


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## Steamchick (Oct 8, 2020)

Hi All, Coming from a mass production factory where Loctite, 3M, Bostic, and many others supply assembly materials and chemicals, I have lived and worked with the "abuse" of language an consequential mis-understandings that can arise for decades. Hence my jaundiced views below:  
To pick-up on advantages of assembly with a fluid chemical bonding agent: There is also the situation where the Loctite liquid in an application acts as a lubricant during assembly, which may help some applications assemble "better", and if chemically cleaned will chemically adhere to the components being assembled, thus increasing the shear strength of the joint. 
N.B. LOCTITE is a Company name, not a product, as with many other Chemical companies... But we write with a Biro, clean carpets with a Hoover, but we don't light our rooms with a Swan or Edison....
As Loctite et al produce MANY products, as well as "Industrial adhesives": I read this thread as referring to Anaerobic Adhesives, and the title of product gives the game away. They are adhesives, when used correctly. Although they may only provide a few percent extra in the shear strength of some joints, in other joints you go from "zero" to "Something" - which is an infinite improvement if that's what you need. What these liquid products cannot do is correct alignment - as with taper-on-taper assemblies that are badly worn, or 10 thou gaps between wheels and axles. Precision Fitting is the proper Engineering (I mean that in it's truest definition of "problem solving") that should be adequate (because that's why the Engineer that designed it did it that way!). The use of "vibration resistant" and "gap filling" materials" can and does increase the strength of joints, and is used widely by Design Engineers to resolve such problems and make assembly easier and CHEAPER. But please don't confuse a 10 thou clearance bonded with sticky stuff with Engineering, as it is a bodge (However you spell it.). For "Bodge" read "A repair", which may have a long life if performed correctly, but is usually likely to fail after a short lifetime compared to the "proper" Engineered assembly. So if you pride yourselves in your machining and assembly work - and the resulting Models -  then you will use liquid adhesives etc. with the respect and caution in their intended applications, which mostly rely upon very precise dimensional control for their strength and durability, as do press fitting, silver soldering, friction welding, riveting, etc. and many other joining methods. 
Model Engineering designers may not always follow the "traditional" assembly method - particularly due to scale and strength not always being simple and linear - but anyone associated with making steam plant will be very aware of the laws for following assembly methods correctly where steam is used at pressure. But that does not mean that for other models we should not be responsible in our model making for considerations of Safety, as well as simple personal integrity that we have made "the best we can". 
So please use Anaerobic Adhesives wisely, carefully, and as intended for your assemblies.
Sorry to preach, but it seemed a bit appropriate here, although there are some very sensible comments already.
K


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## steve-de24 (Oct 8, 2020)

I think that Loctite 648 is the one to use for interference fits


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## tornitore45 (Oct 8, 2020)

FWIW    When the only practical method to lock a round part in a hole is Loctite I machine the male part for a slide tight fit and then reduce the diameter in the center portion to provide the necessary gap. The untouched shoulder guarantee the alignment and concentricity.    For model work a well made press fit has all the strength one needs. If the press fit is not enough to handle the torque, counting on a minimal gain from the adhesive seems irrational. Find a better design approach.   If one needs to fix something and Loctite is the most practical solution anything goes, just get her done.


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## davidyat (Oct 8, 2020)

*Beware of pessimists, they find a problem in every solution*


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## Badhippie (Oct 8, 2020)

Holmes 
If you are talking about a real locomotive axle and wheel combo. You can not use anything besides Castrol oil or actual wheel lube that’s made for pressing wheels on. This is per FRA and AAR rules anything else is not approved. But after writing this I have a feeling you are talking about small gauge stuff instead of the big boys. Lol wouldn’t be the first time my mouth over rode my ass
Tom


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## Badhippie (Oct 8, 2020)

Loctite even makes a wicking formula that is used after bolts and nuts are assembled and torqued. They also make a formula that is made for a slip fit and a formula that is for a press fit. A sleeve retainer and a bearing retaining formula. The only thing better then all this stuff is sliced bread. Lol lol lol


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## Howder1951 (Oct 8, 2020)

Read the instructions and specs, they do make a product for nearly every application, and I have seen some remarkable repairs done with anaerobic products that out perform the expectations. I have also seen failures when not done properly, but generally anaerobic is pretty good insurance on assemblies.


