Thread: Cutting Circles

lets start woth what tools do you have on hand, and we could give you some options

Hi Gra,
Power tool wise I have a router, jigsaw, circular and mitre saw and an electric plane. As far as hand tools go I have a couple of panel saws and some tenon saws, hand planes, chisels etc.

Hope that helps. So far I was thinkin of making some sort of jig or something to spin the router around.
Thanks
Mick

From looking at your tools, I would suggest two methods;

1. Router tramel, basically a stick attached to you router base at one end, and a pin in the other end. Pin goes in the middle of your required circle, then rotate router a fixed distance from the pin, repeat until you are all the way through.

2. If you have a table to mount the router in, then affix a pin to the table the radius of the circle you want, and Pin goes in the middle of your required circle, then rotate the stock a fixed distance from the router bit, repeat until you are all the way through.

Router Trammel might not be practical for a 10cm diameter circle.

You didn't mention if you had a drill but if you're going to buy one, a hole saw bit might be the go. Although it will leave you with a hole right in the middle of your circle.

Originally Posted by Afro Boy

Router Trammel might not be practical for a 10cm diameter circle..

Oops missed that bit...... You are right.

I have a router jig made of metal for cutting circles. I will be doing a review of it soon but essentially it is a simple bar of metal with some bends and attachment points plus some accurately drilled holes. They cost about $30 and are for sale in Williamstown at Get Woodworking (9399-1963). I am not sure if the jig will go down to 10cm.

Thanks for that folks. I am going to get some hole saws this weekend.I'll look into the router jig too.

Thanks again!!!

You'd think a circular saw would be good for cutting circles, wouldn't you?

Kahlua, just be careful if you have a disc only 10m diameter on a router table. Your fingers may be too close to the cutter for comfort. If you happened to get the direction of rotation wrong - which is not unimaginable because once I did it - a small workpiece can get snatched and whizzed around with nasty results. I am sure you will be careful near the router cutter, but be absolutely sure of what you are doing. Personally I would avoid getting my fingers too close to something that could get grabbed and pull your fingers round and about.

Thanks fencepost, I'll take it nice and slow so I make sure I don't fall into any traps like that.
Thanks again

it is fairly easy to cut 10cm holes (or even smaller ones) using a router trammel. Just make sure the pivot point is sitting underneath your router base plate. Make sure you don't cut through the materail (since you will loose the mounting for the pivot point). Instead go down 2/3 thirds - this will be your guide later to clean up the last 1/3. Then rough cut the 10cm hole with a jig saw or something. Clean up the last 1/3 with a straight router bit that has a guide bearing wheel and follows the first 2/3 that you have routed out cleanly. The guide wheel can either be at top or bottom - you can flick over the material (the clean 2/3 cut is now facing down) if guide bearing is at the tip of router bit.

hope that makes sense ;-) good luck

A 100mm hole saw will need a fair sore of drill to go through hardwood. If you use a drill press you can remove the centre pilot drill bit once you get a bit of depth Otherwise you can sandwich a scrap piece to your hardwood with a hole already cut in the top (scrap) piece. In both these setups the existing hole will guide the rim on the saw and you don't get a pilot hole on both faces of the circle.

What thickness is the timber, as this may limit your choice of techniques.

Regards,

James

Here are a couple of trammels, one for cutting small holes and the other for larger ones http://www.wealdentool.com/acatalog/tips_4.html

Hope this helps.

Cheers

Paul