Bandsaw Getting Stuck

[Wyatt Holm]

I was bandsawing some bowl blanks yesterday and I had the problem of the saw lugging out an flipping the breaker. I thought it was just a dull blade like usual, so I replaced the blade. Then I started to cut about a 20" bowl blank and then it did it again stopped the saw and flipped the breaker. I tried to back it up to get the blade out of the cut but it was pinched. I finally got it off I had to take the blade clear off and used a chainsaw. So am I doing something wrong? Or should I have some more aggressive blades than 3 tpi x 1/2 blades?
Wyatt

 

[Odie]

I was bandsawing some bowl blanks yesterday and I had the problem of the saw lugging out an flipping the breaker. I thought it was just a dull blade like usual, so I replaced the blade. Then I started to cut about a 20" bowl blank and then it did it again stopped the saw and flipped the breaker. I tried to back it up to get the blade out of the cut but it was pinched. I finally got it off I had to take the blade clear off and used a chainsaw. So am I doing something wrong? Or should I have some more aggressive blades than 3 tpi x 1/2 blades?
Wyatt

Wyatt.......

You didn't say how thick your 20" bowl blank is, or how much moisture content you estimate it to be. Both of these might be a factor for you. It should be obvious that the thicker the wood is, the more drag on the blade it will create.....a curve cut will add to the effect.

About the moisture content........I've found that very wet wood, and particularly when turning a circle or curves, will hold wet sawdust inside the kerf and can cause binding between the blade and wood. Also, different species, and even different individual chunks of wood within a parent species will react differently. If you've got a lot of "wavy" grain in your bowl blank, it may, or may not be a factor, as sometimes the grain of the wood makes the bandsaw blade react to it.

I'd say the 3 teeth per inch blade you're using would be a good choice......you will be more interested in speed, rather than fineness of the cut. At 20" diameter, you could probably get by with a wider blade than 1/2", but I don't see any problems with it.

otis of cologne

 

[David Wilkins]

Round off the back edge of the blade for cleaner curves, a shot of pam cooking spray will help the blade slide through wood.

 

[john lucas]

Are you forcing the blade to cut too fast. If you do the blade will try to make a conconvex cut and will cause the blade to bind.

 

[Bill Boehme]

The blade is not going to bog down unless it is being forced, pinched, twisted, or otherwise binding in the cut. When cutting a curve, it is important that the blade does not twist as the wood is rotated -- it it does then the wood is being rotated too much. For cutting blanks, a wide kerf blade with a pitch of about 2 or 3 TPI is about right so that the wood can be rotated without twisting the blade. The other thing to be mindful about is proper tracking of the blade and alignment of the guides so that they do not rub when the blade is running without cutting. If there is reaction wood then pinching can be a problem. If that is the problem, try using radial relief cuts so that the waste can be removed in sections.

 

[MichaelMouse]

Twisted and pinched can be minimized by using a circle jig. Makes sure you feed as you press.

Other good sense information on wet wood, and stringy species being tougher to clear, especially on deep cuts is why I like the AS blades from Suffolk with the big set in the teeth. They take a kerf and a half, and keep the gap cleaner. Little bit of lube with the saw off and some oil on a paper towel is good. Rotate the saw in reverse by hand so you don't chew up your fingers. Good practice to do it after cutting acid woods, too. Combine it with a good table conditioning.

On the subject of squirrelly wood, I don't like relief cuts. Makes you back up, and that has its own can of worms. I'd rather make straight ahead cuts and take a tangent. If you keep a couple of shims handy to use as kerf-keepers, you'll never need 'em.

 

[Curt Fuller]

Part of what you're experiencing is also the the same forces in the wood that cause warping and splitting. As your saw cuts, your're releasing the stress in the wood and some of the other stresses are causing the wood to move and bind the saw blade. I've try to stop when I can feel the blade starting to bind, back up, and go again, hopefully widening the kerf enough to finish the cut.

 

[Wyatt Holm]

The wood was probably 7 to 8 inches thick. Thanks everyone.
Wyatt

 

[rjones]

just a question on this, if you are running your saw off an extension cord could be the problem I have seen that happen to someone before, the cord could not be big enough and causing a heating problem to throw the breaker. just a thought.

