Festool DOMINO DF 500 Guide D'utilisation page 23

Symptom
Tilted or misaligned
mortise slots
Workpiece joint
won't close (gaps
between pieces)
Tearout or rough
mortise slots
Tapered mortise slot.
The Domino tenon
fi ts only part way
into the slot
Possible causes and corrections
Make sure the fence is set to the correct angle (e.g. 90 de-
grees).
Make sure to hold the Domino joiner fi rmly to the work surface.
Make sure the proper plunge depth is set.
Make sure the joiner is tight to the face of the workpiece.
The mortising bit may have been sharpened too many times and
is too short.
Excessive dust may be present inside the linear slide.
Excessive glue may be present at the bottom of the mortise.
Plunging speed too fast. Slow down the rate of your plunge.
Low-grade materials and plywoods will tear out more than solid
woods. Decreasing your plunging speed will improve the results
but may not eliminate the problem completely.
Dull mortising bit.
The plunge speed is too fast and the bit is not cutting the sides
properly. Slow down the plunge speed.
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