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 way in
today's world.

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.: "(-x,-y)"

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.