I've got one, and it works OK. It's not going to be as accurate as a
purpose built humongo caliper, but if you are OK with the tolerances,
they work fine. They also take a little bit of assembly, so swappping
back & forth can be a pain. They fit some calipers better than others.
I think I contacted the manufacturer and they recommened B&S. I kept my
eyes open for a good sale & got one that is semi-dedicated for the
I've tried to use one of those.
The jaws of the caliper tend to interfere with the measurement using the jig.
It looks like they photoshop-disappeared the jaw ends in enco's ad.
I can't imagine being able to hold +- 0.005" with one.
For $60 more you can have a tool that is much more accurate and much easier to
Have a look at use-enco.com Model #890-9822
If the budget will allow, the Model #505-1811 will last you as long as you could
possibly ever need it. I have two Mitutoyo Digimatics and I can't break them.
JTS Machinery has some great buys on calipers. I have their 12" stainless dial
caliper and am quite happy with it.
Their 24" SS dial caliper is part #10-24-001, $88.00
If you can get by with a vernier caliper, their 24" model is #106-755, $45.00
If you order on Tuesdays, everything is 10% off. These part numbers are not on
their web site or eBay store, only in the sale flier. Their number is (800)
I've got an extra 24" Starrett 123. They have a couple thousandths
wear at the extreme tips of the jaws, otherwise in good condition. I'd
sell them for $100 +shipping if you're interested.
Like these, but no box.
Hmm ... what you've pointed to *looks* (in the absence of real
specs) as though it will only make it out to 18" maximum.
Try looking on eBay for older large vernier calipers.
Or -- does your milling machine table have 24" of travel? If
so, you might be able to use a centering microscope to detect the ends
(and since both ends of the workpiece are likely to be beyond the worn
center of the leadscrew, if you are careful to approach both ends from
the same direction you can probably get a pretty good reading. Or -- if
you have a DRO (and that much travel), you can do it more easily.
You'll still need the centering microscope or some easy way to verify
where the ends of the workpiece really are. If they are machined
cleanly, just an edge finder should do it -- at the cost of needing an
extra 0.400" or so of travel.