Trying to form tap 5/16-24 threads in 4140 prehard making connecting rods. Hole size before the tap is .295 & using lots of oil on the tap. The threads don't look smooth as I would expect. They look rather torn. Spent all afternoon drilling & tapping in test material to get size, depth, right drills etc. and I'm not happy with what these threads look like.......crap! I even torqued some cap screws down to 35 ft lbs to see if I can strip the thread but it looks fine & not stretched out. The bolts spin in fine and are not sloppy and the hole shrinks to .276. The tap on the end looks galled after 2 holes. What do I do? Thanks
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