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Electronics => Repair => Topic started by: Vince on June 17, 2018, 05:25:11 am

Title: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 17, 2018, 05:25:11 am
Hi everyone,


When I tightened the nut recessed in the center of the delayed sweep knob on my 2215 Tek scope... it broke ! The threaded part just sheared off. Now I can't use the knob anymore obviously...

Finding a complete knob is hard and expensive. Only one I found so far is 15 bucks from "Sphere", so add expensive shipping + customs to bring it to France/Europe, and I end up with a rather expensive collet...

So plan 'B' is  to buy some generic/non-Tek, new collet type knob, so I can salvage the collet from it and fit to my Tek knob. but even this is not so easy nor as cheap as I would like.

So... I am here asking if someone might know of a place that would sell collets, just the small collet part in itself, not a complete knob.. this way it would be logically dirt cheap, a  few cents each. I could therefore afford to buy lots of different sizes/models, hoping that one might fit the Tek knob.
So far I have been unable to find such a place...

I took measurements from the  broken collet :

- Type : "through-hole", tightened via a nut not a screw.
- Overall length : 8.6mm
- Length of the tapered/conical part : 6mm
- Max/base diameter of the conical part : 5mm
- Shaft diameter/inside diameter of the cone : imperial, 3.2mm or 1/8 "

Measurements from the knob, the cylindrical part where the collet fits : ID 5mm, length : 6.5mm.

Thanks for any address/link if any...  preferably in Europe so I can have affordable shipping and avoid customs. if not well, I will consider US sources as well, as long as it makes economical sense.

This post is my last hope !   ;D


Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: floobydust on June 17, 2018, 06:12:38 am
Tektronix Oscilloscope Repair Part, 214-3159-00, 214315900 Collet (https://www.qservice.tv/vpasp/shopexd.asp?id=14097&bc=no) maybe is the same part?

Tektronix front panel knobs suffer from dissimilar-metal bonding. The aluminium and (chrome-plated) steel interface corrodes and gets almost welded together.
Everybody breaks the collets or hex set-screws. I don't think WD-40 helps?

edit: WD-40 would surely attack the plastics. Maybe a toothpick and tiny drop only on the threads, to avoid calamity.
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 17, 2018, 06:21:58 am
Hi Floobydust,

Thanks for the link !  From the picture it looks like it won't fit the 2215 knob, so thanks Tek for making a trillion different parts for your sweep knobs... however it's interesting to see that this part bears a Tek part number ! ... because in the service manual, the exploded view does NOT detail the collet. It's only a complete knob assembly, take it or leave it.  So looks like it was enough of a problem that Tek sold these collets separately to service centers, hence gave them a part number of their own...

I guess it's worth e-mailing Qservice and Sphere in case they might have collets for a 2215, but just have not bothered listing it on their website because it's such a small part.

Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Dubbie on June 17, 2018, 11:15:50 am
Just buy a lathe.

Free collets!
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 17, 2018, 06:08:48 pm
Yes sure, why didn't I think of that sooner, thanks, will go get that ! Can't be more than a couple bucks total, right  ? Otherwise it's not viable.

Just gimme a link and I will go buy one.


Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: tautech on June 17, 2018, 06:16:36 pm
Do you have any Mens Shed, Maker groups or Model maker groups handy to you ?
Any old timer engineer or Fitter and Turner could spin one up with little fuss or bother.
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 17, 2018, 06:28:25 pm
Hi Tautech,

I don't know, would have to go search for such people, don't have any address that springs to mind.
The part is quite small, doing an accurate job on something like this requires good eyes and tiny fingers... a tiny miniature lathe maybe.... and a good magnifying glass...

To be honest I am surprised that it's so difficult to sort this collet out, I feel like I am the first one in the world that runs into this problem, when clearly I am probably not ?! ...  :-\

Maybe you are right.. maybe it's so easy and cheap to get one made locally, that there is no" business" selling these little puppies on-line.

If so then surely someone will be able to get some made for me and ship them to me... if I can't find someone locally myself...

It's kinda frustrating to have a non-operable scope just because of such a tiny ridiculous piece of metal...  :(
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: tautech on June 17, 2018, 06:35:07 pm
Actually they are easily made on a big lathe if you know how.  ;)
ANY half decent engineer could spin that collet up, no sweat!

