Thread: drawing curves

Drawing curves: buy or make yourself a set of trammels. You can get them with a point on one and a pencil holder on the other. Then you just clamp them to a length of timber of the appropriate dimensions and you have an instant compass of any length.

Cutting circles: You can make a circle cutting jig for cutting perfect circles on the bandsaw or with a router. Usually you need to fix something to the centre of your stock which becomes the pivot. On the router version, the stock stays still on your bench and you rotate the router - the jig holds the router in position so that it is always exactly the same distance from the pivot point. Same idea on the bandsaw, except that the work rotates.

I've seen heaps of versions of this set up. There's one for the router in the last issue of FWW for example. I bet if you search on 'circle cutting jig' you'll find hundreds of them.

Gidday Redback


This is certainly not the only way you can go about this but for what its worth its my method of choice.

I tend to use a template and flush trim bit to get clean accurate repeatable curves. The key is making a really accurate Template:

1. Mark out using your favourate method then cut out on the Bandsaw just shy of your markout line. 16mm or 18mm MDF is cheap to use and will do the trick.

2. Either using your Sanding Station or by hand sand back to your markout line so that you are just kissing the line. If need be you can tape some 220 grit sandpaper to some flexable stock eg (Thin Ply) so that it will easily follow the curves of your template whilst sanding back.

3. Once you have finished your Template stick it to your stock with some good quality double stick tape. The template can then be used as a guide for a bearing guided flush trim bit by slowly and steadily following the template guide with the bearing of the flush trim bit.....then.......Hey Presto!!!!! you have perfectly edge jointed curves or circules!!!!!

Master Woodworker David Marks often uses this technique see our forums web links thread to get some info on how to go about this.........


A really quick and easy way to mark out curves is by bending some thin flexable stock and use this to mark out the curves that you want


Alternatively try this circle cutting Jig for use with a router:


http://www.taunton.com/finewoodworking/pages/wvt114.asp


Hope this helps Redback


REgards Lou

I cut it near enough with a bandsaw and then use a spokeshave.

Arron

I use trammel points for drawing circles:



and for cutting perfect circles, I use a 3 HP plunge router with a plunge bit attached to an 8" wide by 8' long board. I simply measure the desired distance away from the bit and drill an 1/8" hole through the board. Then I turn the board (and router) over and put the bit back through, and then into my pivot point. I can cut a perfect circle or radius of almost any size in about 10 minutes with setup.

Fairing battens and icepicks are the easiest. Just make sure your wood is straightgrained and bends fair.

In the complete absence of "ice picks" :eek: I use 1 1/2" panel pins, tapped in barely a mm, can be easily removed by hand.

Cheers,

P

Wot Arron said.
Draw curve by any of the means set out above. Cut it close with band/jig/bow saw, then fair with compass plane (bigger curves) or spokeshave, or if you just HAVE to breathe your daily quota of sawdust, a drum sander...

Takes far less time and effort for a one-off than fooling about with templates, jigs, etc.

Cheers,

Another method is to suspend a fine chain, like the sort you used to attach to ball point pens so no one would pinch them, on the piece of timber and when the desired curved is achieved spray paint over and cut along the outline.
Did that sound right?