I’m getting ready to start working on my next printer and wondered if anyone has used drill rod with a diameter +/- tolerance of 0.013 mm for the smooth rods in their machines.
That sounds acceptable mike. Should be fine if you are using lm8uu bearings or bushings for that matter.
O1 tool steel rods are the best cheap-o linear rods that you can get for the price (at least in self-sourced printer quantities), IMO. They work fine, though they’re obviously not as smooth as the precision-ground and chromed ones intended for use as linear rods.
OTOH, if you check Aliexpress, you can find sets of the aforementioned precision/chromed rods for surprisingly reasonable prices.
As @Whosa_whatsis mentions Search for ‘8mm linear shaft’ on Aliexpress.com, I then usually filter by highest rated and free shipping.