Thread: Circles

Hi Robert

Depending on exactly what your doing and how thick the material. you could go two ways.
The first method I've only ever seen once in a book about band saws but I can't say more than that, so find a book on bandsaws and you may find something similar to what I saw but never used.
The second methond which I have used is to make up a template first then cut your blanks to a rough round but over cut so you leave the pencil line intact. You then attach the template to the blank and by using a straight router bit with a bearing on the end, you ride the bearing on the template and follow it around. once you have made a complete pass bobs your uncle.
the router bit cannot dig into your blank any deeper then the bearing riding on it.
this will give you a consistent result and you won't even have to drill a hole in the middle of the blank.
when I did mine I used the triton router table as this will be easyer then doing it in the over head method.
If you should do it in the over head method make sure that you rotate the router in the anticlockwise direction so as to feed against the rotation of the router.

hope this helps

Gino

I am not sure what catalogs you see down under, but the Woodcraft (USA) catalog has a template that attaches to the bottom of your router, steel pin, etc. It is really a small trammel and makes perfect circles
up to 7" diameter. The template was originally made for the sound industry, making perfect openings for speakers in auto radio setups.
I have had great success with this item.
Does a fine job every time.

Website www.woodcraft.com

Cheers, Phyllis

PS Now that I have re-read your post, there is also a larger size trammel from the same material, in same catalog, might be of use to you. PK

[This message has been edited by sunshine (edited 01 November 2002).]

Hello Robert,

I have made a circle cutting jig for my router. If you are interested send me a EMail and I'll send a diagram/drawing. I made it out of perspex. Basically its an oversized base plate you fit to the bottom of your router. It works really well. You can EMail me at work on [email protected]. I'll whip up a quick drawing for you if you are interested.


Peter

Hi Robert,
If a central hole is not a problem then try a 75mm holesaw.
Cheers
Barry

Thanks for the suggestions. They rang bells in my memory.
I located a plan and description of a jig to clamp to a bandsaw table. It allows the material to be rotated on a spindle that can be moved to a fixed distance from the blade. Bingo, a circle with a predetermined radius. If the required radius I want is too tight for the smallest blade I have for my bandsaw then I will clamp the jig on the table of the scroll saw and cut the circles at snail pace.

If you have to do a lot of them & you don't mind a hole in the middle.
I've found the electricians down light cutter in a drill press to be great, you will need to grind a new tool steel cutter to account for cutting a cleen circle rather than a clean hole.
I use mine for cutting bobin cheeks from mdf by the box full.
nice clean edge.