Source for small adjustable circle cutter?

[Richard Hash]

I'm looking for a small circle cutter, something that will go down to 5/8" diameter with a 3/16" center hole. Does anyone know of a source for such a thing? I'm pretty sure they existed at some point, Raymond Levy mentions having one in his "Mechanical Marvels" book.

The Fuller #4C only goes down to 7/8".

Half an hour of searching did not yield anything smaller than 7/8" dia. I may have to resort to using alternative methods (ie trammel and sander)...

--/Richard

[Grant Wilkinson]

Since you mention that you need a 3/16" center hole, I'm assuming that you want the disks that are cut out rather than the hole that is left, yes?

Could you use a hole saw, or do you need the ability to change the size?

[Bill Dufour]

Do you want the hole or the plug? In other words is the 5/8 the hole diameter or the plug diameter? I doubt if you will find anything that is under one inch outer diameter. Below that hole saw, annular cutter, or twist drill. I have seen adjustable auger bits. but not power drill bits.
You could buy a straight shank boring head I suppose but I would not recommend it in a drillpress due to side loading.
Bill D.

They do make one for power drills!
http://www.irwin.com/tools/drill-bit...able-wood-bits

http://www.shars.com/products/toolho...ombo-11-pc-set

[Ben Rivel]

What sized discs/pucks are you looking for? What about just slicing up a dowel rod in the diameter you need and drilling holes in the slices? You can get dowel rod in many different species.

[Jamie Buxton]

Lenox sells a hole saw with 5/8" OD. It goes on an arbor which usually has a 1/4" drill bit for the center hole. If you can't tolerate the quarter inch, perhaps you could use a 3/16" diameter router bit with a quarter inch shank.

[Mike Heidrick]

Curious to know what you want the make.

[Richard Hash]

I want the "wheels" (eg plugs/disks), not the piece with the hole in it. I've thought about using a 5/8" hole saw, but by the time you cleaned up the disks they wouldn't be 5/8" anymore. I'm leaning towards borrowing a friends lathe right now. This is to make the wheel pieces that attach to the center spider for the "Roller-Gearing Mechanism" in Raymond Levy's "Making Mechanical Marvels in Wood" book.

I found a picture of a rendered model to give you an idea - http://dl36mmdz94630.cloudfront.net/...sion360Hub.jpg

[Jim Morgan]

You could also use a router circle-cutting jig, like the Jasper 400. It's calibrated for hole size, using a 1/4" bit, so a 1" hole would yield a 1/2" disk (or a 1 1/8" hole would yield a 5/8" disk). The jig uses a 1/8" center pin, but you can always enlarge this afterwards. Just be sure to secure both the center disk & the surround with double-faced tape.

[Larry Edgerton]

Buy a 3/4" hole saw and bend the teeth in just a tad on the inside, then chuck your disks on a 3/16 arbor [carriage bolt] and carefully sand to final size on the drill press. Make up a right angle out of plywood and glue sandpaper to the upright face and work this off of the table so as to remain square. Just a random thought.........

[Grant Wilkinson]

As Ben mentioned, your easiest solution may well be to buy a 5/8 dowel, cut slices from it and center drill them.

[Richard Hash]

Thanks for the suggestions. I'm sure there is a micro circle cutter out there somewhere, but I can't find it.

These "Mechanical Marvels" models have considerable precision (I've built 8 so far, the most slop I've got so far is about 0.006-7", or a bit less than 1/128"). Store bought dowels (even the "precision" ones I've found) aren't even close to their advertised size, most are undersized 0.010 or more. I don't have a lathe (yet!) but have resorted several times to visiting a friend with one to make fairly precise dowels. I think I would need to bore the hole first, I am not sure I could precisely center a hole on a disk that was already slabbed off. Wood choice is important too, since I live in a pretty humid area (massive understatement there).

Thanks again.

[Doug Garson]

Good luck with the dowel idea, I tried it once with little success. The dowel splits easily since its end grain.

[Brian Deakin]

I am not sure if I am understanding correctly but if you have access to a lathe could you not turn cylinders ,use a micrometer to measure the diameter and either part them off or use a band saw / hand saw to cut the cylinder into round discs of appropriate thickness

This approach allows you to choose any wood you desire , you may be apply to find wood scraps for nothing or use pen turning blanks

regards Brian

[Grant Wilkinson]

If you have easy access to a lathe, I would agree that's the way to go. I also would agree that your best approach would be to drill the hole through the square stock first, then mount it between centers, so that the hole is in the exact center of the finished piece. As an aside, I'm surprised that you can't find dowels that are more precise. I guess that I'm in a good market.

Just out of curiosity, Richard, could you not simply cut the dados to match the dimension of the pucks? That way, if you used dowel that is a bit plus or minus 5/8", if would not matter. I've never made one of these machines, so this is a question out of ignorance, but on the face of it, it would seem to be another solution.

[Richard Hash]

Well obviously I thought using a circle cutter would be the easiest!! ;-) (with that minor issue of actually finding one)

Yes, I agree using a lathe with pre-bored hole is next in line in terms of effort, that's next on my list.

And yes, I could completely remanufacture the wheel to have bigger/smaller dados, if I had only given consideration to making the rollers first and sizing the dados to fit, but I did it in the reverse order, thus my predicament. Making a new wheel sounded like a whole lot more work than ordering a circle cutter, at least so I thought! (especially since I see references to people owning very small circle cutters, so I know they must be out there somewhere). But alas, doesn't look like that's in the cards for me.

I was really looking more for a source for a circle cutter, and less for alternatives, but it's on to alternatives for me... I think the lathe idea is the way to go, and I agree with Doug, end grain is tough, but by turning your own dowels you can orient grain however you want..

Thanks again.