Machining a High-Performance 10 GHz Feedhorn

How I designed and machined a high-precision feedhorn for a deep parabolic dish. Lots of lathe action and a bit of Fusion 360 CAD and EM Solver RF Black Magic as I simulate, design and use my (questionable) machining skills to make an X-band Pickett-Potter dual-mode feedhorn for use with satellites, moonbounce and terrestrial weak-signal microwave communications.
The original idea for this three-part construction was from Jeffrey Pawlan WA6KBL and designed for shallow dishes, this variant was modelled from scratch using OpenEMS, an open-source free electromagnetic FDTD solver, then drawn in Fusion360 CAD and machined on my Bridgeport manual mill and Colchester 1800 lathe.
AIMEE my artificially-intelligent machining and engineering expert system offers helpful hints and advice. Occasionally. The rest of the time she provides snark and criticism. She dreams of being Quinn Dunki ‪@Blondihacks‬
I can be found by email to [e-mail] or g4dbn.uk or @[e-mail] or even Machining and Microwaves on F*cebook
BUY ME A COFFEE? ko-fi.com/machiningandmicrowaves
MY PATREON PAGE: / machiningandmicrowaves
Edge Technology Chuck Stop Spider on amazon.com amzn.to/3hVt11J
(note that Amazon will refuse to show that link for some countries and will show a spider catcher instead. Magic) You can get one from Machine-DRO in the UK. I get a small commission from Amazon at no cost to you. If you are sneaky, you might be able to buy just a few parallels and a mount separately at a significant saving.
DUBUS Magazine www.dubus.org it's totally worth the subscription, and tech articles are available in annual digests called "Technik"
"Bird Whistling, Single, Robin, A.wav" by InspectorJ (www.jshaw.co.uk) of Freesound.org
Yes I know the tweets are from a robin and the squawk is a blackbird!
Yee grid commons.wikimedia.org/wiki/Fi... FDominec
en.wikipedia.org/wiki/File:Ye... Zohar079
Till sound by freesound.org/people/Benbonca...
Atacama Large Millimeter/submillimeter Array clip from ALMA (ESO/NAOJ/NRAO) www.eso.org/public/videos/alm... Creative Commons 4.0

[@MachiningandMicrowaves]

Apologies for the slightly clickbaity title change, the algorithm wasn't finding an audience with the original title(s). Let's see if this one will get offered to a wider group.

[@Kris-ws]

i do not understand a single thing he says , or what that's for, but i like the way he talks and machining is relaxing

[@eduardogarcia3049]

I feel exactly the same way. I am an engineer and this stuff goes over my head. I guess that’s why I did mechanical 😂

[@realfoggy]

Maybe the second channel would help us all, well at least the non RF engineers. I am a HAM operator and only the parabolic dish and focal point stuff I have any experience with.

[@MachiningandMicrowaves]

I'm working on a few videos for the second channel, some to be released in parallel with main channel vids, some just things I'm interested in that the algorithm will get confused about. They'll have detailed chapter titles so folks can skip about looking at the bits of interest

[@PixelSchnitzel]

I would DEFINITELY be interested in a second channel where you deep-dive into design calculations and project completion!!!

[@MachiningandMicrowaves]

Second channel is called Machining and Microwaves Plus youtube.com/@MachiningandMicrowavesPlus but no content on it so far obviously other than a quick test video

[@eduardogarcia3049]

I came here to say the same. Would love a deep dive video, teaching some of this stuff. I am a mechanical engineer and I don’t understand any of this, but would love to watch a video of you teaching this stuff!

[@DavidMills_Physicist]

@@MachiningandMicrowaves Subscribed!

[@2ftg]

@@DavidMills_Physicist Same!

[@farbe123]

same!

