How do I troubleshoot a bandsaw cut?

Question

I recently bought and set up my first ever bandsaw, a Laguna 14/12. While I understand that bandsaws make rougher cuts than, say, a table saw, my new saw is leaving quite a rough surface given the fineness of the blade I’m using.

Here’s what I’ve done so far:

• bought a third party blade (13mm wide, with 4tpi)
• tensioned the blade so that it deflects about 5mm when I press it
• tracked the blade so that the teeth are nearly centered on the tires, based on advice from the internet
• set up the blade and the guides to the best of my ability, such that they are very close but not touching

Here are some test rips I did, in walnut and construction pine.

Is the problem likely the choice of blade or setup? Or is this normal for a brand new bandsaw/blade?

Answer 1

A couple of thoughts:

1. bandsaws do not cut clean like table saws. If you google for images of band sawed wood there is a texture from the cut.

2. Assuming correct tension (which also helps clean cuts), ensure the guide blocks' setups, top and bottom, match and are correct. If they are wayout you will hear a pulsing sound to the cut.

Shorten the opening of the cutting clearance as much as possible.

These two adjustments will minimize the side-to-side motion which leads to the rough repeating texture you are seeing.

3. Sometimes the weld on the saw blade may be a little off and that will cause the blade to have a slight wobble or skip. If you turn off the saw and rotate the blade until you see the weld mark, you can feel the difference, if any, with your fingers. If so, replace the blade.

4. While there isn't space here for all the details, there are a great range of blade thicknesses, and teeth shapes and spacings. Loosely speaking a thick deep blade with more teeth leaves a smoother finish, but I'm grossly simplifying.

5. Adjust your feed speed! Generally, a slower feed speed equals a smooth cut. This is the easiest adjustment on the list!

I assume the wood to be cut is held with enough downward pressure to avoid extra movement that cutting may introduce. If the lumber is bouncing around, none of the above will help that much.