Aircraft Drill Accessories

Key accessories for aircraft drilling include drill bits, countersink cage, countersink bits, drill guides, drill stops, and a de-burring bit.

Standard wire gauge drill bits are #40 (3/32”), #30 (1/8”), #21 and #10. These bits will drill the holes for most standard aircraft fasteners. It is recommended to have a full set of 60 wire gauge drill bits just to have the exact size needed for any critical holes you may need to drill. Generally 3” to 6” drill bits are standard for most drilling applications. Occasionally you may find a need for a 12” long bit in the #40 and #30 sizes for hard to access areas. On ¼-28 threaded bits for the angle drill the #40 and #30 are generally the sizes needed. You will find that spring type drill stops are great to keep from damaging your skin and parts – you won’t need to worry about the drill chuck marking the aluminum.

A countersink cage with 1,000th adjustment increments is perfect. Ball-bearing types are preferred. You will need 100-degree (aircraft standard) countersink bits with pilots that match the drill bits in #40, #30, #21 and #10 sizes. Countersink bits need to run at a high-speed in order to cut a clean neat countersink. Adjust the countersink using a piece of scrap metal and test the fastener fit to get it as flush as possible before countersinking you airplane skins.
Drill guides are needed if you have holes that need to be perfectly straight. These are generally plastic guides with a metal collet that matches the drill bit diameter. Rest the guide on your part and drill straight through.

A de-burring bit will make it easy to remove burrs from the holes (although I prefer the hand type speed de-burring tool that uses the countersink bit to de-burr. See the link above.

Pneumatic Angle Drill Aircraft Tools

Quite often you will find that you need to drill in an area of your airplane that does not have enough room for a pistol type drill and bit. In this case the air angle drill is the answer. The angle drill normally requires less than 2” of space, depending upon the length of the drill bit. Drill bits have a ¼-28 threaded adaptor that screws into the drill chuck. Bits are available in all standard aircraft wire gauge sizes. I would recommend a drill that is over 2,000 RPM which will provide the best speed for drilling aluminum or composites. I would also recommend an air swivel which will keep the air hose from binding during the drilling operation. See the link above for a photo of the angle drill.

Pneumatic Drills for Aircraft Fabrication

For aluminum sheet metal a high-speed air drill will cut through the aluminum the easiest. The high-speed drills range from good quality economical models to high quality drills like the Sioux drill. These both have teasing triggers – a trigger that will allow you to operate the air drill at a slow speed until the bit starts grabbing the aluminum, the full throttle to complete the hole.

For steel you will need a low RPM air drill from 400 to about 650 RPM range. This will allow you to drill a neat and controlled hole in harder metals without burning up the drill bit.

Aircraft Tools for Drilling

There are a wide range of drilling tools required for building a Van’s RV aircraft or any other experimental homebuilt airplane. These include a tabletop or stand-mounted drill press, air drill and battery powered drill. Also, you may need a variety of drill bits, countersinks, de-burring bits and other miscellaneous items like drill guides, hole saws, etc.

The drill press is needed for making small parts of wood, plexiglass, aluminum, steel or any other material you are using. The drill press allows accurate drilling of straight holes for torque tubes, control sticks, rudder pedals, bearing mounts and many other items. It is also an excellent tool to use for drilling and cutting out an instrument panel or a switch panel. For the panels it is recommended you use metal hole saws rather than a fly cutter on the larger holes. This will provide a much better cut out and these are safe to use. Place a piece of scrap wood under the part you are cutting or drilling to provide a good clean cut all the way through the panel.

An air drill for most aluminum applications needs to be fast. The faster the drill the easier it will be to drill holes for rivets and other fasteners. Minimum should be 2,600 RPM and you may easily go up to 6,000 RPM.

A battery drill is great for de-burring.

I will discuss drilling in more detail in future writings.

Other General Purpose Cutting Tools

The band saw is a fantastic cutting tool – just make sure to have the appropriate blade for the type of material being cut. I use the band saw for wood, plexiglass, aluminum and some steel. It is great for cutting small parts or jigs from wood. For plexiglass and metals you will need a fine tooth blade. For hard metals like steel you will want to run the blade at a very slow speed.

