Author Topic: When M6 thread is funky on thermocouple  (Read 751 times)

Offline PekkaNF

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When M6 thread is funky on thermocouple
« on: May 19, 2017, 06:15:26 PM »
So, when M6 is not standard M6.

Bought M6 thermocouple with PID controller. I made a fitting with standard M6x1 thread but the thermocouple would not fit in it.

OD is 6,22 mm and lead is 1,25 mm as close as thread gauge shows it. M6 bolt next to it on the picture.

Suggestions?

Pekka

Offline philf

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Re: When M6 thread is funky on thermocouple
« Reply #1 on: May 19, 2017, 06:21:03 PM »
Pekka,

Looks like 1/4" X 20 TPI (1.27mm pitch) Whitworth thread to me.

Phil.
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Location: Marple, Cheshire

Offline PK

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Re: When M6 thread is funky on thermocouple
« Reply #2 on: May 19, 2017, 06:35:14 PM »
I had exactly this problem the other day installing the T/Cs on our new reflow oven.  They are indeed 1/4"... Which is odd....

Offline awemawson

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Re: When M6 thread is funky on thermocouple
« Reply #3 on: May 20, 2017, 02:31:13 AM »
Could well be 1/4" X UNC if it's Chinese, which is very close to Whit but 60 degree rather than 55
Andrew Mawson
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Offline PK

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Re: When M6 thread is funky on thermocouple
« Reply #4 on: May 20, 2017, 05:45:14 AM »
I cant recall If I got UNC or BSW.. I just walked into the "Old peoples fasteners" section of the hardware store and grabbed a packet with 1/4" written on it....   :thumbup:

Offline PekkaNF

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Re: When M6 thread is funky on thermocouple
« Reply #5 on: May 20, 2017, 01:23:56 PM »
It deos look like UNC, walked into shop reachec for 1/4 UNC marked drawer, pulled out packet of two taps, checked that they were 1/4" and came home. At home I noticed that the taps are 1/4" UNF! dikeytyduckeytyfiqeyty. I "always" double check, it must be my specksavers moment or it's about time to have my head checked.

This really does not want to go together voluntarily.

Pekka

Offline PekkaNF

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Re: When M6 thread is funky on thermocouple
« Reply #6 on: May 21, 2017, 10:22:58 AM »
Walked back to shop and that spot was filled UNC/UNF taps - all mixed!

The "M6" was 1/4-20 indeed!

It needs some brackets to holde the puck against the vat.

Pekka

Offline PekkaNF

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Re: When M6 thread is funky on thermocouple
« Reply #7 on: May 21, 2017, 02:45:19 PM »
Pressed three nuts, put three springs and screws to it.

This holder lies on small ledge of the fritti cooker frame, when the dish is put top on on it springs will press the puck that contains thermoelement onto enameled dish.

It works, but is a bit slow....Temperature overshoots and takes 10 minutes to stablilize to 80 degrees C.

Pekka
« Last Edit: May 22, 2017, 01:10:00 AM by PekkaNF »

Offline eskoilola

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Re: When M6 thread is funky on thermocouple
« Reply #8 on: October 01, 2017, 03:20:30 PM »
PID parameters can be painful to set up correctly.
I quess there are as many methods to do this as there are dudes to set them up.
In fact, there is so much information on this subject int he WWW that it is just overwhelming.

I quess You already did what there is to be done for those parameters.

If not, then there might be something to do here.

Offline PekkaNF

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Re: When M6 thread is funky on thermocouple
« Reply #9 on: October 01, 2017, 03:31:11 PM »
Controller parameters are lot of fun. When I was young, used to tune electrohydraulic servosystems. There was allways a starting point, but few cascaded loops took some thinkking and time.

I used a lighter sensor immersed into liquid, improved time constat a whole lot.

Pekka