How To Make Removable Metal Spark Plugs

[hot ford coupe]

Many moons ago, I had planned to write a tutorial on how to make removable, relatively realistic spark plugs. Unfortunately, I never got around to it. Since I’m doing a well detailed Big Drag, I decided it would be the perfect time to make good on my promise.
Making removable spark plugs is not as difficult as it sounds and it doesn’t require a lot of specialized equipment. The pictures below shows the basics required. Also needed is a Dremel motor tool and a vise to chuck your brass rod. You can find a decent, inexpensive vise at Home Depot or Lowe’s that can clamp onto a table top. If you don’t have a vise, you can still make the plugs by carefully stabilizing the motor tool in your hands. The vise is just a lot more convenient and safe.

The first step is to take your 1/16” thick rod and with the 1-72 die, cut a threaded section about 3/8 of an inch long. A good hemostat can be used to hold the rod while cutting the threads. Next, cut the rod off about ¾ “ long and thread on a 1-72 brass nut. Make sure you tighten the nut well or put a little CA glue to hold the nut secure. Next, chuck the piece, threaded end in, into the Dremel which has an adjustable chuck. The pictures show how your piece should look. The chuck can be found at any store that sells Dremel tools and accessories. I got mine at Lowe’s. It also helps to have the handpiece extention but it’s not 100% necessary. Turn the motor tool to a low to medium speed and use the corner of the file to cut the squiggly sides into the rod. If you want to make a straight sided plug, just cut your rod end down so you can slip your spark plug wire onto the end. Next, take you 1-72 tap drill and thread the inside of a piece of 3/32 “ tube. Cut off a 1.5 to 2mm piece and thread that onto the end. You may need some CA to hold it in place. Trim the threaded end to about 2-3 mm, paint your plug as needed.
Now you need something to screw the plug into. I took a piece of rod, threaded the end with the 1-72 nut, heated it and pressed it into the plastic of the engine to make a hexagonal hole. If you want, you can drill a hole and cut the hexagonal pattern into the plastic. The easiest way to glue the retaining nut into the engine is to take another threaded piece of rod with a 1-72 nut on it, add CA into the hex hole, hold the piece until the glue sets and screw the rod out of the nut. Just make sure you position all the nuts the same way so your plugs will look straight and uniform and voila! Removable spark plugs. Clean up the area around the inserted nut, fill any gaps and paint the engine.
Now if you don’t have the die and tap which you can get from Scale Hardware, you still can have metal plugs but they won’t be removable. Instead, chuck your rod directly into the Dremel , cut your pattern with the file, glue a 2-56 nut onto the rod, slip on a piece of 3/32 tube over that and cement the end into a 1/16” hole in the engine. It’ll look pretty much the same as the removable plugs. If you have any questions, just ask.

If you really are into detail, you can drill a hole in the end of the threaded section and glue in a piece of thin aluminum and bend to shape. Then the plug will look super accurate.

[kmeaders@q.com]

Nice work , I can't wait to try this out. Thanks for posting. Ken