I just LOVE making spacers, jigs and fixtures. Machining tiny parts to within a few ten-thousandths of an inch on a 1980s manual lathe is nicely challenging. Microwave coaxial low pass filters must be made to exacting tolerances to ensure they perform the same as the simulations and calculated dimensions. Assembling them needs some very precise spacers and fixtures.

This is part 3 of the series on a 1.3 GHz high power low pass coaxial filter for the 23 cm band. Lots of fixturing and precise machining, plus a quick look at characteristic impedance. AIMEE my AI advisor gives me a hard time as usual. It's richly deserved. I'm a rubbish machinist and don't even know the difference between a jig and a fixture. And anyway, some of these are spacers. But part of a fixture.

Dedicated listeners to BBC Radio Four and the BBC World Service may recognise my correspondent Mrs Trellis of North Wales. For fans of British Humour, Humphrey Lyttelton on "I'm Sorry, I Haven't a Clue"    • I'm Sorry I Haven't a Clue—The Comple...   is transcendently marvellous.

For a little more context, and the rules of Mornington Crescent, see: https://en.wikipedia.org/wiki/I%27m_S...

The cutting oil I use is Millers Millicut J40, chlorine free biodegradable ester based neat cutting oil. Also makes a lovely squelch, Mrs Trellis. https://amzn.to/3wnE3Qz

I get a small commission on all the short Amazon links listed, at no extra cost to you, it all helps the channel. I paid full price for all of the items in the video. I'm not famous so I don't get free stuff!

The marvellous 3" Knew Concepts piercing saws are available from Amazon.com: https://amzn.to/3sN95kb and for the 5" https://amzn.to/3kWye7v and for the radically expensive Titanium version https://amzn.to/37C4cD6

In the UK it's probably better to order via amazon.co.uk: https://amzn.to/3L1bT39 or https://amzn.to/3M2xpGa if those are out of stock. Folks in Canada, Germany and a few other locations should get redirected to their own local Amazon stores.
The Vallorbe 3/0 blades are here: https://amzn.to/3NlUp3l
The lovely Starrett auto centre punch is at https://amzn.to/3kWvB5t

More info on Vallorbe blades here:
https://www.vallorbe.com/file.cfm?cms...

Full playlist for this project is at    • 1.3 GHz Coaxial Low Pass Filter Project  

Chapters:
00:00 Why?
02:35 Slots
07:16 Tolerance
19:26 Fixturing fixture