How do i locate the center of a circle?


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Old 08-29-15, 12:31 PM
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How do i locate the center of a circle?

I bought some round wood knobs for an old dresser and to attach them I need to drill a hole in the center and then fasten with a screw- but how do I accurately locate the center to drill the initial hole?
thanks!
 
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Old 08-29-15, 01:00 PM
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Rather then trying to describe the method I use.... I looked for and found a video that is similar. I use a square when I do it..... you tube/watch?v=n4nrzMPX5Uc

In your application you can probably approximate the center as it's not critical to be 100% in the center.
 
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Old 08-29-15, 01:48 PM
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For a consistent placement on cabinet doors you may want to invest in one of these. Handle & Knob Jigs - PERFECT MOUNT HARDWARE TEMPLATE - CABINET DOORS

But for just finding center of the drawers, measure what would be slightly over center, mark it. Measure the same distance from the other direction and divide the two marks in half.
 
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Old 08-29-15, 01:49 PM
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I would probably use a tape measure.
 
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Old 08-29-15, 01:58 PM
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Old 08-29-15, 01:58 PM
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I believe the OP is asking about drilling a hole in the center of a knob with no hole.
 
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Old 08-29-15, 01:59 PM
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Interesting video but you don't have the liberty of drawing a square around your knob.

If you want to copy this technique shown in video:

- Trace the knob onto a sheet of heavy paper
- Draw your square as shown in video and mark center point as shown
- Cut the round part of paper out only and use that as a template for your center hole

Use an awl or punch to mark your center hole so drill bit doesn't walk.

As Pete said, there are easier ways, but this won't take long and is pretty accurate.
 
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Old 08-29-15, 03:01 PM
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Old 08-29-15, 03:49 PM
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NOW you know why you shouldn't have slept thru hy skoul geeometree
 
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Old 08-29-15, 04:33 PM
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Center of Circle

Place the knob on a piece of paper and trace around the knob to make a circle.
Use scissors to cut out the circle.
Fold the paper in the center to form a semicircle.
Fold again so that you have a quarter circle.
Unfold.
Where the folds intersect is the center of the circle.
 
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Old 08-29-15, 04:35 PM
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Ken, you're no fun...............................
 
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Old 08-29-15, 05:48 PM
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Wirepuller is a genius. .............................
 
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Old 08-30-15, 11:29 AM
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I believe the OP is asking about drilling a hole in the center of a knob with no hole.
That is correct.
thank you all for the great advice (and links) and fortunately because of the application, I can be a little off without being noticeable (I think) so if I screw it up a little, hopefully it won't matter!


More neat tools. Buy WoodRiver Pen Blank Key Chain Center Finder at Woodcraft.com
THIS is really cool and I may go out and get one today !(there's a Woodcraft near me)
 
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Old 08-30-15, 11:31 AM
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Circle

Well, I figured a paper template would come in handy if the OP has several knobs to drill. That is how I would do it myself. I do, however, appreciate the geometric construction techniques.
 
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Old 08-30-15, 05:11 PM
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With the great feedback, now I know what to do with this combination square I inherited from dad!
 
 

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