I have actually a 2" diameter, 11" length dowel. I desire to drill a 5/16" hole precisely in the facility of every end, 2" min depth. It requirements to be precise because the is for axles that the dowel needs to spin freely about without wobbling. I must do both end separately, no all the way through.

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How perform I uncover the center and also drill a feet there? (Note: I have actually one handheld rotating drill. I perform not have a drill press. I have accessibility to one if necessary yet it is not convenient. I also have these guides.)

I know how to discover the center of rectangle-shaped boards, yet not circles.

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edited Nov 23 "15 in ~ 13:10
Jason C
request Nov 22 "15 at 20:15

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Finding the centerUsing Geometry

There room a pair of ways to perform this. Due to the fact that your dowel is large enough you can do this by hand relatively easy.

First would be to do 3 currently on the outside of the dowel the cross 2 different points follow me the one (each line). Then attract 3 perpendicular lines indigenous the facility of those lines. The suggest where every those lines intersect is the facility of the circle. This picture makes way more sense than my words.

That seems like much more work 보다 it is precious though. Something simpler, that needs a square (or anything with a known 90 degree angle), dubbed Thales" Theorem. This one is also easier come explain. Draw a right angle and also the leaf of the dowel. The political parties from this angle will bisect the one of the dowel. Illustration a line in between those two suggest will acquire the diameter. Repeating this procedure a 2nd time (starting from one more point.) will obtain you a second diameter. The point where the two diameters fulfill is your center. This is what i would do as i don"t need to do this to often.

Just use a tool

A center square, or comparable tool favor the one in Jason"s answer would work very quickly and efficiently and also would take much less time and be less error prone. If you have to be perfect every time and plan on doing this a lot than a center gauge, or similar tool, is the means to go. Press it up against the dowel and also draw her line. Do this twice and you uncovered your center.

Might even have the ability to make a home brew variation of this relying on your acceptable tolerance.

Drilling the hole.

This can not work-related for her case yet in basic I would certainly recommend using a drill press for something choose this whereby accuracy is important. Take it a deep block and also drill a hole, through the press, that is the very same diameter together your dowel. Hopefully her table moves down far enough. The depth of your block, if possible, must be close to the size of her dowel. Store in mind the you still have to clamp it to the table yet the depths the hole the less error friend will get from the dowel moving.

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Then ar your dowel in this void. That will save it perpendicular to the table. Usage a punch to mark your center and also then guide your drill right into that hole.