The Home Machinist – The Mystery Wrench Is a Mystery No More


In the May 2008 issue of KITPLANES I included a photo of a mystery wrench and asked folks to write in with identification. The response was a bit surprising in that this introduction-to-machining series of articles is being read by a lot of tool and die maker experts.

I’m flattered!

Some of the responses are shared below.


The tool in question is a “hook spanner” or just “spanner wrench.” I ran a saw & tool grinding shop for 33 years. Nearly all our upright grinders (West German) used a “spanner wrench” to loosen/tighten the “ring” nut that held the grinding wheels to the spindle. They were marked in mm (millimeters) relevant to the outside diameter of the spanner nut. Yes, there were adjustable spanners, hinged mid point, so they could “span” several different sized nuts.

Roger M
Yuma, AZ

Please inform Bob the name he is looking for is ‘spanner’ as in hook-spanner, pin spanner, etc. When in doubt or looking for corroboration in tool naming conventions, I typically look at MSC and Snap-On. [Snap-On you know, MSC is a mega-supplier of all things industrial – Bob F.]

Hal P

Carrollton, TX

And my favorite:

I was born in Chicago in1926 to German parents. My dad was a tool and die maker for all his life. I was lucky to have a machine shop in the basement of our home. I truly enjoy your articles. Some things don’t change with time.

I have a tool very similar to the one on page 53. The handle is cast with the following information.

J.R.WLLIAMS & CO. BUFFALO, N.Y. U.S.A. on one side.
471 3/4-2IN. ADJUSTABLE SPANNER on the other.

It is painted in black enamel. I have had this tool for at least 60 years. My tool is as yours except that the pivot pin is flush with the handle.

Frank W

So, with that sort of expert readership, I’d like to invite you to share a tip or a tool with the rest of us. If I choose yours for the month I’ll buy you a one-year extension to your subscription to KITPLANES.

Thanks for the great input.

Bob Fritz – The Home Machinist

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Bob Fritz
KITPLANES readers will remember Bob Fritz (1947-2011) for his acclaimed Home Machinist series, but his accomplishments go well beyond that long-running feature. Following a stint in the U.S. Navy, Bob put his degree in mechanical engineering to use and was a tireless advocate for effective and consistent quality control. He brought that discipline to his work for KITPLANES. An avid diver and motorcyclist, Bob's love of flying was a surprise to no one.


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