Bandsaw kickback

[Anthony Whitesell]

Anything is possible. I was cutting a a piece about 4" square. More of a resaw cut. Just as the cut finished, the piece rotated about the blade, came back through towards me. One piece hit the tips of my fingers shattering the ends of a few fingernails then proceeded to curl my fingers and skin some knuckles. The other piece hit me in the stomach. Ironically I have never had a kickback from the table where the piece got launched. I have had a few situations where it almost or could have happened but was able to save or stop it.

[Roger Pozzi]

I've read this over and over but still don't understand just what you're describing.
Since a bandsaw blade's force is straight down, what caused the piece to be "launched" back at a 90 degree angle from the original driving force?

[Anthony Whitesell]

The piece came out of the saw like a frisbee on end. What I am thinking is somewhere in the top half of the trailing edge the blade caught causing the front edge to lift up and then proceeded to rotate up and back.

[Rod Sheridan]

I've read this over and over but still don't understand just what you're describing.
Since a bandsaw blade's force is straight down, what caused the piece to be "launched" back at a 90 degree angle from the original driving force?

He was cutting a 4" square piece in a resaw type of cut.

The 4" square piece is an unstable shape, the same as cutting a round cross section object.

All pieces that are capable of rotation must be held in a jig or clamp when sawing.................Regards, Rod.

[Matthew Hills]

Bandsaw kickback was the topic leading off the 18-March episode of the ShopTalk Live podcast.
Someone had followed a FWW article on a bandsawn box, and likely hadn't kept the leading edge flat on the table...

http://www.finewoodworking.com/item/123421/stl-107-tips-master-jim-richey

Anthony: what blade were you using? (am wondering if a coarser blade might be more likely to grab?)

Matt

[Anthony Whitesell]

To the best of my knowledge the leading edge was flat. But the piece was short (not a lot of leading edge weight to help resist lift or rotation). I was using a 1/2" 0.025" 4TPI blade. It has a nice twist in it now. At least I had gotten some use out of it before this happened.

[Jason Beam]

What were you pushing it through with?

[Prashun Patel]

Thanks for the safety reminder. The risk makes perfect sense. I have unwittingly made the same kind of cut in fact just this week.

[Chuck Raudonis]

I agree. I wasn't aware that this was even a problem and I've been bandsawing for years. It opened my eyes to something I need to be aware of. My fingers thank you.

[Anthony Whitesell]

What were you pushing it through with?

A regular push stick in my left hand for feeding and a safety push stick (narrow grrriper style) in my right to keep the piece against the fence.

I'm trying to recall if I had ever attempted to cut something of this size or shape on the bandsaw before. It was only about 4x4x5 and I was trying to rip cut a 1" piece off. It was too big for either the scroll saw or the table saw. The bandsaw was the first and logical choice.

[Anthony Whitesell]

My eyes were wide open as well. :eek: (about like that)

[Anthony Whitesell]

Bandsaw kickback was the topic leading off the 18-March episode of the ShopTalk Live podcast.
Someone had followed a FWW article on a bandsawn box, and likely hadn't kept the leading edge flat on the table...

http://www.finewoodworking.com/item/123421/stl-107-tips-master-jim-richey

Anthony: what blade were you using? (am wondering if a coarser blade might be more likely to grab?)

Matt

I would think finer (high TPI, shorter tooth height, shallower gullet) would have been better. The rule of thumb I had read was at least 4 teeth in the piece, I had 16 total (4 tpi, 4" tall).

Interesting commentary on the ShopTalk podcast about having the contact point of the blade being on the table or a cut that won't allow the piece to rise or pivot. If you were to follow those rules, what kind of jig or rigging would you need to cut cookies (large round slices from a log or branch) to meet that requirement?

[glenn bradley]

Thanks for sharing this Anthony. I can really see that frisbee effect in my mind and it is not a comforting visual :eek: Too many people consider the bandsaw a "safe" tool. We do know what they saw up animal carcasses with right?

The bandsaw is amazingly forgiving when cutting un-milled material due to the bands flex. This is what draws me to it for roughing out parts blanks prior to jointing, planing, etc. I do use some sort of carrier to cut small parts on any tool; a handscrew, a temporary sled, whatever.

That being said I did manage to embarrass myself at a woodworking gathering. I had been cutting discs off a large round limb at home. At the event I tried the same thing with a smaller piece. I must've been in a woodworking coma since I was NOT using my head about this. The piece grabbed and frisbee'd off into a corner. I froze hoping everyone was looking somewhere else . . . they weren't. Thankfully the only blood was the blood rushing to my face. :o

[John Schweikert]

Do you adjust your blade guard/upper guide bearings to sit close to your workpieces? That alone creates a blockade and prevents the wood from rotating up and flying at the woodworker.