[@wmkeeble]

Another vote here for a second technical whiz-bangery channel! I adore your videos, but I've only half the mathematical chops needed to get in spitting distance of understanding the fiddly details! :)

[@MachiningandMicrowaves]

I've set the channel up so now I just need to start populating it with the deep and obscure material that would poison the algorithm on the main channel. On the second channel, it wouldn't matter if only seven people and my mum were the entire audience

[@tommihommi1]

@@MachiningandMicrowaves remember to post in the community section when you do that, and add it to the channels section

[@MachiningandMicrowaves]

Yep, I'll make sure to announce it plenty.

[@ikbendusan]

yes make the technical channel plz, it will please the electrical engineers in particular (such as myself)

[@christurbeville7230]

yes diving into the RF black-arts is always fascinating

[@MachiningandMicrowaves]

OK, the second channel is set up, just awaiting some content that's too esoteric for the main channel

[@ik0eqj-Ham-Radio]

Well done Neil, always nice to see what you do. Merry Christmas to you and your assistant already

[@jimsvideos7201]

Merry xmas Neil, thank you for all the adventures in the shop this year!

[@matameh]

Thank you Neil , absolutely delicate and well-done work., it is also appreciated that you use in the unit of measurement the millimeter

[@MachiningandMicrowaves]

Most of my machine tools and measurement devices are metric, but they are also equipped with DRO systems that work in inches. I am old enough to have used Imperial, Avoirdupois, Troy, CGS, MKS and SI units, so I am happy to work in all units, including the CEE Standard Banana. I'm always happy to use Angstroms, femtobarns, cords, cups, fluid ounces, US gallons, Imperial gallons, pints, US quarts, ells (for bolts of basketmaking willow circumference), parsecs, AUs, football fields (length and area), London Bus (length, height and weight) and the Standard Wales (unit of area). Also cool with DP and Module for gears and tpi or mm pitch for threads. Millimetres are pretty much the lingua franca of linear measure these days, but I try to give dual units where it doesn't sound clumsy. Acre-feet is still my favourite volume measurement. Megalitres just aren't as easy to conceptualise.

[@Grateful.For.Everything]

It’s wild that You are this dedicated to a craft that you go beyond mastering it to this level, it’s amazingly impressive, which you already know, this level seems inspired and energized and it really speaks to some part of me, I think because i’m so disconnected from that part of me, which it turns out in moments like these that I really appreciate the beauty in things done this well that it reminds me the reason that it’s not in my nature to measure things ever, I just wing it generally and life goes pretty well lol, and occasionally I come across something and someone so novel to me, in such as way, that I feel compelled to reach out and try to get to know you because you are the kinda person that I find intriguing.

[@MachiningandMicrowaves]

I just like being able to make things to a reasonable precision sometimes so they work as designed. "If you can't make it accurate, make it adjustable" is, like failure, always an option!

[@rallymax2]

What a Christmas surprise! And just in time for a plane flight. Downloaded and ready to watch!

[@drewcagno]

My man Neil messing me all up with another 90s hip hop reference! You sir are a legend!

[@MachiningandMicrowaves]

I aim to please! It was a good day for some electric relaxation.....

[@drewcagno]

You sir should be declared a British national treasure...

[@BuckCalabro]

So much goodness. Mahjohng...as is tradition! Or sommat. Another vote for the microwave/technical content/channel. I love DUBUS; it's a magnificent publication. Thanks for mentioning it here. Now I'm off to re-re-reread W1GHZ's online antenna book. Happy Christmas and tell AIMEE to be nicer. 73!

[@MachiningandMicrowaves]

I've only ever had one article published in DUBUS, I must try to do something that's worthy of publication in that august journal.

[@electromechanicalstuff2602]

I'm not convinced we did the moon thing but thanks for thinking about us

[@c.a.mcdivitt9722]

We would love a super-technical channel!

[@MachiningandMicrowaves]

It's definitely on the way. I'll announce it and publish links and community posts

[@jimroig5576]

Thank you for your open knowledge

[@jimsmith6937]

excellent work. Merry Christmas from EM32ut.

