Searching for a 1/8" through-hole collet to repair a Tek sweep knob

[Dubbie]

Yes. I can do the 1/8 bore no problem. Yes, M5 could be 8mm across flats. I’ll think about it. What clearance do you have to get a socket in there?

[tautech]

Yes. I can do the 1/8 bore no problem. Yes, M5 could be 8mm across flats. I’ll think about it. What clearance do you have to get a socket in there?

Dubbie, I'm more than likely to have some UNF #10 nuts but I'll have to have a scrounge around.

Want to pop out for a coffee, chat and some nuts ?

[Dubbie]

Want to pop out for a coffee, chat and some nuts ?

Now there is an offer! 

Sounds good. Will have to be next week sometime after my current work rush.

[Vince]

Dubbie, clearance is 10,5mm no more.  I looked at my 8mm wrench... if I were to grind one down, there would not be much metla left around the nut...

Had a look on Google, M5 is indeed 8mm nut/wrench, crap.... 

Also M5 is gonna be potentyially a tight fit (depending on  machining tolerance), since the knob is bored at 5mm also !  So a 3/16"  thread is just a tad smaller than 5mm and fits just perfectly.

Boy looks like Tek designed the knob around that 1/4" nut / 3/16" thread, arrrrrrgh ! 

Had a look at a UNF table (not knowing anything about it). Looks like yes 3/16" does use 32tpi, as does metric M5 ! Real close then, apart from M5 being a split hair, 0.2mm larger in diameter and requiring a tad too large a nut 

[Vince]

Want to pop out for a coffee, chat and some nuts ?

Now there is an offer! 

Sounds good. Will have to be next week sometime after my current work rush.

Oh OK ! So you guys do know each other and live  in the same vicinity ?!   

[tautech]

Dubbie, clearance is 10,5mm no more.  I looked at my 8mm wrench... if I were to grind one down, there would not be much metla left around the nut...

Had a look on Google, M5 is indeed 8mm nut/wrench, crap.... 

Also M5 is gonna be potentyially a tight fit (depending on  machining tolerance), since the knob is bored at 5mm also !  So a 3/16"  thread is just a tad smaller than 5mm and fits just perfectly.

Boy looks like Tek designed the knob around that 1/4" nut / 3/16" thread, arrrrrrgh ! 

Had a look at a UNF table (not knowing anything about it). Looks like yes 3/16" does use 32tpi, as does metric M5 ! Real close then, apart from M5 being a split hair, 0.2mm larger in diameter and requiring a tad too large a nut 

That makes perfect sense to me.
3/16 UNC/Whitworth thread would be too coarse and require too much tightening torque on such a delicate hollow threaded shaft. Also the thread root depth will be too deep and further weaken the threaded portion.
1/4" nut is a common size too.

Yep, it all fits together right by me. 

[tautech]

Want to pop out for a coffee, chat and some nuts ?

Now there is an offer! 

Sounds good. Will have to be next week sometime after my current work rush.

Oh OK ! So you guys do know each other and live  in the same vicinity ?!   

Yep, R** is less than 30 minutes away and a valued customer. 

[Vince]

Oh OK, I see ! 

Nice to have the shop near by : if the instrument fails, goes straight on your desk ! LOL 

OK... looks like I am screwed then (sorry couldn't resist !) : it's more reasonable to stick to the original 3/16" imperial thread....

Question : given that the thread pitch is done by setting up the speed (in translation) of the cutting tool, hence we can do any arbitrary thread we want (?)... why would it be more difficult to cut an imperial thread than a metric (or anything else) ? Is it because you have to adjust the speed with gears, and the gear set  supplied by default with the lathe, is designed in such a way as to allow for metric pitches rather than imperial ? So unless a particular imperial thread happens to accidentally match/coincide with a metric pitch, then you can't do imperial ?

Anyway, midnight over here in Frog land, so good night gentlemen...

[Dubbie]

I was planning on using a die nut in my lathe. Single point threading up to a blind shoulder on such a tiny part is pretty tricky.
I have some UNF die nuts at home somewhere.

[tautech]

Vince
Thread cutting is normally done at slow headstock speeds and thread pitch is only governed by the carriage traverse speed in relation to the headstock speed.
Some lathes require change of pitch gears to accommodate metric or imperial thread cutting whereas others just have a change over lever to switch from one to another like mine thankfully does.

(hobbyist turner with a Harrison 12)

[Vince]

Vince
Some lathes require change of pitch gears to accommodate metric or imperial thread cutting whereas others just have a change over lever to switch from one to another like mine thankfully does.
(hobbyist turner with a Harrison 12)

How convenient indeed ! 

Might get a little lathe some day, am tempted... a matter of money as always, but it's nice being able to do little things every now and then, to save one's bacon...

