Created a part for 3d printing and thread sizes always to small

[g_burke]

I created a drawing for 3d printing, and have one thread an m12x1.5 and it seems to always print at around 10mm i have increased the hole size to 12.2 and it sill around 10mm when printing, the printed prints all the correct sizes as far as hole spacing and all just the m12 is off size, i will attach a copy of the model, if anyone has any suggestions, i did use extrude for  creating the thread, but i can't seem to get scale to work..

Thanks gary

[TheCADWhisperer]

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@g_burke wrote:

 i did use extrude for  creating the thread

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Use the Hole feature - Threaded rather than Extrude and Thread.

Offset for clearance.

Your Sketch1 is missing Tangent constraints and dimensions.

Not symmetrical?

Your Fillet blocks the thread - not done correctly - fastener will bind.

Check back in a moment...

One simple sketch.

Notice the Offset Face(s) in the thread for printing tolerance.

[g_burke]

Thanks got it now, the only thing it's not supposed to be a perfect triangle, i imported a mesh file that has holes to mount it to in a triangle but it also has connectors around the triangle that are not a perfect triangle so i drew it up to get it as close as i could to clear the connectors.. but you are right it wasn't constrained

and thanks for your help you did show me the way forward.

gary

[TheCADWhisperer]

@g_burke 

I did not explain one critical tip.

When placing a Chamfer (or Fillet) on the edge of the threaded hole - you must do this with the thread in cosmetic form rather than modeled.  Then change to Modeled.  Otherwise the feature closes off the entry of the thread lead-in.

Additional tip:

In many cases it is better to add Fillets as placed features rather than as Sketched arcs.