Precision Machined Body for my 1.3 GHz coaxial low pass filter

[@GermanMythbuster]

Very good intro! You know right a way what's up. Your editing style gets better and better. I think you have found your style 😊👍 Great job mate! 🙂

[@MachiningandMicrowaves]

I reckon by the time I get to 100 videos, I'll be mildly competent. Long way to go....

[@BravoCharleses]

@@MachiningandMicrowaves Well you're doing a good job fooling us all.

[@bobwilson7684]

@@MachiningandMicrowaves sexy lightning is crucial, it comes out good, your images are atractive to the eye.

[@9h1gb]

Nice Neil. As alway you got me hooked till the end.

[@makerspace533]

I'm surprised AIMEE didn't point out that whenever you use the knee for precision movement, the last move should always be up to prevent backlash from getting you.

[@smash5967]

I've been able to get really good surface finishes in aluminum with a 5 insert face mill on Bridgeport with an R8 spindle, the trick is light cuts and plenty of cutting fluid. Having seen videos of fly cutters explode/fly through machine enclosures and multiple walls, plus being aware of how they aren't the best for the spindle bearings I tend to avoid them.

[@MachiningandMicrowaves]

I do have a really nice end mill with inserts that makes an excellent finish, but it cost about five time what the cheap shell mill did. Actually I got if FREE when I bought 20 inserts. The cheapie has a variance in cutting edge height or at least 100 micrometres, which is enough to leave multiple lines. Two of the pockets are accurate to 5 um, so I sometimes run with a pair, but there's still the impacts and the large variation in tool pressure because of the missing inserts. What I need is a high quality 125 mm face mill which can take inserts that are perfect on aluminium and copper. Those beasts tend to be expensive, and then there's what to do when the heatspreader or case is wider than the cutter. Always end up with a faint herringbone pattern.

[@dumdidumdumification]

I understood some of these words, but you're an excellent presenter :)

[@MachiningandMicrowaves]

[blush] I need a lot more practice and I have a huge number of software tools and machining things to learn. Once I reach 100 videos that are not too embarrassing to watch, I might start to get the hang of this 'Choob lark.

[@joaopaulocoelho5401]

I believe that your videos could become much better if the actual RF project, and some theory behind what you are doing, would be provided. Even if metal machining is fun to watch, I would be very much interested in its driving reasons and prototyping details (maybe in an extended version). Showing the final HF test results of the microwave parts you made would also be nice! Nevertheless, I really love your content!

[@MachiningandMicrowaves]

The next episode of the low pass filter series will show the results of the filter when it's in use and carrying about a quarter of a kilowatt. I'm 6-8 weeks behind with editing and I have four videos partially complete, three of which have either a technical deep dive or some practical results and comparisons with the theoretical model. Working five days a week at the day job and managing a 1.6 acre garden and woodland, plus a large backlog of machining jobs means I have very little time for editing videos at the moment. I hope to go back to part time working from next week, then I should be able to get up to my target of at least one video per week. I have a part-completed video on the theory of coaxial low pass filters and how that translates into practical designs, looking at the require precision and the effects of the insulating "pips" and the transitions. I'm trying to learn Manim (originated by 3 Blue 1 Brown) so I can present the results in an animated graphical form. I've been talking to the distributor of Sonnet software to see if there's any way I can get an affordable licence to run larger designs in Sonnet. Also I've got the free versions of Antenna Magus and CST and I'm trying to learn those as well. I'm tied up 100% this week on putting together ninety transverter kits for 10 GHz that have been waiting for my attention for more than 18 months. At some point I'll get caught up and (hopefully) have a small stock of completed videos that I can release on a regular schedule, a nd with more of a mix of machining, practical experiments and theory. I'm a total beginner at all of this and it's going to take me AGES to get efficient and fast.

[@joaopaulocoelho5401]

@@MachiningandMicrowaves Thank you for your kind response. Please accept my apologies. It was not my intention to put any kind of pressure on you. I think your content is so singular and wonderful that I'm sure many of us would like to dive deeper into the engineering side of many of your videos (i.e. be able to learn from your vast knowledge on the subject :) ). RF design is so strange and counterintuitive that seeing first-hand the matching between the design and the final implementation would be fantastic. My remark was only to highlight the fact that microwave engineering is very fascinating and showing only the machining of the component, even if very entertaining, does not provide the whole story. However, I understand that you may have many different occupations that need your attention. I will be patient and wait for your upcoming videos :D!

[@rogeronslow1498]

I love the machining. I find it very theraputic. However, many of the microwave precision machined filters have been superseded by SAW and BAW filters nowadays, and very often they're dirt cheap, but not tune-able.

