thermal expansion and contraction ?

[ACME]

hi,
please tell me how to insert brass bushing into connecting rod very ties tight? something like RC nitro engine connecting rod, see pic.


thanks

[rossmkly]

put it in the freezer for a few hours then press it in ... you can also use loctite ti make sure it stays put ... if you have too much press fit you can buy dry ice at a hard serve ice cream shop and use it to take the bushing down to 50f deg. below zero. you can also heat up the rod end in an oven to about 300 deg to give yourself some more room for the (shrink fit)

[ACME]

if connecting rod inner hole is 5mm, what is a best outer diameter for brass bushing?

yes, i need some tricks about how induction heating can be used for shrink fitting two pieces of metal(7075 and brass).


big thanks

[handlewanker]

Hey man, there is a limit to how much press you can achieve on a brass bush.
If you go by the rule of .001" per inch of diam, that is a normal press fit, you won't get a tighter fitting bush by squeezing it more.
The bush will just contract and close up the bore which will have to be reamed out to size which makes the press fit slacker.
If you expand the rod and shrink the bush to achieve .002" per inch of diameter then you will just close the bore down more and the bush will find it's own size by making the bore smaller.
Your biggest problem will be in measuring the bore of the rod and the OD of the bush to get correct sizes.
Ian.

[Rally]

10 X 5 Freeze with L. Nitrogen. If you set this bush. in a 10mm hole you could add .002" to o.d the i.d should then be machined aprox. .001" bigger than 5mm.

[tecnovist]

Hi be carfull what you heat it may up set the temper of the steel or partley anneal the part that couse cause failer---