Toolmaker's vise Question

[Lets Roger That]

I just purchased a 3" toolmaker's vise and at the base of the front jaw there is a v groove. The front jaw is integrated in the base as one solid piece of steel.
Anyone know why manufacturers cut this groove? I looked at many brands and they all seem to have it.

It makes it difficult to use slim parallels. Your thoughts.

Gilles

[mklotz]

The groove is there in case burrs on the edges of workpieces prevent the work from seating solidly (and therefore aligning with) the fixed jaw. What happens is that the burr "slides into" the relief slot; with nothing to butt against it can't influence the alignment of the part.

Look carefully at quality machinists' squares and you'll see a similar relief slot.

Of course, good machinists deburr parts before clamping them in their vises.

[12L14]

It is second reason, first one is grinding wheel - ever tried grinding corner?
You can find cut like that - or 45degree slit - even in original Hermann Schmidt ones.

[ductape]

A thicker parallel could be placed against the jaw in order to bridge the groove when thin parallels are needed with the work piece. Not all of them are a precise or consistent thickness, though.