Home Made Wrench Tester

Some Vices Never Leave

Remember those kids on the block that always seemed to have the coolest toys?  You know - the ones you didn't have.  If I had the GI Joe with lifelike hair and kung fu grip, Tony had Joe's Jeep.  I had Hot Wheels cars and tracks while my cousin had the Evel Knievel stunt cycle.   Of course my toys were cool in and of themselves, but the other kids' toys seemed cooler!  Well, that was just the earliest examples of envy in our lives, a vice that never really seems to leave us.  Please keep reading, there's  point to this - promise!

The "need"

I was watching a YouTube video the other day of this guy restoring an adjustable wrench from the 1920s.  In the "before" shots, he showed how the wrench jaws were worn and the knurl, also known as the worm-screw was sloppy.  To demonstrate the effect of these problems, he adjusted a bolt on what he called a wrench tester.  After his restoration, he went to the tester again and showed how much nicer the wrench fit on a bolt head, and how it stayed tight instead of loosening and rounding over the corners.  Well, I instantly knew I "needed" this fine piece of workshop gewgaw!  So I watched the video closely a time or two and figured out its beautiful simplicity!  Here are the components...

It is in the character of very few men to honor without envy a friend who has prospered. - Aeschylus

The parts

As you can see, the parts are simplicity itself.  A bolt, a couple washers and its nut, a piece of spring and a little hunk of wood.  The best thing is - I already had each of these pieces, so total cost of the build - $0!  The first thing I grabbed was a piece of scrap wood and drilled a hole just a little larger than the bolt in the middle of the wood.  

Oh, and see that little screw in the front?  Remember that, you'll be shaking your head over that one.  Then I needed a piece of spring.  As it turns out, I had this old storm door spring that was on the old back porch door, you know the kind...you can just make out the old storm door in this shot...

Knowing a day like this would eventually arrive, I saved the old spring that kept that door from being ripped off its hinges in a gust of wind...

Quite a robust spring for such a job, and just perfect for what I needed now.  All I had to do was dismantle it:

Then, using my hacksaw, I just cut a short length of the spring for the tester!  After that it was just a matter of staining the little chunk of wood, and putting the pieces together.  

Totally random House 173 posts
The front porch exterior reveal - Oct 2013
∙ May 2018 - New lights, outlet & switches for the hallway
Yardsticks and door frames - May 2020
∙ June 2017 - Paint for the kitchen
You might also like: Painted Furniture posts on House 173

Here's what the tester looks like from beneath:

The spring puts enough pressure on the nut, that the bolt turns without loosening the nut from the bolt.

Using the final product

That's pretty much it!  Once assembled, I lock it in my vise and test wrenches.  This way when I restore an old wrench I can see if there is any sloppiness or unevenness in the jaws.  If the jaws are uneven, or not paralell in the case of an adjustable wrench, there's a chance they will round over the corners of the nut or bolt, and may be difficult to take off the bolt and reapply without constantly adjusting.  If they're too sloppy - round over once again, or just won't work!

Oh, and remember that little screw?  Look at this little gap:

That's there because the scrap of wood I used was really exactly that.  I grabbed it, rounded over the edges and made the tester.  When I put it in the vise, it turned out that scrap was more a trapezoid than a parallelogram.  But not enough to make me want to square it up.  Instead, I made it adjustable by putting in that little screw.  Totally worth the laughs and snickers you're making right now! 

One last thing

On a lark, a couple weeks ago I ordered a letter punch set so I could put my initials in some of my stuff, like the wrench tester...

Of course, it was a quick lesson that I really didn't need to strike the punches quite so hard!  That said, here's the final product:

Stay safe out there!
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