"Tom Veatch" wrote

As I understand it, a riving knife and a splitter have similar functions.
They
guide the work downstream of the blade and prevent the kerf from closing
with
the intent of preventing/reducing any tendency for the rear of the blade
to
catch the workpiece and throw it back in your face..

I believe that the difference between a splitter and a riving knife is that
the splitter can be set some distance behind the blade, yet a riving knife
is curved so that its profile follows the profile of the up-running teeth.

The riving knife can also play a part in preventing the contact of the
workpiece or offcut with the uprunning teeth and causing a violent ejection
of same. A splitter, as above defined is less effective in this regard.

A problem with many riving knives is that they are also designed to support
the crown guard, thus bringing the top of the knife above the crown of the
blade and so requiring their removal for rebating and grooving.

As far as I recall, official British safety requirements say that the top of
the riving knife should reach further than 25mm (1in) below the crown of the
saw. Hence it seems to be regarded as satisfactory to use a slightly shorter
than full-height knife.

Truly safe use, of course requires a crown guard mounted independently of
the knife or a Shaw guard or tunnel guard.

Hoping this helps; there's much more about sawbench safety on my web site.

Jeff G


--
Jeff Gorman - West Yorkshire - UK
Username for email is amgron
ISP is clara.co.uk
Website - amgron.clara.net