miter saw whirring sound, blade vibration, and loosening arbor nut

[Larry Edgerton]

Get into the habit of only using the Brake when you need it instead of an automatic reaction if that is possible on your saw. The nut loosening is most likely from braking and those older Deltas had a very strong brake. If the blade spins on the arbor enough saw is useless as the cost of repair is too high to justify. Saws with brakes require a very tight arbor nut as the braking forces want to make the nut back off.

[Brian Tymchak]

The nut loosening is most likely from braking and those older Deltas had a very strong brake. .. Saws with brakes require a very tight arbor nut as the braking forces want to make the nut back off.

+1. I had the same experience when I changed to WoodWorker II on my Makita a few years ago. I could not find any reason ( dirt, dust, etc) that would have been the cause. I tightened the arbor bolt tighter than I did the first time, and it has held since. I think I tightened that bolt the first time thinking along the lines of tightening the arbor nut on the table saw, where you don't want to crank down on it as the rotation will serve to tighten the nut. Did not consider the blade brake was working against the bolt.

[Larry Edgerton]

Also, check your brushes. a brush past its service life will get to the holder and if run unchecked it gars the armature. A brush in that condition can make a whiring noise like a card in the bicycle spokes.