Hinsdale DOE Wrench

[Bierisch]

I recently came across a Hinsdale wrench at a Pawn Shop and figured it was basically free so I picked it up.

I was just curious about it as the sizes on each side of the wrench are not fractional or metric, but they are decimal equivalents.(One being 0.866" and the other being 0.827")

Does anyone else have any info on this, or have any of their own to share?

 

[Sam'sAutoParts]

Just a WAG but could it be for AN fittings?

 

[Bierisch]

The WAG I have is that they are just metric equivalents as they are basically 22 & 21 MM respectively, but they are slightly bigger/ slightly less than even. But I have no idea.