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I've restarted my forms after about 4-5 years of sitting. They are based on the Penrose instructions and the Lawrence Waldron adjustment method, with a few minor tweaks by myself and the machine shop I hired to do the hard part.

Notice I said "hard part", not laborious part. The hardest part of the whole process to me has seemed to get the two bars perfectly aligned and the adjusting hardware drilled and tapped precisely. I found a local shop whose foreman was intrigued by the project and agreed as long as I didn't push them to complete the job. It took about six months with him putting a guy on it when there was some down time, but when they were done, I had two sets of roughing forms 4 feet long and two sets of finishing forms 7 feet long for about $500 including materials, which included 1" square bar stock. These puppies are beefy (almost 50 pounds when finished). After they were done, the shop foreman wisely said, "Never again."

I had pre-sold one pair of forms to another maker for $400, so I got my pair for $100. All I had to do was to true the tops and file the grooves. I spent more time trying to invent an adjustable grooving jig than my buddy spent filing his forms. I got sidetracked, but he finished his and they work phenomenally well. I could never have gotten the dowel pins in so perfectly, or even gotten the bars so carefully aligned, so I'm real glad I paid an expert to do this demanding work. Now comes all the drudgery.

I used a belt sander to level the roughing form since no great degree of accuracy is needed there, and that went quickly. I found that a brand new 10" Nicholson bastard cut mill file had the proper tooth for the job of leveling the finishing forms, and I am only cutting in one direction, without lubricant. A quality file will cut well for a long time. Both sides are almost leveled, then I plan to clean them up with an 8" second cut mill file, although they are pretty smooth as is.

I plan on using a 60º thread cutting tool that is micro adjustable and held in alignment by spring loaded 60º points at either end of the grooving jig to keep the cutter working evenly. I will cut the groove so that when the small end is on the left (I'm a righty) the shoulder bolt heads will be on the opposite side. This will stop me from jamming my thumb into them in use. It will also place the set screws on the side I am working on and give me something to visualize on the "blind" side of the forms when I am setting the taper and have to locate the hole for the hex key.

When the groove is close to depth, I will switch to a three-cornered file and finally, I will lap the grooves with a three-cornered ruby dressing stone and kerosene.