PM-836S

Man, .007 seems nice and tight to me. Worked on some bridgeports with 50 thou and that wasn't a huge deal. If you are new to milling machines, you'll learn the feel and technique of taking up backlash every time you move the machine, it is like riding a bike. Down the road you can add a DRO and you'll never look at the hand wheel again. Zero backlash is unreasonable with ACME screws and would cause extreme wear.

Maybe others who own manual machines in your size range could add comments. Currently my only mill is a CNC, but I've worked on probably 50 different knee mills over the years at school and jobs.
 
.007 is very good.
My 73 yo SB9 has .010 on the crossslide and .005 on the compound.
My mill/drill has about .006-.008, it was used very little by the PO.
 
That adjustment is not a conventional split-nut. It is essentially two separate nuts at each end of a yoke. It’s similar in concept to a double-nut on a ball-screw. To remove backlash, you loosen the two cap screws on one of the two bronze nuts, then rotate the bronze nut to tension (preload) it on the lead screw threads, then re-tighten the cap screws. You’ll essentially be increasing or decreasing the distance between the two opposing nuts. See the photo below of the lead screw yoke on my PM935. I have mine adjusted to about 0.002” backlash. Any less backlash and the table has excessive friction. It’s challenging to get at the cap screws without a hex-bit on a long extension with ratchet. Twisting the nut once the screws are loose is best accomplished with a long punch (or long screwdriver ground to fit) in the spanner-wrench hole you see in the bronze nut, then applying twisting force on the nut while rotating the lead screw back and forth. As you giggle the lead screw back and forth, the nut will settle into a preload against the nut at the opposite end of the yoke. Make sure your gibs are honed and well fitting in the dovetail ways or this will be a wasted exercise in frustration.



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Awesome and thank you for the pictures and detailed instructions.
Would you rotate the nut closer to the other(clockwise) or would you go counter clockwise with it? I would imagine either way will make preload correct? Just wondering if there is a standard way of doing it.
 
Either way should work. Good luck - it helps if you grow 15" long fingers. :)
 
There is an oiler on the knee, to the left of the crank. I can't tell what it distributes to. I'm pretty sure there are others here besides my self who'd really enjoy that in their shop.
 
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