Sieg SC3 7x16 Mini Lathe Question...

The lands are 30.01mm, the LMS part number is 5579. Is 0.01mm going to make that much difference. Another noob question I have is how do you set the preload on these lathes.
 
The lands are 30.01mm, the LMS part number is 5579. Is 0.01mm going to make that much difference. Another noob question I have is how do you set the preload on these lathes.
0.01mm can be the difference between a tight sliding fit and a press fit. I actually spun my c3 spindle in the SC3 using some 600 grit on it to get the bearings to a tight slip fit. For the SC3, I did it by hand.

Do you have replacement bearings to hand? if so, spin the spindle beteen the chuck and a live tailstock centre (I used a 60mm pipe centre), run some 600 grit paper over the lands until you get a tight slip fit. Trust me, you will be thankful you did it as it will mean no more need to press the bearings on or use a puller to remove them.

Also, invest in a PAIR of C-spanners for the tail end lock nuts, makes pre-load adjustments so much easier when you have A/C or TRBs fitted.

As for pre-load, that depends on bearing type.

If using Angular contact (A/C) bearings or Taper Roller Bearings (TRB's) yes, you add preload, but only enough that you have .0005" (half a thou) or less movement when pushing/pulling along the length of it or pulling up/pushing down vertically.

Too much pre-load and you overheat the bearings.
 
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