radial arm saw grooving jig for safety

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Central (upstate) NY
While working on the thresholds I made a little jig to keep my fingers further from the blade on my RAS while making a groove (i.e. a ripped dado).

Here is the jig in all of it's glory:

jig.JPG

And here is how it is used:

in.use.JPG

Only the 2 by 4 bit is an offcut from Ned's shop. I had to dip into my own stash for the plywood bits. :eek: :rofl:

I needed to nibble off the top corner of the 2 by 4 so that the jig would pass under the motor housing - and yes, I did check this before getting to the middle of the first cut and having one of those :doh: moments! This jig is, of course, unidirectional - if I wanted to rip from the other direction, I would need to make a jig with the "L" in the other direction. A future version of the jig might look like a "T" instead of an "L" in order to be bidirectional.

The strip of 3/4" plywood (picked up from the shop floor where all the choice smaller offcuts are carefully stored :huh:) was added because the thresholds had the top roundovers already cut and I was concerned that the 1/4" luan plywood wouldn't have enough contact - a slip into the blade while using the jig would totally defeat the purpose of extra safety!

I am currently going through the thinking stage of making a ripping sled for through ripping on the RAS - this will be analogous to the tablesaw users who make crosscut sleds.

One thing I learned during this project is that my Timberline (Amana) combination blade (with one FTG tooth followed by 4 ATB teeth then a large gullet) has the ATB teeth hanging lower than the FTG tooth, giving a non-square final cut at the bottom. Do any combo blades have the FTG tooth as the lowest tooth? If not, could someone explain why it is better to have the ATB teeth be lower?
 
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