Wrong Diameter for M14x1 Screw

Forum|Forum|2 years ago
December 3, 2023
2 replies
2319 views

Hi all,

im new to Creo. I have the student version of Creo Parametric 9.0. I send a screenshot, where you can see my problem. The diameter of the shown screw is 0.5118mm. In the tutorial which im learning with there is a diameter of 13mm for a M14x1 Screw. Is there im doing wrong? If so how can i change that diameter. I hope you guys can help me out. Sorry for my bad english.

General

Best answer by MartinHanak

Hi,

your problem is related to length units.

13 mm = 0.5118 inch

KenFarley

21-Topaz II

Hole features for tapped holes model the hole diameter with the tap drill diameter. For metric screws, the tap drill is simply the nominal thread diameter minus the thread pitch.

Hole dia = Tap size - Pitch = 14mm - 1mm = 13mm.

E

EJ_10863305

Author

4-Participant

Thank you very much for your fast Answer. I coudnt exactly understand what you wrote can you maybe show me a video on how you do this?

KenFarley

21-Topaz II

A video? Of what?

The reality of tapped holes is that they are made by drilling a hole that is the "minor diameter". After drilling this hole, a tap is twisted into the part to form or cut the threads.

The tap drill is smaller than the nominal thread size. How much smaller? Well, for a metric thread, like your M14x1.00, the drill size is the nominal diameter minus the thread pitch. 14 - 1 = 13 as stated before. That's why the hole you are seeing is 13 mm diameter and not 14mm. It's what you get when you use a HOLE feature that is tapped. You get a physical hole at the tap or minor diameter, and a surface that represents the thread diameter.

EDIT: Ah, I see that Martin has found the real culprit. Odd though I would expect that if standard threads are used the units would be handled correctly. Probably the units of measure in your model are inches, not millimeters.