Smooth n' Curvy Star Knob (Customizable)

by thehans May 14, 2016
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Nice thing!

I want to print 3 compact 3 point-knobs for hex nuts, but the hex nut pointed right towards the narrow of the wall (see picture).
Therefore i added "rotate([0,0,boltHeadRotation])" at the beginning of line 172 and defined boltHeadRotation = 30;

I'd suggest to add that rotation by default, but with boltHeadRotation = 0;


I wanted to go and by some butterfly nuts, but decided to check thingiverse first.
the knobs created by your customizer work perfectly!

Always nice to hear another success story! Cheers!

One of the best customizers I´ve ever used. Worked like a charm.

Needed an replacement-knob for the roof box of my car.

Thank you very much.

Kindest regards,

Wow, just wow ! I was trying to design my own, but this is way too cool :)
Thanks ! I was able to design a 5/16 3 point that was printable without support.
All 4 ended up very nice and sturdy ! :)

Nice, I'm glad you like it! Would love to see pics of your makes.

could you add a nutkeeper, basically a cover over the nut area (accessible during printing with a m600 command in the gcode or a "color change" pause

edit: here is what i ended up by eyeballing it in tinkercad. not perfect but good enough for now. but i truly think it would be a great addition

PS, this is an awesome customizer, and you are a great designer. I am bookmarking this one for the next time i need to generate a nob. This saved my kayak trip!

I don't see much need for it. If the nut cutout is sized to press-fit the nut in place, there's no issues of it falling out. Tightening a screw from the other side can help evenly pull the nut in and seat it.

Feel free to remix the script and add your own features if you want.

i am using it on a kayak rack, so the nut is upside down and even pressfit doesn't hold it from being pushed down or even out when trying to get the bolt coming from the top into the knob at the bottom. plus I am using abs which is hard to design pressfit since it shrinks.

I was just thinking of it this way, you know the depth of the nut so putting a top over it doesn't seem like a huge addition. I would do it if i knew how to do openscad, but i am barely tinkercad capable.

Thank you again for the awesome design! you saved my weekend!

I can not generate knobs. No matter what I set, I always get an error message. What am I doing wrong?

How would I tell you what you did wrong if I have no idea what you are doing? What steps are you taking, what error message are you seeing? Are you talking about customizing on the thingiverse website? Thingiverse website is not supported/maintained by anyone apparently and the code is rotting away. Try viewing in OpenSCAD.

If you get an error in OpenSCAD, copy and paste the error here.

OK, a little more info would be useful:
I opened the model in the customizer and adjusted the desired parameters. Then I clicked "create thing" and hooked the email notification. Shortly thereafter, I received an e-mail saying that there was an error and the creation was aborted.

Yeah unfortunately I have no control over how Thingiverse handles its customizer jobs. It might be that your job was too complex and took too long. This could happen from any combination of: too fine resolution, too large of a knob(more vertices), too many star points.

I would recommend installing one of the OpenSCAD snapshots here: http://www.openscad.org/downloads.html#snapshots and try rendering the scad file on your desktop machine.
The latest versions have some customizer functionality built in, you may need to enable it in the menu: uncheck "View -> Hide Customizer"

Then you can use F5 to preview, F6 to render(takes some time) and then "File -> Export -> Export as STL..." to save the result.

Thank you very very much!! Works like a charm!

Hey, Just a couple of questions.
What resolution would you recommend changing to before exporting?
Also, would it be possible to make the hex cutout square instead for a cup head bolt?

OK, I've added two more configurable parameters for your case:
boltHeadSides and boltCounterboreDiameter

Since you want a square cutout, you can set boltHeadSides to 4. And since carriage bolt head is much wider than the square portion, you will need to manually specify the counterbore diameter also.

The counterbore was originally calculated automatically based on the assumption of a hex-head bolt with 1mm additional clearance. A value of 0(default) for boltCounterboreDiameter parameter signifies to use the default hex-head calculation. Hope that makes sense.

For the resolution, that is mainly a matter of preference. It correlates roughly to the maximum width of any flat face in the output STL. The default of 0.75 is a good general number that should create a decent output in a reasonable time. I tend to set mine a little finer at ~0.4-0.5mm when I'm finalizing a design because I like the things to look extra smooth. I also tend to render in OpenSCAD on my computer though, and not through Thingiverse Customizer.
Keep in mind that finer resolution will take longer to compute and will result in larger STL file. The overall time and filesize will also be depend on the overall dimensions of your knob and other complexities (number of star points mainly). If your resolution is too fine, Thingiverse Customizer might time-out and fail to render the part, but you can always try again with another number.

What a great tool! Thanks for putting the time into this and posting it! Long gone are the days of buying knobs at the hardware store...

Thanks, glad you like it. Please post pics if you make some!