Reply by Madmark2

Looks like you pressed down too hard on the heel. This pivoted the workpiece up into the blade and BANG!

Work slower. Plan your steps, this groove should have been made before cross cutting. Thing your cut thru. Know if, when & how you will change your grip. Don’t stand between the fence and blade. THINK

You should have had the dado away from the fence and not close. This amplified the twist and let it get away.

By the location of the damage on your push block I can tell the block was tight to the fence. This prevented you from pushing the stock into the fence, thus allowing the stock to twist. The push block should really only contact the stock.

The dado at 1/4” fights the push 2X. Your push block doesn’t have a heel to prevent the piece from slipping.

I use a push shoe with a heel and a tapered side stick. The tapered side stick ends at the center of the blade. The shoe block helps push down on the leading edge. The tapered side stick keeps the stock against the fence and prevents the stock from twisting into the blade.

My go-to safety devices.

1. Workpiece too small
2. Pressing down too hard on the heel when feeding
3. Rushing
4. Dadoing near edge
5. No heel on push block
6. No feather board or side stick
7. Push block was against fence allowing twist into blade

Don’t let the desire to avoid scrap make you take risks.

-- The hump with the stump and the pump!