How to make curved pattern for pattern routing?

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Forum topic by dichdoc posted 05-31-2010 12:43 AM 5680 views 1 time favorited 9 replies Add to Favorites Watch
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14 posts in 2940 days

05-31-2010 12:43 AM

Recently built a blanket chest with a curved base. I used 1/4” ply for the pattern traced out my curve, cut it out on band saw and sanded with drum sander in drill press. Didn’t come out perfect, and all bumps transfered to my work piece, any other techniques for making a curved pattern or do I just need to be more precise at sanding?? Travis

9 replies so far

View thatwoodworkingguy's profile


375 posts in 2952 days

#1 posted 05-31-2010 12:59 AM

Just spend more time on it then you feel like haha
You can also use a file or spoke shave to get the high spots down.
Usualy on templates if I see high or low spot I stay awesome using the sander to fix it because its easy to make another h/l spot trying to fix one. With hand tools you can smooth those areas down a little more tenderly.

-- ~Eagle America~ ~Woodcraft~

View a1Jim's profile


117114 posts in 3599 days

#2 posted 05-31-2010 01:17 AM

If you spend a lot of time making the pattern perfect then the thing you trying to make will come out perfect . The bearing on you router bit will pick up every imperfection. If you a have chucks to fill in on your pattern you can use body filler. If you haven’t gone to far with your project you can smooth out your pattern and make it just enough smaller to take out your in perfections.

-- wood crafting & woodworking classes

View Gregn's profile


1642 posts in 3005 days

#3 posted 05-31-2010 01:33 AM

I like to use my 6”x 48” belt sander to sand my outside curves. It allows me to sand down to the line with a much wider surface than the drum sander. I use the sander in the vertical position and use the fence to keep things square while sanding down to the line. When I do inside curves with my oscillating spindle sander or drum sander I use a starter pin like you use on the router table. This allows me to have more control in maneuvering the material to the spindle/drum sander. Always use a very light touch to allow you to pull away if need to keep from sanding past your line. I have used hand tools but find I can do it quicker with the sanders.

-- I don't make mistakes, I have great learning lessons, Greg

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404 - Not Found

2544 posts in 2991 days

#4 posted 05-31-2010 01:48 AM

How are you with the jigsaw? Any curved templates I make I draw on the computer and print out, glue onto mdf (with spray adhesive) and cut out with the jigsaw using a fine cut blade – incredibly accurate and a whole lot less cleaning up than with the bandsaw. Even if your curve is 4/6/8’ in length, you can print out ‘tiles’ and join them together to get a continuous pattern to cut to. I usually cut to the centre of the line and even with a slight wobble might only deviate by a quarter of a mm. My opinion would be that MDF is a superior material for template making anyway as the edges are clean, its easy to sand, no tearout and no voids. If you know how to with your drawing program, you can also factor in guide bushes and cutter offsets etc.

View HokieMojo's profile


2104 posts in 3750 days

#5 posted 05-31-2010 02:04 AM

I think the best way to get a curve cut that has a fixed radius, is to set up a router jig. As long as the curve has more than a 3 inch radius, you could probably do it with a router. I plan on building a jig because I had the same exact problem as you did when cuttign my last project.

One idea for sanding curves. Cut a mirror image of the curve out of insulation foam. Glue sandpaper onto that. The squishyness might help a bit to get a more even curve.

I still think a router jig is the best though.

View rance's profile


4258 posts in 3182 days

#6 posted 05-31-2010 02:46 AM

Key is to get the template PERFFCT before moving on. Convex – I’d never do a convex with a drum/spindle sander. Rough cut it close to the line, then rough in with a bench belt sander. Final sanding with a stiff hand-sanding block.

Concave rough in with as large a drum as possible. Take the waste from the rough cut and smooth it out, then stick sandpaper to the edge and use it to smooth the concave.

Once you have the pattern perfect, then move to pattern cutting.

As Jim mentioned, bondo can be a tool to use. You have to

-- Backer boards, stop blocks, build oversized, and never buy a hand plane--

View dichdoc's profile


14 posts in 2940 days

#7 posted 05-31-2010 03:35 AM

Great info! It was a concave curve. I like the thought of a start pin for added control. What typw of router jig are you thinking of? Any pictures of it??TB

View Gregn's profile


1642 posts in 3005 days

#8 posted 05-31-2010 07:15 AM

Don’t have any pics. Most router tables have a 1/4” hole for the pin. I adapted it to my auxiliary drill press table for the drum sander, and my oscillating spindle sander. Place the pin before the drum sander so that the piece rests against the pin before contacting the drum sander. I just bought some 1/4” steel rod to make the pins. If you go here and click on the Router Workshop you can see the start pin set up and in use. Its the same principal for the drum sander.

-- I don't make mistakes, I have great learning lessons, Greg

View Ger21's profile


1074 posts in 3153 days

#9 posted 05-31-2010 02:52 PM

A spindle sander is preferable to a drum sander. Either way, though, the key is to move the part quickly, and don’t stop in any one place. Going slow and or stopping will result in dips as too much gets sanded. You might also consider making a curved sanding block and hand sanding it. This will get you a lot smoother, more consistent arc.

-- Gerry,

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