1/2" Dowel Pin Hole Sizing

I’ve picked up some Saunders Machine Works fixture plates for my Shapeoko 5 Pro 4x4.

I’m working with hardwood and I’m using some dowel pins to hold the piece. The pins are 1/2" in diameter.

What’s an appropriate size hole to cut in the work piece to have enough tolerance that I can lift the piece off without a huge amount of trouble?

Sounds like what you’re looking for is a “Slip Fit”. Usually a hole 0.0005" - 0.002" larger than the dowel.

Best bet is to machine the hole exactly 0.500" & measure it, then adjust from there.
You might just end up with a slip fit the first time due to spindle/cutter runout. Or if you’re using CC, the fact that it likes to conventional cut.


The way I tested for fit was to machine several holes on scrap of the same material to be used.

I have found this to change depending on humidity and moisture content of the material.

you could do several test holes from the same size diameter on up to .005 maybe more over sized.



:man_facepalming: Yes, humidity is definitely a factor that I foolishly didn’t think of. I was practicing with MDF, but it’s a sponge. I’ll test out on some scrap. Worst case, I can enlarge the holes with my drill press if they almost work.

I’m using Vectric, but I’ll give a conventional cut a try to see if that gives me enough room to drop the work piece onto the pins. Thanks!

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I took some spare wood and had the Shapeoko make 6 holes - 0.5”, 0.51”, …, 0.55”. I ended up finding 0.52” worked well.

Thank you both for the tips.

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