Test Equipment Anonymous (TEA) group therapy thread

[McBryce]

... stupid human tricks. 

mnem
tsssssssssssssssss...

Everything in this video is suspect. First off, the guy doesn't understand the difference between things that are acidic and things that are reactive. An acid is only hyper reactive against things that are alkaline, so in many circumstances there would be very little reaction. If he'd thrown the phone into sulphur it would have looked a lot different. Secondly, he has no idea of what pH means, because pH is a scale from 0 to 14. Claiming it has a pH value of -31 is crap, what he actually means is that it has a Ho scale of -31, and anyone who doesn't understand the difference between these shouldn't be fuckin around with anything more corrosive than vinegar. Thirdly, I very much doubt that he actually had real flouroantimonic acid, not just because it's ridiculously difficult to obtain, but also because the container he had it in would be insufficient to contain it. I'd expect more reaction if he'd put the phone in a bucket of off the shelf diluted drain cleaner.

McBryce.

McBryce.

[AVGresponding]

'twer the die that survived, Sir Dragon, and 'twas the tube that collapsed.

Reminds me of a, hmm let me think of the correct terminology here... nope, can't use any of the words I'd like or I'd be censored.
One former sparky and now Health and Safety Enforcement Officer in our Empire of Metropolitan Mediocrity had, and for all I know still has, "Electrical Guru" as a subtitle on his business cards (name withheld to protect the witless).

Said electrical guru once wasted half a day trying to cut a thread onto some 25mm PLASTIC conduit.

He insisted it could be done, despite advice to the contrary, and after destroying a length and a half of tubing (they come in 3m lengths, and the work-piece was around 200mm) simply left the job for someone else and pretended he was simply too busy to do it.
The person that finished the job probably (I don't know, it wasn't me) just used a 25mm metal nipple (that's what they're called, don't blame me) to adapt between the whatever it was the guru was trying to connect.

Incidentally, it is usually possible to cut a thread onto a 20mm plastic tube, due to the walls being proportionally much thicker.

[mnementh]

Lessons learned today: Do not believe tap drill charts that say 2.5mm pilot hole for an M3 tap in aluminium.

Just failed miserably by following that advise - screw stripped the thread straight out. (Lucky it was a test piece.) Just to add insult to injury the nearest drill down I had was 2mm and I couldn't even get a taper tap started in that. Had to 'peck' a 2.5mm hole at the start of it and could finally tap the hole.

TEA value? I'm doing a little practical pre-design for making some instrument cases (cf previous discussions, esp. with bd139) and was seeing if I could get away with 3mm of thread in Al to hold covers down. Conclusion, yes, just about, but it would be chancing it. Better to go with steel or more thread.

2.5mm into aluminum CASTING for m3 COARSE thread; 2.3mm for m3 FINE. As with steel, go a little smaller OR make the hole with a prickpunch/die for sheetmetal.

Also, make sure you are in fact using a m3 tap not a m2.5, m2.6 or m2.8...

mnem
been dere, dunnat. 

The evil chart in question claimed 2.5mm for 1050 Al plate and rod, which is exactly what I was tapping. And it was M3x0.5 coarse (or just M3, what kind of weirdo uses M3x0.35 fine). Theory says that 3mm - 2 x (0.5mm thread x 0.614 thread factor) => 2.386mm thread root (or top depending on what way you're looking at it) for a 100% thread. The chart claimed to be for a 70% thread (sounds reasonable in Al), which calculation says would want a 2.57 mm hole and with plastic deformation as well as cutting you'd get a little bit more than 70%. So, in theory, what the chart says is reasonable, in practice in something as soft as 1050 it clearly is not. The point of using a chart is that it ought to temper theory with practice, not just save you from doing the arithmetic (which is not exactly onerous) which the chart I'd foolishly saved away didn't - bastards.

