If the typical cast iron slot which can be mounted on the front of
the bench (Rio and Esslinger have it; probably also others) will not
fit your pin, perhaps it could be filed until it did. It seems to be
pretty thick in the catalog pictures.
If this doesn’t work, I’d suggest, chiseling or sanding your current
slot until it is relatively squared up again and then shimming it
with wood strips on the bottom and one side until the slot is
slightly too small to take the pin you want to mount. Then sand
and/or chisel again until you have a snug fit. If you slide the
chisel sideways by gripping it close to the edge with fingers and
thumb, you can take off thin shavings as you can with a plane.
Probably the bottom shim can be glued and clamped with a C clamp or
two and the one at the side may need to be glued and screwed with a
countersunk screw that is below flush so as not to interfere with the
You could also, after shimming, make a horizontal slit in the slot
at the bottom extending about an inch and a half to each side. Then
vertical holes and put two wood screws into them from the bottom.
Then you can tighten them and squeeze the slot tighter on the pin. If
you do this, you’ll have to “clamp” the shim on the side by wedging
something in the slot while the glue dries or find a way to make the
horizontal and vertical screws pass each other. Use a fairly thin
wood screw and you can drill out the hole if, after some use, the
screws get loose, and use larger ones. You don’t change the pin that
often, so this arrangement will probably last a long time.
Just another idea…