One of the most import tools to use with your forge is a set of digital calipers. I bought mine from Harbor Freight. I was working on a project last night and need to take some measurements and my battery was dead again. I eyeballed using the printed marks and got pretty close. But I was trying to hunt down tiny watch batteries.
If you measure current, you will see that the power off state draws 90% of the current of the power on state. For some reason, all electronic calipers seem to be this way- power off is actually display (only) off. THIS is why the batteries go bad quickly.
I was able to 3D print a battery holder and was back in business in 30 minutes.
It pained me to toss the one I mentioned. I hate wasting stuff. As well as chewing thru batteries, it was unreliable (inaccurate) as well. I stripped it down and cleaned it twice but in the end just had to suck it up and get rid of it. It was highly-rated on Amazon when I bought it but the listing was deleted when I went back to write a review.
Why buy? Well, I only had the smaller Mitutoyo when I bought it, only got the 2nd on my most recent visit to my folks in 2018. It also had a nice feature that it turned on as soon as you moved it - which is likely why it chewed thru batteries.