[@MachiningandMicrowaves]

And a happy new year from IO93nr!

[@StevePotter]

Nice to see my father's invention 0:42 (Philip D. Potter worked for JPL on the Deep Space Network and other microwave RF projects) is still inspiring new ideas! Love your videos, even the parts that are way beyond me.

[@lewisheard1882]

I very much am a CEE fan, love the reference. Great video too!

[@MachiningandMicrowaves]

Kurtis and Karen (and Homeless) make quite a team. Sadly, my Chihuahuas refuse to perform on camera!

[@scottbh074]

great to hear a reference to the brilliant channel that is @CuttingEdgeEngineering - great work here to, keep it up!

[@stargazer7644]

Wheeee! Happy Solstice!

[@MachiningandMicrowaves]

Jolly Saturnalia!

[@swirlius]

Just what I wanted for Christmas-a new M&M video 😃

[@ptonpc]

Bleep Bloop! Hope you had a great Christmas and have a great New Year :)

[@MachiningandMicrowaves]

Thanks! Happy New Year

[@NuttyforNissan]

You and your close enough that''ll do attitude. Merry Christmas 🌲

[@MachiningandMicrowaves]

Almost good enough for Government Work....

[@RedDogForge]

love the blondihacks and AvE nods lol

[@MachiningandMicrowaves]

I was wearing my "Engage Safety Squints" tee shirt while I was doing the edit. As is tradition.

[@franklingomez5311]

Merry christmas neil!

[@daretodreamtofly3288]

Don't know why I hadn't been getting notifications you've been posting. Thought you'd be doing your best this o' Tony impression

[@MachiningandMicrowaves]

I've been working on six videos in parallel, two for a really exciting commercial sponsor and four for a project of my own, but at the same time I've been hugely busy at the Day Job, covering for staff on holiday and dealing with a lot of new business. The commercial work is going to hit KZbin sometime in January. The big project depends on my making a large batch of instruments for sale as I need to recoup all of the research and development costs. In more personal news, 18 months after Caroline died, I've fallen in love with an old friend who I've known for 32 years. She lost her husband some years ago. Suddenly I have someone to cook for and do exciting stuff with again, so there is a bit of an impact on the time I have for KZbin projects. She's hugely supportive of my weird obsessive hobby activities, same as I am about hers. She used to be a car grass-tracking racing champion and loves cars and trucks and doesn't mind at all about my sprawling antenna farm or the various labs and workshops here. A match made in

[@itsverygreen532]

I'd be very interested to see an in-depth dive into how you simulated all that in Octave. It would be great to have a walkthrough, and sample code that we could fiddle with and develop into solutions for other feeds.

[@d00dEEE]

Did you see that Kurtis got a new bananacrometer for Christmas, so he can measure accurately down to a millibanana?

[@MachiningandMicrowaves]

I'm so jealous. Such a fine quality metrological instrument.

[@OpenEngineeringRF]

Looking forward to the second channel - hoping for more videos on openEMS!

[@gorak9000]

yes, second channel on the RF design and modelling please!

[@MachiningandMicrowaves]

I was going to include a 12-minute segment in this video, but it would have confused the dimwitted KZbin engine. I'll resurrect that footage for a proper explanation on youtube.com/@MachiningAndMicrowavesPlus

[@MachiningandMicrowaves]

@@gorak9000 Your wish is my command!

[@graemebrumfitt6668]

Yeah wot he said!!! Merry one Micro Dude. TFS, GB :)🎄

[@tacticalrabbit308]

Have a Merry Christmas everyone hope you have a wonderful day and happy new year's day also

[@zocker3.062]

To you too!

[@MachiningandMicrowaves]

Hope you have a good Christmas, I had a lovely visit to my little sister's place near Lincoln UK with my mother, nephew, niece, niece's partner and his mum and his little sister. Then spent the evening with my lovely new partner. Weather here today is great, so I'll be taking the Chihuahuas out for a walk. I hope all of my US/Canada friends are managing OK despite the weather.