You're talking to a man who meters out diodes before soldering them, of course I read the engraving on the tap even though it came out of the little box with all 3 types of M3 tap in, that says 'M3' on the front. What do you take me for, some normal person without an obsessive distrust of what Murphy's going to do to me?

Anyway, I think I'd have got off better with a random M2.8x0.5, had I owned such an aberrant non-standard beastie, and left the steel screw to finish the actual thread forming as even the finished thread drilled at 2mm feels slack. These are supposed to be decent taps, but I think a new set of something reassuringly expensive is in order; I've never been particularly pleased with the results from these ones in anything apart from Perspex or similar hard plastics - where they give a lovely result. There's something deeply satisfying about a well tapped hole, satisfaction that I'm not going to be permitted to have today. At least I was just mucking about.

Jeez, I wasn't trying to pee in your cornflakes, C... I was passing on hard-won experience for those playing along at home (and maybe for you a little ) and commiserating.

I tap threads from m2-m6 (mostly m2 & m3) size in aluminum all the time... in fact, I'm doing it right now on one of these:

2.5mm drill tends to drill a hair small in a drill press; larger if you're doing it by hand and a bit worbbly. But I use 2.4mm or 2.5mm drill (which I double-check with my Chinesium digital calipers EVERY time) for m3x0.5 all the time. Works perfectly, and if you try to cut m3 threads from a 2.3mm drill, you have a more than fair chance of the tap snapping off or the metal galling and ruining the thread. If you can see aluminum welded to the threads of the tap after you're done, this is probably what happened, tho not likely if you used a 2.5mm drill.

Cheers,

mnem
 

[mnementh]

'twer the die that survived, Sir Dragon, and 'twas the tube that collapsed.

Reminds me of a, hmm let me think of the correct terminology here... nope, can't use any of the words I'd like or I'd be censored.
One former sparky and now Health and Safety Enforcement Officer in our Empire of Metropolitan Mediocrity had, and for all I know still has, "Electrical Guru" as a subtitle on his business cards (name withheld to protect the witless).

Said electrical guru once wasted half a day trying to cut a thread onto some 25mm PLASTIC conduit.

He insisted it could be done, despite advice to the contrary, and after destroying a length and a half of tubing (they come in 3m lengths, and the work-piece was around 200mm) simply left the job for someone else and pretended he was simply too busy to do it.
The person that finished the job probably (I don't know, it wasn't me) just used a 25mm metal nipple (that's what they're called, don't blame me) to adapt between the whatever it was the guru was trying to connect.

Incidentally, it is usually possible to cut a thread onto a 20mm plastic tube, due to the walls being proportionally much thicker.

Oh, I assumed that when the tube failed it did so as expensively as possible (witness C's comment above about Murphy, etc...); this usually by crumpling into a ball jammed between the gullets of the die such that it's nigh-impossible to extract. 

I'm sure you know this, but for those playing along at home conduit comes in schedules just like water pipe; of course schedule 40 EMT is pretty thin if up to spec, and those who ply the thin waters make it barely thicker than radio antenna tubes. Plastic conduit is available in Schedule 40 & schedule 80; the latter is rated for direct burial and definitely has plenty of meat for threads.

mnem
 

[0culus]

Ahh that makes sense. I just finished a successful transaction to get the 585A and plug-in adapter + plugins + manuals. Unfortunately it seems to have developed a short but it’s very clean and shiny. Pics once I get home!

A quick photo for now...

(Attachment Link)

And a few more...look at all those 'bugle boys' safe from the prying hands of audiophools. 

[SilverSolder]

I have had good luck with Forming Taps for aluminum (also known as cold-forming or fluteless taps).  These press threads into material without cutting it, by forming the metal, no chips are created.  They produce stronger threads than other taps.  The downside is that more torque is required to drive them into the work piece, so your lubrication has to be right.  (TapMagic or similar).

[Cerebus]

Jeez, I wasn't trying to pee in your cornflakes, C... I was passing on hard-won experience for those playing along at home (and maybe for you a little ) and commiserating.

