What should be the allowance for press fitting?

[ukazak]

Thank you guys…,

I was expecting something on that nature like Pix Man said that would come. I thought of pointing out the problem would save all much time… I will do that next time.

But, I was hoping something like what Dave explained. I got the picture.

I had few times press fitted some parts on Engine projects.. each time I got lucky. Than again, working with soft materials I was.

This case is 4mm stainless shaft will go in brass crank disks. I drilled the center with 3.5mm. and thought I had somewhere around another drill bit between 3.5 to 4mm. but I cant find it. Now, I have all the other stuff fixed to the sizes I cant change. (ball bearing 4mm) so I need to enlarge the hole to a size that I can fasten to the shaft.





Someway I have to enlarge the center hole a bit more, but how?
Unal