How tight should the guides be to the blade? If the guides are too close, will that create too much friction with the blade?
(Sawing and Drying Forum)
From contributor S:
If you have guides that have ball bearings, then they contact the blade. In that case the blade should be deflected past the contact point about 1/8 to 1/4 inch. Your manufacturer may have a requirement for you to follow.
Some saws have ball bearing guides on the top and friction guide bearings on the bottom. In that case the ball bearing guides deflect the blade and the friction ones do not touch.
Here's a portion of the blade setup article at Cook's Saw and Machine website, which talks about down pressure:
"First you need to put your blade on and tension it up. Now make sure that the rollers are off of the blade. Then start on the stationary guide side. Bring that roller down to the blade. Once it touches, push the roller down another 1/4 of an inch. This is called down pressure. If you have everything running right, you might be able to run with just 1/8 inch down pressure.
To begin with, I like the 1/4" because it guarantees that I am able to control the blade. Some people like even as much as 3/8" down pressure."