Crib sheet for Creating threads

[HaroldL]

Every once in a while someone posts a question about how to create threads. Other than the cosmetic threads that are carried over to the drawings and called out in the drawing view, sometimes the thread form needs to be created for "show".

Some time ago I came across a YouTube video that showed how to create the threads without having to decipher the standard profile illustration that is sometimes shown above screw thread data charts. I have been using that process for those times I needed to create a thread form.

Since I have some free time I thought I'd use some of it to condense the info from the video into four illustrations for creating internal and external threads using both the Helical Boss and Helical Cut in Alibre.

Be aware that creating threads add a lot to the model and can have a detrimental effect on you computer performance, especially if you happen to have a lot of fasteners with threads. So reserve the use of thread features to those times when it is necessary, like in a render for example.


I am uploading the crib sheets here for anyone that would like them. Hope you find them useful.

Edit:
I uploaded this crib sheet to the Resources along with some spread sheets of thread data. Only the data used for the thread sketch profile and location are in the spread sheet..

 

[GIOV]

Thanks HaroldL. May be will be good same kind of sheet description for draw straight and twisted gears.

 

[HaroldL]

Thanks HaroldL. May be will be good same kind of sheet description for draw straight and twisted gears.

GIOV,
There already is a script to create straight spur gears. My guess is that for twisted/helical gears someone could modify that script to twist the extrusion along its depth (thickness) for a twisted/helical gear.

 

[Lew_Merrick]

Thanks HaroldL. May be will be good same kind of sheet description for draw straight and twisted gears.

Hi Giov -- To create Spiral Gears you need to create a Plane at the appropriate angle of Spiral and then create (on a Plane perpendicular to your gear tooth's Base Plane and Elliptical Arc along which the Tooth may be Swept to create a proper Spiral Gear. -- Lew

 

[albie0803]

Are you looking for "eye candy" gears that you can put in a model so that it 'looks' right but doesn't really matter if the tooth shape isn't perfect or are you looking for a model you can 3d print from?

I work at a gear cutting workshop so all the gears are drawn dimensionally correct for turning but the actual tooth shape is only an approximation. If that's all you want, then I am happy to share my gear template part. You enter the tooth count, helix angle, OD, tooth root diameter, thickness, tooth chamfer, bore & bore chamfer via the Equation Editor and it will create a 'pretty good looking' gear.



I have also written a little script which asks you for all the values but it takes so much longer to run than just editing values in the Editor.

 

[Lew_Merrick]

I work at a gear cutting workshop so all the gears are drawn dimensionally correct for turning but the actual tooth shape is only an approximation.

Hi Albie -- As somebody who served his apprenticeship in a shop that made Gear Hobs for "Western Gear" and "Mantell Gear Works" I would guess that we have similar perspectives with respect to gearing. [The opposite perspective was modelled to me by a genuine Harvard MBA whilst working on a Department of Defense program in the early 1970's. He "complained" about the time we spent designing & fabrication gears by saying, "Nobody makes gears, you only buy them!" I went out the next time I had a "work day off" and had a bumper stiker printed up that read "Nuke Harvard NOW!!!."] It may be worthwhile for us to collaborate on a "Gears in Alibre" presentation. ??? -- Lew