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## William May (Oct 8, 2020)

I have worked on aircraft for 44 years, and since I was a tadpole, Loctite products such as 635 and 680 have been an approved and REQUIRED item in assembly of nearly any aircraft part. Nearly all of them are press fit applications, such as the installation of uni-ball bearings in flap arm assemblies, bushings in forgings, etc.  If it is not a nut or a bolt with a cotter pin, when  you put it together, there is nearly always an engineering requirement for one grade of Loctite or another. It is in the manuals and on the blueprints.  The inspectors always checked to see what was required, and what had been used. 
I was shown early on that, even with a press fit, the addition of Loctite-type products gives a BIG increase in retaining friction, sometimes as much as 200% over the simple press fit.  It may sound like "snake-oil" but having used it for many years, I can attest to it's effectiveness. I have yet to see a Loctite-assembled press fit assembly ever come loose or wallow out.  The bearing assembly may be rough or even failed, but it stays where it is installed. until it is pressed out  so a new bearing bushing, or stud can be pressed in.


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## propclock (Oct 8, 2020)

Just my 1.414 cents worth. With .0625" wall thickness cast iron cylinders after being perfectly
bored and pressed in are no longer perfect and have to be honed back to size.
With a good slip fit and 680 no problem. Also some castings are not perfect,  and if you
have porosity that needs to be water/gas tight Loctite solved that problem also. 
Just IMO.


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## Steamchick (Oct 8, 2020)

Glad to know many of you professionals have had success with these products. That's the same as my experience.
But I was cautioning against use where the "consequences are not understood!" - or the designer intended a different assembly as suitable. (Designers and professional Engineers make their money by getting it right.... despite abuse from many quarters).
Hats-off in respect to Aircraft people - the best certified, disciplined and safe people in my experience. (As someone once told me, you can get a ladder up the side of a building, a ship usually won't sink, but when an aircraft goes wrong even prayers can't stop gravity from working while you fix it!).
Enjoy!
K


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## Badhippie (Oct 8, 2020)

The thing about aircraft techs are the reason they don’t have comebacks is because they don’t make it past the thud of hitting the ground. Now I only say that because it came from a aircraft tech of 35 + yrs that told me that joke. As for the loctite repairs I have personally on the professional side used about every formula they produce and always had great success with their products. As long as the proper cleaning procedures and the proper formula was used for the repair. The stuff really is as good as sliced bread when used within its own boundaries. I also own 3 Harleys so I think I might be a part owner in the loctite company 
Lol lol
Tom


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## Charles Lamont (Oct 8, 2020)

tornitore45 said:


> FWIW    When the only practical method to lock a round part in a hole is Loctite I machine the male part for a slide tight fit and then reduce the diameter in the center portion to provide the necessary gap. The untouched shoulder guarantee the alignment and concentricity.    For model work a well made press fit has all the strength one needs. If the press fit is not enough to handle the torque, counting on a minimal gain from the adhesive seems irrational. Find a better design approach.   If one needs to fix something and Loctite is the most practical solution anything goes, just get her done.


A push fit is fine for Loctite. Reducing the central portion to provide the 'necessary gap' is unlikely to be an improvement: a gap is not necessary, and you may well be weakening the joint.
The main reasons I often use Loctite instead of a press fit are because it is easier - the tolerances are wider, and I don't have to worry about dimensions (of a bush, say) being altered.


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## William May (Oct 8, 2020)

propclock said:


> Just my 1.414 cents worth. With .0625" wall thickness cast iron cylinders after being perfectly
> bored and pressed in are no longer perfect and have to be honed back to size.
> With a good slip fit and 680 no problem. Also some castings are not perfect,  and if you
> have porosity that needs to be water/gas tight Loctite solved that problem also.
> Just IMO.


Those are EXCELLENT points that I had not even considered, but are VERY important when talking about hobby machining, and small engines, whether they are steam or petroleum.)


