# Shaping large boards



## steve4king (Mar 19, 2018)

I'm building a bed and considering adding a little more shape to my project than I'd originally planned. 
I realize that I could do this with a ridiculous amount of sanding.. but imagine some of you probably know better ways to accomplish this, and probably far more accurate/consistent than sanding.

If I wanted to shape a 2"x8"x8' length of Red Oak, adding a convex curve along the top and concave (cove) down the length of the board.. Is there a better way than sanding (maybe in combination with a cove cut on a table saw for the bottom half, and a large roundover router bit for the top.) See the picture below in case my description is unclear.

Thanks!
-Stephen


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## Toolman50 (Mar 22, 2015)

Based on the design you show, I would start by cutting a cove on the table saw for the lower part. 
The top is a thumb cut with a router or shaper. 
Final finish can be done by making an inverse of the design to use as your sanding black. Lots of hand sanding starting wit 60 grit through 220grit to get a very smooth design.


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## Steve Neul (Sep 2, 2011)

steve4king said:


> I'm building a bed and considering adding a little more shape to my project than I'd originally planned.
> I realize that I could do this with a ridiculous amount of sanding.. but imagine some of you probably know better ways to accomplish this, and probably far more accurate/consistent than sanding.
> 
> If I wanted to shape a 2"x8"x8' length of Red Oak, adding a convex curve along the top and concave (cove) down the length of the board.. Is there a better way than sanding (maybe in combination with a cove cut on a table saw for the bottom half, and a large roundover router bit for the top.) See the picture below in case my description is unclear.
> ...


How much woodworking experience do you have? What I'm proposing is dangerous for the novice. The concave part of the rail could be made by setting up a wooden fence on a table saw and run the wood across the blade on an angle.


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## Terry Q (Jul 28, 2016)

It can be challenging feeding long and wide boards flat on a tablesaw, router or shaper with out a power feeder. The very best way to do this is to pay some who has a molder. Perhaps you could give an idea of where you live, someone nearby might be able to help. Might cost up to $200 to get custom knives made, but it will do a much better job.


In woodworking there is always more then one way to accomplish something.


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## 35015 (Nov 24, 2012)

steve4king said:


> I'm building a bed and considering adding a little more shape to my project than I'd originally planned.
> I realize that I could do this with a ridiculous amount of sanding.. but imagine some of you probably know better ways to accomplish this, and probably far more accurate/consistent than sanding.
> 
> If I wanted to shape a 2"x8"x8' length of Red Oak, adding a convex curve along the top and concave (cove) down the length of the board.. Is there a better way than sanding (maybe in combination with a cove cut on a table saw for the bottom half, and a large roundover router bit for the top.) See the picture below in case my description is unclear.
> ...


Hi Stephen,

Even as a professional woodworker, if I didn't have a large production run of something like you are suggesting. I would save it for a Friday's work schedule and do it all by hand with plane, scraper, draw knife, gouge and/or a combination there of. 

Its pleasing work, and much faster than most would think...My go to is almost always the gouge, being perhaps the fastest of non-powered tools...

Surface gouge work


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## pro70z28 (Feb 26, 2018)

I would generate a 2 rail sweep, 3d file and run it on the CNC with a 1/2" bull nose cutter.


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## woodnthings (Jan 24, 2009)

*There you have it .....*

Everything from a CNC, hand gouges, table saw and a molder.
Here's what I would use if I owned one:





There are quite a few of these out there, and I wouldn't be surprised if you searched or ran a want ad for custom moldings or millwork you will find someone who could help you. That's if the other approaches fail .... table saw round over bits and such.

Here's the one I do have, but I've never used the molder aspect of it:


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## woodnthings (Jan 24, 2009)

*Another approach*

I remembered this old boy who impressed me with his use of the RAS to make moldings. There will be a hue and cry as he says when anyone uses a RAS to do anything because they are "inherently unsafe" according to "expert" You Tube viewers..... :wink:


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## Brian T (Nov 3, 2018)

How about a wood carving method? Less than $50,000.



I will use a 3/4" bit in my oldfashioned straight router.
I will plow a bunch of tracks, nearly side by side at calculated depths, to hog out the waste.
Then I will bash out the ribs with a mallet and gouge, maybe a 5/35. The ribs were essential to support the router.

