shrink fit - 303 stainless steel 0.375" square bar

[askjall]

i have two 0.375" 303 stainless steel square bars - they are overlapping (one bar is on top of the other at the ends). each bar has a 0.500" bored and reamed hole at its end where they are on top of each other - so the holes align. I am trying to shrink fit a 0.502" 303 ss solid shaft through the holes while the square bars are on top of each other and aligned. when i do this the bars move independently creating a shelf.

i heat the bars to 800 degree f. so i get the shaft in the first hole no problem, but because of the shelf created i can not get it into the second one.

does anyone have any suggestions? should i go smaller with my shaft from .502" to .501"? will this be strong enough?

Thank you

 

[CorBlimeyLimey]

??? How can you bore a .500" hole in .375" square stock?

 

[askjall]

sorry correction to above post.

the bar is .375 deep and .75 wide - they are not square bars.

is there a way to edit my original thread?

 

[btrueblood]

You should not double-post. Either delete the thread in the s.s. forum, or delete this one.

 

[CorBlimeyLimey]

Decide which thread to keep, and then use the Inappropriate post? If so, Red Flag it! link at the bottom-centre of your first post, to request removal of the other and a correction to the title.

Try inserting the shaft faster so that the bars don't have time to cool down or for the shaft heat up. Maybe try cooling the pin also, to create even more clearance.

 

[askjall]

what do you think the tolerance for the shrink fit should be with a .75" deep hole by 0.500" wide? should the shaft be 0.001" larger or 0.002" larger? i think the force being applied is roughly 1 ton.


i red flagged my other thread.

 

[Timelord]

Press pin into the bars seperately. A small counter bore in the first bar should fix your problem.

Timelord

 

[CorBlimeyLimey]

You ask, "should i go smaller with my shaft from .502" to .501"? will this be strong enough?", but we don't know what the application is, nor what forces the fit will be subjected to.

I imagine there will be some deformation at the thinnest (1/8") wall section, which could substantially reduce the 'gripping' force.

Having a decent lead-in chamfer on the shaft should help.

 

[askjall]

the force will be approx. 1 ton. the application is part of a frame for one of my tractors.