If you can find a hobbyist group local and they have some wise old guys as members, they'll know how frustrating it is to not be able to get a simple part and will most likely gladly help.
Check your local papers and ask around.
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 17, 2018, 06:41:49 pm
Well you know better than I dod for sure.. so I will ask around... sure would be fun to manufacture a part for that scope... what wouldn't people do to restore these old Tek scopes !  ;D  We must be mad...
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Dubbie on June 17, 2018, 08:58:47 pm
If you can’t find anyone to make you one, I will make one for you if you send me a proper dimensioned drawing. I can make it from aluminium or brass. Postage will be 10 euros. It might take me a week or three to get around to it.
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: tautech on June 17, 2018, 09:04:11 pm
If you can’t find anyone to make you one, I will make one for you if you send me a proper dimensioned drawing. I can make it from aluminium or brass. Postage will be 10 euros. It might take me a week or three to get around to it.
Vince probably won't have a thread pitch gauge so the OA dia of the nut could be all you need and then supply one that fits your work.
Nice gesture Dubbie.  :-+
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Dubbie on June 17, 2018, 09:06:36 pm
I’m hoping someone here might know the pitch. Looks like 1/4” UNC but I have no real clue about these scopes. Could be some weirdo thread for all I know
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 17, 2018, 09:46:45 pm
Hi dubbie,

Wow, you are my hero, an d a hero in the Euro zone as well, lucky me !  :)

I will try and make as accurate and comprehensive a drawing as I can...
I can also send you the knob and the two bits of the broken collet (and nut) to help you out... since these are of no use to me anyway, as it is...

Indeed I am too equipped for mechanical stuff, other than fixing my car... not the same scale  :(

I don't think we have to worry too much about the thread since we can just make a metric pitch, and I would just go buy a metric nut to go with it ! At least this part should be easy and cheap, I would think...
Problem is that what remains of the thread is soooo short (as you can see on the previous pictures), that it's hard to get a reliable/Accurate measurement.  Normally to measure a thread pitch (since I don't have gauges, I measure 10 "turns" with my calipers, and divide by 10... this is usually accurate enough.
So here I could only measure only one turn, so precision is catastrophic. My best attempt would indicate it's about 0.8mm. Way more than 0.5 and less than 1.0mm, at any rate.

OD of the thread looks to be 4,8mm.... rings a bell, this must 3/16" , since everything in this collet appears to be imperial size...
The flat nut that goes on it, requires a 1/4" socket, at least this bit is for sure..

Will try and do as accurate a drawing as I can, today maybe, and post it here.

If you can give me your address via a private message, I would send you the knob and all the bits and nut from the old collet, in a padded envelope.

No worries about the delay... I have plenty other stuff in the lab (and else where) to keep me busy...

For once I really ought to resume work on the restoration of my old Tektronix 317 scope... it too, requires me to order a bunch of imperial size spanners and wrenches for me to be able to remove all the parts that need to be removed

Aluminium or brass... I think brass is the best. Less prone to cracking than aluminium I think.

I have an old Nixie tube Frequency counter, 10 years older than this Tek scope... all the knobs have brass collets and they didn't break when I took them on and off.. it just inspired more confidence, somehow...

I guess ideally a collet would be "hybrid" : have a brass "cone" to grab the shaft, but a steel thread to that it's strong despite being extremely thin because of it being hollow. Obviously that would be too much trouble/cost, so it gets made from a soft metal all the way... and the user just has to be really, reaaaally careful not to over tighten it... which is sooo easy to do unfortunately ! Maybe these collets should come with a tiny torque wrench like high-end RF connectors do.. so that you don't over tighten them...  ;D
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 18, 2018, 03:32:57 am
Dubbie... just took some macro shots of the collet, and spent a little time measuring everything. Sorry for the CAD drawing... I hardly master CAD programs as I hardly ever have to use them. So, " Vince CAD (tm) " will have to do !   ;D Hope you can still understand it... I did learn industrial/technical drawing at school... 25 years ago ! Hopefully my drawing makes enough sense... if not, don't hesitate to ask !  The representation of the threaded part I know is not how I am supposed to draw it.. sorry.  Anyway, I carefully drew it to scale (20:1) on 5x5mm paper.