The fun part is to clean it all up with an "Inshave". 

Like a spokeshave but it's curved for carving the hollow part of a wooden chair seat.
Maybe a bunch of sanding. 

I'd prefer the cutting action of cabinet scrapers (DIY) to the shreddy mess of papers if you need smoothness.


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## woodnthings (Jan 24, 2009)

*here we go again .....*

This thread was started in March of 2018 and brought back to life yesterday. If the OP has not returned since March of 2018, chances are he's either passed on or passed by. For a limited run of 8 ft, the minimum tooling cost suggestions are the most reasonable, that includes the cove cut on the tablesaw, the router adjusted to various depths since you will need it to round over the ends regardless. Hand tool approaches may require some specialty tools like a scorp or roughing blade in your hand plane.


The advice should always fit the application realistically cost wise, so a 50K to 100K CNC is not gonna "cut it"..... :vs_cool:


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## gmercer_48083 (Apr 9, 2016)

I would use a cove cut on a tablesaw using a flat bottom ripping blade to get a smooth finish, then finish the rest with a #4 hand plane.


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## Brian T (Nov 3, 2018)

Some old threads are still juicy ones. Always something to learn.



Missed my chance = Lee Valley used to stock an "Inshave". No longer.
Should have bought one just for the hell of it.


In that case, risky as it is, I'll go with the bias cut on the table saw.
Maybe, just, maybe, do the router treatment first to reduce the load on the saw blade.


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## gmercer_48083 (Apr 9, 2016)

Brian T, The bias cut on the table saw is done 1/8" at a pass, and if you use a flat top rip blade it comes out pretty smooth, and safe if you capture the piece using a guide on each side of your molding. Your table saw blade has more cutters yet works as a router.


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## Brian T (Nov 3, 2018)

Is that guaranteed to improve the quality of my sleep?
Not.
An extra blanket is VERY cost-effective. 



My table saw bucks so bad at the start that it can unlock the fence.
You guys make this. I'll watch.


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## woodnthings (Jan 24, 2009)

*A bucking table saw... WOW!*

You either have a lousy table saw OR a lousy fence... maybe both?
I have a few, I can probably spare one for Ya? :vs_cool:


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## gmercer_48083 (Apr 9, 2016)

gmercer_48083 said:


> Brian T, The bias cut on the table saw is done 1/8" at a pass, and if you use a flat top rip blade it comes out pretty smooth, and safe if you capture the piece using a guide on each side of your molding. Your table saw blade has more cutters yet works as a router.




Upon thinking about this statement I would like to revise. I used sketchup to see how the radius would conform by using this method. As it turns out, in order to hollow it to a depth of 3/4" you would have to run the board at 90 degrees to the blade and I advise against doing this for two reasons.

#1, when going over the blade at an angle beyond 45 degrees would invite kickback. I would recommend an angle of less than 30 degrees from being parallel to the blade.


#2. when shearing the grain at an angle of more than 30 degrees you would get more tear out and would require a lot more cleanup.


I could be done in stages of a lesser angle by making two or more coves in order to rough hollow the shape...But the hollowing must be sheared away using the down cut portion of the blade when doing this, and removing less than 1/8" per pass.


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## woodnthings (Jan 24, 2009)

*The You Video I posted is relevant ......*

The old boy who uses the RAS to make several of the cuts/profiles to create a similar shape molding demonstrates how setting the blade at an angle relarive to the feed direction will create a shallow cove in the material. The RAS just works from the top down rather than from the bottom up like the table saw. However, there are more dangers involved when the exposed blade is spinning above the work. He uses a combonation of the standard saw blade and a molding cutter head, Sear/Craftsman brand in the video. He is quite accomplished in the operation and set up of his machines:
https://youtu.be/JRviFZLXBi8?t=37


https://youtu.be/JRviFZLXBi8?t=806


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## Brian T (Nov 3, 2018)

Buy the flat bed boards. Buy several profiles of attractive molding. 

Glue them together and paint. We're done with this.


I paid a whopping $100.00 for a brand new 10" Ryobi table saw at Home Depot. 

It gets used 1-2 times per year, if that. Came with a 40T t/c blade.
The fence might need a little adjustment, one of these years.
In the mean time, I'm the winner. I carve, don't power saw much.