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## chrsbrbnk (Oct 8, 2020)

holmes_ca said:


> But how can you prove that its the loctite working as opposed to the press-fit? surely any loctite applied is squeezed out with the press-fit, yes?


well after building hundreds and hundreds of  lamination plates  and trying out several methods of assembly  like just press fit , no loctite or loctite with a gap and different gaps   turns out the superior method was .0005 press  with loctite  applied to both hole and bushing and prepping with a light sand blasting  on the bushing  and really clean holes kept the bushings in the plate best


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## ICEpeter (Oct 8, 2020)

I understand that Loctite when used for retaining purposes in conjunction with different metals, other than steel,  like for bronce / brass / aluminum, etc.  has varying retaining characteristics / strenght depending on the metal combination. Typically lower of what the retaining strength for steel is as indicated on their application data sheet. What is the experience of forum members in this respect? 

Peter J.


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## Chiptosser (Oct 8, 2020)

No ferric, (iron based) metals are treated differently for activation.
Activator is needed for some applications and the application of heat.
This was communicated in a seminar presented by the manufacture of locktite retaining products, previous to Henkel purchase.
For retaining stainless steels aluminum and brasses, apply material to both surfaces, assemble and apply heat,  roughly, heat to around 150 degree F.
I used 660 for a retaining brass to SS, Alum. to SS, ect.   This is threads ,bore fits, Bearing retaining, lots of different appictions, up to .020 gaps.
The application of heat helps to excellerate the set-up with out loss of strength.


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## petertha (Oct 8, 2020)

I will volunteer some other Loctite comments/experiences, although kind of a tangent issue. Recently I volunteered to help a fellow who was restoring a vintage drill press. He had a fit issue where the bearing ID was 0.001-0.002" oversize the spindle shaft. And it was also a convoluted sequential assembly procedure to pre-assemble the bearings on the shaft which are spaced out about 12, then into the spindle cartridge, then anti-backlash nut...some other constraints. I had 0.001 & 0.002" brass shim stock & was using it mostly to size the gap & verify bearing fit. 

I had an idea to simply pre bond the shim stock to the arbor & then slid the bearings down over it. I was more concerned by the permanence of bonding. Both parts were given about 600g light sanding treatment & cleaned with acetone. Loctite 680 was applied, securely taped & left it overnight. Next day checked it over - if I lifted the end of the shim just slightly, it peeled off very easily. I had tried 2 flavors of retainer, I think 0.005" gap & 0.015". These worked excellent on my prior bonding but were completely 'failing here'. I suspected maybe brass shim stock is some other alloy? I tried some red & blue Loctite with/withou primer, same results.


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## petertha (Oct 8, 2020)

Then I tried what I had done before, bonding regular C360 brass to the end of a makeshift arbor, one steel, one aluminum, same variety of Loctite. I could turn it in the lathe & it was difficult to pop off even with a chisel. Usually this requires heat.


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## petertha (Oct 8, 2020)

Eventually I found some carbon steel shim & tried that with same Loctite's & also JB weld. JB actually held pretty good, I was able to turn the brass down until it was quite thin foil.


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## petertha (Oct 8, 2020)

So what is going on? Bearings can be very difficult & sometimes impossible to remove from shafts with the exact same Loctite even without interference fit. You can see on my tester pics the green film adhesive remnant is fully hardened & has to be filed or sanded off the steel.

Here is graph from #680 spec sheet, steel pins & collars at different controlled gaps. I interpret this to mean the annulus is 100% adhesive filled, no metal contact. The middle blue line of 0.25mm ~ 0.006" gap cures slower for sure. Only 75% strength is achieved after 24 hours vs say 90% strength for the black line 0.05mm = 0.002" gap over the same period.

Here is my opinion, maybe you have other thoughts. I think the 'peeling back' action of the shim is putting very high localized stress on the adhesive, because its basically a teeny pencil line width of equivalent area. Once it lifts up a bit (fails), it easily perpetuates along the joint. The joint stress is also mostly tension & adhesives are generally weaker in this mode vs. shear. I don't think its related to the material itself at all, but purely to this effect. 

Contrast that with a rigid bearing or collar. It could never never be peeled back like this which is why we don't see parts dropping off in real life. It needs to be pushed off axially, therefore the entire bonded surface area is resisting and doing so in shear mode not tensile, which is more favorable to the adhesive. And I think that also explains why my mandrel turning in the lathe didn't fail the glue. Its again acting more in shear & the parts are thicker so not easily allowing the peel up like shim stock. At least that's my armchair engineering notion. 

