|Project by jfk4032||posted 01-12-2014 03:34 PM||3115 views||7 times favorited||20 comments|
After researching LJ and Youtube for spline jigs, I found a simple model from The Homestead Craftsman on Youtube and modified that version to fit the Delta Unifence weird profile.
I added some knobs, threaded inserts and threaded rods for functionality. Nothing too complicated or fancy about this jig, but it does the trick and works great. But something strange was happening…
I bought a new Freud flat top blade and set that up to the desired height into my jig. When I cut the splines for the cutting board in the first picture, this brand new blade began to spark as if I was cutting into some metal or a nail. I double checked all around the cut to make sure I didn’t have a bonehead design with a nail or screw in the path of the blade, and that was not an issue. I rotated the cutting board and made the next cut and the same sparks happened for that cut and the next two. I inspected the blade afterwards and it look fine to me, just some discoloring on the carbon tips, which you would expect from being used.
I called up Freud and explained the situation and they never heard of such a complaint. They sent me a new blade by returning the “problem” blade.
After the second new blade arrived it occurred to me what the issue possibly could be and was hoping that perhaps any of you Lumberjockers out there have had such an issue, or are versed well enough into physics to concur with my idea.
The little triangle block clamping wedge is loose in my design, so like many of my jigs, I countersunk a rare earth magnet into it and a corresponding rare earth magnet onto the face of the jig so I don’t lose it. As seen in the second to last picture above. Perhaps the proximity of the magnet when the clamping block is in use to the rapidly rotating saw blade (as seen in the last picture) when passing each other within an inch or less created some kind of eletro-magno thingy (you like my scientific terms?).
Am I delusional or could this be possible? Or could this be just a freak bad blade? I’d love to get some feedback from all of you MacGyvers or physics teachers out there.
I have since cut a different triangle clamping block out of some scrap particle board and didn’t attach any magnets and when testing that, the second blade didn’t spark. I had to send back the original blade that did spark in order to get the new one with no additional cost to me. So there is still a slight doubt in my mind as I couldn’t test one clamping block with magnet versus the other without all other things being the same.
-- ---Joel; Central MD...rookie empter nester and getting back into woodworking!