 

[Nate Hawkes]

I just have a ridgid 14" BS, but I souped it up with a riser block & 2HP baldor motor. I only have problems with binding if I let the guides get loose, or the piece is really offbalance on the bottom. Is the saw on 220 or 110V power?
You don't have it on inside out, do you? J/Kidding. I actually have done that once, though. Just couldn't get that thing to cut right....

 

[Wyatt Holm]

It is a Jet 18" runs on 110 power.

 

[Bill Boehme]

Somebody that I know really well installed the blade inside out on his saw, but I won't mention any names because I do not want to embarrass him. 😱 When the teeth are pointing the wrong way, it does not cut very well.

 

[Joe Greiner]

Mouse's signature says it: "cut the wood as it wishes to be cut." You just offer suggestions. Any suggestions it doesn't agree with can produce barrelling and other adventures.

Another tip: Alternate the direction of rotation (CW, CCW, CW, CCW, etc.) to reduce unbalanced set wear. This can apply to tangent cuts too. And is there any need for more than 16 tangents? Let the lathe make it perfectly round later.

Joe

 

[Bill Boehme]

"cut the wood as it wishes to be cut."

I've been thinking about that lately after using a bowl gouge on myself (see page 6).

And is there any need for more than 16 tangents?

Very good point -- in fact, anything more than an eight sided polygon is way overkill, especially considering that after the piece of wood is mounted on the lathe, it is not going to be perfectly centered anyway and will still need some work to get it trued up. It is hard to cut a circle with a wide blade and a thick piece of wood without at least a minimal amount of twisting even when we are careful about keeping the direction of cut straight ahead so that it is tangent to the circle. The easier way is to just make a crude approximation to a regular polygon.

 

[Wyatt Holm]

Somebody that I know really well installed the blade inside out on his saw, but I won't mention any names because I do not want to embarrass him. 😱 When the teeth are pointing the wrong way, it does not cut very well.

Are you mocking me?😱 I have done that before. The blade was almost dead but this time it didn't cut.

 

[Malcolm Smith]

There are circle cutting guides that mount on the band saw table. An adjustable pin goes in a shallow hole drilled in the center of the blank. I don't know who makes it but have used one for years. The pin accurately guides the blade as one rotates the blank. Though I turn mostly very hard tropical woods, I find the use of the guide avoids any problems.

It goes without saying that one should use high quality blades.

Malcolm Smith.

 

[Bill Boehme]

Are you mocking me?😱 I have done that before. The blade was almost dead but this time it didn't cut.

The person to whom I refer can be found in my shop whenever I am there. I think that his name is "Not Me".

The really bad part of the story is that I was showing a friend how well my new bandsaw cuts wood and he was asking why the wood was smoking. When we discovered that the blade was wrong side out, he asked who did it and I said, "Not Me".

 

[Joe Greiner]

If I were doing production turning, or making bowl blanks for sale, I might use the bandsaw. But I've found octagonal blanks satisfactory, cut with a chainsaw; and trimmed with the Lancelot if necessary for balance, or clearance to the banjo or motor. I use the bandsaw for other things that are too thick for a scrollsaw, but still need intricate cuts.

I guess we're all SOITs at one time or another (Safety Officer In Training, for those who didn't). Glad you can smile about it, boehme.

Attached: chainsaw "tree" and adjustable sawbuck. Outboard donuts indicate need for sharpening. Swimming pool "noodles" cover the pointy things in storage.

Joe <2007_04_12/75.jpg

 

[MichaelMouse]

There are circle cutting guides that mount on the band saw table. An adjustable pin goes in a shallow hole drilled in the center of the blank. I don't know who makes it but have used one for years. The pin accurately guides the blade as one rotates the blank. Though I turn mostly very hard tropical woods, I find the use of the guide avoids any problems.

They are a simple thing to make. Two strips of wood and a piece of ply will do. Plans in any bandsaw book or book of useful workshop jigs. As mentioned above, they prevent twisting while not cutting, a common cause of binding, or pressure sideways into the blade. http://woodworking.about.com/od/woodworkingplansdesigns/ss/CircleCutJig.htm or http://www.twistedknotwoodshop.com/bsjig.htm For bells and whistles. The principles are easily accommodated with less.

