Join Date: Mar 2018
Location: Huntington Beach, California
Assuming that your project wood has gone through the usual preparations and is reasonably smooth, sanding needs to be done in several phases. I'm going to say a few really horrid things but it works very well.
If you have saw marks, you may need to start with 80 or 100 grit. Assuming that you have removed the saw marks start sanding DIAGONAL to the grain. Make 4 passes 100 grit paper with a sanding block alternating the diagonal. Follow up in the same manner with 120, 180 grits. Finally sand with the grain and 220 grit. You are now ready to apply oil or stain.
The very coarse 60 grit is generally used for shaping rather than smoothing.
Finally on the end grain sand to about 400 grit. This will help to seal the pores of the wood and when oil or stain is applied the color will be the same as edge and face grain.
You may use a Random Orbit Sander with grits up to than 220. But always finish with 220 grit on a sanding block going with the grain. If the finish is oil (Watco or Minwax Antique Oil Finish) you may want to make 180 grit the final sanding and on a sanding block.
If you get the wood too smooth with too fine of a grit, you stain may turn out to be blotchy.
A word of caution about inexpensive sandpaper. The grit may come off the paper and when you go to the next higher grit there may be that one piece of larger grit that scratches the surface. Use a shop vac between grits.
The known brands of sandpaper are worth every penny. (3M, Norton, Klingspor) These brands are less likely to lose grit that mars the work of the next smaller grit.
In furniture 1/32" is a Grand Canyon