# Drilling holes?

**URL:** <https://forum.onefinitycnc.com/t/drilling-holes/12226>\
**Category:** Uncategorized\
**Created:** [April 3, 2022, 11:47pm UTC](https://forum.onefinitycnc.com/t/drilling-holes/12226 "2022-04-03T23:47:59Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![SailorMike](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.onefinitycnc.com/sailormike/32/3290_2.png) [@SailorMike](https://forum.onefinitycnc.com/u/SailorMike)\
**Post date:** [April 3, 2022, 11:47pm UTC](https://forum.onefinitycnc.com/t/drilling-holes/12226/1 "2022-04-03T23:47:59Z")

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I wasn’t quite sure where to post this, “Uncategorized” seems as good as any. I’m working on a simple project to get familiar with the new machine and software. I needed to drill some shallow 1/4 inch holes for some joinery dowels. I knew that I didn’t have a CNC drill bit, but not to sweat, it should take a regular 1/4 inch twist drill bit in the 1/4 inch arbor, right? Wrong! I tried many different plunge rates and bit speeds, and the holes turned out oversize every time. The same bit in my drill press makes perfect holes. What am I missing?  
I wound up pocketing the holes with a 1/8 inch router bit, worked a treat, VERY precise. I’m SUPER impressed with the new machine! Light years ahead of what I had before. ~Mike

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**Author:** ![WaywardWoodworker](https://avatars.discourse-cdn.com/v4/letter/w/e79b87/32.png) [@WaywardWoodworker](https://forum.onefinitycnc.com/u/WaywardWoodworker)\
**Post date:** [April 4, 2022, 12:25am UTC](https://forum.onefinitycnc.com/t/drilling-holes/12226/2 "2022-04-04T00:25:08Z")

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I’d say there are a few areas to look at, first what RPM were you using? Twist drills aren’t usually balanced/straight enough where you can spin them at 10,000 RPM and not have wobble and therefore runout.

Second, what operation were you using to drill the holes? Are you using a drilling cycle which pecks and lifts the chips out every 1/4-1/2"?

I frequently drill holes when they’re smaller than 3/16" larger holes I can employ a 1/8" endmill, as you stated, this operation of ‘boring’ a hole will produce an accurate hole. Smaller than 3/16" I’ll usually use a drill bit at 1800 RPM or so with a peck style drill operation to clear the chips out. I normally don’t drill deeper than 1.5 inches for most of my operations.