Jeez, who's being touchy today. I was railing at the muppet who wrote the chart.

Perhaps it's because your acid-base balance is off. 

[BU508A]

Ok guys, here is the ultimatively chart for M3, the ISO DIN 13-1:

https://schraube-mutter.de/gewinde-m3/  (Google translate is your friend    )

English Wikipedia:
https://en.wikipedia.org/wiki/ISO_metric_screw_thread

A picture explains more than a thousand words:


Schraube = bolt
Mutter = nut

For the bolt (M3):

Nenndurchmesser ( d )                  3,00 mm Steigung ( p )                               0,50 mm Gewindeflankenwinkel                   60° Grad Flankendurchmesser ( d2 )            2,675 mm Kerndurchmesser ( d1 )                 2,387 mm Steigungswinkel ( ß )                    3,40° Grad Höhe des Profildreieck ( h )           0,433 mm Gewindetiefe ( h3 )                       0,307 mm        Radius am Gewindegrund ( r )                                                          min.    0,063 mm                                                    max.   0,072 mm

For the nut:

Nenndurchmesser ( D )                3,00 mm Steigung ( P )                              0,50 mm Gewindeflankenwinkel                  60° Grad Flankendurchmesser ( D2 )           2,675 mm Kerndurchmesser ( D1 )               2,459 mm Steigungswinkel ( ß )                   3,40° Grad Höhe des Profildreieck ( H )          0,433 mm Gewindetiefe ( H )                       0,271 mm        Radius am Gewindegrund ( R )                                                        min.   0,063 mm                                                  max.   0,072 mm        Vorbohrdurchmesser ∅       für das Gewindeschneiden ( Kernloch )    2,50 mm

[mnementh]

Ahh that makes sense. I just finished a successful transaction to get the 585A and plug-in adapter + plugins + manuals. Unfortunately it seems to have developed a short but it’s very clean and shiny. Pics once I get home!

A quick photo for now...

Noice!       Tho honestly, my back aches just LOOKING at that heavy iron! 

mnem
Better thee than me.   

[0culus]

Ahh that makes sense. I just finished a successful transaction to get the 585A and plug-in adapter + plugins + manuals. Unfortunately it seems to have developed a short but it’s very clean and shiny. Pics once I get home!

A quick photo for now...

Noice!       Tho honestly, my back aches just LOOKING at that heavy iron! 

mnem
Better thee than me.   

It's plenty heavy, but it's not the heaviest piece of test gear I own.  Once I got it from the garage into the house, I took a page from the "work smarter not harder" school of thought and placed it on a heavy old towel and dragged it across my bare floors to the lab (I have tile and laminate in 90% of my house, just two bedrooms have carpet). 

[BU508A]

And a few more...look at all those 'bugle boys' safe from the prying hands of audiophools. 

What is this on the left? These white pipes on the door. Is that for (water-) cooling?

[0culus]

And a few more...look at all those 'bugle boys' safe from the prying hands of audiophools. 

What is this on the left? These white pipes on the door. Is that for (water-) cooling?

That's the delay line!

[Cerebus]

I have had good luck with Forming Taps for aluminum (also known as cold-forming or fluteless taps).  These press threads into material without cutting it, by forming the metal, no chips are created.  They produce stronger threads than other taps.  The downside is that more torque is required to drive them into the work piece, so your lubrication has to be right.  (TapMagic or similar).

Good point. I've had success in the past using thread forming screws in awkward materials, which are essentially single use forming taps that just happen to be fasteners too. They kinda feel like a cheat, but if it works - meh. Gotta be careful in materials that undergo significant work hardening, if you get it right it's perfect, if you don't you can be only half way there and everything seizes up on you.

[BU508A]

That's the delay line!

What a beast. How many ns delay time?

[0culus]

That's the delay line!

What a beast. How many ns delay time?

I shall have to consult the manuals. I also got the 585A manual and the manuals for each of the plugins I got with it!