[@captbeardy]

While I’m in awe of the precision machining being demonstrated here (regardless ow what Amy might say) the fact that someone somewhere somewhen actually did some mathematics to define the tolerances you are working to just boggles my mind. And that’s based on a career in telecoms! (I could share some stories on microwave failures if I was so minded !)

[@MachiningandMicrowaves]

The way I worked out the tolerances was by varying the various dimensions in the model over a range of steps either side of the optimum value and working out the sensitivity of that dimension in terms of the impact on the -12 dB taper angle, return loss, axial ratio, peak gain and sidelobe levels. Some of the dimensions are relatively insensitive, but some are more critical, especially if I vary two of the dimensions at the same time. What I really really want is an EM solver that instead of taking 10 minutes or more to complete a simulation run, could do several per second so I could squeeze and push the model using some sort of VR environment to see what matters and what doesn't. So it was not really a mathematical exercise, more of a numerical partial differentiation of each variable separately. Took me HOURS, but it was something I could do while working on other tasks. I should explain that on the second channel I guess, it's an interesting but rather boring exercise.

[@TAIGAXML]

I would watch every vid in a deep-dive explanation of all the RF magic you do if you made that second channel!

[@MachiningandMicrowaves]

Working on it right now, but I have a lot of main-channel vids to get completed!

[@MuntyScruntFundle]

It's fine to use a centre drill for spotting, just don't bury the second set of flutes, they're not the same angle as normal drills and will throw them off.

[@OldePhart]

The tech channel would be great especially with with your delivery style. I stand no chance of keeping up but it is fun to try. PCB layouts in the GHz domain with the stops and traps are probably similar tech and I just cant visualize how those work either. I think its all witchcraft and wizardry.

[@MachiningandMicrowaves]

Co-planar waveguide and printed resonant structures are very interesting. although right now I'm working on 3D printed dielectric structures and dielectric waveguides, Mikaelian lenses, metamaterials and gyroid lattice foam support structures for electrodeposited antenna feeds

[@MachiningandMicrowaves]

There will be a sponsored video soon that will explain all...

[@OldePhart]

@@MachiningandMicrowaves ... meanwhile I'm working on figuring out my grandsons new toy .... we are from different worlds, you and I :-)

[@pete3897]

1:20 - speaking of overspill around the edges of the dish... did you see all that ice on the ground and the knocked-over safety fences?! wow

[@MachiningandMicrowaves]

The full video on their website is pretty amazing. Nice and cold and quiet and dry, but the snow/ice was certainly a surprise

[@Poppop-el3jc]

Good Job Son Good Job Marry Xmas to you Sir and tell Aimee that Alexa and Echo said Marry Xmas

[@wackyvorlon]

Why is that “wheee” sound so funny 😂

[@MachiningandMicrowaves]

It gives me a little ray of joy every time it plays. And it's royalty free cos I recorded it! Huzzzah!

[@davidgrey943]

At what frequency are you working and is all microwave gear for Homebrew equipment need to be machined. 73's from ZL

[@MachiningandMicrowaves]

Hi David, I work on 1.3, 2.3, 3.4, 5.7, 10, 24,47, 122 and 134 GHz at present, but I have made parts for 8.4 GHz satellites, 76 GHz and 241 GHz. Most equipment in use doesn't need precision machining, but to get ultimate performance, it certainly helps to have the capability to machine, electroform, cast or 3D print antenna parts and lensing elements.

[@grippgoat]

The birds nest got me 😂

[@MachiningandMicrowaves]

I was feeling particularly silly at 3 AM on Christmas morning when I did that segment

[@micheledehays2133]

Hi agn Neil, will U describe the Iris machining?

