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best lube for this press fit

S

slowmotion

Cast Iron
Joined
Mar 31, 2013
Location
Danville Virginia
Aluminum sub frame that needs these solid wall bushings pressed in. I was going to use liquid nitrogen (they shrink .010") but I measured the holes and they are .030" out of round. Wall thickness is about .250" so I'm sure (pretty sure, maybe, I hope!) they will conform when the bushings are pressed in. My question is the what would be the best lube for this?
DSC01781 (640x361).jpg
 
Need more info to give any kind of answer.

Need full dimensions of both parts, and materials. No lube needed if you are going to shrink them together. Thermal shrink plus press will not work on thin parts because once they are in contact, heat conduction will rapidly eliminate the temp difference.
 
If you chill the alum and heat the sleeve, then it will probably conform better, but you also run into the problem of they wont go together to well to begin with.

Sent from my SM-G960U using Tapatalk
 
Not sure of what exactly is going on here, but this info may help answer one of your questions. The od on small needle bearings is not perfectly round and becomes round as the bearing is pressed into the bore. The needle bearing will become lets assume as round as the bore it is pressed in as long as the press is done properly and the bore is sized properly for a good press.
 
magneticanomaly said:
Need more info to give any kind of answer.

Need full dimensions of both parts, and materials. No lube needed if you are going to shrink them together. Thermal shrink plus press will not work on thin parts because once they are in contact, heat conduction will rapidly eliminate the temp difference.
Click to expand...

Sorry, I don't know the bushing material, 6061 maybe? Aluminum at any rate. O.D. of 3.158", about 4" long with a 1" through hole. I've experienced the fast transfer of temp from one part to the other which is why I nixxed the nitrogen plan. I use it a lot but always a sleeve into a round and straight bore.
 
Booze Daily said:
How do you make a hole .030 out of round?
Click to expand...

sounds like automotive suspension parts . so " How do you make a hole .030 out of round? " big hammer . up now i see op reply a lot of this automotive stuff is just stamped out and it may have been sorta round when it was made and then they cram this thin wall bushing in there and it fits just like the bushings that go in upper and lower control arms . ya put some cam lub on it and cram it in there it will conform and it will be just like 99% of the shops would do it . you think that's fun install some split cam bearings
 
funny thing about that part is the hole in in that tube was never round to .001 to begin with and never will be the best it will ever be is when the bushing get pressed in and if its an oem part and its the same as what came out and goes in tight what more do you want. now if you want to mess around and go on a big ego trip you can make a mandrel that's undersized and try to iron the thing out but why if its that big a deal new will fix it but for the most part your just over thinking this thing it not going to the moon and if it comes out the other side of that tube blue it with some dykem and i would be vary surprised if there any on the bushing when it comes though just put some moly on it and press the dam thing in there hell loktite will work as a lub and it won't move after that . i have a pal that's an optical engineer he is a lot of fun to talk to he see every thing at a fringe how he ever dose any thing most of its just ego and ego don't pay the bills
 
Why do racecar guys etc?.....maybe cause they never got any money,and cant get any kind of engineering done cause they never pay their bills ......and get aggro when you tell them that......Just maybe.
 
I "fix" bores by shoving correctly sized ball bearings through them. Obround? Undersize? Galled? Not anymore it isn't. Makes a satisfying *kapoonk* when the press ejects it out the other side of the bore. Not for blind holes, obviously.

I have also made a loose fit into a press fit using sand, so take my advice with a grain of... sand.

For lubrication of things we want to stay put after we use soapy water, but my experience here is limited to shoving things into rubber. I have also used loctite 545 for something way back that didn't want to go together. Not because it's the right choice, but because I had some and it's slippery when wet and becomes very not slippery when dry. It's a thread sealant so the next guy has at least some chance to get it free again if need be.

If you hate yourself enough you can slop a press fit part into a loose hole and then weld around the outside of the part with the bore and it will shrink right up. I have all sorts of terrible solutions, if you need more.
 
I'll try this again. This subframe is out of a V8 BMW road race car that greatly benefits from replacing the standard steel/rubber bushings to solid ones. Nothing half ass here, serious customer who I normally just do engine machining for. I've installed thousands of sleeves/bearings/cam bearings so I'm not new to interference fits, but it's always been dissimilar metals where heating or cooling would help. I've just never had a combination like this where it's alum in alum. So if anyone has direct hands on experience with an application like this, I'd appreciate a recommendation. The moly cam lube suggestion might work, being a pressure lube to begin with.
 
No hands on with this much, but I’d go to the loctite site and look up their compounds for assembling aluminum fits like this. They seem to have a solution for almost every kind of assembly problem. With the right magic goo found, I’d consider a looser fit if that’s what is called for. The whole thing might get solved with a small $50 bottle of magic goo.

The other thing to consider is if the size of the factory steel and rubber bushing is what it is because it compresses to fit the hole. Your new bushing may not be as compressible as the factory part.
 
Slowmotion, I get that the sleeves are out of round but how do the small and large sleeve diameters compare to the bushing? That is another way of asking what the internal perimeter is of the sleeve vs the circumference of the OD of the bushing. If you measure the two conjugate diameters it is possible to make a good approximation of the perimeter of the ellipse. It is the difference in perimeter of the ellipse vs the circumference of the bushing that wil determine interference and how much thermal expansion of the sleeve is needed.

Perimeter of Ellipse

Denis
 
Oh, a part on an old Mitsubishi laser I used to work on was a press fit between aluminum parts. The inner parts was anodized, and it survived being pressed together and removed several times without issue.
 
dgfoster said:
Just out of curiosity, how did you keep the sand from being scrubbed off while making the assembly? I can see something like loose silicon-carbide grit being especially good for such an application.

Denis
Click to expand...

The bushing was a little greasy on the end so the sand stuck (fairly fine sand from a blaster) and I added a little bit around the edges every so often while pressing it. I don't know how much made it in there but it was certainly enough to not come out.
 
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