I hear ya about projects. Your help is very much appreciated. I'm not sure what code is running on Tempduino or where to get it. Since cellularmitosis made it, I checked his two GitHub accounts, but didn't see anything that looked like it might be it.
https://github.com/cellularmitosis
https://github.com/pepaslabs
I'll pester Jason if needed. Can't be much to it.
What is this go/no-go gauge: To see if an RF connector was made so far out of spec as to damage the connector it would be mated with?
Precisely. I was testing a batch of Chinese 50 ohm SMA terminators with a Tek 11801 and 20 GHz SD-26 and the male pin pulled out of one! The 11801/SD-26 combination is amazing for checking RF stuff. You can evaluate the devices as fast as you can connect them. At least, you can if you know what the time domain response should be.
Making the gauges is easy relative to rebuilding a 7x14 Chinese minilathe to hold tolerances of 0.0002". I'm still collecting the required tooling, but I think it will be a fun project. I don't expect to get much better than 0.001" on the first pass as I don't have adequate temperature control. But that's OK. The whole point is to take on a project sufficiently difficult that I learn lots of things in the process.
I've owned a 10x20 Clausing lathe and 6x24 mill for 20 years. So I have a pretty good notion of what I'm attempting. What's amazing to me is the nasty attitude on the 7x12minilathe list on groups.io. They bad mouth the machine at every opportunity and my post analyzing the spindle bearings was greeted with contempt as being "reading rather than doing". I'm not an ME, but the more I study the machine, the more impressed I am with the design. It was designed to meet a *very* low price point. Every decision was guided by manufacturing cost and expected level of buyer's skills. As delivered for under $550 US it's just a complete parts kit, assembled at the factory to make sure they don't leave out any parts. But with appropriate modification and a skilled user it need apologize to no one. There is plenty of iron where it is needed. The major compromises are in the ergonomics of infrequent adjustments such as tailstock setover for cutting tapers.
In the late 1940's, David Broadhead, an amateur, was engaged by John Strong, one of the preeminent experimental physicists of the day, to make the screws for a ruling engine Strong was building at Johns Hopkins. In preparation for the work, Broadhead rebuilt his 13" Southbend to eliminate all periodic spindle errors and make the ways straight and parallel to 0.0001". The screws were tested by interferometer to less than a millionth of an inch. After the screws were turned, they were lapped. The June & July 1952 issues of Scientific American have some fantastic articles about it.
At 6e-6"/"-F expansion, it doesn't take a lot of temperature differential to blow through 200e-6". The really attractive part of rebuilding a mini-lathe to such tolerances is it's a *lot* smaller. I plan to recondition my Clausing lathe , but I probably won't go past 0.0005" because of the size.
All the fasteners need to be replaced and some serious work done to true it up, but I know of nothing else that can touch it. A used name brand machine will require as much or more work and parts are much harder to get. I had planned to document the rebuild on the groups.io forum, but I'm looking for an alternative which is more pleasant. The list has 15,000+ members, but only about 2 dozen who are active and *very* unpleasant and outright hostile. As best I can tell, they simply BS about YouTube videos they watch. And occasionally mangle there lathes a bit more with some poorly thought out modification.
I have IDC connectors and ribbon cable. I just have not made GPIB cables up yet as I don't have an interface or a multiplexer. I've got all the parts, but have not gotten around to it.