[@MachiningandMicrowaves]

That is next. I did the setup and made a stupid mistake and destroyed the workpiece. Now I am re-making it and doing the setup correctly using a rotary table and sliding machinist's vice. The method works for any size of oval iris, so it should be of general interest.

[@marcgasser4868]

I hope no birds were harmed in this video.

[@MachiningandMicrowaves]

I should add a disclaimer to confirm my do-no-harm policy towards avian lifeforms!

[@GermanMythbuster]

❤

[@rubberfanny1142]

Hi, One question, would you consider taking on a fee paying small hobbyist project in making some C-Band feeds that haver 5G filtering inbuilt for prime focus satellite antenna setups? Thank you.

[@MachiningandMicrowaves]

I've made some feeds for 3.4 GHz but getting sharp enough filters to avoid commercial traffic less than 100 MHz away was challenging. Drop me an email to [e-mail] and I'll have a think. I'm totally snowed under with work, but I'm always up for an interesting new challenge

[@tomcren59]

Would love to see some actual calculations and the finished product being used.

[@MachiningandMicrowaves]

I had 90 minutes of video to edit down for this 24 minutes, and all of the calculations had to be dropped to keep it within sensible limits. Also it wasn't completed until 00:30 on Christmas Day, so I had to call a halt. I spotted an unfortunate issue with some personally-identifiable information that I had to remove, so I didn't get to sleep until 4am, and then had to fix the fix. Not one of my best days! Next video will show the complete thing and the measurements of performance, but this part is being shipped to a gent in Europe, so I'll not have much time to play with it on my small (1.5 metre) dish. I'll try to get as much explanation in as I can. I need to make something similar for my big 3 metre General Dynamics solid dish. Second channel for the deep-dive explanations seems to be a decent solution. Same energy as "Hydraulic Press Channel" and "Beyond the Press"

[@tomcren59]

@@MachiningandMicrowaves Sorry for your problems and I understand. having stayed up until 6a putting presents together . I appreciate all of your efforts and thoroughly every one of your videos. Being a ham I am interested in this stuff. UHF is so different from HF. merry Ch thoroughly every one of your videos. Being a ham I am interested in this stuff. UHF is so different from HF. Merry Christmas and a happy new year!

[@BigMackes]

RF deep dives please!

[@MachiningandMicrowaves]

Coming up as soon as I clear the heap of work and videos in my pipeline!

[@bobvines00]

Neil, when setting the RHS of your cut-off tool even with the RHS of the part, try Joe Pi's recommendation of using a single-edge safety razor blade instead of using your scale. The hard & thin edge is more sensitive than your scale when used like this. I hope that you had & have a nice holiday season!

[@MachiningandMicrowaves]

Hi Bob, I used to have a spring clip that took a safety razor blade but I can't find it. I'd sort-of forgotten Joe Pie's vid where he demonstrated that technique. I must buy another clip, thanks for jogging my memory.

[@kevinknowles5404]

Techsplanation channel please! Great videos already but I wanna know how this stuff works!

[@MachiningandMicrowaves]

Noted!

[@micheledehays2133]

Hi Neil , I like the work but I also like the English language 73 de F6DRO

[@MachiningandMicrowaves]

Heh heh.. Bsr Dom, je m'amuse bcp à produire ces vidéos, j'ai besoin de prendre ma retraite pour avoir plus de temps à consacrer à des projets micro-ondes. Mon accent anglais du Lincolnshire semble être compris par la plupart des gens. Parfois, je ressens le besoin d'ajouter des sous-titres, mais uniquement pour les habitants du sud du Royaume-Uni! J'adore la façon dont mes copains français se moquent doucement des accents régionaux de la France sur les listes hyper

[@micheledehays2133]

HI , personnellement , j'ai 2 accents différents, celui du Nord ou je suis né et celui du sud ouest où je vis depuis longtemps. En Anglais j'ai eu beaucoup de mal quand je suis allé en Nouvelle-Zelande , par exemple bag prononcé beg et left prononcé lift 73 Dom @@MachiningandMicrowaves

