Modifying Tools


Building an airplane in the mountains has its downside. The nearest tool store is 45 miles away so, as they say, “necessity is the mother of invention.”

One of the tasks we all stress over is torquing nuts. We check the table, add the resistance factor, and dial in the torque wrench. Then we look at the nut and fret over how on earth the socket and wrench will fit in the space.

Today, the bear was winning for a few hours ’til “mother” showed up. The nuts in question are in the space between my RV-7’s center-section spar caps. An inch and a half was all the space available.

Clearly, a socket was out of the question. Maybe a crowfoot? Mine are 3/8-inch drive, so a 1/4- to 3/8-inch adapter would be needed. Got one, but there is no way the setup will fit. I could have used a wrench and fish scale, but the fish scale is not accurate enough for the small range. A new set of 1/4-inch-drive crowfoot wrenches costs over $100, plus the time lost waiting for them to arrive. Oh, bother! Hours were spent goofing with tools, visiting local hardware stores, and even thrift stores. I did find a dozen great vinyl albums for $1.00 each!

Epiphany! I noticed the adapter was far deeper than the torque wrench’s 1/4-inch drive and longer than the depth of the crowfoot. I marked the depth of each end and ground both down to the bare minimum. The total ground off was over inch. Now the torque wrench, adapter, and crowfoot fit in the confined space, and the nuts can be properly torqued to spec. Remember to do the math. The additional length of the crowfoot affects the total torque applied.

The best part is, I beat the bear. No money spent, and I got some great music.


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