Friday, July 28, 2006

A Spanner Deviantly

Here's to old Uncle Albert! He lived a life that spanned three centuries. I now have most of his old tools. Today, using some down time at work, I bead blasted a few old wrenches. The gnarliest was a double ended spanner of 13/16 and 7/8 ends. The thing looks like it was salvaged from a wrecked pirate ship. Someone commented that they've seen tools salvaged from a shop fire that didn't look half as nasty.

The real puzzlers are two small double ended spanners. I measured the span and checked our charts to see what it might be. It was certainly not U.S. Standard or SI (metric). Someone suggested that it might be the old British Standard Whitworth. So we got out the machinists handbook since none of us knew what the old Whitworth measures were. Turns out the heads, the only part I was concerned with for my project, are the same as U.S. Standard so that wasn't it either. I do have a double spanner that is clearly marked 11/32 on one end and 13/32 on the other. Nobody in the shop, not even the old school machinists who often wow me with their machining lore, was aware that nuts and bolts of that size were ever in use. But these two little wrenches still defied all classification. Even allowing for broad tolerances, their sizing did not make sense with any known standard. One had the number 721 stamped into it. The other had the number 23 (and it was certainly NOT a metric 23 on either end) and the word "BUHL" stamped on it.

I'm going to take a few more of old Uncle Albert's deviant spanners into work for clean up and see if I can't piece this puzzle together.

2 comments:

X said...

I recall hearing once that before the advent of assembly lines and interchangable parts, farm and industrial equipment didn't have any standardized bolt sizing, since they were all machined individually by the manufacturer. So when you bought a piece of machinery it came with a set of tools required to do all of the servicing. I wonder if it is possible that the numbers correspond to various part numbers instead of sizes? Just a thought.

Unknown said...

The same recollection had crossed my mind. The machinists at work seemed to think with standardization taking root around the time of the Civil War that any non-standard spanners would predate mechanized farm equipment. Regardless, I'm keeping the farm implement theory in the number one slot for now.

And for once the internet is really not helping my research.