Panzerrohrgewinde - Grinding a threading insert
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- Опубликовано: 3 фев 2024
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Mechanical detail like this panzerrohrgewinde hints on a secret conspiracy to keep toolmakers in business :D
Something stupid like an American tank blows you up they can't screw on bits from your tank for repairs.
With my pidgin German I first thought that you were finally going to do an episode on machining the breech of a tank cannon. That was a happy second and a half.
With my pidgin Deutscheglish, when Stefan said "we have two thousand and three" I thought he was talking about the run size.
Hmm ... No wonder he wanted to adapt a carbide insert instead of using HSS, I thought....
You and me both buddy. At least now I know how to say pipe fitting thread in German. Gotta look at it on the bright side.
Thanks for another great video. I hope you are aware how much your viewers from all around the world appreciate the time and effort you put into your videos passing along your knowledge and experience. I can't thank you enough ...
In Sweden it's called pansarrör. Until now never understood why. Thanks for the explanation.
Imagine having to identify such a thread in the field. I learned something new again! Thanks for the video
Great that you left in the pitch error and correction by the way :- I was surprised that a man who normally sweats the microns would be happy to use a ruler to judge pitch, but I forgot you were also a man who invests in thread gauges, and thinks👍
Excellent work again, nice that you showed the change gear boo boo aswell! looking forward to the real part video, cheers!
I only ran it to that thread twice in my years of selling cutting tools. Both times it was a medical company part.
If the insert is ground to an accurate 80° angle when square to the wheel, when it's held at a slight angle (to give rake and clearance) in the tool holder, the angle will be slightly greater.
I think.
yep, you are correct - At 5° tilt, thats only ~0,5° profile error, which is at a length of the thread flank of ~1,5mm a practical error of ~5-8 microns.
@@StefanGotteswinter Did you do the calculation (excellent, BTW) before you did the grinding, or in response to my question?!
In hindsight ;)
From experience I know that the error is very small - Also I am bad at math, I sketched it out in cad.
But in this case, you re-ground the top of the insert flat when held in the toolholder, so no error.@@StefanGotteswinter
No, the error is still the samein the horizontal plane. I learn to be so picky from Stefan videos😂
Being American, I just assumed that all pipe threads are tapered because NPT. You have expanded my horizons once again.
Oh Boy, Pipe threads are a nightmare in variation. You get tapered, straight and combinations. 55/60/80° thread angle. Metric or imperial pitch. Metric or imperial diameters. Diameters that have nothing to do with the actual pipe diameter because they where derived from the ID of ancient cast pipes.
And combinations of all of them.
I have made it my personal mission to TRY to learn from those more adept than I, thank you for the opportunity to learn from you
I thought everyone had a bioreactor in their junk drawer. Thanks for the video! Always interesting to see how stuff gets set up.
Cable glands in Europe still use PG threads (now less so).
Brass glands usually have bouth threads in PG size and female side can be used for reference if gauge is unavailable.
Little trivia, in Italy PG is called Passo Gas.
Excellent video,Stefan.Thank you.
Those twin curly chips were gorgeous!
That result leaves me smiling! 👍 Thanks Stefan
There’s always something new to learn on your channel . Thanks !
Great video as always Stefan! Looking forward to the next part. 👍👍
Always entertaining and educational. Thanks Stefan!!
Thanks Stefan, helps a lot.
Very interesting, especially with the freebie language lesson👍👍
Awesome discussion and setup tips/craftsmanship….thank you for sharing
Hi Stefan - I can echo some of the comments below about leaving in the bloopers. I spend about 1% of your time in my metal shop so it took me a while to realize that everyone screws up and the path to improvement is to just keep trying. When we fall we have to get back up again.
Starved for new Stefan content I started going back over your old material. That brought about a content idea you might consider. Your later videos have much better editing and audio. You might consider re-editing old classic content (please keep the old ones too!). @matthiaswandel did this for some of his old videos turning a few classics into 5 minute and very enjoyable watches. I still like the full length versions though because there are many little subtleties that can be caught on review if we try variations on our own.
All the best for 2024.
Always enjoy your videos. Keep up the great work!
Thanks Stefan, another very informative video.
Good job stefan,,,thanks for your time
Clever solution. Thank you for sharing such an interesting video. 👏👏👍😀
Well done 👍 good to see you.
Nice video Stefan. I tried drilling with the carriage on my lathe with power feed and it worked great. Thanks for sharing.
For deep holes on a lathe, that's the way to do it!
Made my day, thanks.
Thanks for another great video.
I’ve had to tap those PG threads in Aluminum electrical boxes in the past.
I knew what you are talking about.
