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With the epoxy cured, it is time to bring the center electrode to length. At this point there is about 3/16 of an inch sticking out from the insulator. This needs to be reduced to 0.016 inch. If I try to just grind this to length it is probable that the heat from the grinding will damage...

Now to gllue the electrode assembly into the insulator. I use 5 minute epoxy for this. The epoxy needs to be reasonably thin so it can be worked into the insulator. My epoxy of choice is IS made by Bob Smith Industries. and is packaged as two 4 ounce bottles in a package. It is a 1:1 mix...

Time to do some assembly. The 0-80 screw needs to be soldered to the end of the center electrode. I start by making some solder preforms from 0.015 diameter electronic soft solder. Don't worry if you don't have any sine solder like ti as other methods work as well and I will talk about that...

The center electrode is made of 1/32 hobby shop music wire. Before starting to cut them I wipe the wire down with a paper towel saturated with acetone to remove oil from the surface. It's just easier to do the whole length than the individual pieces. Revoving the oil makes the soldering job and...

The 0-80 screw for attaching the spark plug wire to the plug is next. It is held in a 1/16 collet in the lathe and a #65 hole is drilled through it. I use a solid carbide printed circuit board drill bit for this. The point on these drill bits are very good about self centering. If the screws...

Center drill and drill the 0.047 hole in the 5/52 end. This hold does NOT go through the insulator. About 1/16 inch remains undrilled. The 1/16 inch is not critical and can vary +/-0.025 is no problem. It is necessary to peck drill this hole to to keep the drill flutes from clogging...

The drilling of the insulator is done on a manual lathe. One end could have ben done while in the CNC lathe before cut off but for me it was easier to just do in on the manual lathe. The insulator is held in an 1/8 inch collet. No collet stop is needed as the part will stop when the 5/32...

Back to making insulators. With the 3/8 diameter held in a collet the end is faced off with the 0 radius right hand cutter and the Z axis 0 is established. To mimimize then cut the 1/8 diameter about 1/2 of its length using several passes. I then cut the remainder of the 1/8 dimiter, again...

Hi Doc -- I watched your excellent videos when you first posted them and wanted to reference them when I started this thread. I was having trouble finding them because of problems on my end. Thanks for chiming in and saving me the trouble of finding soI could llink to them.Our methods are a...

EDIT: SEE POST #44 IN THIS THREAD FOR AN UPDATE ON INSULATOR MATERIAL. Next up is the insulator. I make my insulators out of Corian. Corian is the trade name for a filled acrylic plastic used in the USA for counter tops. There are some generic versions that work just as well. It machines very...

Back to the milling machine and the 3/16 AF hex is milled on the body. I used the vertical collet closer and CNC for this, but it would be easy to do with either a rotary table of a spindex on a manual machine. Then back to the lathe to put a slight chamfer on the edge of the hex to make it...

An anvil was made form a length of 1/4 steel. The end was turned down to 1/8 diameter for a length of the body, minus the electrode, plus about 3/64 inch. The edge of the end was broken slithtlllly with a fine file. The anvil is clamped in a vice using a vee block and the body is slid on...

The body was moved to the milling machine where it is held in a 5c collet in a vertical collet closer. Since I was doing multiple parts I put a stop in the collet. The ground electrode was milled to width with an 1/8 inch 4 flute end mill. The milling operation was done in 3 steps 1/32 deep...

The body is the most complicated part. On most construction projects I generally start with the complicated parts first, then I can alter the simple parts to fit if I mess up the complicated part. I started with 1/4 inch diameter 12L14 steel bar. The end was faced off and three diameters wore...

Spark plugs always seem too be of interest to the IC crowd so here is another construction thread on my recently finished d production run of plugs. These are threaded 10-40 and are just over an inch long overall. They are similar to the plugs I used in my tinyengines which were detailed at...

A few things you might check. These might sound silly, but they are things that I have seen others or my own engines. Check that the spray bar is clean on the inside. I have seen an instance where there was a chip inside that prevented the needle from closing all the way resulting in too rich a...

Norm, You and I both hit the jackpot. With two main flavors of AMD, you and I both got one of each. Mine started a bit over a dozen years ago. Mine was fairly well under control and then I had a stroke and was unable to receiver treatment while I was in rehab learning to walk, talk and scratch...

"What are the responsibilitys of a global moderator?" Global Moderators, keep HMEM a friendly and fun place to visit for the members. Spammers are a constant threat. HMEM has good automatic spam filters that keep most of it out, but spammers find new ways around the filters so some gets...

I have been using loupes for about 60 years. When I was a young man it was as a aid to building small parts, but now I am legally blind they are a part of my daily life as well as in the shop. Firs t tip. When setting a loupe down ALWAYS place it with the lens up. First reason is for safety...

I did the original treae on boot molding that Steve referenced. It is at: https://www.homemodelenginemachinist.com/threads/ignition-boot-molding.14539/#post-148814 Since that thread I have used othermold compounds. I use it for other purposes also. This one I purchased on eBay for about...