# Rounding over inside diameter of a hole



## jschaben (Jun 21, 2009)

Mother just handed me another addition to the honey-do list:sad:
Should fit somewhere on page 27.....:blink:
Anyway, fairly simple, rotating scissors rack. Uses two discs stacked 4 or 5" apart with holes around both about halfway between the axle and perimeter, 18 in all. Holes roughly 3/4" in diameter. 
Question is: What is a good way to roundover the inside diameter of those holes, 3/16 to 1/4" roundover would seem to be about right for them. I'm thinking to equip the roundover bit with a bearing the same diameter as the hole and let it guide me in then just plunge down and go to the next one. I think with the fairly standard 1/2" bearing things could get a bit hairy as it would be very easy to get on the wrong side of the bit. I thought about the router table for a second and quickly dropped that idea as I had visions of wood flying all over the place. I noticed the picture doesn't have them rounded over so it's obviously not necessary but I think it would look better.
Any suggestions:help:


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## bobj3 (Jan 17, 2006)

Hi John

I would suggest a ball end bit and safe to use on the type of hole..but it looks like it will take a big one..to get the nice round over inside cut.


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jschaben said:


> Mother just handed me another addition to the honey-do list:sad:
> Should fit somewhere on page 27.....:blink:
> Anyway, fairly simple, rotating scissors rack. Uses two discs stacked 4 or 5" apart with holes around both about halfway between the axle and perimeter, 18 in all. Holes roughly 3/4" in diameter.
> Question is: What is a good way to roundover the inside diameter of those holes, 3/16 to 1/4" roundover would seem to be about right for them. I'm thinking to equip the roundover bit with a bearing the same diameter as the hole and let it guide me in then just plunge down and go to the next one. I think with the fairly standard 1/2" bearing things could get a bit hairy as it would be very easy to get on the wrong side of the bit. I thought about the router table for a second and quickly dropped that idea as I had visions of wood flying all over the place. I noticed the picture doesn't have them rounded over so it's obviously not necessary but I think it would look better.
> Any suggestions:help:


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## Ralph Barker (Dec 15, 2008)

I don't think you'd want the bearing on a normal roundover bit filling the hole.

How about a mini-roundover bit in a Dremel with their plunge base?

Amazon.com: Dremel 692 6-Piece Router Bit Set: Home Improvement

Amazon.com: Dremel 335-01 Plunge Router Attachment: Home Improvement


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## jlord (Nov 16, 2009)

Hi John,
I think your biggest problem will be the center sections getting in the way of your baseplate unless you can take it apart. If this is a picture you are building a new one from then it is an easy job. Round them over before you assemble. If you are building this new then you can fit an 1/8" to 3/16" roundover with a 1/4" shank easy. Hitting the wrong side of the bit as you say in a hole this small will not be that bad. I've put roundovers in small holes where the bit has very little room no problem, but never have where the bearing is same size as hole.


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## LexB (Apr 12, 2010)

I don't understand your problem. If the hole diameter is 3/4 inch, then a standard 1/4 or 3/8 inch roundover bit will easily fit in there. If you put a larger bearing on the bit, then the bit won't touch the wood--the bearing will keep it well away from the edge of the hole. If you use a 3/4-inch roundover bit, it will only slightly ease the edge--it won't round it over. It seems to me that a standard 1/4 inch bit with its bearing is all you need.


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## jd99 (Jun 17, 2009)

How about just using a C-Sink on the edge of the holes, you can get them in 1" and above, and single or multi flute. It will center it self on the hole and cut an even chamfer all the way around the hole. For the drill press though not a router bit.:nono: I don't think it would self center in the router.


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## harrysin (Jan 15, 2007)

jschaben said:


> Mother just handed me another addition to the honey-do list:sad:
> Should fit somewhere on page 27.....:blink:
> Anyway, fairly simple, rotating scissors rack. Uses two discs stacked 4 or 5" apart with holes around both about halfway between the axle and perimeter, 18 in all. Holes roughly 3/4" in diameter.
> Question is: What is a good way to roundover the inside diameter of those holes, 3/16 to 1/4" roundover would seem to be about right for them. I'm thinking to equip the roundover bit with a bearing the same diameter as the hole and let it guide me in then just plunge down and go to the next one. I think with the fairly standard 1/2" bearing things could get a bit hairy as it would be very easy to get on the wrong side of the bit. I thought about the router table for a second and quickly dropped that idea as I had visions of wood flying all over the place. I noticed the picture doesn't have them rounded over so it's obviously not necessary but I think it would look better.
> Any suggestions:help:


John, how about something like this, the disc was from a previous job, the rest as shown here took about 15minutes, that of course includes making the simple jig.


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## Titus A Duxass (Jan 6, 2010)

An elegant solution Harry.


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## Al Robins (Jul 13, 2009)

Another happy customer......thanks Harry


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## jschaben (Jun 21, 2009)

Thanks for the input guys. She dug out some of her scissors today and it looks like the holes will be an inch in diameter. Harry strikes again. I was trying to figure the best way to clamp the stock and had been planning on using my cam board but I think Harry's jig will be easier and safer. Based on the input will just use a stock roundover bit.
Bj - I thought about a ball end but that would leave a cove instead of a roundover.
Thanks again for all input.


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## bobj3 (Jan 17, 2006)

Hi John

You know I like jigs,,but why not just use a 1/4" shaft and a small 1/8' or 1/4" round over router bit in your T4 .....the bearing will do all the work for you.

http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/bt_round_over.html
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jschaben said:


> Thanks for the input guys. She dug out some of her scissors today and it looks like the holes will be an inch in diameter. Harry strikes again. I was trying to figure the best way to clamp the stock and had been planning on using my cam board but I think Harry's jig will be easier and safer. Based on the input will just use a stock roundover bit.
> Bj - I thought about a ball end but that would leave a cove instead of a roundover.
> Thanks again for all input.


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## jschaben (Jun 21, 2009)

bobj3 said:


> Hi John
> 
> You know I like jigs,,but why not just use a 1/4" shaft and a small 1/8' or 1/4" round over router bit in your T4 .....the bearing will do all the work for you.
> 
> ...


Hi Bj - I think that's what I'm gonna do. I liked Harry's jig for securing the stock though. Probably will use the T-4, haven't used much else since I got it. Could use the 3000 though, take a heck of a kickback to faze that moose.


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