BTW I've used this same arbor technique with CA glue & it works quite well. Not my idea, saw it on YouTube (Clickspring).


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## petertha (Oct 8, 2020)

Some pics of the spindle assembly. Eventually all it too was some TLC & steel shim stock carefully put in (dry) & he has a very nice low runout classic machine.


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## Ken I (Oct 9, 2020)

FWIW - My tip for repairing an undersize (worn) press fit shaft is to clock it dead true in a four jaw, diamond knurl it, skim back to press fit diameter and assemble with Locktite.
The residual knurling grooves are filled / wicked by the locktite - works great.
Regards - Ken


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## ajoeiam (Oct 9, 2020)

William May said:


> I have worked on aircraft for 44 years, and since I was a tadpole, Loctite products such as 635 and 680 have been an approved and REQUIRED item in assembly of nearly any aircraft part. Nearly all of them are press fit applications, such as the installation of uni-ball bearings in flap arm assemblies, bushings in forgings, etc.  If it is not a nut or a bolt with a cotter pin, when  you put it together, there is nearly always an engineering requirement for one grade of Loctite or another. It is in the manuals and on the blueprints.  The inspectors always checked to see what was required, and what had been used.
> I was shown early on that, even with a press fit, the addition of Loctite-type products gives a BIG increase in retaining friction, sometimes as much as 200% over the simple press fit.  It may sound like "snake-oil" but having used it for many years, I can attest to it's effectiveness. I have yet to see a Loctite-assembled press fit assembly ever come loose or wallow out.  The bearing assembly may be rough or even failed, but it stays where it is installed. until it is pressed out  so a new bearing bushing, or stud can be pressed in.



Interesting reading!
Having been involved with some serious interference fits I'm a little confused. 
The fits we were doing were assembled with the internal part being cooled by dry ice and the exterior part was at 300 F. 
Just dunno how you would get that 'compound' to actually help. 
In fact I'd bet using a compound would likely hurt your assembly. 
Now if you're talking room temperature press fit then maybe but you can't press fit a 0.004" interference on a 2" shaft. 
If you do that without a serious delta T - - - well you just gall the crap out of everything which would mean that you're going to be making those parts again.


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## Steamchick (Oct 9, 2020)

Thanks Tom. There are plenty of jokes about various professonals. E.g. "a doctor buries his mistakes", or "a bad doctor has many undertaker friends...". Or - from a Civil Engineer friend - "what is the difference between a Builder and a Civil Engineer? The builder suckling his teeth when he tells you how many thousands it will cost. The Civil Engineer sends it in writing, so you can count the letters after his name to know how many zeros will be on the end of his bill!" - or something like that.
What's the difference between a fitter and an Engineer? The fitter will fix it with gaffer tape, the Engineer will use the gaffer tape to fix a notice on it saying "condemned".
Etc.....
Incidentally, I ride  Moto Guzzi... and don't need Loctite products to affix everything against vibration... But it used to blow the tail bulb frequently, when I rode it at anything over 6000 rpm... can't get the Loctite to fix that!
Ya pees ya money.... n teks  yer choice!


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## Steamchick (Oct 9, 2020)

I have to agree with you all. The correct application of the Designed fit of parts can sometimes include anaerobic adhesives - and sometimes not. I certainly would not knowingly risk my life in a car held together with an adhesive holding the wheel to the shaft/spindle unless that was the proven design. (So far, I have only experienced hubs held onto spindles using a precision taper fit and a very large nut, locked with a steel pin). But almost all cars use a lot of adhesives - especially holding the body together as it spreads the load better than spot welds - and I'm sure that there were well over a dozen different adhesive materials used in the car factory I worked in for 30-odd years...
Square pegs must be used in square holes....


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## len1042 (Oct 9, 2020)

All of the above is very useful and informative but keep in mind that the strength of "locktite" type of adhesives is dramatically effected by elevated temperatures. I am not sure of the limits, see the spec sheets, but I do know that you must apply heat to disassemble some slip joints. Do not heat that high as to effect the strength of the metal though.


