M3 thread projects a 2.529mm hole

[rprovideo]

Hi

I have two sheet metal components that will be held together by an M3 hole. I created a hol (I think it was d=3 but that should not matter anyway) in the inside component, then added an M3 thread to it. This created a hole thats visibly smaller. its not a modeled thread, but I assumed its so its displaying the thread itself.

Now if I project this circle to the outer component, the projected circle will be 2.529mm in diameter. And it I put this on a drawing, this will end up as 2.5 because of my 0.1mm precision

here you can see the projected hole (overconstrained) and a 3mm hole I drew around it.

its actually visible on the lower compenent too

now I'm new to F360, but I would suppose this is wrong. an M3 screw actually needs a d=3.2 hole. This will result in a component that wont fit together. 

[seth.madore]

A hole that's defined as an M3 threaded hole will (or should) have a minor diameter of 2.5mm, which is why you are getting that size projected onto your mating parts.

[rprovideo]

Correct me if I'm wrong, but should a hole what needs the screw to go thru needs to be the size of the major diameter?

if its created like this now, I wont be able to screw them together.

[seth.madore]

Did you define it as an M3 tapped hole or an M3 clearance hole. The former will give you the minor diameter, the latter will give you a 3.4mm hole

[seth.madore]

Like this:

 

[rprovideo]

I did not use the Hole function, I used the Thread function on an existing hole:

this doesnt ask for anything but should create a standard M3 thread

[seth.madore]

AFAIL, it's going to reduce (or increase) the hole size to the minor diameter of the thread size specified. 

[rprovideo]

hence my point - the projected hole should still be the major diameter for the purpose of why you'd project a hole.

[g-andresen]

Hi,

It might be helpful if you take a look at the characteristic dimensions of threads.

günther