D bits revisited

[chucketn]

I need to make a 'D bit' to ream a bearing for a connecting rod. I purchased 1/4" O1 drill rod for this purpose. This is my first "D bit", as well as my first reamed hole.
I cut a 3" piece, chucked it in the lathe and faced the ends. Next, I placed the blank in my mill vise on a paralell and attempted to mill to 1/2 the diameter. I touched the mill cutter to the top, zeroed the Z axis DRO, and lowered the Z axis to .125, locked it, and milled the blank for approximately 1/2". The bearing is 1/4" thick brass. When I removed the blank from the mill vise it measures .118 on the "D" part. Is this going to work? How critical is this thickness to the accuracy of the reamed hole? Do I need to try again?

Chuck

[tel]

You might need to try again Chuck - 0.007" is a fair bit undersized. You need to try and hit about 0.001" over the size (0.126" in this case). Far better to sneak up on it than try and whiz it all off in one pass.

[chucketn]

Thanks, Tel. I figured that would be the case. Back to the shop...

Chuck