# Surface planing with router



## LAvery (Nov 19, 2014)

I would like the groups comments/opinions on this... I have a small project where I want to flatten/plane a 14” square work piece with a router. The materials are Purple Heart and hard maple. I don’t own a thickness planer. YouTube videos and Sketch-Up plans suggest using co-planar rails on opposite sides of the work piece and building a “bridge” spanning them on which you slide a handheld router back-and-forth in successive passes.

Alternative idea: Because I own a fairly large router table with 3 ½ hp router, why not move the work piece across the router rather than the router across the piece? The advantages as I see them are you don’t need the handheld router swinging a fairly large planing bit nor do you need the bridge arrangement across the rails. Also the table is very flat as a running surface as opposed to potential sag with the bridged arrangement. I would rip the guide rails parallel and ensure they are co-planar by clamping them to the work piece while sitting on the flat, cast iron, machined router table. I would then flip the whole arrangement over and re-clamp from the top. This arrangement would run against the fence in successive passes (by adjusting the fence) until each surface is complete. Each pass would be the lightest skim-cut possible to ensure the full surface is flattened. Too, I would have spacers between the rails and the work piece to allow the bit to overshoot the piece slightly to get the entire surface.

I have not seen this approach used anywhere and this make me a little cautious. Are there drawbacks that you see? Would it not yield a good result? Does it appear dangerous? Has anyone done it this way?

Your feedback would be very welcome and thanks.


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## fire65 (Oct 29, 2008)

I see no reason that would not work as long as you have the piece secured in some type of sled. Let us know if you do and how it works out.


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## kp91 (Sep 10, 2004)

The advantage to skis and doing it from above is you can see what is going on. You are also controlling the cutter, so you know exactly where it is as well. When you invert the process, you have a big bit spinning at 10000 rpm, and you really can't tell exactly where it is.

If you could add stops to prevent the piece from travelling far enough to expose the bit out from the side it might be a little safer.

Trust me, you don't want to find a router bit by surprise.


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## LAvery (Nov 19, 2014)

I will use stop blocks on the fence for one axis and mark the table for the other axis. Thanks for the input.


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## sunnybob (Apr 3, 2015)

Doesnt seem safe to me. What thickness are you trying to achieve? Anything sub 1" and the sides would move away from the clamps under pressure from the cutter.

The rails would have to be sacrificial because the cutter has to go past the board edge, and youre risking losing control.

Your idea scares me. The table router is the only woodworking machine that has ever scared me, and I always take extra care when using it.

much safer to use a sled. I have a home made sled from scrap wood and my router is mounted on an MDF board 30" x 12".
The base is a large kitchen tile resting on a chip board floor with chipboard side walls.
Hot glue the piece down, rout it to whatever thickness you want, and then just break the hot glue off.
I can go as low as 1/8" even thickness.


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## fire65 (Oct 29, 2008)

sunnybob said:


> Doesnt seem safe to me. What thickness are you trying to achieve? Anything sub 1" and the sides would move away from the clamps under pressure from the cutter.
> 
> The rails would have to be sacrificial because the cutter has to go past the board edge, and youre risking losing control.
> 
> ...


 It is a sled just upside down. It is just a 14x14 piece no different than using a regular sled. AS LONG AS YOU SECURE THE PIECE IN A SLED. Can not say this enough, do not try to do this by running it across a router table without a sled of some kind.


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## Tiny (Aug 12, 2012)

I would no do it as you explaind it. Just to many risks. You can achive flat timber with ridicilous amount of money as it is explaind to be done with skis so I wouldn take the risk to chop my fingers. 
Ive some rules in my shop. The most important is to allways see where the bit or sawblade are when using a ww machine.


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## Arcola60 (Jul 4, 2009)

I have used double sided tape to hold small pieces for flattening with great success. I mounted a piece of 1/4" Plexiglas to a raised platform. I made a "U" frame for the router to slide along, out of 3/4" plywood. Based on the "Wood Whisperers' design for flattening a work bench. Very light passes to achieve the thickness desired. I used strips of 1/2" plywood for the Frame to travel along. It works really well, with not much expense to set up. There are many versions of this technique that can be found. I have used this procedure many times. It is safe and works well. Just another suggestion, to consider.

Ellery "Bud" Becnel


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## Cherryville Chuck (Sep 28, 2010)

It would seem to me that the sled (or skis) would be easier to set up. You won't need to worry about sag over the distance you are describing. I once built a sled about 4-5 feet across and ran down the edges of 2 4x8 sheets of 3/4 mdf to level my woodworking bench.


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## OPG3 (Jan 9, 2011)

I've used my routers for planning on a couple of occasions with sleds and it worked extremely well.
I would not feel safe doing that on a router table for the reasons explained by Doug (above).
I'm quite fond of my fingers and losing one to a router leaves nothing to reattach but soup.

Otis Guillebeau from Auburn, Georgia


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## LAvery (Nov 19, 2014)

*Surface planing w/router*

Thanks to everyone for all your advice and responses. Although I would take every precaution with stop-blocks etc. the consensus is that my proposed approach appears to be unsafe.

I've decided to go with the planing sled on top where I have the visibility and control needed.

Thanks again for all the input.


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## fire65 (Oct 29, 2008)

LAvery said:


> Thanks to everyone for all your advice and responses. Although I would take every precaution with stop-blocks etc. the consensus is that my proposed approach appears to be unsafe.
> 
> I've decided to go with the planing sled on top where I have the visibility and control needed.
> 
> Thanks again for all the input.


 Good idea, I think that will be much safer. I meant to add yesterday that a thickness planer will not flatten a board unless you were to put it on some type of sled, it will just make it thinner. If it is bowed going in it will be bowed coming out, just thinner. You would need a jointer to flatten.


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## pinehunter (Oct 18, 2016)

Maybe this system could be adapted to plane the piece. The image shows a setup to thickness hardwood for a musical instrument fingerboard. The sled moves against the battens. It is held at its end and the holes are thumb spaces. The blocks are stops to bear on against router base and provide hand protection if piece comes free during cutting. The dark wood piece on sled is held with double side adhesive tape. After each pass the router is moved along the rails to make another overlapping cut. The router is a 1.1hp T4 and the bit is a 1"dia 2 flute.


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## Herb Stoops (Aug 28, 2012)

I think you made the right decision to abandon the idea of planing upside down. I can envision the bit grabbing the material and throwing it out of control. also the shavings will all be trapped under the board causing the board to ride up on top of them only to make room for more to get trapped. Thus causing you to loose control of the depth of cut. 
I agree with the rest of the comments here safety wise, and that a router is a tool not to take lightly.
Herb


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