Replies

1. 
   seajai | May 15, 2008 06:24am | #1

   First, your work should be tight against the fence.

   Second the small "fall off" piece should be on the open side of the miter. With the way you have it set up, the small piece you cut off gets trapped between the fence and the blade and the rotation of the blade pulls the scrap piece into it.

   The radial arm saw blade is pulled through the work and therefore will not trap the piece like a chop saw will.

    

   
   

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   Edited 5/14/2008 11:26 pm by seajai

2. 
   saschafer | May 15, 2008 06:25am | #2

   Was the end of the workpiece (the part that was about to be cut off) pressed up against the back fence when you made your cut? If so, I think that's what went wrong: Because there was no way for the cutoff to freely move away from the blade, one of the teeth on the blade caught it and wedged it into the triangular gap between the blade and the back fence.

   -Steve

    

3. 
   forestgirl | May 15, 2008 07:42am | #3

   I  wonder what percentage of woodworkers have had a similar accident?  I'm guessing 85%+, me included -- nearly gave me a heart attack.  Always beware of leaving a small piece like that as an offcut that can get caught, jammed, whatever, per the posts above.  And always, always wear safety glasses!

   forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-) 
   
4. 
   miller | May 15, 2008 08:14am | #4

   My vote is on the fall off getting trapped.  I have a fairly expensive miter saw blade that is warped badly from a similar incident.

5. 
   hammer1 | May 15, 2008 01:48pm | #5

   That's a dumb way to cut miters on a miter saw! Just swing the saw to 45°, that's what it's made for. If your work isn't up tight to the fence of the saw, there is a good possibility the piece will get grabbed and sent flying. Guess you know that now!

   There are times you need to cut an angle that is greater than the saw will swing. Leave the saw at 90°, secure a block to hold the work on the desired angle but make sure the work piece also makes contact with the fence. Radial arm and miter saws naturally pull the work against the fence with great force. If the work is not against the fence or if the fence is weak from cuts or has a gap in it, you are in a dangerous situation.

   Beat it to fit / Paint it to match

6. 
   MikeHennessy | May 15, 2008 02:12pm | #6

   Besides what the others have said, it looks to me like your jig (fixture? I could never keep them straight) may have rotated towards the blade, since it's only clamped in one spot at the end, compounding the already high liklihood of something catching. This is a bit of a wierd setup -- not necessarily bad, just weird. It looks like a workaround invented to compensate for an inaccurate saw setup.

   Here's what I (and several others in this forum) do on my RAS. I set up the saw carefully to cut exactly square to the fence. This should be no problem with your MS. Then, I make a jig, similar to what you have, but at an exact 45° angle. Use that *against the fence* to position your workpiece at a 45° angle to the blade.

   This is inherently safer on the RAS since the workpiece can still be supported by the fence. The large gap in the fence on the MS precludes this. Your problem is that the spinning blade tries it's best to push the piece back. This twists the piece and binds the blade and the whole thing escalates into an "incident" like you experienced. Fortunately, though these "incidents" can get your heart pumping a bit, they're usually not particularly dangerous for the operator since the shrapnel is usually directed away from the user. (But it's a good idea to never let anyone stand behind the saw when it's in use.)

   All that said, most good MSs have very accurate (at least when they're new) stops at 90° and 45°. I've found mine to be very reliable in that department. Just use the stops, and keep the workpiece tight against the fence. Still not exactly perfect? That's what shooting boards, or a Lion Trimmer, are for.

   Mike Hennessy
   Pittsburgh, PA

7. 
   marty456 | May 15, 2008 02:13pm | #7

   Thanks for the explanation - the loose piece trapped against the fence then jammed into the blade.  I didn't think about the difference between the radial arm saw and the miter saw.  I, of course tried the 45 deg slot and it was not accurate enough.  I'm making a large picture frame 4' x 3'.  I'll look for another way.

1. 
   joinerswork | May 15, 2008 03:44pm | #8

   marty,

   Frankly, this set up looks risky to me on a radial saw as well.  Any time you end up with a triangular cut-off trapped between  the blade and a fence, it is an invitation for binding, kickback, thrown cutoff, bent blade, split fence, or all of them at the same time.

   Ray

2. 
   saschafer | May 15, 2008 04:00pm | #9

   "I, of course tried the 45 deg slot and it was not accurate enough."

   There should be some adjustment for that.

   -Steve

    

3. 
   flairwoodworks | May 15, 2008 08:15pm | #10

   Marty,

   As long as your fence is straight, you should be able to cut the joint to get a perfect 90 degree corner.  Just set your saw to approximately 45 degrees.  Then cut one piece against the left fence and the other against the right fence.  This should guarantee a perfect fit, providing your saw cuts true.  For example, if your saw's left 45 degree setting is actually 30 degrees (exaggeration), the piece you cut on the left will be 30 degrees and the piece you cut on the right will be 60 degrees.  30+60=90!Chris @ http://www.flairwoodwork.spaces.live.com

    - Success is not the key to happines.  Happiness is the key to success.  If you love what you are doing, you will be successful. - Albert Schweitzer

1. 
   marty456 | May 16, 2008 12:17am | #11

   hmmm.  Great info, same principle as I was trying with the jig having the 2 cuts equal 90.  I don't really have room on the right side of the saw to flip the longest length for the frame, but its smarter to move the saw and add a support than go through that again.

1. 
   Henley | May 16, 2008 03:20am | #13

   Also take your time and dial the saw in.
   A few dedicated minutes to adjusting the saw will usually get you very close.
   Then error towards a closed point and an open heal(I'm exaggerating).
   Make it 45 but proud is better then shy.

8. 
   BruceS | May 16, 2008 02:33am | #12

   I really enjoy my radial arm saw for some procedures,  But I am pretty fussy about keeping a "fresh fence" in place to keep it ZERO clearance.

   Work Safe,  Count to 10 when your done for the day !!

   Bruce S.