[mnementh]

Jeez, I wasn't trying to pee in your cornflakes, C... I was passing on hard-won experience for those playing along at home (and maybe for you a little ) and commiserating.

Jeez, who's being touchy today. I was railing at the muppet who wrote the chart.

Perhaps it's because your acid-base balance is off. 

You mean THESE muppets?   

I've been referring to this chart in one form or another since I was knee-high to my grand-dad; while he MIGHT not have known what he was talking about (even being a master machinist during & after the war), I'm pretty confident they do. At least to the point I'd blame a mislabeled tap or drill before that chart.



mnem
My base is a size 13EEE; as the old man would say, "I have a solid under-standing". 

[AVGresponding]

Orbix screws:
https://www.oscsales.co.uk/orbix/products

For when you really don't give a fuck

[SilverSolder]

I have had good luck with Forming Taps for aluminum (also known as cold-forming or fluteless taps).  These press threads into material without cutting it, by forming the metal, no chips are created.  They produce stronger threads than other taps.  The downside is that more torque is required to drive them into the work piece, so your lubrication has to be right.  (TapMagic or similar).

Good point. I've had success in the past using thread forming screws in awkward materials, which are essentially single use forming taps that just happen to be fasteners too. They kinda feel like a cheat, but if it works - meh. Gotta be careful in materials that undergo significant work hardening, if you get it right it's perfect, if you don't you can be only half way there and everything seizes up on you.

I snapped more than my fair share of them before investigating tapping lubricants...   aluminum does work harden which is what makes the threads so bulletproof - tight and smooth.

[mnementh]

Orbix screws:
https://www.oscsales.co.uk/orbix/products

For when you really don't give a fuck

For when you hire muppets and you want it done^* by lunchtime.

mnem
*or at least LOOKING like it might be...

[Cerebus]

Jeez, I wasn't trying to pee in your cornflakes, C... I was passing on hard-won experience for those playing along at home (and maybe for you a little ) and commiserating.

Jeez, who's being touchy today. I was railing at the muppet who wrote the chart.

Perhaps it's because your acid-base balance is off. 

You mean THESE muppets?   

I've been referring to this chart in one form or another since I was knee-high to my grand-dad; while he MIGHT not have known what he was talking about (even being a master machinist during & after the war), I'm pretty confident they do. At least to the point I'd blame a mislabeled tap or drill before that chart.



mnem
My base is a size 13EEE; as the old man would say, "I have a solid under-standing". 

No t'was'nt a Starett one, just a random one that I'd previously saved away. As I said:

... which the chart I'd foolishly saved away didn't - bastards.

Just realized that I'd only touched on it tangentially - this chart purported to be specifically for aluminium, so much so that it had columns for different groups of grades. That's why I'd saved it as "useful".

[AVGresponding]

I hate the things, but they are sometimes useful.

You have to be careful though, as they need the high rpms of an impactor to work, and if you don't let off the trigger as soon as the hole drills, you're likely to screw it in and strip the threads in one easy move.

[Cerebus]

Orbix screws:
https://www.oscsales.co.uk/orbix/products

For when you really don't give a fuck

For when you hire muppets and you want it done^* by lunchtime.

mnem
*or at least LOOKING like it might be...

Bumper pack includes 4lb installation tool.

[AVGresponding]

You guys not coming to discord tonight?

[Cerebus]

Orbix screws:
https://www.oscsales.co.uk/orbix/products

For when you really don't give a fuck

Just to be clear, a proper thread forming screw like this tri-lobular one:


isn't the same as the evil and ubiquitous 'self tapper' like those from Orbix:

[med6753]

Ahh that makes sense. I just finished a successful transaction to get the 585A and plug-in adapter + plugins + manuals. Unfortunately it seems to have developed a short but it’s very clean and shiny. Pics once I get home!

A quick photo for now...

(Attachment Link)

And a few more...look at all those 'bugle boys' safe from the prying hands of audiophools. 

Damn, that scope is clean.