Thanks Peter!Peter_Frank wrote: ↑Wed Jul 15, 2020 1:54 pmI am not in doubt at all, how much to tighten my bolts, as I work with these issues for a living also, different material combinations.
But to share in numbers, just checked, I tighten 6 mm screws in brass around 2 to 3, max 4 Nm.
And the baseplate T nuts never more than 3 Nm, just checked now.
8 Nm is way too much, even for an 8 mm screw in brass T-nuts.
You could do it this hard, if long screws in an aluminium mast yes, but I see no reason to do this, except if they come loose too fast.
Some T-nuts are stainless steel, stronger, but in my experience it is better to tighten for the often used brass ones, as it is more than sufficient, and then you dont have to remember if you got one or another in your board, safer in the long run.
Back to our often used brass T nuts in the board slots, or carbon foils with brass inserts like in my case.
The brass is the soft thing here, that goes bobcus (horrible wrong soon) if tightened too hard, thread is ruined and screw just goes around without force now.
Especially the short flat T nuts for the baseplate, they can not take much.
Getting a torque wrench is overkill, way too expensive and you dont need it, once you got an idea of how much we are talking about here.
I use torque wrenches in my work yes, but there is a lot better way to find out "how much do you tighten" your screws.
Took a picture right now, use an angled Unbrako/Hex/Allen key, and a fishing scale.
Put your hand on the side of the tool to support, and pull the fishing scale till the screw either tightens further, or loosens again - even better, do it both ways so you get an idea.
Now, having the force and the distance, you can calculate the torque:
Torque in Nm = Force in newton * Distance in meter.
In my example it could be I measure 2.1 kg on the fishing scale, and my Distance is 135 mm.
10 Newton is roughly 1 Kg or 2.25 pounds (so you can use your own fishing scale or luggage weight and convert).
Meaning I measure 2.1 * 10 = 21 Newton, and the distance is 0.135 meter.
This gives me a torque of 21 * 0.135 = 2.8 Nm.
You dont need to have a foil with Allenkey screws, you can just go and find ANY other screw in your house or shed, where you can use an Allenkey, as everyone got these.
Because you just have to measure a few times, and then feel with your hand, how tight it is, to know what range we are talking about
Hope this can help those who dont work with bolts or materials and numbers, to know how much they really tighten a screw/bolt
We can discusss how much we find it good to tighten, we might not agree, but important for many to get a number of how much do THEY tighten, way too much or okay?
Most often not too little is my experience...
Thats is very well explained. I just remembered that I have a fishing scale that has never been in use. Finally it can help me in foiling, amazing!! Lets see how many big fish I need to open my bolts..