In my last installment, I tried to explain the unique features of my favorite series of bench planes, the Sargent Autosets. Well, if you read that epic post, you may be wary of reading this one, as it also deals Sargent Autoset bench planes. I promise to keep this one short and to the point. So, let’s get into it.
As I stated in the last post, Sargent made several sizes of Autoset bench planes. The largest of the series were the #718 fore plane and the #722 jointer. Those two planes included one extra feature that their smaller siblings did not have, an adjustable front knob. By simply loosening the barrel nut on the top of knob, the knob could be moved from side-to-side, or backward and forward, depending on one’s preferences. The side-to-side adjustment allegedly provided knuckle clearance when the plane was used up against a barrier. That makes some sense. The backward and forward adjustment was provided to add comfort to craftspeople with longer or shorter arms. Yes, that’s absolutely true! Sargent actually touted the backward and forward adjustment as a selling feature for people with longer or shorter arms. The #718 and #722 are the only planes I’m aware of that tried to fill the short arm/long arm niche.
Looking at the photos below, it’s easy to see how Sargent accomplished the knob adjustments in a relatively simple manner. A cast iron domed base was mounted onto raised screw bosses on the main body casting. The domed casting has four slots that allow the knob to be shifted into a position and tightened in place with the barrel nut on top of the knob. If the photos don’t tell the story, just let me know and I’ll elaborate more on the adjustment mechanism. Does anyone really want that?
I like the adjustable knob concept for its “contraptionism” but don’t entirely buy the practicality of the mechanism, and have seen MANY of these planes with cracked, broken or missing front knobs. Original knobs are relatively fragile. Often, the knobs have been replaced with non-originals. An original knob’s base is manufactured to match the curvature/shape of the domed base. If you come upon one of these larger Autosets with the adjustable front knob feature, be VERY sure that you’ve done your homework, and you know what to look for.
The first few pictures below compare a #718’s adjustable front knob (on the left) to the fixed knob of a #714 (on the right).
Jim C.