Getting started designing a knob
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Getting started designing a knob
I've got a new project for my old (1972) car...printing a new AC knob as the old one is cracked...
I'm looking for suggestions on how best to get started (I'm still relatively new to FreeCAD having designed/printed about 4 projects). The items I' most curious about is :
1. the 'embossed' arrow on the face of the knob
2. the knurled grip around the circumference
3. the 'D' shaped hole in the back
Here's some pictures of the current knob - I'd like to reproduce it as closely as possible.
I'm looking for suggestions on how best to get started (I'm still relatively new to FreeCAD having designed/printed about 4 projects). The items I' most curious about is :
1. the 'embossed' arrow on the face of the knob
2. the knurled grip around the circumference
3. the 'D' shaped hole in the back
Here's some pictures of the current knob - I'd like to reproduce it as closely as possible.
Re: Getting started designing a knob
Dimension accordingly:
- Attachments
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- Knob_kiss.FCStd
- (115.75 KiB) Downloaded 45 times
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Re: Getting started designing a knob
Very nice, but it is differs somewhat from the original he wants to reproduce.
And when you are doing a restoration, facsimile is vital, not just something close.
The triangle on the top is just that, a single triangle sticking up not a triangular shaped recess going down.
The knurling is pointy and continuous not rounded and intermittant.
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Re: Getting started designing a knob
I would start in PartDesign, sketching on the X-Y plane. Numbers below correspond with your ownSteve76063 wrote: ↑Fri May 06, 2022 10:04 pm 1. the 'embossed' arrow on the face of the knob
2. the knurled grip around the circumference
3. the 'D' shaped hole in the back
1. Draw a single triangle on the X-Y plane, the correct size and distance from the origin. Change its attachment to the height of the knob and then pad it upwards.
3. Draw a circle centred on the origin. Constrain its diameter to the correct measurement. Draw a straight line parallel to one axis (horizontal or vertical constraint, offset distance to suit the 'stem' of the 'D'. Trim the line both ends using the circle. Once the main body of the knob is made, use this sketch to form a pocket the correct depth. This is the same as is done in the example file above.
2. You will have to count the number of points on the knurling and guess the angle (maybe 60 degrees). You can measure the OD of the knurl points. Use a calculator and geometry to work out the ID of the knurl inner points. Draw a polygon with twice the number of sides as the number of points, to suit the OD measurement. Draw another polygon, same number of sides but to suit ID measurement. Join alternate points on ID and OD polygon with a polyline.
One thing you might have to look at is the relative position of the 'D' and the arrow on the top (the clocking relationship between the two). You can import the 'D' sketch geometry into the arrow sketch and then change it to construction lines to help with this.
Re: Getting started designing a knob
It looks like a colored recess to me from that picture. Any way it can easily be replaced with a Pad at the same place in the tree.
And this again is just as easy as replacing the Pad with corresponding pocket and fixing the polar pattern to use that.
For orientation of the arrow just rotate its sketch around sketches Z axis the needed value.
The general design and steps are basically the same.
- Shalmeneser
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Re: Getting started designing a knob
The Kisolre file is perfect for understanding the different steps.
You can use Image_Workbench. With good pictures (perpendicular to the object), you can rescale it to match the original dimensions and use it to copy dimensions. https://youtu.be/PMUxmlnYv1M?t=234
You can use Image_Workbench. With good pictures (perpendicular to the object), you can rescale it to match the original dimensions and use it to copy dimensions. https://youtu.be/PMUxmlnYv1M?t=234
Re: Getting started designing a knob
Hi Steve76063, greetings to the Community!
Given that we intend to give an idea of how to do it, attached an example of the many modeling possibilities or workflows offered by FreeCad.
The "Draft" and "Part" workbenches were used.
Since it was not possible to attach the complete file created with "Part Design", we attach the file containing the sketches (with the progressive steps indicated) that can be used as a "guide" for modeling.
The sketch used for knurling should be repositioned using as a reference a "shape binder" obtained from the edge of the revolution of sketch002.
Not being in possession of the real dimensions, obviously it will be necessary to redefine all the sketches indicating the right dimensions detectable by the physical model.
Obviously, everything can be improved and / or optimized.
Correction: step 3 (sketch004) is a "Pad" not a "Pocket", I apologize for the mistake.
- Attachments
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- knob_sketch.FCStd
- (12.37 KiB) Downloaded 29 times
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- knob_Part.FCStd
- (610.97 KiB) Downloaded 24 times
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- knob_Part.png (239.54 KiB) Viewed 1824 times
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- knob_Sketc.png (85.11 KiB) Viewed 1824 times
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Re: Getting started designing a knob
You guys are AMAZING
You've given me wonderful ideas to get my know printed, and I thank each and every one of you.
You've given me wonderful ideas to get my know printed, and I thank each and every one of you.
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- Posts: 33
- Joined: Wed Feb 09, 2022 2:47 pm
Re: Getting started designing a knob
@Steve76063 Glad I could help. I hope you learned something from that file