If you're looking for the biggest piece you can swing over the ways, you will of course want to use the bandsaw. Keeps you from having to trim nubs or cut smaller than possible to avoid it.

 

[Nate Hawkes]

It is a Jet 18" runs on 110 power.

Do you have 220V abailable? You're probably running at or near the max of your breaker's capacity. I assume it's either a 1HP or 1.5HP saw, and 12-18 amps of draw?? Ex: a 1.5HP baldor 1725rpm motor draws 18amps max. Its more than possible that your breaker is tripping a little soon, and needs to be replaced. A better solution would be to use 220V, so you're only drawing 9amps. You probably already know this. I personally ran 8ga. wire to my shop, and a 40amp 220/240V circuit. It can handle 2x 2HP machines running at once, like a bandsaw and dust collector. I hated to spend the $$$ on that wire, and the hours digging the trench and laying PVC pipe to the shed, but it was worth it!!!

 

[Dick Sowa]

The only time my bandsaw blade jammed, was when I was sawing a round, on a blank that wasn't very flat on the bottom. When it racked slightly, the blade bound, and I had a devil of a time extracting the blade. After that, I've made sure the bottom is flat on the table, or secured to a sled.

Also, like others have suggested, taking relief cuts around the perimeter can help a lot. You're then taking chunks out around the perimeter, rather than a single round...a lot easier to do. Practically, there is no reason why you need to cut a round in one pass...several will do just as well.

 

[Wyatt Holm]

Do you have 220V abailable? You're probably running at or near the max of your breaker's capacity. I assume it's either a 1HP or 1.5HP saw, and 12-18 amps of draw?? Ex: a 1.5HP baldor 1725rpm motor draws 18amps max. Its more than possible that your breaker is tripping a little soon, and needs to be replaced. A better solution would be to use 220V, so you're only drawing 9amps. You probably already know this. I personally ran 8ga. wire to my shop, and a 40amp 220/240V circuit. It can handle 2x 2HP machines running at once, like a bandsaw and dust collector. I hated to spend the $$$ on that wire, and the hours digging the trench and laying PVC pipe to the shed, but it was worth it!!!

It is not hooked up to 220. I do not know how to hook it up to 220. I think a new motor might be a good idea, because the one it has is quite a wimp.

 

[Matt Rabe]

Blade pinch

I think the tension in the wood is causing to much drag on the blade. Cut some wooden shims, and place them in the kerf behind the blade. I have had this problem several times and it was a simple fix.

That or just get a bigger and more hp bandsaw.

 

[Steve Worcester]

The only time my bandsaw blade jammed, was when I was sawing a round, on a blank that wasn't very flat on the bottom. When it racked slightly, the blade bound, and I had a devil of a time extracting the blade. After that, I've made sure the bottom is flat on the table, or secured to a sled.

Without a flat bottom, it becomes a BIG safety issue also. The band saw will rip it right out of your hands and take your hands with it.

 

[Wyatt Holm]

Without a flat bottom, it becomes a BIG safety issue also. The band saw will rip it right out of your hands and take your hands with it.

How do you know? Have you had it happen to you?😕



Just kidding,😀


Thanks everyone, I had a friend fix the lower roller guides, should work better now. I will use shims if I have to do any more pieces that big.

 

[Nate Hawkes]

The offset of the blade teeth should take care of the binding, unless as has already been mentioned, the bottom of the blank is not flat. A bandsaw blade takes a kerf substantially wider in most cases than the blade thickness itself--a .025 blade might take .035 for example. I have no idea of the exact measurements or tolerances, but that the kerf is definitel wider than the blade is thick. Although I often repeat the same experience, I would agree that with an irregular bottom, there is often the danger of the blade grabbing and binding in the cut if the blank gets out of plane with the blade.


Edit: I really like the 3/8" woodturner blades from Highland hardware. I had a problem with a few blades' welds breaking a while back, but HH replaced the blades, and I sent them the old ones for quality control inspection. The new ones were great. They are thicker than other blades, and have their back edges rounded over to make it easier to turn a blank in the cut. They're a little more than standard carbon steel blades, but seem to be worth it.