Bandsaw tuning

[michael langman]

My little band saw was doing the exact same thing Keith, and I replaced a bad bearing on the lower support arm and made sure the saw blade guides were supporting the blade all of the way up to the gullets in the blade.
The saw cuts straight and clean now.

[Keith Downing]

Finally got the blade in and had time to do the tuning.

Overall we went from horrible to "reasonable". Certainly not perfect though, so I had a few follow up questions/observations.

1. My saw screams with this new blade when it starts to cut. Is that normal? I mean, it's pretty darn high pitched and loud. I thought one of my bearings had gone out at first.

2. I went ahead and followed the recs of most of the posters here and went with a 1/2" Timber Wolf Bandsaw Blade (137" x 1/2" x 3 TPI Positive Claw) for the new blade ($36 via amazon). It looks like a good blade, but now I'm questioning if it isn't too small. Most of what I use the bandsaw for is ripping large pieces down to manageable pieces. The reason I'm concerned is that the wood is sawing slowly and coming out looking pretty rough on the sawed face (albeit mostly straight now). And again, this is just some soft pine, not even trying anything difficult yet. Should I be sawing pieces 8-12" thick on a 1/2 inch blade?

3. I noticed that with this blade properly tension-ed, the closest I can get my top right bearing is about 1/4 (maybe 1/8" if I'm being really generous) away from the blade. Is that normal? It's almost like the blade is off center in between the top guide bearings. But I didn't see any way to adjust the entire upper guide left to right. Obviously I already have the right bearing "tightened" as far left as it will go.

4. Finally, my top wheel really looks strange when the saw is running. Admittedly, I can't see any noticeable wobble in the outer edge of the wheel when looking at the blade on the tire, but if you look towards the center you can definitely see something is crooked our not built perfectly balanced. Is this a major worry? Or should I just assume that they shaved down/balanced the outer edge of the wheel properly when they assembled the saw?

Thanks again for all the help so far guys. Definitely a learning experience.

[John TenEyck]

Are you sure it's the blade screaming and not a bearing? A cutting blade makes noise, but it doesn't scream.

Are you saying that if you set the guides when the blade is at low tension and then increase the tension that the guides shift out of alignment with the blade? If so then the frame is flexing and it sounds like a lot for the guides to move that far. An 18" saw should have no trouble tensioning a 1/2" blade especially a Timberwolf which is designed to run at low tension. If the frame really is flexing that much then you definitely can't go to a wider blade.

Does the machine vibrate when it's running? If it does take the blade off and then turn the machine on. Is it still vibrating? If so, something is wrong in the drive system/lower wheel. If it only vibrates when the blade is on, put another blade on. Still vibrate? If so, then it's something in the upper wheel/tire/bearings.

John

[Thomas Canfield]

I find after doing a lot of radius cutting that the blade tends to become dull on one side. I can still do reasonably well doing radius cuts since I am continuously feeding to the curve, but there is a tendency for the cut to drift when doing a straight cut. I try to keep a dedicated "straight cut" blade on hand and change blades for the few times that I am making straight cuts or trying to resaw.

[Keith Downing]

Are you sure it's the blade screaming and not a bearing? A cutting blade makes noise, but it doesn't scream.

Are you saying that if you set the guides when the blade is at low tension and then increase the tension that the guides shift out of alignment with the blade? If so then the frame is flexing and it sounds like a lot for the guides to move that far. An 18" saw should have no trouble tensioning a 1/2" blade especially a Timberwolf which is designed to run at low tension. If the frame really is flexing that much then you definitely can't go to a wider blade.

Does the machine vibrate when it's running? If it does take the blade off and then turn the machine on. Is it still vibrating? If so, something is wrong in the drive system/lower wheel. If it only vibrates when the blade is on, put another blade on. Still vibrate? If so, then it's something in the upper wheel/tire/bearings.

John

I don't know how to specifically test the bearing correctly, but all move fine when I spin them; and the noise only occurs when the blade is advancing in the wood.

On the top guide, maybe it happened when I changed the tires and I never noticed, but the left bearing adjusts to where it will touch the blade. The right bearing, will not contact the blade. At it's max adjustment (towards the blade), it is still at least 1/8" away. I will look up tonight to see if the entire upper guide can be moved left to right, but I didn't think it could be.

[Susumu Mori]

I'm completely with Andrew. Bandsaws are still mystery for me; there are good days and bad days. Maybe the species and sizes of the wood. Or maybe just my perception about the noise, vibration, and the roughness of the cut.

In any case, I think it is a good exercise to strip down your bandsaw and see what happens by putting back the parts one by one.

> Take the blade out and run just the lower wheel, or even take the V-belt out and run the motor. It should be smooth with almost no noise.

> Turn the upper wheel by hand and see if it rotates freely without wobble. Some people check if the wheel stops at random locations, which means the wheel balance is good.

> Put the blade back and set the blade guides far away. Crank up the tension and see if it runs smoothly and quietly. The level of the sound heavily depends on the type of the blade, in my experience.

> Set the blade guides and see what happens. I guess the noise could be from the guides and this test will tell you.

> Cut woods. If you hear shrieking noise when you push the material, it is likely from the thrust bearing.

I really like the video by Mr. Wandel (https://www.youtube.com/watch?v=fK9m5PadmiI), which brings quite a different view of bandsaw from the Alex's lecture. One of the critical points starts at around 3:00.