The Basics / Wrenches



Looking at the list lets group them together and try to touch the highlights.

The list calls for a standard SAE combination wrench set starting at 3/8 inch, which is woefully short of my most used list.

Missing are the small wrenches that are used on shoulder nuts on modern turbines and airframe alike. The ignition wrench set covers those sizes but unless you buy a high quality set they are not adequate for the job.

My line bag wrench set starts at 1/4 inch and I took out the 1 inch to save weight. I have added three Long Double Box End Wrenches; 1/4″-5/16″, 5/16″-11/32″ and 3/8″-7/16″.  A long 1/4″ box is an absolute necessity.

The next two on the list are an 1 1/8 inch and 1 1/4 inch combination wrench. I’m not sure why 1 1/4″ is required but the 1 1/8″ fits Oxygen / Nitrogen bottle regulator fittings. I don’t carry either in my line bag due to weight issues. Instead I rely on my “Ford” wrench or Knippex Pliers (more on that later). I used to carry an 1 1/8″ Service Wrench (Bonney) but someone decided they needed it more than I did. Although the Bonney wrench set is too heavy for my line bag I think they are a must for an aviation roll-away because they are narrower than most standard combination wrenches.

Next on the list is the ignition wrench set. I carry a cheap Craftsman set that I don’t use much and could be substituted with two individual wrenches; a 7/32″, 9/32″, but by the time I bought these two wrenches from Snap-On I could buy three or four of the Craftsman sets. I have had to update my wrenches with the addition of my Snap-On 1/4-5/16″ off set box wrench.

Next is a 10″ or 12″ Crescent wrench. Again, I’m not sure why these are necessary and they are far too heavy for my line bag. Instead I rely on my “Ford” wrench and Knippex Pliers. Some people prefer the “Boeing” wrench (Rigid Hex Wrench) but at nearly 12 pounds it is much too heavy for my line bag.

Finally although they are not spanner type wrenches the list calls for a set of Allen Wrenches. I find that not all allen wrench sets include the .050 size used on many instrument knobs. Buy a quality set and make sure it includes that size. Not mentioned are the Bristol wrenches that Gables Engineering uses on their audio selector panels. I still run across these occasionally.