Never used one, but I know some guys love them. They look like they completely suck. How big is that table saw table? 10" by 12"? They seem gimmicky to me. They are like those 15 in 1 fishing tools people like to get me every year for Christmas. Theres a reason I have a $150 pair of abels and not some dumb scale, pliars, clippers, toothpick, measuring tape, hook sharpener, and flashlight combo tool. Might be worth it to help him drag it out for free, and then part it out to the poor mopes that still have them. Then, go buy real tools with your earnings.
I'm a caliper woodworker too but I've never once in my life needed a caliper on my planer. I even bought one from Barry a long time ago and it just sat in a drawer for a couple years until I sold it to someone else. I just don't see the need for it. I know I've already been given two examples of how they've been useful but there are other ways to skin that cat. If you get one for free...by all means, slap it on your planer. But it's not something I would spend money on unless I had every other conceivable tool already purchased. A Wixey gauge on a drum sander, on the other hand...that's something that I could consider. Although I've gotten this far without that, either. It just so rarely matters that boards are a particular thickness if you're using a logical workflow. As for calipers, I just have a cheapish i-gaging or whatever it's called. It has settings for fraction, decimal, and mm. It works fine, but I'd love a Starrett because Starrett is Starrett.
I got a fractional caliper at Woodworkers Supply. It reads out fractions to 1/128" also, but there's a chart on the back of the caliper with decimal equivalents - pretty handy, as long as you have your glasses on!
Thanks for the link. Back when I was a kid, right after the wheel was invented, I remember we had a high chair that would break down, (intentionally) where the bottom platform would fold out and up, and the bottom became a play table. Pretty easy to visualize from that description, eh? About 15 years ago I found one just like it at an antique store and bought it with the intention of refinishing it for my grandkids. They just started high school this year and have never seen it . So when you said breakdown, I thought maybe it was something similar.