I'm religious about adjusting the bearings to sit at most a 1/4" above the workpiece. Not for the rotation issue but just because excess open bandsaw blade is a recipe for something bad.

[Anthony Whitesell]

We do know what they saw up animal carcasses with right?

I tell my daughter the same thing my father told me. Saws don't know the difference between cutting wood, metal, or flesh and since flesh is softest it will the easiest.

I allow her to use a coping saw and she is very careful about it. She also has her own safety goggles, hearing protection (ear muffs), and work gloves that she uses willingly.

[Anthony Whitesell]

Do you adjust your blade guard/upper guide bearings to sit close to your workpieces? That alone creates a blockade and prevents the wood from rotating up and flying at the woodworker.


I'm religious about adjusting the bearings to sit at most a 1/4" above the workpiece. Not for the rotation issue but just because excess open bandsaw blade is a recipe for something bad.

I adjust them as close as possible. Normally about 1" above the piece, there is a lot of stuff in front of the blade and much closer I can't see what the cut is doing. Unfortunately, the resaw fence is just over 6" tall and only cutting 1" thick the upper bearing/guard was about 6 1/2-7" above the table.

[Andrew Hughes]

I too have had the blade grab onto small blocks on both my bandsaws.I will use a half inch sheet of ply or mdf to cover the throat plate.Pretty sure the throat plate will flex some things get grabby and spoil the cut.I also keep the guides low.Standard operating procedure.

[Steve Peterson]

It sounds like the trailing edge cut through the bottom of the block and pushed the top corner down, allowing the block to rotate. Maybe this would be enough to cause the block to "Frisbee".

Steve

[Peter Aeschliman]

I'm probably being dense here, but I still don't get it.

I think this is one of those cases where a picture is worth a thousand words.

When we say "kickback" in this context, we're not talking about table saw style kickback, right? Where the workpiece goes flying across the room and puts a hole in the wall?

Are we really just talking about a quick jolt, where the piece pops back an inch or two? Like, the downward-moving teeth pinch the workpiece against the throat plate, causing it to almost kind of "squeeze out" like when you squeeze a slimy pumpkin seed?

[Chris Padilla]

I'm still trying to grasp what exactly happened here. I've broken a blade on my band saw (nice expensive Trimaster, carbide tipped) that cause soiling but I've never been able to get any sort of kickback from it (not that I've tried to).

[Jason Beam]

A regular push stick in my left hand for feeding and a safety push stick (narrow grrriper style) in my right to keep the piece against the fence.

I'm trying to recall if I had ever attempted to cut something of this size or shape on the bandsaw before. It was only about 4x4x5 and I was trying to rip cut a 1" piece off. It was too big for either the scroll saw or the table saw. The bandsaw was the first and logical choice.


Was the push stick high or low on the piece? Was it supporting the 'back' of the stock well?

[Prashun Patel]

The piece was probably around as tall as it was long . the blade cause the leading, top edge to be pulled down, flipping the trailing bottom edge up and creating a frisbee or bizarro ninja star, i think.

[Chris Padilla]

The piece was probably around as tall as it was long . the blade cause the leading, top edge to be pulled down, flipping the trailing bottom edge up and creating a frisbee or bizarro ninja star, i think.I assume then that the piece that was launched was between the fence and blade? That is the only pressure point I can think of for something to get stuck for a period of time and then suddenly becoming unstuck.

[Anthony Whitesell]

Prashun has the right picture. I do mean kickback such as is usually associated with a tablesaw. Actually both pieces went flying in this case. The piece between the blade and the fence was more airborne than the offside piece. The push sticks were close to vertically centered, but it happened so quickly. It may be a chicken and egg situation. Did I push low that caused the rotation or did it catch and rotate the part that caused me to push low.

[Chris Fournier]

There is no such thing as bandsaw kickback, the cutting force is towards the table. This is a case of operator error plain and simple. As others have mentioned caution must be taken with piece dimensioned as described, it's tippy and as you pressed against the resistance of the cut you did not control the piece. The bottom of the piece was not sitting flat on the table because of your feed and all bets were off and you the the piece without serious harm thankfully! The piece between the blade and the fence had more force because it was trapped and the blade had it's way with it.

