A.J.’s kickback

Reading A.J.’s recent post about experiencing a serious kickback got me thinking about one time when I was visiting a fellow cabinetmaker’s shop.

While I was there, this guy walked in with a bunch of plywood pieces he had cut to size and wanted mitered so he could assemble them into a cube. Henry (the cabinetmaker) told him that he should have just brought him the whole sheet because mitering the pieces after they were cut to size was dangerous. He went and got a piece of 3/4″ plywood and leaned it up against the wall behind his table saw. Then he cranked the blade over to 45 degrees and moved the fence over until it was just shy of touching the blade. He told everyone to keep clear of the saw and started to cut the miters.

Just as he was finishing the first cut, the customer walked behind the saw. We all heard that “ka-blang” sound A.J. was talking about and then a loud cry of pain. The triangular fall off piece which was trapped between the blade and fence had shot out the back of the saw just as the customer was walking past. It hit him in the thigh and stuck there for a moment before falling to the floor. The guy had a perfect little red triangle imprinted in his thigh. Henry smacked himself in the head and said, “I told you not to get near the saw!” Then he finished making the cuts and as he did, piece after piece ka-blanged out like arrows, making a very loud whacking sound as they slammed into the plywood leaning against the wall. Several actually stuck. The customer paid Henry and limped out of the shop with his plywood.

What many do not understand is the force a kickback can have. While my example is extreme, you are still looking at several horsepower concentrated in a very small area. You let the blade grab a piece of wood and there is no way you are going to be able to resist that force.

There is no better way to close out the year by wishing everyone a safe and happy holiday, free of kickbacks or any other unfortunate events. I, for one, am taking an “actual” vacation which, for me, means that, instead of not going to the shop for one day, I will not go to the shop for at least a week, leaving me free to go somewhere else and do something besides woodworking.

D.D.

COMMENTS

  1. BOB RENNER wrote:

    This past August I had a piece of 1/4″ MDF kickback on me and it required 16 stitches to put my thumb back together. Dumb me. I knew better.

  2. Carl Stammerjohn wrote:

    The customer was extremely lucky to only receive a “red triangle.” Where I teach, a student was making beveled cuts for a staved vessel on a 5HP cabinet saw. He failed to push one of the pieces all the way past the blade. The blunt ended piece, about 1 1/2″ x 2″, kicked back with such force it broke through (yes, through) a piece of 3/4″ MDF about eight feet away. We have kept it to remind students of the consequences of a kickback.

  3. Peter Cohen wrote:

    I am very familiar with the seriosu kickback issue described above. About 25 years ago, I was working at Savanah Oak in Madison, Wisconsin. I needed to cut some mitered edges of white oak and I experienced the same result, only the fall-off piece, kicked back with the power of our four horse saw. The little 5/8″ x 5/8″ x 25″ triangular stick hit me in the crotch. It felt like I had been kicked by a horse! I folded over and went down to the ground. As I started to get up, my boss came running in having heard the kickback from the adjacent room. He put his arm around me and asked if I was O.K. After telling him that I thought I was fine, he told me not to panic, but blood was staining my pants and running down my leg. Well, to make the first part of this story short, luckily the wood stopped when it hit my pubic bone about 1/2″ above my penis. Two or three stiches was all that was needed to get me back on the job.

    Since then, I have used a technique for cutting those miters and I have converted every shop that I have worked in. It is safe, fast, and accurate method. I cut a rebate in a piece of 3/4″ MDF, and attach it to the fence on the tablesaw, usually with two FlatHead brass machine screws, tapped into the fence. It requires different rebate hieghts for different thicknesses of material being edge mitered. The center of the blade’s thickness runs into the rebate’s top edge. This relieves the pressure on the fall-off piece after it has been cut free. the top edge of the board being cut has a continous surface to ride on against the fence. The vibration of the saw running and the wind on the blade slowly blows the cut-off piece backward. Often I will place a small trash can just under the rear edge of the fence to collect the triangular sticks as the slide backwards off the saw. In the summer I have to wax the bed of the saw so that they slide easily enough to fall into the trash can.

    Using this technique, I cut all of my parts to size with square edges. This is much more accurate than cutting the miters directly off the large board, because if the board is not absolutely flat it affect the perimeter dimmensions of the parts. If your fence has flex in it and you are getting burning in the cut, this will comprimise the glue joint. To alleviate that problem, I clamp a board to keep the fence from flexing away from the pressure I apply when cutting the miters.

  4. Peter Cohen wrote:

    Please excuse the spelling and grammer in the above comment, I depend on spell checker and glasses, neither of which seem to be available in the commennts* box.

    If anyone envision the set up described above, I would be happy to send diagram/cross section via email. peter.cohen@yale.edu

  5. Ted Sager wrote:

    Merry Christmas,

    In my shop, I was getting a large amount of glass or glazing work, and had purchased several sheets of glass, 5 X 10 feet. Stacked very carefully against a wall some distantance from the work area. Safely?

    A new hand was in the processing of ripping some 2x4x8 pine for some minor project. I was across the shop, heard a “swish” and crash. No need to turn aoround. From the stack of glass, I got 4 or 5 pieces, about 12X18 inches, and two 30 gallon trash containers of glass shards. I’ve since stopped doing glass work, just make the frames and send them to my local shop for glazing. Much faster and cheaper in the long run.

    A little older, and a little wiser (?) I try not to work on projects that do not belong in a wood shop.

    Ted Sager

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