Recreation of knobs

Hello all,

beginning with learning to create 3D printable models, I am at the very start and therefore I would like to ask you a few more questions if I may. Let's say, I want to recreate a knob of a device, that I do not have at hand, but just see from pictures. How do all the pros on different forums and libraries, recreate the buttons in a CAD model? is there any source where one can get the exact dimensions being used? Or is there any other way, how to recreate that? I just want to start with a simple example like a knob, but what would be a proper way to re-engineer this?

You can certainly recreate the shape of an object with just pictures ... though that is far from ideal unless the pictures are precisely top down, profile, front.
However, those will only be scaled versions as you cannot really be sure of the dimension.

If you want to avoid trial and error, its better to have something at hand.

Did you have one in mind or an example you could show us?
If you're looking for some typical knobs and other hardware, McMaster-Carr's website has CAD files for a lot of their catalog.
Usually, if I can't find dimensions but i can find some good pictures that show a side or a top view - I'm not above holding a ruler up to the computer screen and measuring the longest side, making up a Scale Factor and modeling it from that. It's best to use the longest dimension..

(Final Size you decide) / (Measured longest side) = (Scale Factor)

From there, keep measuring and multiply by the Scale Factor to get the rest of the dimensions - some extrapolation may be required...

This is what I would like to do:

http://www.leobodnar.com/shop/images/ELMA-knobs.png

Pretty difficult I guess? :) Sure I could buy one of these... But they are pretty expensive. So why not 3D Print them for my own usage, as I will need more than 1... Do you think this is a feasible endavour?

So if you go to the product page for that knob - next to where is says Product Description is a tab Product Downloads. Click that and you can download the Datasheet - there's some dimensions there at least.

oh this is awesome.. I didn't know about them! I unfortunately don't have found any dual rotaries like above.

Quote:

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Originally Posted by oic-u3d2

Did you have one in mind or an example you could show us?
If you're looking for some typical knobs and other hardware, McMaster-Carr's website has CAD files for a lot of their catalog.
Usually, if I can't find dimensions but i can find some good pictures that show a side or a top view - I'm not above holding a ruler up to the computer screen and measuring the longest side, making up a Scale Factor and modeling it from that. It's best to use the longest dimension..

(Final Size you decide) / (Measured longest side) = (Scale Factor)

From there, keep measuring and multiply by the Scale Factor to get the rest of the dimensions - some extrapolation may be required...

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You can approximate the exterior of a knob like that from photos, but to actually reproduce a working version of it you'd need to know what's going on inside, and details like how it fits onto the shaft. I'd suggest you buy one, take it apart, measure everything you can, and make a CAD model that incorporates all these things. Then you can try printing it.