With a piece if this dimension I'd be careful and use two push sticks, the rearward stick would be of equal height (ish) and drive the piece into the blade. The second stick could be anything and it would direct the piece into the fence.

If your work piece is planted on the table and tight to the fence the bandsaw will "catch" nothing and be a predictable shopmate.

My advise is based on my own misadventures so take no offense. Too many woodworkers go on and on about how safe the bandsaw is compared to the tablesaw. The bandsaw will bite deep if provoked. Of course it was the right saw for this particular cut.

[Chris Padilla]

I take "kickback" to mean the wood flying back at the operator...i.e. 'kicking' back at you. I do not think it is specific to a particular tool. In this case, it sure sounds like the wood decided to head back towards the operator. Sounds like the very definition of "kickback" to me. :)

[Chris Fournier]

I take "kickback" to mean the wood flying back at the operator...i.e. 'kicking' back at you. I do not think it is specific to a particular tool. In this case, it sure sounds like the wood decided to head back towards the operator. Sounds like the very definition of "kickback" to me. :)

This would dilute the meaning of "kickback" and make it meaningless in my opinion. Might make you feel good about yourself because you fell victim to a "phenomenon" but it won't make you safer and safe should be our goal. Nothing wrong about admitting that you made a mistake that the outcome was dangerous; nothing wrong about pointing this out to help someone be safe either. Not to do so will ensure that you are in a dangerous situation in your shop again soon enough. I am the first to admit that I have learned by my mistakes.

If you want to be safe in the shop then you need to be honest and rational about incidents like the OP describes and every time you have to take responsibility for your actions and their consequences. In this case the wood came back at the operator not because of "kickback" the idea, but because the wood was not fed safely into the bandsaw blade.

It's not my intention to be harsh and I certainly am not judging anyone but bending language so that we can all feel good about ourselves isn't helpful in fact it's gotten us into a lot of trouble.

Respectfully,

Chris

[Peter Aeschliman]

If you want to be safe in the shop then you need to be honest and rational about incidents like the OP describes and every time you have to take responsibility for your actions and their consequences. In this case the wood came back at the operator not because of "kickback" the idea, but because the wood was not fed safely into the bandsaw blade.


Why does it matter? His point is that the wood flew back at him and caused minor injury. He's reminding us to not be complacent, and to provide us the opportunity examine and learn from his incident.

Let's focus on substance here.

[Chris Fournier]

Why does it matter? His point is that the wood flew back at him and caused minor injury. He's reminding us to not be complacent, and to provide us the opportunity examine and learn from his incident.

Let's focus on substance here.

I agree completely Peter and to my way of thinking I have. If you are comfortable with wood flying back at you being the same as "kickback" in commonly accepted terminology then we aren't in agreement about the very substance of this thread.

I hope that we all remain safe in our shops!

[Alan Schwabacher]

In this case the wood came back at the operator not because of "kickback" the idea, but because the wood was not fed safely into the bandsaw blade.

If you are suggesting that tablesaw kickback happens without any mistake by the operator, I'd disagree in most cases. If you are suggesting there's only one thing called "kickback", I'd say the type of tablesaw kickback caused by the kerf closing on the blade is significantly less dangerous than the type caused by pinching the stock between blade and fence. Perhaps those should not be called the same thing, but they are.

I approve of your suggestion that avoiding dangerous situations requires taking responsibility for your actions in an honest and analytical way. I just don't understand how calling this kickback or not has anything to do with that.

[Anthony Whitesell]

If you want to be safe in the shop then you need to be honest and rational about incidents like the OP describes and every time you have to take responsibility for your actions and their consequences. In this case the wood came back at the operator not because of "kickback" the idea, but because the wood was not fed safely into the bandsaw blade.

Chris

And could you describe the proper way to feed a square piece of wood through a bandsaw? I am unaware of where my technique was incorrect.

On an analogous topic, what is it called when the work piece is launched across the shop from the router table?

[Alan Schwabacher]

To resaw a square of wood, you need to control it as it passes through the blade so that you never cut where the wood is unsupported below the cut. Apparently yours tipped, and wound up in this situation. A pushblock that holds stock against the fence, and uses a cleat at the back to push the workpiece would allow you to retain control. Another option is to clamp into a handscrew that sits flat to the table and prevents rolling of the stock. This approach works with rounds that otherwise would require unsupported parts that could turn. Depending how it's held, the clamp might require repositioning to complete the cut.

It is possible that the two pushstick method you used would work safely, as long as you made sure to push near the bottom of the piece.