[tautech]

Yeah it's a nice lathe Vince.
Some pics below when I'd just got it and spruced it up with a good clean.


And Dubbie, I have plenty of 8mm brass rod that could be suitable for Vince's insert if you need any.
Hopefully today I'll find some #10 UNF half nuts.

Pics now visible.

[Vince]

Crap, I can't check your links, Yahoo won't let me ! I do have a Yahoo group account (from before TekScope moved recently to a new forum infrastructure), but still I can' t see your pics, they wson't load : " You are not a member". I though the whole point of a forum was to SHARE... yet the first thing you need to do is to subscribe... I don't get it. 

Anyway, I searched for "Harrisson 12" on ebay, and got a result :

https://www.ebay.fr/itm/7-x12-Mini-Metal-Lathe-Metalworking-Woodworking-Gears-Motorized-Milling-GOOD/201985425093?hash=item2f0744fec5:g:eLgAAOSwIWNZ5GhC

450 Euros (ONO) sounds like a good deal ! At this price I am sure tempted indeed (well, not right now as I said... other priorities atm). It does look real cute. Large enough (300mm of capacity) to handle long parts, yet small enough that you don't need a hangar to host it...
Variable speed, can do threads metric and imperial as you said, at the flick of a lever...
Sounds like the kind of mini lathe that would be affordable yet useful.. for small parts only, but that's all I envision working on anyway.
Making or reworking parts for the chassis of whatever piece of electronic gear, or custom projects : being able to make custom length spacers, studs, what have you. Any small part that you might need to put together the chassis of your project.
Yeah... at this sort of price I am definitely seriously interested !

[tautech]

Crap, I can't check your links, Yahoo won't let me !

Fixed.....with pics from my archives that I should've used instead. 

[Vince]

Thanks ! I can see your pics now.... glad I do because, hum hum... as you can see the "Harrisson 12" I saw on Ebay, has hardly anything to do with YOUR "Harrisson 12".... I guess they used this model name twice then (albeit probably 30 years apart...) , how confusing.

OK, so yours is a "real", professional, full scale, full blown, heavy duty lathe... the real thing. The kind of old school lathe I had at school when I was learning the rudiments of turning and milling... sure brings back some memories... that was cool making stuff, and watching the swarf catch fire at times !      

Well still, a mini lathe like that other Harisson 12 on Ebay, would be nice for my budget and purposes/intents...

[tautech]

Thanks ! I can see your pics now.... glad I do because, hum hum... as you can see the "Harrisson 12" I saw on Ebay, has hardly anything to do with YOUR "Harrisson 12".... I guess they used this model name twice then (albeit probably 30 years apart...) , how confusing.

OK, so yours is a "real", professional, full scale, full blown, heavy duty lathe... the real thing. The kind of old school lathe I had at school when I was learning the rudiments of turning and milling... sure brings back some memories... that was cool making stuff, and watching the swarf catch fire at times !      

Well still, a mini lathe like that other Harisson 12 on Ebay, would be nice for my budget and purposes/intents...

Yeah mine's a great unit despite a little bed wear but it is nearly 50 years old !
I was showing a bit of wear at that age too ! 
Even more now. 

Here's a great resource for looking at older gear:
http://www.lathes.co.uk/

[tautech]

Yes. I can do the 1/8 bore no problem. Yes, M5 could be 8mm across flats. I’ll think about it. What clearance do you have to get a socket in there?

Dubbie, I'm more than likely to have some UNF #10 nuts but I'll have to have a scrounge around.

Dubbie and Vince
I've got piles of #10 UNF fasteners but not so many nuts, actually none that are 1/4" across the flats.
So we've got a few options to use of what I have here, they're mostly steel however some are alloy of some sort and I know they're all good quality as they've all come from Mr Boeing. 

Pic shows a small selection.


Actually Vince, check the hole size through the knob as if we have just a little clearance M5 could possibly be used instead of UNF #10.

[Dubbie]

I can just make some nuts.

[tautech]

I can just make some nuts.

There's one @ 5/16" so a couple of wipes with a file will have it down to size.

[Vince]

Yeah mine's a great unit despite a little bed wear but it is nearly 50 years old !
I was showing a bit of wear at that age too ! 
Even more now.   

No worries... just keep the brain working and age won't show !  " A scope repair a day, keeps the doctor away ! "   
Or was that an apple a day, confused now ... 

[Vince]

So we've got a few options to use of what I have here, they're mostly steel however some are alloy of some sort and I know they're all good quality as they've all come from Mr Boeing. 

Oh ! I didn't expect that ! LOL
Now you are talking to me ! 

