12 of the diameter of the round steel can be M12 out of the thread is not
No problem。 M12 coarse thread of the pitch is 1.75, the outer circle to be processed to 11.8mm, the thread of the most beautiful shape. If the outer circle is too large, the tip of the tooth is too small and very easy to deform.
It depends on your material straight straight, generally should be right, you check the metric thread specification table, there is large size can be much, I think you are a little round a little better, so that you may get the car, do not appear to have a side material shortage phenomenon