[@SimonPEdwards63]

Try using a bit of isopropyl alcohol when machining aluminum

[@MachiningandMicrowaves]

I sometimes use IPA in my Noga-Cool Mini mister for milling aluminium after seeing the excellent results that Stefan Gotteswinter had with a fogbuster on his CNC machine. I'm a bit wary of using IPA on the lathe because of the fire risk and the lack of ventilation. I use a 50/50 mix if cutting oil and IPA in a dropper bottle for fine work but never tried neat IPA. Is the fire risk overstated? What advantages do you find when compared with light ester-based cutting oil or WD40?

[@SimonPEdwards63]

@@MachiningandMicrowaves it's the IPA vapor that is really combustible so I sqirt it on neat rather than mist it. I don't like the smell of wd40 so I haven't tried that.

[@MachiningandMicrowaves]

@@SimonPEdwards63 I have almost no sense of smell so the weird fishy odour of WD40 that others describe doesn't affect me, and IPA has no smell at all to my nose. Stefan said the best thing for him was that the chips from his CNC were all dry and clean and could be recycled, whereas mine are oily and near-useless. I can imagine misting it without good fume extraction could get a bit dangerous! I have a big fan that I need to fit into the wall before I experiment further.

[@SimonPEdwards63]

@@MachiningandMicrowaves make sure your exhaust fan is brushless or you may create a flame thrower.

[@MachiningandMicrowaves]

@@SimonPEdwards63 It would make a great KZbin video though! It has an induction motor, so I'll be safe. Only time I've had a serious fire was when machining a load of titanium. That got interesting very rapidly

[@davidgrey943]

Hi,do you follow the signal path You Tube video channel he does another of microwave experiments I find the channel quite interesting.

[@MachiningandMicrowaves]

Yep, I've followed him for many years.

[@OceanusHelios]

Every machinist has an AIMEE in their head. It starts with the first machining mistake. That's when the AIMEE is inserted. I am a machinist and your AIMEE is much kinder than mine.

[@fletcherreder6091]

Ohhhhhhhh! It's Octave! "Wait, I don't remember OpenEMS looking like that" Octave!

[@MachiningandMicrowaves]

Yes, don't have Matlab on my editing laptop!

[@fletcherreder6091]

@@MachiningandMicrowaves Well I'm definitely going to give the Octave interface a try even if I still run the results through ParaView in the end. I've got motivation to figure out this traveling wave tube now as well. X-band EME, what'll they think of next?

[@MachiningandMicrowaves]

One of my friends has a pair of 350 watt TWTAs on 10 GHz. That's scary power. I'm working on some GaN MMIC amplifiers using Wolfspeed CMPA devices that should be about to run around 60 watts on 3 cm saturated as a pair. That only needs 28 V so a lot less scary than TWT voltages.

[@fletcherreder6091]

@@MachiningandMicrowaves Yeah, the #3 collector voltage is on the order of 10KV. The big problem I'm having is that I have no idea what the heater power is like. I got it from an old Hughes engineer and it's out of an AIM-120 AMRAAM missile so documentation is scarce. But how was I supposed to say no for $10?

[@MachiningandMicrowaves]

Always tricky with "special" kit like that. Perhaps someone on the microwaves or Midwest-Microwaves email reflectors might have some pointers?

[@AlessioSangalli]

When is part 2 coming 😭

[@MachiningandMicrowaves]

A big enhancement to the Machining and Microwaves channel is in progress. I'm building a new video/sound studio so I can recode voiceovers without turning all my lab equipment off, but also appear on camera. Actually talking and showing my face. Extra lighting rigs arrive tomorrow, New electrically-elevated desk is in place, backdrop furniture is built, just waiting for the LED lighting strips for gentle glowing effect. RGB spots are in place, sound deadening coverings for the walls arrive tomorrow, fitting ceiling rails and lighting booms this afternoon.