I work at Airbus on the A350 XWB (bit of A400M too, years ago), I spend all day long in these type of fasteners ! Look, I got a lot of them in the workshop ! 
These are 'LGP'/swaged fasteners, not screw type fasteners like you have. The ones on your pics, the matte golden ones with a countersunk head, are of the "hi-lite" type (or could be "hi-lock", if they are old.. but the difference is so minor that one couldn't tell from the pic).  We use these all over the place on the 350. Every time the machine that they use to swage the LGP, can't be used due to restricted access, we use these Hi-lite fasteners, because the nut can be tightened with hand tools and the agile and, small and thing fingers of the workers...

Anyway, those Hi-lite you have got here, or any LGP as well, are all made of titanium alloys (particular composition of the alloy differs from on fastener type to the other). They are good all-rounders : good performance for both traction/tension,  and shear loads. The entire air frame/cell of the aircraft is held together with these LGP and Hi-lite fasteners, does the job...

[tautech]

Great Vince, we each know a bit about the industry. 

My ex neighbor and very good long time friend spent his whole life as an passenger aircraft engineer but he now lives a few km's away but we see each other probably weekly for a chat and coffee. He's retired now and has a great workshop and I still get little boxes of stuff he no longer needs, mostly air frame but some bigger engine fasteners too. I don't think any of it's titanium but I'd need to look harder. Is titanium magnetic ?
Some without a head have a hex inside the shaft so they can be held and tightened for the same side/position.

Many of the nuts are pressed deformed lockers so unless we run a tap through then they won't be any good for your job so we'll stick to the few plain nuts I have.

Are Airbus fasteners metric ? I'd have thought they would be. As we know M5x1 is quite close to #10 UNF.

[Vince]

My ex neighbor and very good long time friend spent his whole life as an passenger aircraft engineer

So got to fly, lucky him !     I don't...

But he now lives a few km's away but we see each other probably weekly for a chat and coffee. He's retired now

Lots of stuff/stories to tell then, lucky you 

I don't think any of it's titanium but I'd need to look harder. Is titanium magnetic ?

Never had the opportunity/need to take a magnet to it, but as far as I am aware, not it isn't...
Hardly a metallurgist expert, just old school boy memories... but I though only ferrous materials could be magnetic ?...
I see that Wikipedia states that iron can be used in Titanium alloys... so maybe an iron doped Titanium could have some magnetic properties....
Still on Wikipedia, it does not say whetever Titanimum is "magnetic" or not. ather it states a "degree" of magnetic "susceptibility", whatever this means exactly.
So maybe it's not an all or nothing things, maybe metals are all magnetic, just to a varying degree...
Boy there is so much knowledge in this Wikipedia thing, one could spend his entire life reading about science and technical stuff.....

Some without a head have a hex inside the shaft so they can be held and tightened for the same side/position.

All "screw type" (Hi-lock, Hi-lite...) fasteners (those used for the airframe I mean) have this hex at the tip of the screw, it's simply to keep it from turning round and round and round, as you try to tighten the nut ! Otherwise it would drive you crazy real quick ! I mean, depending what degree of interference is specified for the particular hole where the fastener goes (depends on loads applied, type and magnitude, and what material the various parts being held together, are made of), I mean "clearance fit", "transition fit", or slight interference, or strong interference...  If it's a clearance fit then the fasteners is kinda lose in the hole, so it would just spin round and round as you try to tighten it. So in this case, you need that hex at the end of the fastener to keep it still, otherwise you are screwed, so to speak ! 

Are Airbus fasteners metric ? I'd have thought they would be. As we know M5x1 is quite close to #10 UNF.

Nope. 100% of the fasteners used on Airbus aircraft, be it LGP/Hi-lite used for the airframe, or fasteners for "mechanical" stuff (ie : anything that is not either the airframe, or electrical related stuff), or even the "blind" type fasteners used to mount light-weight trim panels here and there (mostly lining in the cargo bays)... any and all type of fasteners are all originated from the USA, historically. So they all use imperial dimensions !  The diameter and length are coded using fractions of inches.   Most of the time, the diameter would be expressed in multiples of 1/32" , up to a diameter of a 1/4", then above that it will use larger steps (1/16"). repair/oversize is defined as a 1/64" above nominal diameter (for first oversize/"R1", and 1/32" for 2nd oversize/"R2"). Lenght is coded typically in multiples of 1/16" .   

So for example in my pictures, you can see the label on the plastic box : " ASNA2042-4-07"

ASNA = Name of the norm (you could have "DAN" for the German norms, or "NAS", or "ABS" in the case of the most recent norm in use at Airbus).
2042 = "part number" : defines the type/model of fasteners... though strictly speaking, it could also link to not just parts, but also technical documentation/papers... You can get "ASNA" or "ABS" XYZ for pretty much anything. Only the 4 trailing digits will tell you what type of thing is being referred to... a fastener, a washer, a nut, a collar (for an LGP fasteners), or some technical paper about this or that...

