Precision square - a bit of buyers remorse.

[Brian Lamb]

First post, I'll start with an introduction, my name is Brian Lamb and we make the Lamb Tool work items, the square you have been talking about in particular. I have been in woodworking for 35 years or so now, also a retired aerospace machine shop owner/operator/programmer. I have had Felder machinery since 2001 and Robland before that for maybe 5 years, I also moderate the Felder Owners Group on Yahoo, I see a few familiar names in this post.

Why I'm responding.... there seem to be some questions about accuracy. I have had the squares double checked on a CMM (Coordinate Measuring Machine) and they check within approximately .001" of square between the 16" and 24" legs, we guarantee .002" as a general rule just in case we are a few tenths of a thousandth over the .001" value. When we first started making these, I also did what one poster above mentioned, butt them back to back and run an indicator along the straight edge formed by two of them together. This is a distance of just under 48" and I have a youtube video I posted (forgive me for the lack of focus and poor video skills) and you can see the results for yourselves, that is an Interapid indicator with .0005" graduations:

https://youtu.be/kLaKDMFVmRo

In regards to the 5 sided cut, while it works pretty well and can be amazingly accurate, it is also dependent upon the operators ability to get the board located 5 times exactly correct, otherwise your final result is ruined. I used to use it and found too many times I could run the whole process 3 times in a row without moving anything and get different answers each time. That is when the idea of a large square and an indicator base became a lot easier and quicker to calibrate the fences.

If anyone has any question, feel free to ask and we will be happy to answer, or you can see the items we make, and most have PDF files on how to adjust and use them also on the website.