Air grinders are really a must have tool. For the most useful set you will want a straight and a 90 degree head angle grinder that turns around 12,000 RPM. Generally the 12,000 will give the most torque (power) for grinding, sanding, polishing, and de-burring. Get a high-quality grinder as the cheap ones do not have the torque needed.

Razor blades or utility knives are good for everything from opening boxes to cutting and scraping all kinds of items.

A hacksaw is a required item which works great for almost every material you will need to cut. Have extra blades on hand.

Cutting Tools for Aircraft Tubing

Most projects include some amount of 4130 steel tubing. One of the most economical methods to cut tubing is the hacksaw. A bench grinder may be used to curve the edges to mate for welding. If you have a lot of tubing work there are regular tubing jigs available that will drill and cut the tubing at different angles in one operation. This is one of the fastest ways to cut and prepare the steel tubing for welding. Another economical method, which I generally use, is a fiber blade steel cutoff saw. I finish the end using an air grinder to mate the surfaces before welding.

Cutting Tools for Aircraft Composites

If your project includes composite materials, which most do, you will benefit from some special cutting tools. Fiberglass is relatively easy to cut and trim. Tougher composites can be cut using the same tools but you will need extra blades, cutters and wheels. I have found that the easiest method to cut composite materials is using a grinder type air saw with a 2” saw blade. The high speed saw cuts through most composites very fast. Other options include a fine tooth jig saw or band saw, however this method may delaminate the edge of the material being cut. Another good method is to route the cut. You may do this using a high-speed router, preferably an air router, and a router guide. For materials other than fiberglass it is a good idea to check with the material manufacturer to see what cutter and cutter speed will work the best for that material. In most cases you can sand the edges with fine wet/dry sand paper to smooth and finish the cut.

Cutting Tools for Aluminum Aircraft Sheet Metal

This is one area where high-quality tools are very important. Cheap tin snips will tend to dull quickly and cause the aluminum to roll rather than to shear clean when cutting. Another important consideration is ease of cutting. Regular tin snips require your hand to be right between the two sharp edges of the aluminum being cut. Good offset aviation tin snips will allow the hand to be above the sharp aluminum and may avoid getting a hand cut. Another benefit of the offset tin snips is that they are easier to get a lot of leverage when cutting. The tin snips come in straight, left and right cut. Use them exactly as they are labeled. Yellow handle straight snips for cutting straight pieces, red handled left snips for cutting curves to the left, and green handled right snips for cutting curves to the right. In judging the quality of tin snips based upon retaining sharpness and ease of use I would rate them as follows: #1 Klein Tools Offset Tin Snips, #2 Klein Tools Straight Tin Snips and #3 WISS Brand Aviation Tin Snips.

For very large and flat sheet metal parts, such as a wing skin panels, you may want to locate someone with a foot shear or power shear which will provide a very quick and clean straight cut.

Marking Tools for Aircraft Sheet Aluminum

Van's RV Aircraft kit is the basis for my writing but the same principles apply to all experimental homebuilt aircraft whether you are building a rag-wing or sheet metal airplane.

Obviously, the first step will be to mark the sheet metal for cutting and bending. For simple straight cuts and bends a rule and a permanent parts marking pen are the essentials.

On more complex parts you may try a method that I learned in a silver-smith class. Use a paper copy of your drawing and a bottle of rubber cement. Simply coat the back of the paper and the part with a thin layer of rubber cement, allow to dry thoroughly. This will bond much like contact cement when you stick the paper and metal together. After the part is cut the paper and rubber are easy to remove.

Introduction to Aircraft Tools

Building an airplane is a monumental task. You will undoubtedly develop a passion for really nice tools. The right tools will make your Van's RV aircraft or any other homebuilt project go much smoother, faster, and the quality of your project will be GREAT!

In my writings I will attempt to explain the tools needed for specific tasks, compare the quality of different brands, and try to answer any questions you may wish to send to me. I am intimately familiar with Klein Tools, Snap-On Tools, and almost every air tool brand including DOTCO, Chicago Pneumatic, Cooper and others.

I also have a pretty good network of tool users including RV and T-51 aircraft builders, general aviation and commercial large get mechanics. My friends and myself are using tools everyday and I will be happy to pool our collective knowledge to find an answer to any question you may have about aircraft tools, their use, quality, maintenance or repair.

Bookmark the page and come back often to check out the tips I will include as I write. GOOD LUCK on your aircraft project!

Brad