How much torque is 5N-cm?

myleftear

Member
Paid Member
2017-09-10 6:33 pm
Luzern
Hi!

I just found this quite useful info on properly mounting jfets (or other to-220 / to-247 etc. devices):

https://www.infineon.com/dgdl/Infineon-AN2013_12_Screw_Tightening_Torque-AN-v1.0-en.pdf

The recommendation is 0.6 - 1 Nm.
(hold ~60 - 100gr at 100cm distance, or ~6000 - 10000gr at 1cm distance)

If I understand it correctly, this is quite tight for a M3-thread, but not "as tight as I'd tighten the wheel-bolts of a car"...

...
 
Last edited:
Firstly convert to Nm, 100Ncm = 1Nm, so 5Ncm = 0.05Nm

My rough guide to torques from human arm:

0.1--0.3Nm - finger and thumb twisting
1Nm - whole hand turning screwdriver
10Nm - both hands turning a steering wheel
100Nm - break your arms!

The symbol for the newton is "N", not "n" which means nano.

SI units and multipliers are always case sensitive.

0.6Nm is pretty normal rating for M3 steel-to-steel fastening. Direct into soft aluminium you'd use much less, 0.1Nm perhaps, or risk stripping threads, so it depends if using bolt and nut or bolt and tapped Al heatsink.
 
Firstly convert to Nm, 100Ncm = 1Nm, so 5Ncm = 0.05Nm

My rough guide to torques from human arm:

0.1--0.3Nm - finger and thumb twisting
1Nm - whole hand turning screwdriver
10Nm - both hands turning a steering wheel
100Nm - break your arms!

The symbol for the newton is "N", not "n" which means nano.

SI units and multipliers are always case sensitive.

0.6Nm is pretty normal rating for M3 steel-to-steel fastening. Direct into soft aluminium you'd use much less, 0.1Nm perhaps, or risk stripping threads, so it depends if using bolt and nut or bolt and tapped Al heatsink.
Excellent data.

Doubly useful because in Audio/Electronic Forums people is concerned into minute details of Electrical units (which is fine of course) but in general ignore mechanical ones, which are also very relevant to DIYers. (which are supposed to roll up their sleeves and get their hands dirty)
 

myleftear

Member
Paid Member
2017-09-10 6:33 pm
Luzern
That converts to 5.3 to 8.8 lb-inch (or inch-lbs in the old days), probably not a critical specification with that wide a range but clearly hand tight with a screwdriver and avoid using your 20V impact gun!

I wasn't sure wether it was just tight or veeery tight.
But, as you say, the range is so wide that it should be ok to go as far as you want it to sound good afterwards (so don't exaggerate, it's not shipyard work...)

My first (ACA, recently) was way too loose, but all went well though :p

(PS: The experts are explicit: _don't_ use tools like in the image below)
 

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