Sorry about the crappy colors in the pics as well : I did take the time to adjust the white balance of the camera, colors looked natural/nice in the LCD/ preview screen, was happy... but somehow the pictures that the camera recorded on the SD card, aren't true at all to what I saw in the preview LCD ! I hate cameras... 20 years on, and they are still crappy  :-\
I made a quick attempt at correcting the colour balance on the computer, but I am no expert... Still, I feel it's a bit better, short of being what it ought to be.

Pics don't lie about the manufacturing quality of this collet... it is.... "rough".. to say the least. "Atrocious" dare I say. Still... gets the job done I suppose !

FWIW, I noticed that the collet is actually... magnetic ! So, some ferrous material, no brass nor aluminium.
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: MadTux on June 18, 2018, 04:48:56 am
Thread pitch might also be important. If it's metric, I could do it on my (shitty) lathe. For the slots I would have to buy a saw blade for the mill, though (something in the 10€ range).

Add:
With a bit of luck, I could turn a M5 thread down to 4.8mm and also cut a new steel nut on the rotary table on the mill.
Suitable saw blades:
https://www.ebay.de/itm/HSS-Metallsageblatt-Metallkreissageblatt-Kreissageblatt-Frasmaschine-63x0-8x16/202326253837?hash=item2f1b95a10d:g:dNcAAOSwdnZaHQxd (https://www.ebay.de/itm/HSS-Metallsageblatt-Metallkreissageblatt-Kreissageblatt-Frasmaschine-63x0-8x16/202326253837?hash=item2f1b95a10d:g:dNcAAOSwdnZaHQxd)
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 18, 2018, 05:01:30 am
For thread pitch as I said ealier... can't we just make a metric pitch and then I would just have to go buy a (box full probably) corresponding metric nut to go with it ?

There is not enough (length wise) thread for me to measure it accurately with my calipers. Best I can come up with would be to say it's between  0.5 and 1.0mm, and a bit closer to 1.0 than 0.5. Something like 0.8 or there abouts.... assuming that it's an imperial pitch, and that the nut takes a 1/4" wrench, can't we figure it out using some table of the most commonly used pitches ? I think it's safer to just make a common/wide spread metric pitch that I could easily source nuts for.

Don't go buy tools to do the slots (unless you want to have a go at it "for the fun"...), as it would not be economically viable for me, or barely...

I know crap about machining other than the rudiments of turning and milling I was taught at school when I was 15 or so...

But I guess at the very least one would need a 3.2mm drill bit.. this alone is not really your typical metric size ! :-/   3 or 3,5 is common, but 0.1 steps is not in everyone drawers I guess  :-\
For the outside diameter and tapered part, and threading, I guess a general purpose cutting blade could do it ?
Then a thing blade to cut the slots, as you said...
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: floobydust on June 18, 2018, 05:22:39 am
210-0583-00 NUT,PLAIN,HEX 0.25-32 Χ 0.312 INCH,BRS ; That would be 1/4" 32 thread per inch, 0.312" thick, brass. Seem reasonable?
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 18, 2018, 05:32:04 am
Floobydest I don't know how you manage to come up with Tek part numbers that aren't even listed in the service manual parts list, but I love you for that !  :-+

Yes, 32 thread per inch definitely sounds plausible, as this would be about 0.79mm , consistent with the ballpark figure I measured.

As for the 1/4", sounds great too, assuming it refers to the required spanner size... rahter than the diameter of the thread, which is 4.8mm (3/16"), not 1/4".
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: floobydust on June 18, 2018, 05:48:39 am
I was looking at the 2235 service manual May 1983, can't remember where I got it from, possibly ElectroTanya. (https://elektrotanya.com/keres)

I look at service manuals within the product line, to find the newer versions.
The mid or high end models can have more info, and companies use the same parts within a lineup.
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 18, 2018, 06:09:36 am
Quite clever indeed... will try to remember it next time  ;D

Yeah the 2235 is essentially the same as the 2215, just faster.

Just downloaded the service manual for it... indeed this manual does detail the nut, unliek the 2215 manual, go figure.