[@MachiningandMicrowaves]

Indeed, and they are zero fun as a result! A bit like electric cars. Boring consumer products that work suoerbly and are easy to maintain and cheap to build and completely lacking soul and character. Efficient, profitable, quiet and sensible. Now and then it's nice to play with steam external combustion engines and big old V8 petrol burners. Same with 3D printers and CNC. Hugely effective and performant, but feels like work instead of messing about on manual machines and using hand tools. I wouldn't want to be without all of that tech, but it doesn't quite scratch the same itch that my old clunkers and hand tools have. It's about the journey, not the destination

[@rogeronslow1498]

@@MachiningandMicrowaves I suppose it depends on your perspective. I do it for a living and machined RF parts are simply not an option for the products I work with. I want to know that when the products roll off the end of the production line that every one will be perfectly tuned and meet spec. It may be boring but I sleep well knowing they are repeatable and no labout intensive tuning is required.

[@MachiningandMicrowaves]

@@rogeronslow1498 Yep, if I was doing it for anything other than entertainment I would be doing everything very differently.

[@dennishall9173]

Love it when you set them little chips free , weeeeeee

[@tacticalrabbit308]

I like hearing Amy speak to clarify what you said . LoL 😂😂😂

[@MachiningandMicrowaves]

Indeed, she speaks the truth. In my head, she sounds like an ex-colleague. She was a force of nature, and not to be trifled with. Scared the h*ck out of me.

[@WhiskeyDale]

let me say it....... tappy tap tap facing off as is tradition YAHTZEE !

[@MachiningandMicrowaves]

Heh heh, AIMEE didn't feel inspired enough to channel Quinn this time, so thanks for the assistance!

[@AlessioSangalli]

I'm so happy you uploaded, thanks

[@MachiningandMicrowaves]

This is from four weeks ago, I'm still trying to catch up with the backlog. Four more filmed but not edited videos are in progress. I'm working full time at the day job to cover for an absent colleague and that leaves no time for editing videos or playing with microwave things. I just bought some 40 GHz active multiplier devices to get a bit of power at 76 GHz, 122, 241 and 248 GHz, but I must try to clear my backlog of work before doing ANYTHING new!

[@AlessioSangalli]

@@MachiningandMicrowaves I once tried to put down the gantt chart for my home projects and it's ridiculous, the dependency list is so deep - and I am not even running a KZbin channel, that I know takes much more time and resources. However, let me say again, I am always so happy when you can finally upload. Thanks!

[@jimsvideos7201]

Great fun. RF is bananas but machining I more or less understand.

[@MachiningandMicrowaves]

Different type of bananas from those in the CEE Australia videos that Kurtis makes!

[@squelchstuff]

Your filter is shaping up quite nicely. I do hope you plan to share your results when you characterise it. On a side note, is it me or is Amiee off her bytes and giving less sass than usual? I am aware she's off her bits, but that's another story. Great video as ever. I'm hooked.

[@MachiningandMicrowaves]

I'm making eight of these, so it'll be interesting to see how similar they are to each other and how closely they conform to the modelled performance. I think we're both a little distracted at the moment, several big projects all about to happen at the same time. I need to finish the vid about the detailed design process and how that constrains the machining of the physical filter. This is a busy time for radio contesting/sport radio and I've had to make a lot of parts for antenna systems, azimuth rotator couplings and mountings. Sadly, it was all rush jobs, so I didn't get to film much of it, but I'll post a few photos of the finished items. For the next few days I'm finally collating all of the items for some 432 MHz to 10 GHz transverters. I ran a group purchase for the parts and enclosures and circuit boards and I have NINETY kits here, which cost me £7500 and I need to get them boxed and shipped. There are over 800 component sheets, each with up to ten surface-mount component strips which have to be cut to length then taped in the right place on each sheet. Then all of the other parts of the kit need to be bagged and boxed, then shipped. I think it will take less than 40 hours in total, but that is a huge proportion of my non-working time for the next week. The project is 18 months late so I just have to get on with it. Caroline was helping me with it before she died and somehow I was totally unable to restart work on the project. Now it's a year since we buried her, I have psyched myself up to complete the job. I might do a video about making one of the transverters. Perhaps I'll include a time-lapse of me making up component sheets....

[@wilcojuffer5940]

Hello in the early days (40y) I work also bindind a Bridgeport and I used some fix blocks for the deph control, can you show a drawing what you make ? Nice video 👍👍

[@MachiningandMicrowaves]

Exploded model of the filter is at kzbin.info/www/bejne/iWWvc4t-o8x6Z9E

[@wilcojuffer5940]

Tanks a lot I know now what you turning and milling 👍👍😊

[@graemebrumfitt6668]

Awesomeness in a vid Dude! TFS, GB :)

[@aleksandarvasilevski7410]

Favorite machinist, since he is not using wd40 as lubricant for aluminium.

