I am looking to get a caliper just for hollow forms.....I find my figure 8 Sorby calipers have some difficulty with some shapes that are wider, and the width of the metal is wider than needed for measuring the shoulder area when the opening is not large, so I am considering both of these and would like the opinions of those who might have them or be familiar with their design.
The first is from CSUSA, and is designed by Mike Jackofsky.
The second is from Packard Woodworks and is also for large hollowforms. Their product page does not give the width of HF that it will measure, but the MJ one from Craft Supplies says up to 18" wide, which is plenty for me. Here is the one from PW...
Opinions and observations are welcome.......I would like to get it right the first time!