What’s a good, flexible thing for a curve template?

[JonW]

I want to cut some gradual curves into some wood. Not parts of a circle, but rather a gradual curve with a changing radius. I’ll use a jig saw. I figure a nice way to do it might be to use something flexible. Maybe a strip of plastic or something. Curve that over the wood to something pleasing. Then use a pencil to trace the line of the curve against the plastic. Then use the jig saw to follow the line and cut the curve out of the wood. So what’s a good flexible thing to use like this? I’ve got a yard long piece of plastic that I cut from a roof shingle screen. But maybe there’s something better to use out there. Maybe even something I could clamp to down the wood. Just looking for some ideas. Thanks.

[LCHIEN]

I want to cut some gradual curves into some wood. Not parts of a circle, but rather a gradual curve with a changing radius. I’ll use a jig saw. I figure a nice way to do it might be to use something flexible. Maybe a strip of plastic or something. Curve that over the wood to something pleasing. Then use a pencil to trace the line of the curve against the plastic. Then use the jig saw to follow the line and cut the curve out of the wood. So what’s a good flexible thing to use like this? I’ve got a yard long piece of plastic that I cut from a roof shingle screen. But maybe there’s something better to use out there. Maybe even something I could clamp to down the wood. Just looking for some ideas. Thanks.

Art stores/drafting supplies (if they're still such a thing) sell flexible curves of various lengths designed for just that purpose.

This is one of the things google pulled up. (Warning, apparently there's a bra called flexibles curves, too.)

http://store.artcity.com/ctr-tc381.html

[Tom Miller]

Warning, apparently there's a bra called flexibles curves, too.

You forgot to post the URL...

I haven't tried this myself, but a thin piece of polycarbonate might work well. You can get sheets of it at HD, etc. A 1" wide strip up to 36" long would do well.

Otherwise, 1/8" tempered hardboard. Many folks use "real" wood, too, but I always felt it might not be equally stiff along the entire length.

You might consider marking and cutting out a template first. This allows you to use brads, etc. to hold the flex piece in place. Use a router with flush trim bit to transfer the pattern.

Regards,
Tom

[LarryG]

I have personal experience with the type Loring linked to, back in my manual drafting days, and don't recommend it. The core is some kind of dense, pliable material that will indeed curve but is difficult to fair ... that is, the sweep of the curve tends to be "lumpy" rather than smooth, and the more you use the thing, the worse it gets.

There's another kind that's a series of interlocking plastic track-like extrusions that are connected at one end, free on the other, and slide back and forth on each other as you form the curve. This one works MUCH better than the foregoing, but all the ones I've seen were fairly short (maybe 16"-18") and you don't say if that's long enough.

For a changing radius, you will likely do just as well by improvising with whatever you have at hand, drawing the curves as best you can, and then fairing them by eye.

[vaking]

Check this tool.
http://www.rockler.com/product.cfm?page=2461

[JonW]

Thanks for the info, fellas. I was looking for something maybe 36" long. Yeah, maybe it's best to just improvise. The plastic I have from the gutter screen worked better than I expected. But it's not reproducible because you can't clamp it down and also trace a line. Just curious what you pros use.

By the way, this is for the curve in the legs of the shelves I asked about last week- where you folks gave me all this helpful info about dado jigs. I was going to play around with the jigs on Sunday but, umm, got delayed. I went out for a run (it was beautiful out) and a dog attacked me. The bite isn't too bad, but I did have to spend the evening at the hospital. And it was the table saw I was most worried about! No big deal, just some time lost.

EDIT: Those French curves are interesting looking. Are they difficult to use? I've never tried.

[vaking]

I have not tried them myself for woodworking but I used them a lot years ago during engineering career for drafting.

[LarryG]

Those French curves are interesting looking. Are they difficult to use?

Not at all. You just find the portion of curve that suits your fancy and trace along the edge.

However, what the picture doesn't reveal is that the largest of those three is maybe 10" long, and the others are correspondingly smaller. (I have one shaped exactly like the middle size, and it measures 6" long.) As I understand your project, I'm thinking these will all be way smaller than you need.

[scorrpio]

For that gutter screen thing - basically, once you decide what kind of curve you want, you trace it on a piece of hardboard/MDF/plywood. Then, cut it out, shape/sand to exact shape, and use it as template on all parts that are to have that curve.

Personally, I prefer the high-tech route. I design it in Photoshop, divide into 8x10 sections, print, and spray-glue to hardboard template.

A notice: ALWAYS make a template for complex pieces!!! Even if you need only one piece that is curved. If you make a template, and its shape suddenly strikes you as ungainly, you are minus a piece of cheap hardboard, and not a pricey piece of wood. Ditto if in making it, your jigsaw strays over the line. You can shape a template to perfection, and then just use a pattern bit to finish-cut your actual workpiece. Having a template insures you against 'DOH' moments if you somehow mess up an already cutout piece during assembly/finishing. I also saves you the 'UGH' moments when the GF says: That looks lovely! can you make another one exactly like that for .......?

[JimD]

For long gradual curves, a thin piece of wood with a string or something bending it while you trace the curve is handy. Lee Valley even sells something like this with a nicer setup for the string.

Jim

[geopilot]

For fairly long, simple curves, I've used a fiberglass tent pole- the thin kind that come with the dome-style tents. But these are too stiff for complex curve shapes.
Dave

[JSUPreston]

I had a crazy idea about this while driving to work this morning. How about taking and old bandsaw blade and cutting it. Then, I imagine that you could start the ends where you want by slightly tapping them into the wood, create your curve(s), then tap the rest of the blade into the wood slightly. Then, you could trace the line with a pencil to see it a little better, then take it to the bandsaw (you didn't cut your only blade, did you?) and cut it out.

I know it's nuts. I only had 5 hours of sleep last night, and there's too much blood in my caffeine system right now.

Let me know what you guys think of this.

[MikeMcCoy]

Microsoft Word

Most word processing programs have word art capability. I use Microsoft Word quite a bit. Even though you're limited by the size of paper you can print, a series of gentle curves can be joined and traced through carbon paper fairly ease.

[WayneJ]

How about an electricans fishing snake or a slat from a window blind.

[LarryG]

Here's the one I mentioned.

I rec'd a new Lee Valley sale catalog over the weekend, and by coincidence it contained the exact same plastic adjustable curve I attempted to describe in my first reply, up the page:

http://www.leevalley.com/wood/page.a...=1,42936,42958

Years ago I used one of these on the drafting board and they work beautifully, but they're also spendy enough that you'd probably need to draw a lot of curves to justify buying one.