Recent content by joeby

Have you tried looking for metric shim stock? I have some .03mm (.0012") that comes in handy for this sort of thing. We look for anything that can be used for shim stock at work, for use in setups. Trying to shim parts to correct parallelism can be frustrating. One guy will buy pop-tarts from...

Too many little details look wrong on this one. I don't see the scraping on any of the ways as I have on other Rivetts, there is what appears to be heavy rust in a few places, and pitting in others.

FWIW, a friend of mine picked up one of these grinders at an auction. Sort of a scratch and dent sale, I think. The machine was basically new, still in the crate wrapped in plastic and the familiar, smelly rust preventative. It had had a rough life up to the point he had bought it, having been...

I'm not sure what gain you would get from a copper end on the displacer itself. It's purpose is really to just displace air inside the cylinder, although some designs have it doing double duty as a regenerator, I think. If the displacer is airtight, the heating of the air inside it could cause...

A suggestion for workholding, one of the cheap mini-mag type indicator holders (or similar) flipped upside down and bolted to the machine base would make a nice mag chuck for this size EDM. Kevin

I'm not familiar with the burning characteristics of the home-built generators, but I think copper would still be the best bet for electrode material. Copper tube does a good job, especially if you can flush down through the tube. The tube will leave a post, of course, in the center of the tap...

John, I understand your reasoning, and have no issues with the design you posted. I have seen many individuals buy an industrial EDM without realizing the expense associated with maintaining and operating it. My day to day job is EDM, and do not, would not, have one in my home shop...

Fires are a definite hazard with an EDM machine, sinkers in particular. Wire EDM's and most "holepoppers" that I have seen use de-ionized water as the dielectric. Kerosene was used in commercial sinkers at some point in time, as I understand, but I have never actually seen it used. All the...

There are several ways I can think of, depending on how accurate you want to be. For getting the corner of an endmill on the center, which seems to be the question, I would use the center head for your combination square and scribe a couple of lines across the center of the round stock. Bring...

I've been thinking about this little project. The hardest part of the job is going to be the electrodes. Fine grade graphite would be fine for an electrode, even a commercial torx bit could be used for an electrode but the hole will be oversize because of the spark gap. That may or may not be...

Surface grinding shouldn't be considered a finishing operation only. Using the correct wheel and method, a surprising amount of material can be removed in a hurry. We routinely would plunge grind several hundred-thousandths off punches and other tools. Grinding is the easiest method for some...

Extruded aluminum might be a better choice than cast plate. The cast plate will be easier to keep flat than rolled plate, but keep in mind that t-slots will be easier to break out and threaded holes will wear faster in cast. There were a few cast aluminum fixtures at work with threaded holes...

I would agree that four rails is overkill, it could cause you grief with binding if everything isn't exactly aligned. Two rails spaced as far apart as is possible will work fine, I would think. Keep the linear bearings as far apart as possible also, but keep in mind that the rails will need to...

As Mainer has mentioned, you can set the jaws up close to the chuck or you can indicate along the length of the part on the top and front (easier with two indicators) to get it straight. If you imagine the chuck end of your work being constrained to the lathe centerline (has to be) and you...

Just as a reminder, if the center isn't correct on the steady rest you will turn a taper on your work. The spindle and steady rest centerlines need to be coincident. An individual at work scrapped a long punch a few weeks ago because he failed to check this, he just indicated both ends of the...