Funny material! :)

Hi Wayne,
the picture shows a M16 x 2pitch example with a 0.1mm clearance which I created manually using an offset of the form.
Not sure if its this method is best option yet.
Also with the thread form being 60 degrees printing without supports may be an issue.
Anyway i will see if the manual method I used can be transferred to a node.
Cheers
Barry

Hi Barry,
What you are refering to is what the machining industry calls the "H Limit" or the "L Limit"....

You'll find it as a number system for taps and dies like, H1-H7 or L1-L7 etc......

They reference a tolerance value... So aerospace needs high tolerances. Home depot stuff wiggles around on each other before it's tightend...

It's basically/simply achieved by the depth of the thread cutting tool..

so to make workable nuts and bolts, you will need a "3rd object generated" which will be the tap or the die, to boolean the threads, to work with the current "M12 Bolt" etc....

I dont know enough to be able to just give you the numbers... A Machinsts Handbook can, or asking in a CNC forum also...

An image to be explanatory...

If the red form was the thread, the upper and lower forms would be various H and L Limits...

Hi Burr,
thanks I was thinking of offsetting the form to give a constant clearance for 3D printing.
Your method will make it easier the only thing is that to give say 0.05 clearance due to the 60 degree thread form
the former moves 0.1mm but that's no problem.
Many thanks
Barry

Hi Barry,
Sure thing...

Just clarifying because we have such diversity in language in the forum....

The term of offsetting the thread form.... if we use "moi's offset command" you would get erroneous results.... but the term offset, as in "move the cutting form in and out of the cut, is how a guy actually making a nut and bolt would do it...

I am pretty sure you got that part.... just adding it in for the forum....

Always like watching your work go by.....

There is an xml file with metric thread settings for 3d printing which someone prepared in excel. (re: Fusion 360)
Notepad++ shows the text entries. There are external Class 6g, and internal Class 6H, (whatever those are).

There is also a link to Garden Hose Thread xml file contents.

- Brian

hi Wayne,
the attached nod file will allow you to create a screw and nut for 3D printing.
You can adjust the clearance to suit.
There are 2 thread form options 60 degree inclusive and 90 degrees.
The nut is just a cylinder but you can Isect boolean any shape you want from it.
Anyway have a play.

Barry

Hi Barry,

Thank you! I am going to 3d print one tomorrow morning!

Wayne

Hi Barry,

The screw and nut were printed together at the largest tolerance. It worked spectacular with the nut freely going up and down the screw.

The first attempt was at a lower tolerance and the nut seized to the screw. Will be looking for a good midpoint. Your program works great!

Thank you,

Wayne

Hi wayne,
Your printer will have some spacing settings like a step size, pass depth etc... these will affect your tolerance ability there... so the tolerance wont be a direct correlation to a printers "tolerance"...

A step size on an angled surface, to achieve a tolerance on something that has to "slide together" will be exaggerated.....

Just a note....

Hi Wayne,
I printed a 12mm dia screw x 50mm and 3 nuts x 20mm long with a 2mm pitch 90 degree form separately.
The clearances 0.15/0.2/0.25mm.
The 0.25 nut no problem.
0.2 nut required working along the screw a couple of times but fine.
The 0.15 would only go onto the screw about 12mm with a lot of working back and forth.
I think the 0.15 clearance would have worked with a shorter nut maybe its down to shrinkage.
Anyway glad it works.
Cheers
Barry

Great work Barry and Wayne,
Interested to know if the node editor you designed can create a part that is like a hollow sleeve; with thread on inside
and outside?
-Stefano

Hi Stefano,
yes you can disconnect the cylinder and produce the screw for the outer size add a head boolean union, select it and use that instead of the cylinder in the boolean operation of the inner thread.
Then enter the details for the inner thread with desired clearance and rerun the nod.
Hope that's clear.
Barry

Brilliant cheers Barry, will get to this soon and give it a try - looks great! - stefano