According to Sofolatris :
What size rod do I use for 8-32 threads.I tried 3/16 but it is too big.

Well ... the simplest way to find out in your shop what size is
to look in a number size drill index, and see what the "body" drill is
for the thread in question, and turn the rod (in your lathe) a couple of
thousandths or so smaller.

In the case of 8-38 (Or other #8 threads) my "number-screw"
program says:

================================================== ====================
izalco:dnichols 18:26:43 number-screw 8 32
For a #8-32.000 screw:
Clearance diameter: 0.164
Tap drill diameter: 0.133
================================================== ====================

so I would turn to about 0.162" or perhaps 0.160".

I would also be more likely to use the lathe to do the
threading, as it is easier to get the threads straight and concentric.
You might use the die to finish up threads which are not quite deep
enough, as this will at least make it easier to start the die straight.

Good Luck,
DoN.
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