Good video thank you
Yes, I still have to make PG-threads on a regular basis. Its always for electrical connections
Thanks Stefan for the lesson. 👍👍😎👍👍
I recall that during the late 40’s I used to go to some jobs my father did on weekends, installing power cables in buildings, where one had to channel the brickwork to take the black painted steel conduit, which had a close fitting seam, so useless as a pipe to run water or liquids. I am guessing this is the pipe and thread used, being a thin walled tube the thread would not be too deep, yet secure when junction boxes were fitted. I always learn something from your interesting video’s. Greetings from Tasmania Australia 😊
enjoyed very much as always
Thanks Stefan
Nice, I've always just use a little piece of aluminum/copper between the ball and the vise if I don't want to grind a flat on it.
Thats a mindful solution :D
That's a groovy looking thread!
I first glimpsed the title as panzerwagon and I was excited for some tank content. LOL The wrong thread pitch makes it a self locking thread. 🙂
Wanted to say thank you for sharing.
Another great one
again a very informative video...I might have to make very fine threads, and just Grinding my own inserts should be the solution to my "Challenge".. luckilly i have a surface grinder.. so i will have to make me some jigs to put my inserts in.. thanks for the ideas!
As a electrician I never knew PG stands for, thank you. At the moment PG thread cable clands are fased out for metric sizes with 1.5 mm pitch the M20x 1.5 wil fit the PG13.5 nut. I still have a PG13.5 and PG16 tap.
Well that's odd. 🤔 Thank you for the insight as always Stefan!
So, now you're going BIO? :)
I didn't even know that 80° threads existed, so I learned again something new here. Thanks for that.
The reason for the 80° inclusive angle is because the conduit is usually very thin walled and a 60° thread would weaken the thin conduit wall.
I used to work for a bioreactor manufacturer and the PG13.5 is a standard threading for DO (dissolved oxygen) as well as pH and other sensors. From what I learned, the ones who look to be the culprit why this thread is used is Mettler Toledo, as they are one of the first (and arguably the best) developers of DO and pH sensors.
And of course we also had this "go" ring gauge to test the parts which had those threads - as well as "go" and "no go" screw gauges for threaded holes in our stainless steel head plates for the reactors.
We even had compression fittings to use them as ports for 4, 6 or 12mm OD tubes. Interesting to see something like this pop up in my feed ;-)
I'm wondering what they plan to use in terms of sealing. As our fittings, as well as the sensors get screwed into a headplate, we had O-rings in a notch on the inside plane of the threaded parts.
Our surface finish was usually electropolished, as any small area on the surfaces can lead to contamination of the cultivation medium in the reactor.
It's an industry standard fitting but thankfully Ingoldstutzen is more common. Much easier to deal with.
Such a strange thread pitch! Another great video!
I hope you have a good safe new lathe day. Have fun.
A bit more info on the reason for PG conduit threads having a 80° includive angle.
Because the walls of the conduit are usually relatively thin the possible maximum depth of thread is limited by the conduit wall thicknes. This is why a wide 80° inclusive thread angle is used for these class of threads.
I'm in Canada but our shop has a bunch of eastern european lathes,
The fast feed motor is constantly getting filled with coolant, because the flexible conduit was cracked after 40 years, and I wanted to replace it, but I noticed the gland connector hadd some odd threads, and after some research I figured it was PG. Still couldn't get it because none of our suppliers had even heard of it. Found some weird pipe fitting that kinda fit, put a rubber washer and cranked it down real hard. :/
" Found some weird pipe fitting that kinda fit, put a rubber washer and cranked it down real hard. :/" This is Stefan's channel, don't forget! When he read this he probably had to go a lie down for a while to recover😂
@@russellforrest1730I’m sure Stefan has his own share of bodge repairs on his machines .
It’s German threads anyway so isn’t it appropriate to make it gutentight ?
All the reputable makers of carbide threading inserts advise that straight plunge in depth feeding is OK with small fine pitch threads.
A fine example of MetLish !!! best regards Steve
If it was for a flux capacitor, it would be 88 degrees. You can’t fool us!
Do you have a new macro lense or better lighting? The macro shots look amazing! 5:20 or 14:43 for example
Filming in 4k and zooming in factor 2 :-)
PG is still widely used in plastic electric cable strain reliefs for enclosures etc. I have some boxes of them. I believe they are being replaced by M threads, at least here in Sweden.
Use my electronic lead screw to cut threads, so I don`t worry changing gears to get right pitch.
Love you. That is all.
Good morning Brother...Im still holding my breath for the "D-bit upgrade" vids lol have a great day from Canada! 🇨🇦
Ahoi :)
I am slowly chipping away on it, whenever I have a bit of time. Currently theres the new motor on my bench.
@@StefanGotteswinter I'm just teasing you Brother. Keep doing what you're doing, I appreciate the videos 👍 have a great day Stefan
Me too
Thanks Stefan.
