History of Quad-I 'Forward' Vise
Pronounced 'quad one'
The principal reason the Quad-I, pronounced 'quad one,' vise
was born, was to align the fixed jaw to the zero reference
on the Cartesian Coordinate System; and to align it in the
first, (Roman Numeral I) quadrant.
That is to say the Quad-I vise with the stop on the left allows
the part to be programmed in the first Cartesian quadrant.
In this placement the part can have solid references for X=0
and Y=0 and the details machined into the part will be in
the plus 'X' and plus 'Y' dimension's. i.e.: "(x,y)"
This is a big help for machining parts which are drawn this
Engineers who draw pieces in today's convention use the lower
left corner as the zero reference. Programmers also use this
reference. So it is only natural that a machinist would try
to use it as well. Of course after the machinist finishes
with his work, the inspection department goes to the coordinate
measuring machine and guess what? They use the blueprint information
done in the first quadrant to inspect the part.
Most vises built today have the fixed reference jaw on the
far end. This places the fixed reference opposite the part
zero in the 'Y' axis. Any variation in part width will then
compromise the feature tolerances in the 'Y' axis.
There are work around's, but not without added cost or confusion.
1. The material can be machined to exact widths to minimize
the width variation. This results in added costs.
2. The part can be rotated 180 degrees and the stop can be
placed on the right side of the vise. This allows the zero
part references to be on the fixed jaw in back and the fixed
zero 'X' axis reference on the right. However the programming
dimensions will need to be minus 'X' and minus 'Y.' i.e.:
This type of programming is done in the third (Roman Numeral
III) quadrant of the Cartesian Coordinate System. Theoretically,
an excellent setup. The down side, though, is the operator
is looking at a part being made 'upside down' as compared
to the blueprint. The operator then has to rotate the print
to see if the features look like they're where they belong.
That's okay, except he can't read the dimensions because now
they're upside down as well. Other than that, everything is
just fine. *Smile
The whole process is pretty confusing and subject to mistakes.
Nothing like holding a part backwards to help an inspector
reject your work.