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## Paul Gibeault (Oct 9, 2020)

As a high performance model airplane engine aficionado, I was wondering if say a slightly worn (less than a hard press fit) steel crankshaft ball bearing can be installed in an aluminum crankcase with Loctite red (stud & bearing mount) adhesive. Same with a lower connecting rod bronze bushing pressed into an aluminum rod. Obviously they can. My main concern here is I understand these Loctite's are forms or cyanoacrylate adhesives ( CA glue). I run my engines on fuels with up to 70% nitromethane. Nitromethane is debonder to CA glues. So I am querying anybody who uses nitromethane fuels. Would use of such fuel ( just nitromethane and synthetic oil) cause Loctite adhesives to eventually fail in these part applications??  Thank you.


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## SmithDoor (Oct 9, 2020)

A press fit I use light oil.
I know they a loctie that say will work for gap filling.
I had employees  machine  wheels and from time to time they would miss one. So try locktie filler it did not work. Wath work is DOM tube for mistakes. The locktie may work for 0.000,5" but any great just buy a bar of DOM tube and make sleeve.

Dave 




holmes_ca said:


> *Loctite is a plastic that fills gaps anywhere from .002-.015 and up, its application is that it expands as it dries, can someone explain why hobbyists and professionals alike use it on press-fitting two parts together under tonnage, surely that defeats the object, it's said it fills up all the faint irregularities in the fit, but surely the press-fit alone does that? for an exaggerated example, the pressing on Locomotive wheels onto axles, Loctite 680  is supposed to work with up to 0 .010 thou gap,
> 
> Edmund...........Alberta*





holmes_ca said:


> *Loctite is a plastic that fills gaps anywhere from .002-.015 and up, its application is that it expands as it dries, can someone explain why hobbyists and professionals alike use it on press-fitting two parts together under tonnage, surely that defeats the object, it's said it fills up all the faint irregularities in the fit, but surely the press-fit alone does that? for an exaggerated example, the pressing on Locomotive wheels onto axles, Loctite 680  is supposed to work with up to 0 .010 thou gap,
> 
> Edmund...........Alberta*


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## LorenOtto (Oct 9, 2020)

Well said!


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## holmes_ca (Oct 9, 2020)

Badhippie said:


> Holmes
> If you are talking about a real locomotive axle and wheel combo. You can not use anything besides Castrol oil or actual wheel lube that’s made for pressing wheels on. This is per FRA and AAR rules anything else is not approved. But after writing this I have a feeling you are talking about small gauge stuff instead of the big boys. Lol wouldn’t be the first time my mouth over rode my ass
> Tom


Tom, no I am talking real full size where the shaft has highs and lows and as it's pressed on the wheel, the highs roll into the lows giving filling the gaps giving a press-fit, or could it be a  cold shrink? not sure, I toured the shops of Canadian Pacific in Winnipeg in the 80s


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## holmes_ca (Oct 9, 2020)

I made contact with Loctite.com here is their reply, straight from the horse's mouth so to speak,

Walter, the optimum design to maximize the shear strength is a slip fit of approximately 0.002-0.004" for both products.  Also, you reduce the chance of shearing too much product off upon assembly since they're both higher viscosity formulations.  However, they have still been used for closer fitting parts including press-fit and shrink fit assemblies.  With a press fit, we would suggest applying it to both parts instead of what is typically one to compensate for what you may lose.  Ideally, though, thinner products like 609 or 648 work better for snug fits.  With a shrink fit, you heat or cool one part down and shrink the parts together.


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## SmithDoor (Oct 10, 2020)

The only place I use Loctite nuts and bolts where I do not want nut to come off do to vibration 

Dave 



LorenOtto said:


> Well said!


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## Badhippie (Oct 10, 2020)

