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Bandsaw Faux Kickback

1889 Views 7 Replies 5 Participants Last post by runswithscissors, Jun 18, 2016

hackery

Discussion Starter · Jun 14, 2016 (Edited by Moderator)

Hi All

I am new so first of all hello. Not sure if this belongs in this category so if not please feel free to move it.

In general I am new to woodworking and have only recently bought a cheap and nasty band saw (300mm x 300mm x 80mm capacity 350w).

Now I know in theory kickback shouldn't be possible on a bandsaw but I was making a heart shape jewelry bandsaw box for my wife's birthday next month and had successfully cut the heart shape blank and cut both the lid and bottom of the box. Next I brought the solid heart shape back to the saw and started to cut out the inside of the box. I was making relief cuts and stopping the blade to remove the offcut every time I completed a relief cut and all was going very well until the last relief cut was just finished and suddenly there was a very loud bang and I got hit in the chest (table is roughly between my waist and chest height) with my work piece. What I assume was actually a bad kick down had occurred but oddly in the process the walls of my box had been thrown through the blade cutting through it and into my chest which was roughly 6 inches away. I can't really say it hurt but I did certainly feel the force behind it even for a under powered 350w hobby saw. Whatever happened also badly bent beyond repair my new blade which was a 4tpi skip tooth which before that was performing incredibly well for the curves of the heart as well as small resawing jobs.

I am not really sure what I have done wrong and somewhat reluctant to try another bandsaw box until I can figure out how I can avoid the same mistake.

I have Googled bandsaw kickback but there is only a few references to it on various forums and the usual replies are "it wasn't a kickback but a kickdown" but ultimately the work piece did travel with force from the saw into my chest… not really worried about minor blows to the chest but worried similar incidents could easily involve loss of a finger or two. I am happy to call it a kickdown I just want to know what I did wrong and how to avoid it?

The only thing I can think of is that the relief off cut which was contained within the walls of the heart shape has got caught at a funny / freak angle by the blade and that it's just a rare occurrence. I don't see any other way I could have removed the centre of the heart shape differently on the saw and was following the same procedure I have seen no end of other wood workers do.

Anyways sorry for the long post and any advice or insight would be greatly appreciated.

Many Thanks

Hackery

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Unknowncraftsman

· #2 · Jun 14, 2016

It's sounds like you lost support below the piece.It need to be there at all time.
I had it happen once to me and ruined a Resaw King blade back when Laguna made them 1/2 wide.
I also remember Sam Maloof warning woodworker that cutting his chair parts on a bandsaw like he did was dangerous.
Because of the way you can lose contact below the blades downward force.

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kelvancra

· #3 · Jun 14, 2016

I've had kickback several times. Each time, it was cockpit error - a gap between the piece and the table, without a sled or something supporting it farther back.

When I cut pieces out that will leave a gap, I used double sided tape to put them back to provide support for the remaining cuts.

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hackery

Discussion Starter · #4 · Jun 15, 2016

Thanks for your replies Aj2 and Kelly…. just so I am clear the issue occurred because the offcut piece was not touching (at least fully) the bandsaw table or was it because the actual workpiece was not touching the table or perhaps both?

Good idea with the double sided tape will definitely try that next time I am in the shop.

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Underdog

· #5 · Jun 15, 2016

Any time the bottom of the piece that is directly under the force of the blade is not completely flat on the table, you have the potential for it to be slammed down onto the table if the blade binds at all.
Once it binds, then there's nothing to prevent the kerf from twisting and binding even more.

I cut green bowl blanks with a very coarse blade and it's way too easy to have this problem when your bottom surface has been cut with a chainsaw.

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kelvancra

· #6 · Jun 15, 2016

I cut with the cut offs not touching the table and have no problem. Only when the main pieces isn't supported do I have a problem.

Consider log sleds, for example. Whether I'm using one to make boards or one to cut disks, in both situations, the log is supported on the sled, but the cut off drops.

CLEAR CUT OFFS too! I've had a blade grab one and toss it several feet when it was pushed into the front of the blade, as I was cutting knots and things off a limb or something.

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hackery

Discussion Starter · #7 · Jun 17, 2016

Thanks guys for all the replied so the consensus is definitely to control cut offs in some way. I do stop the saw after every relief cut inside the bandsaw box walls / carcass and remove it and then start again. I suppose because the relief off cut is somewhat contained within a small frame it doesn't help matters.

Thanks again!

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runswithscissors

· #8 · Jun 18, 2016 (Edited by Moderator)

It's easy to make a zero clearance auxiliary table for a bandsaw. Simply take a piece of plywood the size of your table, and saw straight to the middle of it. Stop. Now tape the plywood to the BS table to fix it in place. Provides a solid surface under even the smallest chunk.

I surmise that because the offcut piece was inside a closed loop, it had nowhere to drop out of the way, so the blade grabbed it.

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