[Matt Winterowd]

And could you describe the proper way to feed a square piece of wood through a bandsaw? I am unaware of where my technique was incorrect.

He did:


With a piece if this dimension I'd be careful and use two push sticks, the rearward stick would be of equal height (ish) and drive the piece into the blade. The second stick could be anything and it would direct the piece into the fence.

And it sure sounds to me to be exactly what you did. I don't see anything about table saws in the definition of kickback.

Full Definition of kickback



1 : a sharp violent reaction
2 : a return of a part of a sum received often because of confidential agreement or coercion

[Anthony Whitesell]

To resaw a square of wood, you need to control it as it passes through the blade so that you never cut where the wood is unsupported below the cut. Apparently yours tipped, and wound up in this situation.

Given I don't know if the blade caught and caused the wood to tip or if the push stick caused the tip.


A pushblock that holds stock against the fence, and uses a cleat at the back to push the workpiece would allow you to retain control.

I was using a push stick with a cleat to feed and hold the wood against the fence.


Another option is to clamp into a handscrew that sits flat to the table and prevents rolling of the stock. This approach works with rounds that otherwise would require unsupported parts that could turn. Depending how it's held, the clamp might require repositioning to complete the cut.

The piece that launched with the most velocity was the inch thick piece between the blade and the fence. I don't see how the handscrew can control the piece between the blade and the fence. Once the handscrew is cut off, there will be nothing to control the cutoff piece.

[Bob Cooper]

Was your blade sharp?

[Prashun Patel]

As long as this thread has helped people realize there are mechanics of the way a bandsaw blade can grab and slam a piece, then it is a good thing.

both tblesaw and babdsaw blades can grab a piece unintentionally albeit in different ways.

I dont even think the fence has anything to do with the risk on a bandsaw. Its when a piece tips or tilts toward the user so it is not fully supported between the cut entry and the table. Thats what causes the grabbing and slamming.

It can also happen when cutting pieces that cut or taper upward from the table like round bowl blanks (dont ask me how i know that). Its not intuitive to a new bandsaw user and is great to mention here.

[Dave Zellers]

I hope I die before I see any proposal for a riving knife on a bandsaw.

Life has it's risks.

Thanks for posting your experience. Information is knowledge. Hard for me to imaging this happening, but it could be luck, it could be technique.

We learn and then we take the next step, which was the purpose of your post. Glad you're ok.

[Roy Harding]

...
On an analogous topic, what is it called when the work piece is launched across the shop from the router table?

It's called time for new underwear. Don't ask me how I know this.

[Chris Padilla]

On an analogous topic, what is it called when the work piece is launched across the shop from the router table?

Kickback! :D

http://www.merriam-webster.com/dictionary/kickback

[Peter Aeschliman]

Kickback! :D

http://www.merriam-webster.com/dictionary/kickback


Exactly. It doesn't matter what machine it is. If the wood is kicked back, it's kickback. The end.

[Pat Barry]

The piece that launched with the most velocity was the inch thick piece between the blade and the fence.
On the surface this is impossible of course. There must be something else going on that hasn't been explained or that needs further investigation. I personally never worry about kickback on a bandsaw but if I happened to experience it that would change my mind of course.

I believe it actually happened, now please explain the circumstances a bit more clearly, ie: got any pictures to illustrate the parts you were cutting and the relationship of the offending peice to the fence and your pushstick?.

[Anthony Whitesell]

On the surface this is impossible of course. There must be something else going on that hasn't been explained or that needs further investigation. I personally never worry about kickback on a bandsaw but if I happened to experience it that would change my mind of course.

I believe it actually happened, now please explain the circumstances a bit more clearly, ie: got any pictures to illustrate the parts you were cutting and the relationship of the offending piece to the fence and your pushstick?.

I'm not sure what else I can say that I haven't posted already. Here is a summary:

The piece being cut was 4"x4"x5" with a 1/2" 0.025" 4TPI blade (used but still fairly new). The fence was a 6" tall resaw fence. This placed the guard about 6 1/2-7" above the table. The cut was about 1" thick and resaw or rip cut in nature (with the grain opposed to cross-cut across grain). Two push sticks were being used, a Safety Push Stick (~6" long, 1/2" wide with a cleat on the back edge, typically orange plastic) to keep the part flush to the fence, the other stick was used to control the feed rate. As the blade reached the end of the cut, the part rotated about the axis of the blade (think spinning wheel or frisbee on end). The piece between the blade and fence came flying back at me hitting my left hand. The larger off cut piece also came back towards me, hitting my stomach. I don't know if the blade caught the piece to cause the rotation or if I caused the part to rotate with force from the pushstick.

