If you want to talk about microwave precision - phase matching semi-rigid coax cables at 18 Ghz - by hand trimming. I'll let you do the math - wavelength at 18 Ghz divided by 360 = length in inches per degree. Spec was usually 2-3 deg.
RandyC link=topic=682.msg3673#msg3673 date=1296598721 said:I didn't know that the part had to be warmed, I was assuming that the parts that must adhere together would simply have a light coating of shellac applied and then pressed together at the "tacky" stage (which happens rather quickly with shellac). That shellac trick is definitly going to be tried out before the week is over, it beats the tar out of using carpet tape on fragile parts !!!
Another FINE tip that I will not forget: super glue and baking soda ... who would have imagined ? From your photo, I see what you mean about the odd angle of the dressing stone. That is also a good tip, I've turned many motor and generator commutators back in the day (before automobiles had alternators) and using that little Atlas saw to de-burr the copper and undercut the mica was always a pain. (If I still owned that old lathe with the commutator goodies, I would have included photos of those tools in this post - they are pretty clever in their own right.)
Many thanks,
Randy
mumbles link=topic=682.msg3658#msg3658 date=1296593256 said:Funny how common items like Bees Wax and Shellac come in handy for metal working.
These methods that were used in years past, are nearly lost in these times.
Here are Shellac chucks that came with my Levin lathe.
Some, the faces have concentric circles cut in, some are plain. I dont know if the circles help with holding, or are to help centering the part.
The watch guy would shellac the face of the chuck, then use the alcohol lamp to heat the chuck and set the part.
http://s170.photobucket.com/albums/u265/donsmonarch10ee/?action=view&current=levinlathe-1.jpg
I think this is still on subject.
For holding parts with glue "right now", super glue, that normally does not work on metal, plastics, or in this use, gluing an abrasive stone to a stick.
The way this works is, lay down the glue, toss some baking soda on top, blow off the unstuck soda, more glue and soda. Do this until you have it built up like a weld.
You can actually machine this stuff. Sort of hard to remove however.
This application I am gluing a small piece of an "Ideal Industry" commutator dressing stone to a stick, to dress a commutator on my Monarch lathe.
This is done with the machine powered up. Need to do this to get the stone in the tight area.
Harley guys, this works on your old generators!
The Monarch guys scoffed at this, however it says to do this on the electrical panel on the machine.
What is nice about this, it gets the commutator perfectly true, and does not smear the copper between the bars like cutting in a lathe, no undercutting needed.
http://s170.photobucket.com/albums/...?action=view&current=commutatorstones.jpg
http://s170.photobucket.com/albums/...ction=view&current=commutatordressing.jpg
Several years ago, I took some parts that were a high nickel alloy, they were made a couple thou too thick, and were thin. they needed to be ground.
I used super glue and baking soda to nest them on a ground steel plate, building up the super glue and soda around them.
I had to soak them in a solvent I got at a model airplane shop for a couple of days for them to release.
One word of caution, super glue and soda will stick you to anything instantly!