I use a piece of aluminum or copper between the ball and the vice when clamping.
Seems to be the case all over the world... if you want to find threads from distant history ;) still in use... go look for pipes!
Do you use bags in your festool? Or just the filter and the filter purge? We always run bags in our festool with the cyclone. It still bumps but there’s nothing in the filter. I also have the smaller festool that doesn’t have the purge. I also run filter bags in that too. Not a huge fan of most festool tools, but I really like the vacuums.
I had a comedy show, a podcast and your video. So Stefan's video first and then all of that 'the rest'. Thanks! Is it caribide grinding with cbn or diamond? For hardened steel like hss which is the best?
So much to learn as always. I forget... what size multifix toolpost do You have? Size A?
Never disengage the half-nut if possible. Words to live by..... CHEERS
Excellent video, out of interest could you have ground an 80 angle by grinding 20 deg off one edge of the 60 degree tip. This would provide an 80 deg tip, but offset. To square this up the tool would then need to be offset by 10 deg, do you think this would work?
Nice one . Too small a thread for the compound angle to effect things . Cheers 👍
Thread gauge from the GDR.
The reactor manufacturer may be using an odd, obsolete thread to prevent the end user from using inexpensive, off the shelf components to connect to their equipment.
Hmm, I don't feel like thats it, because theres a lot of after market / 2nd vendor items for bio reactors with that thread. I suspect its some kind of legacy thing.
@@StefanGotteswinterI would guess it has something to do with cleaning. This sould be easier to clean, since it is wider than normal thread.
very possible, yeah
@@fkiesel9442PG threads are 80° inclusive angle because the conduit wall thickness is generally comparatively thin. If a 60° angle thread was used it would weaken the conduit tube too much.
Great video of reusing inserts! Now I know why I never throw anything away. Random question. Is the back rail on your grinder mag chuck brass? Or is the lovely yellow color decorative. :)
Thats brass, yes - it came with the magnet chuck. Other than a steel rail it does not short circuit the magnetic field lines and weaken the holding force of the magnetic chuck.
👍👍
Nice tight PG-13 fit, sounds like something this old Tony would say 😂
how is your lathe stopping that fast. Do you have a brake installed on lathe ?
👍😎
Because of the downward tilt of the insert in the toolholder, your thread angle will be slightly less than 80 degrees. I doubt this will be a problem but it got me wondering if the manufacturer grinds the 60 degree tips to a larger angle to compensate for the downward tilt.
Yep, I was aware of that - But its such a small amount, it can be neglected. I suspect the manufacturers do account for it.
@@StefanGotteswinter That old compound angle chestnut as soon as it's tilted for relief !!! Would not make hardly any difference in such a small thread . 👍
Wer hätte gedacht, dass man in doch recht moderner Anlagentechnik im Grunde aufs alte StaPaRohr zurückgreift.
Vermutlich hat vor Jahrzehnten irgendwer in dem Industriezweig sehr klein angefangen und hatte deshalb nur Restmaterial zur Verfügung, seine Anlage aber hatte Erfolg und so hat sich das alte Gewinde aus der Elektroinstallation als Industriestandard bei Bioreaktoren etabliert.
Interesting idea, sounds plausible enough. Seems like many of the odd things in industry come about in a similar way.
So the pitch approximates the √2?
_Very_ interesting.... 🧐
Single pointing at 88 MPH, or 141.622 KPH. I like single pointing on my ancient Hardringe Tl5.
Good job, as usual.
Just to know, what is the repetitive "contactor" noise we can hear every time you start the grinder?
the *THUMP**THUMP*?
Thats the vacuum cleaners filter cleaning.
@@StefanGotteswinter
Yep, that. Thanks.
Fun fact, in Germany the PG threads were replaced by metric threads years ago.
Stefan: Did you add the tip round by hand, and if so do you use CBN hones, or is diamond OK at hand-held cutting speeds? (I've not noticed a problem myself)
diamond for carbide and CBN for tool steels such as HSS etc.
Is an 80 degree angle right?
If you tilt the insert I think the angle changes slightly
Yep, very correct, but I figured its neglectable for this application.
Hey Stefan, I was threading 316 or similar stainless steel, and I found that the process of threading would enlarge the thread by extruding the diameter larger, causing me to have to file it every so often. My insert was new and sharp. How do you avoid this when you are cutting 316?
Keep a keen eye on the OD of the thread and as you say, run a file alont the thread to knock the burr down.
If possible, I use full profile / topping inserts that also cut the OD.
Здравствуйте! А что это за масло которым вы смазываете резьбу?
glad I am not the only one whose screw at the toolmaker vise is ‘verzammelt’. M5x0.5 - 50 anyone?
Sure about the 0,5mm pitch?