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## GeorgeC (Jul 30, 2008)

pro70z28 said:


> I would generate a 2 rail sweep, 3d file and run it on the CNC with a 1/2" bull nose cutter.



Please translate that post into English. I have no idea what it is that you wrote.


George


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## Steve Neul (Sep 2, 2011)

GeorgeC said:


> Please translate that post into English. I have no idea what it is that you wrote.
> 
> 
> George


I think you would have to be trained in the operation of a CNC before it would make any sense.


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## gmercer_48083 (Apr 9, 2016)

GeorgeC said:


> Please translate that post into English. I have no idea what it is that you wrote.
> 
> 
> George


He is referring to using two fences at a parallel angle across the table saw, where you run the lumber trapped between them to make the molding.


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## gmercer_48083 (Apr 9, 2016)

GeorgeC said:


> Please translate that post into English. I have no idea what it is that you wrote.
> 
> 
> George


He is referring to using two fences (guides) parallel across the table saw to trap the board as you make the molding. Could also be helpful using a radial arm saw.


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## Tool Agnostic (Aug 13, 2017)

pro70z28 said:


> I would generate a 2 rail sweep, 3d file and run it on the CNC with a 1/2" bull nose cutter.





GeorgeC said:


> Please translate that post into English. I have no idea what it is that you wrote.


2 rail sweep: 
A design concept with two parallel rails and a contour shape. You can make it as long as you want. The two rails represent the long edges of @steve4king's bed rail design. The contour would match the simple profile that steve4king showed in his drawing. You use a special graphics program on your computer to draw your desired contour and look at a 3D image of the bed rail that would be made by the CNC machine. 

3d file:
When you are done drawing the 2 rail sweep with its contour on your computer, you will save it to a "3d file". This file contains the instructions that tell the CNC machine how to carve the three dimensional shape. In a typical use, you would save the file to a USB flash drive. 

CNC:
This is a computer controlled carving machine with a flat bed and a router (or spindle motor) with a rotating bit. CNC stands for "computer numerical control." The CNC moves the spinning bit around the wood to cut out the desired shape. In a typical use, you insert the USB flash drive into the CNC, load the 3d file, calibrate the CNC for your board's thickness, and tell it to start carving the wood according to the instructions in the 3d file. 

Some CNC machines are limited by the size of their bed. Commercial CNC machines are available that can cut a full 4x8 sheet. For steve4king, a "feed through" CNC machine might be more suitable. Because they pull the wood through as they go, feed through CNC machines can operate on long boards.

1/2 inch bull nose cutter:
CNC machines use carbide bits, like router bits. @pro70z28 suggests that steve4king use a 1/2 inch bull nose cutter bit in the CNC machine to do the actual carving.


Additional Notes: 
* The term "CNC" applies to much more than just wood carving machines, but obviously that is the type of CNC machine that is implied here.

* The reason for this post is to help define terms for George and others. I do _not_ have an opinion on whether CNC is the best solution for steve4king's question.


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## Tool Agnostic (Aug 13, 2017)

gmercer_48083 said:


> He is referring to using two fences at a parallel angle across the table saw, where you run the lumber trapped between them to make the molding.





gmercer_48083 said:


> He is referring to using two fences (guides) parallel across the table saw to trap the board as you make the molding. Could also be helpful using a radial arm saw.


Respectfully, your definition is incorrect. It is true that cove cutting jigs have two fences that might be called "rails", but that is not what @pro70z28 is referring to. See my definition above.

Here is an example of a cove cutting jig with two fences:

https://www.rockler.com/cove-cutting-table-saw-jig

A similar jig with two fences could be used with a radial arm saw as well. Neither is what pro70z28 was suggesting with the CNC. Just because it can be done doesn't mean that it is a good idea. If I were to do a cove cut on a radial arm saw, I would want to plan and prepare it very carefully, with a strong emphasis on safety.


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## Larry42 (Jan 10, 2014)

Simple is good. Use the table saw coving method, 1/8" deep passes. Several set overs to get an approximation of the cove desired. Use hand planes to finish shape the convex areas after sawing away most. Make a cabinet scraper to the desired cove out of an old hand saw blade. This will greatly reduce or eliminate the massive sanding effort. 
Me, I'd run it on my CNC if I was feeling really lazy or on my Weinig molder if I needed multiples. But neither would result in the pleasure of nice hand work.


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