4 = diameter code : 4 x 1/16" = 1/4" = 6,35mm.
7 = length code (of the shank/useful part of the fastener) : 7 x 1/16" = 11,2mm.

Same principle goes for any type of fastener.


Late here again, good night....

[tautech]

My ex neighbor and very good long time friend spent his whole life as an passenger aircraft engineer

So got to fly, lucky him !     I don't...

But he now lives a few km's away but we see each other probably weekly for a chat and coffee. He's retired now

Lots of stuff/stories to tell then, lucky you 

He didn't fly much in later years and only on delivery trips previously when aircraft were sold from our national carrier. So he wasn't a permanent flight engineer.
He finished his last decade or two as foreman of maintenance watch where he signed out all international aircraft as fit to fly. In the years I've known him he went to Seattle a few times to get up to speed on new models at Boeing.
Truly interesting profession as he had to know about all parts of the aircraft. His son followed his path into the industry and is now a top RR specialist.

Are Airbus fasteners metric ? I'd have thought they would be. As we know M5x1 is quite close to #10 UNF.

Nope. 100% of the fasteners used on Airbus aircraft, be it LGP/Hi-lite used for the airframe, or fasteners for "mechanical" stuff (ie : anything that is not either the airframe, or electrical related stuff), or even the "blind" type fasteners used to mount light-weight trim panels here and there (mostly lining in the cargo bays)... any and all type of fasteners are all originated from the USA, historically. So they all use imperial dimensions !  The diameter and length are coded using fractions of inches.   

Surprising really, Airbus being a EU consortium I would've thought metric would be starting to infiltrate the industry.
Yeah, know about dimensional coding as it's common in all sorts of mechanical products. Bearings, hosing, fasteners....to name a few that jump to mind...oh and SMD passives too. 

[Vince]

Surprising really, Airbus being a EU consortium I would've thought metric would be starting to infiltrate the industry.

Well, the EU is not metric !  England is imperial of course, and is in the EU (at least at the time Airbus was created...), and is very much part of Airbus (they make the wings).

Also, it's not really a problem to have imperial fasteners, in practice. I mean all the drawings are of course metric, it's only the fasteners which are imperial, and in fact nobody cares, because nobody even knows they are imperial !

I mean, I do know because I care abut technical things and am curious, but trust me, none of the workers know about it, and sadly none of my fellow collages either. I mean all my colleagues who are specialized in quality control/inspection of the airframe/cell. My colleagues, and my chief/team leader actually make fun of me because of this : "Vince, the only guy who gives a shit about all this inch fraction stuff ". Every time I have to train a new recruit, first this I do was to explain to him how to make sense of diameter and length codes, how it worked. 100% of the time, after only 5 minutes tops, they either tell me to get lost because their head starts hurting... and one some occasions I had my chief come to me, saying that the recruits  complained to him about me "torturing" them with that stuff ! Really ?! Is it too much too ask to decipher codes so that you actually understand what you are doing ?!  Apparently yes, it is too much to ask. Chief clearly required me not to ever bother new recruits with that, because in practice, you did not need to know about it at all !  Drives me nuts.. people just don't get interested in anything these days, not even their very job !

That's because the diameters and length as we have just seen, use codes, not actual imperial fractions... this layer of abstraction keeps all the imperial stuff hidden. All people actually care and know about in practice, in the workshop.. is what CODE that have to use. The job card tells them to pick say a Hi-lite EN6115B4-7 ... so they they just pick that on the shelves, and call it done !  Sometimes the drawings will tell you an actual number for the diameters of the various holes, but in this case they of course use metric, and just round it a bit. So they would write :

3.2mm  (1/8")
4,8  (3/16")
5,6 (7/32")
6,4 (1/4")
7,9 (5/16")
9,5 (3/8")
11,1 (15/16")
12,7 (1/2")
14,3mm and so on

I think the largest diameter I ever saw, was one inch. And that was on the center wing bow, which takes all the load from the aircraft (it's the part/section  which actually holds the entire plane together ! ), so I guess it's fairly safe to say that there is no bigger than one inch anywhere on the plane. At least for the structural part. For mechanical assemblies I am sure you would have bigger than this, like when dealing with the landing gear, or the bolts that hold the rear tail onto the rear cone. Or of course, the couple bolts that hold the engine/nacelles on their mast.

Yeah, know about dimensional coding as it's common in all sorts of mechanical products. Bearings, hosing, fasteners....to name a few that jump to mind...oh and SMD passives too. 

And Lithium batteries and and and... quite common indeed