As for a riving knife, I am not sure it would help on a bandsaw. On a table saw, a riving knife helps the pieces to not contact the teeth at the back of the blade. There are no teeth on the back of a bandsaw blade. Furthermore the piece rotated between the fence and blade, so it would have rotated beside a riving as well.

[Andrew Hughes]

I remember Sam Maloof warning woodworker useing a bandsaw to rough cut some of the shapes in his rocking chair.
If you have ever seen how he cut the arms out you know why.
Ive had my close calls trying to be all creative on my Bandsaw.
Anthony your reminder is well taken here.
Its good that you brought this up for us to consider.

[Glenn de Souza]

The safety warning implicit in this post is a point well taken.

However, I admit to finding myself scratching my head and staring at my bandsaw today trying to envision how a workpiece and offcut could get projectile launched back at the operator. I understand how the blade can grab, and I while it hasn't happened to me, I get the frisbee picture. But even in the frisbee scenario, if the blade is grabbing the top leading edge and causing the back trailing edge to lift, then isn't the rotation of the frisbee in the direction of the outfeed side of the saw (away from the operator)?

Not trying to dispute the post here, just trying to fully understand....

[Anthony Whitesell]

The safety warning implicit in this post is a point well taken.

However, I admit to finding myself scratching my head and staring at my bandsaw today trying to envision how a workpiece and offcut could get projectile launched back at the operator. I understand how the blade can grab, and I while it hasn't happened to me, I get the frisbee picture. But even in the frisbee scenario, if the blade is grabbing the top leading edge and causing the back trailing edge to lift, then isn't the rotation of the frisbee in the direction of the outfeed side of the saw (away from the operator)?

Not trying to dispute the post here, just trying to fully understand....

Glenn; right picture, only it's the other way around. The leading edge lifted at the time when the blade was or was about to break through the trailing edge.

[Pat Barry]

Glenn; right picture, only it's the other way around. The leading edge lifted at the time when the blade was or was about to break through the trailing edge.
Interesting. Was the trailing top edge overhanging the bottom trailing edge such that the very end of the cut was basically directly unsupported at the cutting edge?

[Anthony Whitesell]

Interesting. Was the trailing top edge overhanging the bottom trailing edge such that the very end of the cut was basically directly unsupported at the cutting edge?

No, it was square. ~4"x~4"x~5"

[Malcolm Schweizer]

I had a similar thing happen with a small piece I was shaping. The throat plate actually broke and the piece got sucked into the throat. It pulled my finger to the blade and it just barely grazed me. Scared the heck out of me- I thought for sure I had cut the finger off. My first thought was that I had broken the blade. It took me a few minutes to figure out what happened.

I agree with those that theorize that the piece rotated, but also a flexy throat plate could have trampolined it back at you.

[Glenn de Souza]

Glenn; right picture, only it's the other way around. The leading edge lifted at the time when the blade was or was about to break through the trailing edge.

Thank you, now I get it. This is a good warning, not only regarding less stable shapes and sizes, but also because there's a tendency to feel like you're home free at the end of a cut on a bandsaw, when things can still go wrong.

[Daniel O'Neill]

Thank you, now I get it. This is a good warning, not only regarding less stable shapes and sizes, but also because there's a tendency to feel like you're home free at the end of a cut on a bandsaw, when things can still go wrong.
That's a really good point. I usually relax a little toward the end of a bandsaw cut getting ready to grab the pieces I just cut. I'll have to adjust that tendency.

[John Sanford]

Too many woodworkers go on and on about how safe the bandsaw is compared to the tablesaw. The bandsaw will bite deep if provoked.

Everytime one is foolish enough to think a bandsaw is safe, just recall that the roasts, ribs and steak you eat is cut using a bandsaw....

[Erik Loza]

Reviving this thread. Was browsing Youtube and found this interesting video of a common accident on the bandsaw. It's in Italian but you'll get the idea quickly. I have witnessed this precise accident happen at trade shows and seen the piece go jumping off the table.

Erik

https://www.youtube.com/watch?v=Y-D0AvWAq4U

[Lee Schierer]

If the part of the blade that was close to the table came out of the cut before the blade at the top of the piece finished the cut, it is likely that you would get the type of kick back you describe. The front edge of the piece probably lifted up off the table slightly when the blade started coming free and the top of the piece was still being cut with the down force being applied. That would cause the top corner of the piece to be rotated downward at a speed of 25 ft per second or so.