Geometry question - Router Forums
Old 10-25-2015, 03:40 PM Thread Starter
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Geometry question

I want to make some various sized wooden knobs by drawing a circle, marking evenly spaced points around the circumference, drilling holes at those points and cutting the whole thing out on the band saw. Can any one tell me an easy way to mark those points evenly on various sized circles? Thanks in advance for your help. Woody
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Old 10-25-2015, 04:02 PM
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Originally Posted by woody1401 View Post
I want to make some various sized wooden knobs by drawing a circle, marking evenly spaced points around the circumference, drilling holes at those points and cutting the whole thing out on the band saw. Can any one tell me an easy way to mark those points evenly on various sized circles? Thanks in advance for your help. Woody
I'm not quite sure I understand what the end result is that you are looking for from your description. What do the holes have to do with the "cutting out"?

In any case, decide how many holes you want on the circumference, divide that number into 360°, use a protractor to mark the points on the circumference, and your done.

360°/10(holes)=36°

Find the center of the circle, then mark out the points using the protractor based on the number of holes and the angles you determined.

If you are cutting the knobs out to be hexagon, septagons, octagons, etc., just connect the dots.

Hope this helped. If not post a description of the end result configuration and we may be able to get you there.

Hi, sorry I missed you. I have gone to find myself, but if I return before I get back, please ask me to wait.

Nothing ever gets built on schedule or within budget.

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Last edited by schnewj; 10-25-2015 at 04:05 PM.
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Old 10-25-2015, 04:14 PM
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How many holes (3, 4, 5) or print this.

http://www.routerforums.com/attachme...1&d=1445807579
Attached Thumbnails

Al B

Last edited by boogalee; 10-25-2015 at 04:19 PM.
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Old 10-25-2015, 04:29 PM
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Quote:
Originally Posted by schnewj View Post
I'm not quite sure I understand what the end result is that you are looking for from your description. What do the holes have to do with the "cutting out"?

In any case, decide how many holes you want on the circumference, divide that number into 360°, use a protractor to mark the points on the circumference, and your done.

360°/10(holes)=36°

Find the center of the circle, then mark out the points using the protractor based on the number of holes and the angles you determined.

If you are cutting the knobs out to be hexagon, septagons, octagons, etc., just connect the dots.

Hope this helped. If not post a description of the end result configuration and we may be able to get you there.
Here is a pretty good video showing how the gentleman made a 5-lobe knob The 5-lobe knob seems to be the most common. He's making a specific size. but if you want a different size, follow the procedure that he shows and adjust the dimensions accordingly. In laying out the centers of the scallops, the compass should be set to (1.176*radius) - you would have to adjust the diameter of the Forstner bit used to make the scallops and the washer used to round off the corners.
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Old 10-26-2015, 11:40 AM Thread Starter
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Thanks everybody. Those answers take care of my question beautifully.
Note to SCHNEWJ I want to make star knobs similar to the ones illustrated by Tromp 913
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Old 10-26-2015, 12:18 PM
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Question. I need to make knobs with the threaded shaft fixed in the knob, rather than the knob turning on the shaft. What is the best thing to fasten the shaft to the tee nut?
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Old 10-26-2015, 12:25 PM
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I use this to divide circles for making whirligig propellors. I center the wooden circle (hub) on the pattern and mark the edges at the number of divisions that I want (up to six). It might be useful for your application too, Woody.

http://www.routerforums.com/attachme...cledivider.pdf
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Old 10-26-2015, 01:00 PM
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Quote:
Originally Posted by old coasty View Post
Question. I need to make knobs with the threaded shaft fixed in the knob, rather than the knob turning on the shaft. What is the best thing to fasten the shaft to the tee nut?
5 minute epoxy would probably be the best bet. Less "bulky" then the next method.

Another method is to use a carriage bolt through the top of the knob and use a nut to lock it in the underside.

Hi, sorry I missed you. I have gone to find myself, but if I return before I get back, please ask me to wait.

Nothing ever gets built on schedule or within budget.

Tool Storage Bait and Tackle, LLC.
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Old 10-26-2015, 01:03 PM
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Quote:
Originally Posted by woody1401 View Post
Thanks everybody. Those answers take care of my question beautifully.
Note to SCHNEWJ I want to make star knobs similar to the ones illustrated by Tromp 913
Perfect!

Great video showing how to make the star knobs. However, as a personal choice I would probably use plywood instead of particle board.

Hi, sorry I missed you. I have gone to find myself, but if I return before I get back, please ask me to wait.

Nothing ever gets built on schedule or within budget.

Tool Storage Bait and Tackle, LLC.
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Old 10-26-2015, 02:22 PM
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Quote:
Originally Posted by old coasty View Post
Question. I need to make knobs with the threaded shaft fixed in the knob, rather than the knob turning on the shaft. What is the best thing to fasten the shaft to the tee nut?
Red Loctite is probably the easiest (less messy) way to do that.
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