I don’t think any of us here are saying loctite products is to be used on every application. But it does have applications where without it use the part or parts would have to be scraped. Or where you need that little bit of extra retention. Or to keep a bolt or nut from loosening up. I mean let’s face it if you use the standard of a press fit for a bore approx. .001-.0015 for every 1 inch diam. We all know that for a 8 inch diam you will need approx .008 of a press fit. The chances of that fit ever coming loose is probably never going to happen without being pressed back apart. So would you use a loctite product on this no you would not. Would you use it to fill in any voilds on this fit no you would not. Because if you just machined this ID and OD and you have voilds that need filled then you need to go back to basic machining 101 and try to learn something this time around. Would you use loctite as a assy lube for this type of standard fit? No you would not because it is not a high pressure lube that would be needed for this type of fit if you had to use lube. I guess what i am saying is. Don’t use it outside of its intended purpose. Everything in life has a purpose and when you go beyond that purpose you are pressing your luck. If you have a bearing to bore fit and have gaps of .001 or more then maybe you should look at machining a sleeve and installing it which depending on the thickness of the sleeve is a prefect place to use loctite on the sleeve install. Where I work we fit bearings all day long down to as little as .0002 out of round or tapper. We use a lot of ceramic bearings that are very very strict on the allowed deformation of the race’s. And any loctite added to aid in the bearing install or in the retention of these bearings would be a failure of the bearings in no time. 98% of our pumps, gear boxes, etc run 24/7-365 days a year. Which to give you a little perspective of what I am talking about we have approx 3000 pumps from 6 inch - 30 inch pumps. Approx 1700 gear boxes from small to omg we got to replace that today. Not to mention the Merco’s and Mercon’s and robatell’s and the other 2000 or more pieces of equipment that has bearings on the property. Hell we even take our new oil that we receive and filter it down to 3 microns before we use it. (Use it but don’t use it outside the intended purpose it’s made for)
Thanks Tom


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## Badhippie (Oct 10, 2020)

Holmes 
As I said before as per law you cannot use any product besides what I have listed to install a locomotive wheel on a axle to make a wheel axle assembly. This press fit must be graphed as it is pressed together with a min. Of 180 tons of pressure at the end of its seating. Also you are only allowed to have a certain amount of clearance’s for this fit. Without going into the 15 page work scope to install a wheel on a axle and without explaining the purpose of the graphing the press fit. I’ll tell you this the section the wheel is fitted to the axle requires 50 Micron or less finish on both the axle OD and the wheel ID. And where the brass support bearings ride on the axle that finish must be 7Micron or below. Oh by the way I was a Manager of Component Rebuild area of a major Locomotive builder for 10 yrs. which included Engine rebuild and wheel axle machine shop and truck rebuild and electrical rotating rebuild
Thanks 
Tom


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## Badhippie (Oct 10, 2020)

Holmes 
I was not bragging about what I used to do just giving a reference on how I know about wheel and Axles. We also rebuilt locomotives from the ground up and did a lot of work for CP and UP and BNSF along with other class 3 and class one and two railroads. Sorry if I came across as an ass 
Thanks 
Tom


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## Badhippie (Oct 10, 2020)

SteamChick
I am impressed Moto Guzzi is a name that is not heard much over here in the states. I went to college with a guy that was a true Moto Guzzi nut I believe he had 5 or 6 of them. And he loved them as much as I love my Harleys and you are correct you didn’t have to use loctite on them. And I’ll admit they seemed to be a well put together bike but I don’t know to much about them. 
thanks
Tom


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## holmes_ca (Oct 10, 2020)

Badhippie said:


> Holmes
> As I said before as per law you cannot use any product besides what I have listed to install a locomotive wheel on a axle to make a wheel axle assembly. This press fit must be graphed as it is pressed together with a min. Of 180 tons of pressure at the end of its seating. Also you are only allowed to have a certain amount of clearance’s for this fit. Without going into the 15 page work scope to install a wheel on a axle and without explaining the purpose of the graphing the press fit. I’ll tell you this the section the wheel is fitted to the axle requires 50 Micron or less finish on both the axle OD and the wheel ID. And where the brass support bearings ride on the axle that finish must be 7Micron or below. Oh by the way I was a Manager of Component Rebuild area of a major Locomotive builder for 10 yrs. which included Engine rebuild and wheel axle machine shop and truck rebuild and electrical rotating rebuild
> Thanks
> Tom


Tom, I'm old now and memory is not 100% anymore, my visit to CP was 40 + years now and the tour was amazing I have this vision of watching an axle being pressed onto a wheel I have this vague memory of the explanation given (reason) for the axles being machined with the high and low form and what took place during the assembly I remember they had a very large climate-controlled glass cubicle and inside was a big computer frame, your mention of some kind of  graph as the press was in progress rings a bell with me, it was very impressive, one of the other things that took my eye was a section with 4 very large shapers they were doing something with short sections of track and the chips on the floor were curled up and looked like a giant cinnamon bun the thickness of cut was at least 3/16 thick, 

