hole size for press fit steel pin into aluminum
hole size for press fit steel pin into aluminum
(OP)
Can someone provide a reference for the diametrical interference for a press fit steel pin into aluminum? I need to press a .125" diameter pin into an aluminum extrusion roughly 1/4". All references have an interference of no more than .001 between the hole & pin, but I believe that those values are for materials such as steel into steel.
I want to use standard drill sizes if possible, but the range between sizes is not that small. I was able to press this pin into a hole with .005" interference.
I want to use standard drill sizes if possible, but the range between sizes is not that small. I was able to press this pin into a hole with .005" interference.





RE: hole size for press fit steel pin into aluminum
You need to use an interference that suits your application based on what loads and temperatures your fit might see in service.
You can't just say 0.005" or 0.002" interference without knowing something about the application.
desertfox
RE: hole size for press fit steel pin into aluminum
Mike Halloran
Pembroke Pines, FL, USA
RE: hole size for press fit steel pin into aluminum
Ted
RE: hole size for press fit steel pin into aluminum
My application: These pins are pivots on which lightweight indicators are mounted. The pins are under no load. Temperature range is -100F to 1000F
RE: hole size for press fit steel pin into aluminum
Well I don't know any standard references for steel pins in aluminium, like I stated the first time, you design them around the service conditions, take for example the temperature range you have quoted for your pins, 100F to 1000F now thats 38 degrees to 538 degrees centigrade, now expansion of steel is about 12*10^-6 and aluminium about 23*10^-6 so a 3.175mm pin of steel would have a free expansion of:-
12*10^-6*3.175*(538-38)= 0.01905mm
but the alumium 23*10^-6*3.175*(538-38)= 0.0365125mm
so for your pin not to fall out at 538 degrees centrigrade or a 1000F, I calculate the hole in the aluminium would have to be machined to a diameter of 1.656mm at the point of manufacture and then shrink fit the steel pin of 3.175mm diameter into it. Sadly it doesn't look like its going to work.
What happened to the pins you pressed in with 0.005" interference?
desertfox
RE: hole size for press fit steel pin into aluminum
The difference in free expansion between the two metals is ~.018mm (.0007") at maximum temp. If I wanted an interference of at least .001" at all temperatures, why would I not drill the aluminum at least .0017" smaller than the minimum pin diameter of .124" ?
.124-.0017" = .1223" (3.106mm)
RE: hole size for press fit steel pin into aluminum
Mike Halloran
Pembroke Pines, FL, USA
RE: hole size for press fit steel pin into aluminum
Yes sorry my big mistake, had a senior moment then, I got into equal changes in diameter for a given temperature rise, but my point was you need to design your interference for your needs and that temperature rise shows my point.
RE: hole size for press fit steel pin into aluminum
RE: hole size for press fit steel pin into aluminum
Ted
RE: hole size for press fit steel pin into aluminum
RE: hole size for press fit steel pin into aluminum
RE: hole size for press fit steel pin into aluminum
RE: hole size for press fit steel pin into aluminum
http://www.driv-lok.com/groovedpins.asp#styles