[@MachiningandMicrowaves]

That cutting fluid is about 10% WD40, 5% IPA and the rest is an ester-based cutting oil (Millicut J40). Sorry!

[@MmmmmmmmEarHair]

I know this is over 2 months old, but was that deflection and wobbling of the reamer at 2:08 not caught or just not a big worry in the end? Or third option, im just going crazy

[@MachiningandMicrowaves]

I saw that, but it stopped wobbling after about 2 mm, I wonder if I deburred the hole carelessly? The top few mm of the hole might have been oval or oversized after that reamer wobble, but of course the top few mm were removed but a subsequent operation. The alignment of the socket is defined by the stepped ring on the read face mating with the stepped hole. If the central hole was actually off centre by 0.1 mm or so, there would be a very minor impact on the characteristic impedance of the nominally 50 ohm section of line. Having the same ratio of centre conductor size to bore size and a few percent offset of the centre conductor has an extremely low impact on the surge impedance as the inductance per unit length is constant but the capacitance is reduced on one side and raised on the other, almost balancing out. Measuring the error is rather tricky, as I'd need to make a 30mm diameter mandrel, centre it precisely then push the body over it, then use a dial test indicator on the bore. Well spotted anyway! I'll run a simulation usint ATLC2 to see what the impact on the impedance would be for say 0.5 mm off-centre positioning.

[@MmmmmmmmEarHair]

@@MachiningandMicrowaves Yeah i figured that even if it did wobble, when you put it all together Aimee would have noticed and not let you hear the end of it.

[@BravoCharleses]

I'm a big dummy. What's the benefit of using the face mill with one insert instead of with all the inserts?

[@MachiningandMicrowaves]

It's a cheap shell mill and the precision of the pockets is poor, so if you use multiple inserts, you get a rotten finish with raised lines. Great for bulk removal when roughing, but hopeless for finishing. Also the mill only has an R8 collet. If it had something stiffer like an ISO40 or 50 it might be worth using an expensive face mill with multiple inserts. I need to make a dedicated flycutter which can take lathe tooling and that's super stiff with a lot of rotational inertia to get a mirror finish on copper and aluminium at least. Basically, it's a bodge, but it works!

[@BravoCharleses]

@@MachiningandMicrowaves Sounds a lot like my own misadventures; working around limitations and making due with what I've got! Cheers from The Rubber City, Akron, Ohio, USA.

[@MachiningandMicrowaves]

That's the secret of success, if you can't buy a thing, and can't make it, you can always repurpose something else. All you need is a plentiful supply of cunning and a sufficiently warped mind.

[@paullang1961]

hey long time sub love this channel mate cheers from Down Under

[@MachiningandMicrowaves]

I just wish I had more time for making videos, Real Life is getting in the way of having fun!

[@petevenuti7355]

Ever do anything in the terahertz gap?

[@MachiningandMicrowaves]

Nothing yet. I used to play with big CO2 lasers, and I'm watching closely what's going on with fast photodiodes and mixing a pair of tunable dye lasers to generate beat frequencies in the hundreds of GHz range, but the area above 300 GHz and below 10 micrometres is very tough to get into unless you have a University lab or similar at your disposal. Some of the locals are doing interesting things with comms at 30 THz, but they are using bolometers and FLIR sensors for detection, and sometimes using a sun-tracking mirror as the thermal source to save on battery power when they are on a hilltop. I've been looking at germanium lenses and first surface mirrors for 30 THz, but not done anything more than drooling at old Melles Griot catalogues (now Thorlabs) and browsing the Edmund Optical website. I've played with long distance visible light comms using LEDs putting out about 15 watts of red light into a 300 mm square Fresnel lens, but finding sites in the UK with a long enough free-space path is close to impossible. However, I want to try cloud-bounce over 200+ km, but using LEDs and lasers is like using spark transmissions on radio, very 1900s. There are some Japanese experimenters doing interesting things at 800 GHz, but the practical limit for me at the moment is probably 288 GHz using harmonic mixer diodes and cavities on receive and multiplier diodes in flip-chip packages on transmit. I have more than enough projects to fill the next two or three years without trying to get hold of a die bonder. My aunt used to be an expert wire-bonding operator at a specialist semiconductor fab, so I could get a collab going with her if I can find an old bonder.