Edmund...........Alberta


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## Badhippie (Oct 10, 2020)

holmes_ca said:


> Tom, I'm old now and memory is not 100% anymore, my visit to CP was 40 + years now and the tour was amazing I have this vision of watching an axle being pressed onto a wheel I have this vague memory of the explanation given (reason) for the axles being machined with the high and low form and what took place during the assembly I remember they had a very large climate-controlled glass cubicle and inside was a big computer frame, your mention of some kind of  graph as the press was in progress rings a bell with me, it was very impressive, one of the other things that took my eye was a section with 4 very large shapers they were doing something with short sections of track and the chips on the floor were curled up and looked like a giant cinnamon bun the thickness of cut was at least 3/16 thick,
> 
> Edmund...........Alberta


Holmes
You are very correct it is very impressive to watch this take place it’s even more impressive to watch wheels being pressed back off the axle. I have personally seen over 700 tons to press a wheel off and when they pop at that pressure and only move 1/4 inch and the press you are using jumps a foot off the ground and breaks all the mounting hardware. Now that’s impressive and to watch 4 middle age guys run myself included that was even more impressive. The normal pressure to remove a wheel is approx 250 - 400 tons. Our press was a 800 ton press and was a monster
Thanks 
Tom


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## John Antliff (Oct 10, 2020)

Yes, you need a gap!  I 680'ed my steam loco wheels and they worked fine for 8 years and then one of the wheels slipped!  I think that the firebox heat affected that wheel (it was the rear axle of a Mogul) and also it may have been penetrated by the all pervasive oil that always adorns the motions.   Loctite state that 680 is heat and oil "resistant" but in my case not resistant enough so I inserted 5mm keys to all the wheels and then used the loctiite!  Can't have the wheels falling off again!


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## William May (Oct 11, 2020)

ajoeiam said:


> Interesting reading!
> Having been involved with some serious interference fits I'm a little confused.
> The fits we were doing were assembled with the internal part being cooled by dry ice and the exterior part was at 300 F.
> Just dunno how you would get that 'compound' to actually help.
> ...


On the aircraft, when we were using dry-ice (-95 F) or liquid nitrogen  (-320 F) we did NOT use loctite at all.  For wheel bearing cups in forged aluminum wheels, it was just heat the wheel half to 200 F, chill the wheel bearing cup with liquid nitrogen and drop the cup into the cavity on the wheel half.  For strut axles, the same applied. Heat the strut tube, chill the axle, and then slide the axle in place. You had about 3 seconds before the axle would seize in the strut tube and could no longer be moved.  The axles had a through hole for a retaining bolt, and another hole at an odd angle for the anti-skid wiring that ran out the inside of the axle. These had to be precisely aligned, so normally one person handled sliding the axle into the strut tube, and a 2nd person slid in alignment pins to insure the bolt and wiring holes were correct.  Pressing forces were recorded when axles were pressed out of the struts, and if the forces exceeded 20 tons, both the axle and the strut tube were condemned and scrapped. There were no pressing forces on installation, as they were a slip fit for the 3 seconds.


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## f2dantonio (Oct 12, 2020)

Paul Gibeault said:


> As a high performance model airplane engine aficionado, I was wondering if say a slightly worn (less than a hard press fit) steel crankshaft ball bearing can be installed in an aluminum crankcase with Loctite red (stud & bearing mount) adhesive. Same with a lower connecting rod bronze bushing pressed into an aluminum rod. Obviously they can. My main concern here is I understand these Loctite's are forms or cyanoacrylate adhesives ( CA glue). I run my engines on fuels with up to 70% nitromethane. Nitromethane is debonder to CA glues. So I am querying anybody who uses nitromethane fuels. Would use of such fuel ( just nitromethane and synthetic oil) cause Loctite adhesives to eventually fail in these part applications??  Thank you.


Hi Paul,I tried to glue steel ballbearings on aluminium F2C engine case with Locktite ,it worked for short time,and saw after glue particles all over engine's interior,better to find who can make thin resistant coating,or in the bearing or in the case or both,regards Antonio.


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