Loctite 680 and its use in a press fit application?

[SmithDoor]

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

Dave

Well said!

 

[Badhippie]

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

 

[Badhippie]

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

 

[Badhippie]

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

 

[Badhippie]

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

 

[holmes_ca]

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

 

[Badhippie]

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

 

[John Antliff]

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!

 

[William May]

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.

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.

 

[f2dantonio]

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.