This may be a simplistic question but then I'm pretty simple...
My thread chart gives the OD of threads, e.g. .250 for 1/4-20 and .312 for 5/16-24.
Is it safe to assume that the OD given is the size of a rod one would use for that size thread. Is there a rod diameter equivalent to the
75% or 100% tap drill size?
Full thread form for a given thread would be given by the nominal size, ie 0.250 for a 1/4-20 thread. But like tapping the amount of force require to drive a die onto a nominal size piece of stock is really really high. It helps to reduce the OD a bit to give the die an easier time.
If you can, it also helps to turn a section of the stock down to nearly the minor thread diamter to help the die to go on square - if the extra part can be trimmed off later.
Jim
================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ==================================================
Yes.
Probably. You could probably buy a #7 size drill rod for a 1/4-20 thread.... but then the die would pretty much just slide onto the rod. I don't think that is what you really wanted.
Minimum rod diameters for a class 2A (medium class of fit) thread are:
1/4-20 .2408 5/16-24 .3042
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