The first time most people see a Disston D-8 thumbhole rip saw they wonder how the hell they’re supposed to wrap their thumb all the way around the grip and get it into that hole in front of their fingers. It’s a digital acrobatic feat that few have mastered and many have tried. The other half who don’t yet know the proper name of the saw assume its a finger hole intended to be a home for the pointing finger of their gripping hand. After all, such an important finger must be worthy of its own place to grip the tote, right?
So what the hell is that damn hole for? Your other thumb….
Here it is in the cut…
A two-handed grip like this is quite helpful for ripping.
Anyway, it turns out that proper grip is not the only mystery associated with this historic and much copied saw. With the intent of posting the original patent drawing of the thumbhole in this post, I researched Disston’s patents and couldn’t find it. Odd, considering Henry Disston was as protective of his saw innovations as a pit bull whelping her pups. I even checked with noted saw patent extraordinaire Jeff Burks who confirmed my findings. The closest it seems we can get is the Eisenhardt patent from 1874 as seen here. On early D-8 thumbhole rip saws, the Eisenhardt patent date is stamped on the tote (along with several others) implying that perhaps the thumbhole was the evolution of this patent….right?
So what gives? Well, we may never know. As far as I can tell, the individual thumbhole itself has no patent assigning it to anyone. So maybe it is a finger hole. Or a toe hole. Or perhaps it’s intended for an entirely different area of our anatomy. Your guess is as good as mine.