They still don't detail the collet though, so it must be part of the knob assembly... which ought to be the same... but just because I am paranoid, I checked the part numbers and... they do NOT match ?!  :o

They are real close... only the very last digit differs :  2215 knob P/N is 366-1840-00  and the 2235 knob has -02 at the end.
IIRC when only the last 2 digits differ, it's only a minor change, and the parts are still interchangeable/compatible ?

The descriptions are identical any way.

So yeah, it's not too much of a gamble to assume that the nut/pitch indicated for the 2235 is the same as that used in the 2215...so let's go for that ! ;D

Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: tautech on June 18, 2018, 06:43:43 am
Vince.
How thick is the nut, it looks like what's known in the trade as a half-nut, that is; ~ half the thickness of normal.
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Dubbie on June 18, 2018, 06:53:20 am
I'm not sure about that nut...

1/4" 32 tpi doesn't sound right for this collet. Nobody lists nuts by their spanner size, it's always the thread nominal diam.

Also because I live in a civilized country, I don't do much imperial work, so don't really have the tools.
Doing an M5 thread would suit me just fine. It should be easy for you to find nuts for also.

Thanks for the drawing. No need for a computer, it is perfect.
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 18, 2018, 06:55:01 am
Yes the nut is very thin as you saw in the pictures. I just measured it : 2.3mm thick.

"Half nut" .. alright I learned a new term today  :)
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 18, 2018, 07:02:34 am
I'm not sure about that nut...

1/4" 32 tpi doesn't sound right for this collet. Nobody lists nuts by their spanner size, it's always the thread nominal diam.

Also because I live in a civilized country, I don't do much imperial work, so don't really have the tools.
Doing an M5 thread would suit me just fine. It should be easy for you to find nuts for also.

Thanks for the drawing. No need for a computer, it is perfect.

OK for M5 but remind me : what size spanner will I need for the nut ? I could just about fit the 1/4" (6.35mm) wrench inside the knob. I tried my metric 7mm wrench and it did not fit... might fit if I grind it down a bit, though. No way I am going to grind my Facom tools though, but I could just get a cheap ass wrench and grind that down...  However if an M5 thread requires an 8mm nut, I think it will be way too big, no way I could get the wrench in there to tighten it, there would not be enough space left around the nut, assuming it could get into the knob recess at all...

I think there really isn't that much head room in this knob design ! Either 1/4", or 7mm, but not more...  :-\

Do you have a 3.2mm  drill bit to bore the inside of the collet all the way through ?
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: tautech on June 18, 2018, 07:05:07 am
According to my thread chart 32tpi on 3/16" shaft is UNF #10.

Below 1/4" UNF the sizes are numbered, 12, 10,8 6, 5............
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Dubbie on June 18, 2018, 07:06:49 am
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?
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: tautech on June 18, 2018, 07:12:57 am
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 ?
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Dubbie on June 18, 2018, 07:24:30 am
Want to pop out for a coffee, chat and some nuts ?

Now there is an offer!  ;D

Sounds good. Will have to be next week sometime after my current work rush.
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 18, 2018, 07:28:05 am
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 !  |O

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  :-\
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 18, 2018, 07:30:40 am
Want to pop out for a coffee, chat and some nuts ?

Now there is an offer!  ;D

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 ?!   ;D

Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: tautech on June 18, 2018, 07:35:22 am
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 !  |O

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.  :)
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: tautech on June 18, 2018, 07:38:05 am
Want to pop out for a coffee, chat and some nuts ?

Now there is an offer!  ;D

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 ?!   ;D
Yep, R** is less than 30 minutes away and a valued customer.  :)
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 18, 2018, 07:47:24 am
Oh OK, I see !  ;D

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...

Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Dubbie on June 18, 2018, 07:51:22 am
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.
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: tautech on June 18, 2018, 08:02:01 am
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)
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 19, 2018, 04:41:35 am
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 !  ;D

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...
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: tautech on June 19, 2018, 06:01:57 am
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.
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 19, 2018, 06:38:19 am
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 (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 !
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: tautech on June 19, 2018, 07:06:06 am
Crap, I can't check your links, Yahoo won't let me !
Fixed.....with pics from my archives that I should've used instead.  :palm:
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 19, 2018, 07:28:49 am
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 !   ;D   :scared:

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

Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: tautech on June 19, 2018, 08:07:11 am
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 !   ;D   :scared:

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 !  :-DD
Even more now.  :(

Here's a great resource for looking at older gear:
http://www.lathes.co.uk/ (http://www.lathes.co.uk/)
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: tautech on June 19, 2018, 09:44:54 am
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.  :D

Pic shows a small selection.
(https://www.eevblog.com/forum/repair/searching-for-a-18-collet-to-repair-a-tek-sweep-knob/?action=dlattach;attach=459091)

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.
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Dubbie on June 19, 2018, 10:10:21 am
I can just make some nuts.
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: tautech on June 19, 2018, 10:20:15 am
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.
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 20, 2018, 04:44:27 am
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 !  :-DD
Even more now.  :( 

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

Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 20, 2018, 04:57:28 am
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.  :D

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

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 !  ;D
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...

Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: tautech on June 20, 2018, 07:05:09 am
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.
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 20, 2018, 08:22:46 am
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... :(


Quote
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  :)

Quote
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.....

Quote
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 !  ;D

Quote
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....
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: tautech on June 20, 2018, 09:02:19 am
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... :(


Quote
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.

Quote
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.  :)
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on June 21, 2018, 05:04:26 am
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.

Quote
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  ;D

Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: tautech on July 01, 2018, 11:42:05 am
Want to pop out for a coffee, chat and some nuts ?

Now there is an offer!  ;D

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 ?!   ;D
So that's ^ what we did last night and yarned away a good few hours.
Nice catch up it was too as it wasn't all about business for a change.
Dubbie grabbed a new #10 tap I had and it'll find its way back to me via another member he needs to catch up with. So he's got nuts too now !  :-DD
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on July 01, 2018, 05:32:45 pm
Hi Tautech and thanks for the update !

I am glad my knob and nut problem :palm:  was a good excuse for catching-up  ;D

Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Dubbie on July 29, 2018, 03:26:20 pm
Just in case you thought I had forgotten you, I thought I had better check in. I’ve been waiting for a die to arrive so I can make the collet. It hasn’t shown up yet, although I ordered it a month ago. While I waited, I made a small stainless steel nut. It’s got curious proportions, but I guess that’s what you asked for. Pictured is the nut threaded onto one of Tautech’s #10 32 bolts he gave me.
(https://uploads.tapatalk-cdn.com/20180729/794a3aeb194c491cd8666997f5b4d3ad.jpg)
Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on July 29, 2018, 08:03:25 pm
Just in case you thought I had forgotten you, I thought I had better check in. 

No worries, we are all busy with life ! ;-)  Just back from 10 weeks working on a different site, not as local... the resulting commute killed me (as well as eating all my free time), time flew and I didn't do anything in the lab (or else) during that time !  :(

Back to normal starting tomorrow, phew. Then in a week... I will be on vacation for 3 weeks, so will be able to get some work done at last...


Quote
I made a small stainless steel nut. It’s got curious proportions, but I guess that’s what you asked for. 

Thanks !  :D

Yes the proportions are odd, as Tautech said, it's a "half" nut, very thin. As mentioned in a previous post, the nut is 2.3mm thick.

Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Dubbie on August 22, 2018, 09:43:09 am
I FINALLY got the die I ordered way back ages ago... I suspect it might have been shipped by putting it in a bottle and throwing it in the sea.
I now have everything I need to make the collet.

Standby!

Title: Re: Searching for a 1/8" through-hole collet to repair a Tek sweep knob
Post by: Vince on August 22, 2018, 10:08:01 am
Hi Dubbie,

Maybe it comes from China ? Every time I order something there, it takes a month or more to get to France.

Looking good then, thanks for your effort  ! :-+

Don't know how much time/effort it would take to make one, you will tell me, but it's not insane, maybe make 2 or 3, in case one breaks again ?
Sure I will be very careful when tightening it, but Murphy is always out there waiting to catch you... will this guy never leave us alone ?!  :P

That puts some pressure on me now, then.... I must move my butt and trouble shoot the remaining weird problems with that scope...