[@petevenuti7355]

@@MachiningandMicrowaves that was more than I expected and a lot to digest 😁. Do you remember ricochet wireless? Or, Do you remember Ronja or ever hear of Digital Atlantic? Both involved free space optic communication.Ronja was a hobbyist Russian project that I likely misspelled that used car tail light LEDs and telescopes. The second was a failed startup out of poolesville Maryland , if you look up their patent, the six smaller lenses to be used for tracking and alignment were my contribution.. the main optic was very much like the Huygens optics monolithic from his videos. The whole unit was intended to fit in the size of a soda can doing multigigibit at 1000ft.. after my friend Steve the CEO died it seemed like everything got run by the marketers not the engineers and the company fell apart.. This was back in the 90s when I was trying to start my own wireless ISP, but I was intentionally avoiding microwaves.. preferring optical or the 915 megahertz ISM... I was fascinated how strategic placement of rebar in the trees in the woods could create beneficial Fresnel effects to get around line of sight issues... I still have some free world dialup VoWiFi phones made by Utstarcom from near the end when I gave up..(cable broadband came out) My interest now in the terahertz range is much like when I was a child playing with old radios fascinated with trying to pick up or send signals in otherwise empty spectrum not having any idea what I was doing....( I wish I kept my tube collection) terahertz technology is so much untapped potential, if it could ever be practically and affordably figured out.. well it's not going to be by me because now all I got is a germanium window and $20 bucks

[@mincukspuncuks8694]

Is there final assembly and measurements? Can't find them.... :(

[@MachiningandMicrowaves]

Not yet sorry, Real Life is getting in the way right now!

[@mincukspuncuks8694]

@@MachiningandMicrowaves I'll be waiting for it :).... Just wached BBC bugging video... it is awsome!!!

[@AI7KTD]

Procrastination is your middle name, sure, but where's the next part? It's been 7 months!

[@MachiningandMicrowaves]

I must get that video finished, yes. Too many projects!

[@chopper3lw]

See This Old Tony... you should not have to go through life without a fly cutter.

[@MachiningandMicrowaves]

The real application for the flycutter is for mirror-finishing copper heatspreaders that are 5 inches wide, so controlling chatter and avoiding resonances, tearing and edge impact ripples are critically important. I think I need a steel disk with a heavy cast-in lead infill and a 25 mm toolholder slot to be able to get the surface finish I want but with excellent damping and stiffness. If I tram the mill really well, I can get better than 5 micrometres flatness across a 100 mm copper slab using the single-cutter facemill in two passes, but I should be able to do better with a single pass of a much heavier cutter.

[@chopper3lw]

@@MachiningandMicrowaves I'll look forward to seeing the creation of the lead bearing beast.

[@sommersetcoker5455]

i see it done regualary, but why only one insert?

[@MachiningandMicrowaves]

It's a cheap shell mill and the precision of the pockets is poor, so if you use multiple inserts, you get a rotten finish with raised lines. Great for bulk removal when roughing, but hopeless for finishing. Also the mill only has an R8 collet. If it had something stiffer like an ISO40 or 50 it might be worth using an expensive face mill with multiple inserts. I need to make a dedicated flycutter which can take lathe tooling and that's super stiff with a lot of rotational inertia to get a mirror finish on copper and aluminium at least

[@sommersetcoker5455]

@@MachiningandMicrowaves well, that would explain why i get a rubbish finish from.my cheap shell mill! ha! i learn so much from your interesting videos. dont stop!

[@realfoggy]

Amy and I both love @KentuckyBallistics and nobody likes EGGPLANTS!

[@MachiningandMicrowaves]

I grew some eggplants once. They withered and had mildew. Probably for the best.

[@Tadesan]

May I be your apprentice? I want to expatriate.

[@franklingomez5311]

First again! I'm simply too quick.

[@ikbendusan]

i guess i can't name a certain chinese supplier of goods; comment gets deleted automatically lol. have you thought about getting a monocrystalline insert or end mill from china? i bought one and was pleased with the result. they're relatively affordable (but they're not cheap per se; it's a diamond after all). i would share a picture but words are illegal in the youtube comments, much less hyperlinks

[@MachiningandMicrowaves]

I don't see anything in the quarantined messages, so it must be deleted invisibly. I'll go and look. Never thought of trying monocrystalline inserts

[@MachiningandMicrowaves]

Ali express part number 1005001946379849 for example. Interesting

[@ikbendusan]

​@@MachiningandMicrowaves that's the manufacturer i purchased my insert from. they have a bunch of different types. if you go to the baba website (let's see if this gets deleted lol) you can find sellers that sell milling sticks with the diamond directly attached to the end of them so you could try machining side walls with them too

[@Putersdcat]

This is total shit, I liked and subscribed

[@9h1gb]

By the way Neil, dropped you an email.