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A third method of making the washers is really just a rehash of the punching of boh the ID and OD. The punches are the same but the die has a guide for the punches built in. This allows the punch/die set to be used in an arbor press or the the punches to be driven with a small hammer. The...

Another method of producing the OD is by punching with a setup similar to that done when punching the ID. The punch is made from 1/4 stock and has a pilot turned on it that is a close sliding fit in the ID of the washer. It would be possible to drill the rod and insert the pilot, securing...

Thanks for the comments. All are welcome. If you have a different way of doing things please post them. I apologize for the time lapse in this thread. Life has a way of getting in the way of playing with toys., There are a couple of ways of cutting the OD of the washers. The first way...

A couple of holes are punched. And then a bunch. Notice n the photo that I got some of the holes too close to each other. This will make cutting the parts apart with snips or a saw difficult while leaving enough material for the OD. This will only affect one of the methods that I will...

Since the washers are being made of soft copper the punch and die can be made of any mild steel and does not need hardening of any kind. Unhardened it would be good for at least 500 holes and then a touch of the die on a belt sander would make it good for another 500. I made the punch by...

Moving on to the third method of putting in the 0.190 holes. The holes are punched with a very simple punch and die set. I have a foot press, AKA Kick press. that I normally use. As these are not common in most home shops I set the punch and die up on my small manual mill which has a 6x24 inch...

Just to show how out of date I am with the technology of on line shopping I looked on Amazon with a search for copper sheet and found many listing for 23 and 24 gauge copper sheet. 23 gauge is 0.025 inch thick and 23 gauge is 0.021 inch. Either would work OK but I would prefer the 23 gauge...

The second method is the same as the first as far as setup but done on a manual mill. Put 3/16 holes in the blank with an end mill then finish the hole to size using a 0.180 drill. This will leave mmore of a burr than the first method but it is not too bad to remove. If you try to drill...

With some flat blanks in hand it is time to make the center 0.190 diameter hole.s I have used 3 different methods at different times so will describe all three. The first way is to use a CNC milll. The blank is supported on a pair of thin parallels in the mill vice. Only a moderate...

The copper in the split part is in full hard state from work hardening during the manufacturing process. It will be annealed to a soft state before unrolling it. If you have not worked with copper I suggest that you try to open the piece up a bit before annealing using the method in the...

OK, back to making washers. This time out of flat sheet copper. The first problem is acquiring some copper sheet the right thickness. You can buy copper sheet but most of the time they want to sell you far more than you need. For washers this size What I use is copper pipe as used for water...

Grayhhil: Thanks for joining n. Your method has a lot of merit and I can certainly recommend it. If a #12 drill is used the washer will barely slide on the threads. When building my engines I countersink the plugl hole to the major diameter of the thread. This makes it easier to start the...

All that is left now is to part off the washers to about 0.030 thickness. I use a 0.o30 wide parting tool that has the tip ground to a 15 degree angle so side nearest the part cuts first and the parent stock side last. This reduces the burr on the part to make clean up easier. You will...

While not perfectly straight thee tubine is straight enough to be usable. The tube is clamped in the lathe with about 1/2 inch protruding. If using a chuck. it may be advisable to insert a piece of 3/16 rod in the tube to prevent the chuck jaws from deforming the tube. A collet is preferable if...

Getting staarted on the first method. Sometimes, not often, things just seem to work out our our way. I needed 0.245 minimum on the OD and 0.190 ID. It just turns out that the most common 1/4 copper tube in the USA is 0.250 OD with a wall thickness of 0.030 resulting in 0.190 ID nominal. It...

JTH: Thanks John. I am glad you are finding this thread useful. While the nut was optional in some cases a sealing washer to bo between the plug and engine is not optional. The washer needs to be made from a malleable but stable material that is softer than either the plug or the engine...

The nut used to attach the spark plug wire can take many forms or even be optional in some cases. The easiest nut is of course to use a standaard 0-80 nut. Since my fingers don't work all that well I have trouble with them sometimes so I make a knurled nut. An easy alternative to a knurled nut...

Thank you John (both of you) and Earl for the kind comments. John1958: PEEK should work just fine. Here in the US we use Corian because it is easily available, chaeap and adequate for the application, not because it is the best material. For the type of engines that I build, small low speed...

A moment of truth approaches. Slip te insulator all the way into the body. If all the machining dimensions have been held the center electrode should be about 0.025 inch. from the ground electrode. Minor variances can be taken care when when setting the gap later by bending the ground...

The jig for the final grinding operation is the same as that used for the cut oo except that more materil is milled off so about 1/16 inch of the insulator is sticking out. I mounted the jig in a drill press vice and mounted that on my tool grinder.I could then adjust the position of the jig...