I would be suprised if the import ones used a fine pitch screw - Normaly that should be M4x0,7 or M5x0,8
Am I right in assuming that the angle of the threads cut will be larger as the angle at which the insert is tilted at is increased? And I also assume that we disregard this because it's a tiny amount although the angle of the insert is quite pronounced so I thought it would make a difference so maybe I'm missing something?
Yes, yes and yes, all correct, you are not missing anything :-)
when the carbide gets tilted it is no longer 80 degrees
True - Still close enough :)
if the tool dips 10 degrees you get an 82 degree cutter. great video
Stefan, you made the comment mistake of the overconfident, and challenged Murphy‘s Law. Not saying that your skills don’t warrant the confidence, they are excellent, but sometimes the word, „never“ gets Murphy annoyed. Good catch. 😅
Would you believe it? Stefan needs an "Imperial" thread gauge set. :>D A TPI gauge would have quickly exposed the improper change gear setting. FWIW, the full German word for tank (in the military sense) is Panzerkampfwagen. It's easy enough to see the shortening to "Panzer", for tank.
More trivia: In the beginning germany didnt even have a word for the military vehicle, they just used the english designation "Tank". Hence the Tankgewehr.
I'm guessing the flatter angle of the Pg thread makes it easier to clean, and that's the reason why they use it?
good possibility, yeah :)
@@StefanGotteswinterIt is more likely they choose an odd ball but standardised thread to prevent substitution of non medical rated fittings, much like acetylene and LPG gas fittings are threaded left hand. Not so fun fact, a patient was killed from the wrong gas cylinder being plumbed in during a surgical procedure before the hazard was recognised and threads were changed to prevent such mishaps.
oh! thats a good explanation
@@RobB_VK6ES Very plausible reason indeed. Probably will stop many mistakes, but there is always that idiot that just finds a bigger wrench and sledge hammer when it doesn't fit XD.
It is 80° because the conduit wall thicknes is very thin. By using a wide angle 80° thread profile it means the completed thread isn't cut so deeply into the thin conduit as a 60° thread would be.
You have ground the tool to the 80 degree, but it is tilted, so it has less. That might be a good opportunity to create a simple graphics in whatever modelling software you are using and measuring it. The math done "the hard way" would be more time-consuming.
That is how I measured angles for sharpening engraver tips.
Yes, the profile is slightly distorted, but at such a small tilted angle it can be neglected.
Imagine trying to do this job 200 years ago before there were international standards for threads, stock diameters, etc. We've come a long way since then...
This may sound dumb or inconsequential. Remember, I'm in no way, shape, or fashion a machinist. Would a small flat washer on the ball bearing keep from putting a dimple on the vise?
Those threads are still used in the US for cable glands.
Kann mir bitte jemand mit dem umgangssprachlichen Begriff für die Kabelverschraubungen auf die Sprünge helfen?
Anscheinend bin ich schon zu lange in USA und unterhalte much zu wenig mit deutschen Elektrikern.
Just a (probably silly) question, when you said "we have 2023" with reference to carbide, do you mean that the year is 2023 or that you need to make 2023 of those parts??? Just seemed like a lot of indentical parts for manual machining!
The year :-)
No provision for a root flat/radius?
I honed a tiny radius on the tip with a ruby stone, but not exactly as per thread spec. The stress riser on the thread root didnt occur to me to be critical in that application.
Great video. Why is the scale on the drawing so cursed thou?
I did that, that gave me the biggest drawing on the availible space of paper :)
@@StefanGotteswinter I guessed so. Working in offshore industry I' forced to 5 or 2 multipliers, even if it looks stupodli small/ large
Nice! Could you have used a brass or copper ball instead of a ball bearing to eliminate the threat of dimpling the vice jaw?
Yep.
Might be wrong to rely on it on the second try though?
May I ask why?@@2lefThumbs
@@crichtonbruce4329 because it won't be spherical on the second go, having sacrificially deformed against the flat of the jaw, and the cone of the insert, was my thinking.🤔
@@2lefThumbswon't it just deform again and still to its job again. Then throw it away before you mistake it for a good one.
i wanna see the new lathe 🙄.
its not here.
@@StefanGotteswinter 🤨. Ok. I'll wait for it.
Don't hold your breath :D
Machine arrival, moving it into the shop, getting it ready, etc. will take time.
@@StefanGotteswinter 😬, no lathe work in the meantime?😬
I still have the emco :)
Hmm, you said an included angle of 80 degrees, wouldn’t you need a 40 degree angle block?
Watch further :-)
20° in one, 40° in the other orientation.
6:08
What are, if any beyond a mere "tradition", engineering reasons for using such a thread angle?
on thin walled conduit pipe it was easier to form that thread angle. Not sure why the bio reactors use it, probably some legacy reason.
@@StefanGotteswinter thank you, good info!