Typical engineering discussion to determine the correct Turnlock fastener for an application

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Typical engineering discussion to determine the correct Turnlock fastener for an application.

Please scroll first downwoards and then upwords to read the full story.  (you can also consult us for your engineering challenge)




This looks much more better, and I’m confident that this will work in your application.

Here you have the 3D






Van: Thomas


First, thanks for all support, helpful for me.

I have attached a drawing where I used MHSRF33S. Have I understood your suggestion correctly?




Från: Bart Vandezande



Then you need to add the 0.4mm in your formula

15.7 (grommet 1.2mm included) + 0.6=16.3mm


15.7 – 1.2 +0.4 + 0.6 = 15.5mm


Turnlock LEA series panel description


Which means you have the range 15.5-16.10 ; which is length 27 and not length 28

Furthermore, if you want the connection not sit stiff, and your total paint thickness is less then 0.6mm then it would be recommended to use length 26


length table of stud quarter turn turnlocks


I would though use another type of fastener.

Plastic is not good for outside use: (plastic can swell due to moisture and also sunshine might give issues later)


I would use following:

Total thickness  to cover with the paint: 15.7 – 1.2 + 0.6 = 15.1mm

Which means length number 7

(range: 14.5-15.25mm)




hole size to be drilled into your plate of 2mm is 7.9mm

predrilled hole size for a Turnlock quarter turn stud

If you need to install many, then a tool can be bought

installed retaining washer on a MTH turnlock quarter turn stud

installation tool to install a quarter turn retaining washer


receptacle of a turnlock quarter turn system



You can opt to

rivet mount        https://anemo.eu/turnlock/MTHRF25S

weld                     https://anemo.eu/turnlock/MTHRFWS  (take care: that’s for very high volumes: you need special welding machine for this)


advantage: your rivets do not need to be countersunk, so you can use standard stainless steel rivets.


Hole pattern for the receptacle:

hole patern for a Turnlock quarter turn receptacle panel preparation


The above series have a clamping force range between 30N-60N

Which means in worst case = 30N

Which means pushing with 3kg against the panel thanks to one quarter turn, since you install 4 of them, it would be more, however vibrations will make the quarter turn go under bigger stress levels.


I would therefore opt for a Belleville washer system, with clamping force: 350N-380N

(the current system you selected has only a much lower value, as the spring is in the receptacle feature.


So as a conclusion:

(sorry, I’m writing as I speak)

The MHS series would be ideal.


Total thickness = 15.7 – 1.2 + 0.6 = 15.1mm

Stud length number 26


You can opt for the fixed retaining washerhttps://www.turnlock.eu/mhswcs

Or the more common one:          https://anemo.eu/turnlock/MHSWSS

your receptacle would be:           https://anemo.eu/turnlock/MHSRF33S


the 3D drawing of the stud will be sent later






Van: Thomas


No i mean total paint thicknes off both plates is 0.6mm.
I counted 15.7 (grommet 1.2mm included) + 0.6=16.3mm. Is that correct?
I’m not sure about the thickness of color but we can try both 27 and 28 to see which suits us best.




Från: Bart



Am I assuming correct.

Without paint, the thickness between both plates is (15.7-1.2)

(thickness of grommet =  1.2mm)

Which means thickness between both panels = 14.5mm.

However when adding paint on both sides,

You have as a total thickness 14.5 + 0.6 + 0.6 = 15.7mm

G = P+F+X+0.4 +0.6 + 0.6 = 14.5 +0.4 + 1.2 = 16.1mm


This would mean you need stud length 28 (tolerance 16,1-16,70mm)

(furthermore, imagine the paint is not that thick as 0.6mm)  then you might require length number 27 (15.5-16,10mm)

Or is if with your experience, the paint always enough thick

customer layout of initial design of a quarter turn Turnlock system


Your part numbers:






imagine your paint is not thick enough.

It would be easy to have some seals extra,

To make the part sealant.


This gasket adds approximately 1mm of thickness

Turnlock seal for LEA series


It can be also easily installed:

installed seal on LEA series of Turnlock fastener

Van: Thomas 


See attached drawing.


Med vänliga hälsningar / With kind regards,




Från: Bart



Can you please inform me of your thickness of your panels and it’s distances?

Note: you cannot combine in the different series receptacles

So you’ll have to use another receptacle too.


It would be handy to see your drawing with the different thicknesses of both of the panels and also the gap between the panels.

How much measures P =? ; F  =?