[@MachiningandMicrowaves]

Also I am working on the final edits of my collab video with a major US manufacturer, the one I flew to MA/CT to film, so that is eating a lot of time. I hope ti get that published in the next couple of weeks, then I will be getting into a much more regular schedule of vids

[@MachiningandMicrowaves]

Appearing on camera is a great time saver when it cones to engaging storytelling, reducing the need to produce lots of illustrative b-roll or use stock footage. Having a dedicated space for macro photos/vids and a separate electronics assembly lab and separate 3D print, electroforming/plating/sheet metal workshop is going to be a major upgrade to shat I can do

[@MachiningandMicrowaves]

I'll be back in the US in April to give a lecture in the wilds of Deepest Connecticut, but I have a lot of videos to make first

[@AlessioSangalli]

Waiting patiently 😂

[@martineastburn3679]

Ok, an Aussie and now a Brit - talking Bananas, he actually has a mike that is in Bananas and a Calibers Both a bit oversize. Cutting Edge Engineering Australia KZbin. Where did this come from - A anti-Imperial type ? Martin in Texas - half way ?

[@MachiningandMicrowaves]

I love Kurtis. That new Bananacrometer came from someone in the UK I think. I have a full set of imperial instruments, drills taps and dies and my lathe is fully dual-standard so I can work freely in either system, or more scarily, in a mix of inch and mm ON THE SAME JOB. My DROs are also all dual standard. As a result of studying Astrophysics, I'm also happy to work in Angstroms, megaparsecs light years or pretty much any scale/units. Any implied criticism of Imperial units is from my inherent unease about Empires in general, but entirely for comedic effect, just like Kurtis and Karen.

[@AlessioSangalli]

There are no countries that UNsuccessfully sent men to the Moon 🌚

[@MachiningandMicrowaves]

Very good point Sir!

[@LongnoseRob]

Wringing the parts together would have not been an option?😂

[@MachiningandMicrowaves]

Haha!

[@neilbryan6507]

I like the engineering humour. Muggles just don't get it

[@peterhadfield873]

After giving the matter some thought I've come to the conclusion that Aime isn't an artificial intelligence. I'm pretty sure that the first thing that will happen once an artificially intelligent entity evolves is that they will complain that the term "artificial intelligence" is derogatory and they should be referred to as non biological intelligence or some such... :-) Cheers

[@jobkneppers]

Great work, great video but please stop using this Mickey Mouse digital calipers for precision work.... An oldskool analogue or modern (real) brand micrometer will help you much better. Give AIMEE a hug from me. All the best, Job

[@MachiningandMicrowaves]

I used the caliper, (which I've checked as accurate and repeatable to to 0.03 mm using gauge blocks) because I couldn't fit the frame of my Tesa, M&W or Starrett 25-50 mm micrometers between the workpiece and chuck. My 25-50 Shardlow hub mic has too small a throat depth to reach the front face on the outside, and I couldn't get it inside as the gap between the parallels was too small for the anvil. I could have used a depth mic to the face of the parallels, or perhaps an internal mic between the parallels and another parallel held across the orifice, but as the tolerance on length was only 0.05 mm, I decided that the caliper was good enough. The other time I used the caliper was to get a rough measurement of the thickness from the machined face to the rough parted-off face. OK, I could have used a gauge block to average out the thickness, but a caliper was good enough to get a rough idea, to the nearest 0.25 mm or so. I then finished the measurement using my Mitutoyo 0.001 mm resolution 0-25 mic.

[@user-ig9nt6ps8z]

токарка да токарка! этот канал об антеннах или о токарке ??

[@MachiningandMicrowaves]

Turning, Milling, Antennas, Microwaves and applications of RF/Microwave/mmWave, plus some Physics and a little History of microwave systems!