Router Sled for Lumber

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SteveMaryland
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Router Sled for Lumber

Post by SteveMaryland »

I recently designed and fabbed a router sled. A router sled uses a router mounted to a sliding or rolling platform to shave a flat surface on a workpiece.

Youtube has numerous videos of router sleds built by others. Most of these are used to create flat table tops from tree stumps or wood burl.

I specifically designed my sled to process lumber. I decided that I had had enough aggravation trying to make decent projects from construction-grade SPF lumber. I wanted a way to process relatively cheap and readily available SPF builder's lumber into un-warped, un-bent and un-bowed pieces. I wanted dead flat, dead straight and dead parallel material to work with.

Why not jointer and planer? Because, aside from the cost of these tools (I do not own either), a jointer will have trouble handling 8 foot lumber, and a planer will distort warped and bent lumber while cutting. If it goes in warped, it will come out warped.

My sled will hold and cut the lumber without distorting it. On the first pass, the high spots are partially shaved down to produce a flat working surface, then the board is flipped and the other side is shaved. This process is repeated until a desired thickness is reached or all the high spots are shaved off. The result is two dead flat and parallel board faces.

For the edges, I attach a steel bar (similar to a Shopsmith "miter bar") to the board, which runs in the T-slot in my Shopsmith saw table and provides a straight reference feature. I then shave one edge by pushing the board through the saw, as guided by the bar. I then shave the other edge by running the board against the fence.

The net result, after some work, is an 8 foot long, 1-1/4 inch thick board that is a joy rather than a nightmare to fab with.

Yes, sometimes the wood will still do some more warping and cupping after the cuts. The remedy is to do a first shave, then do a final shave some weeks later.

PDF pictures attached. 3 X 3 X 1/4 inch aluminum angles used for the rails. The white-colored bed shown in the pictures is plaster. This bed is made by screeding plaster to get a surface that is exactly parallel to the rail plane. This insures a consistently flat shave. The sled slides on the rails. Other sleds run on ball bushings but I have found that a sliding action works OK.

The router itself is my trusty DeWalt DW 618. Cutter is a honking 2 inch diameter Whiteside 6220 "spoilboard surfacing" bit.

A useful tool. Maybe Shopsmith will get into the router sled mfg business.
Attachments
ROUTER TABLE PHOTOS.pdf
(2.44 MiB) Downloaded 311 times
Mark V, Model 555510, Serial No. 102689, purchased November 1989. Upgraded to 520
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BuckeyeDennis
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Re: Router Sled for Lumber

Post by BuckeyeDennis »

That’s a great example of figuring out a way to do good work with limited tooling! The screeded plaster is a technique that I haven’t seen anywhere else.

As for boards moving after machining, the one in your pics has a lot of pith in it, and will be prone to cupping. If you want stable construction lumber, I’d recommend buying 2x12’s. The softwood lumber trees are so small these days that 2x12’s are usually the center slice of the log, with the pith smack in the middle. Cut it out when you’re milling the lumber, and you’re left with two nice 5” wide quarter-sawn boards, without a lot of knots.
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algale
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Re: Router Sled for Lumber

Post by algale »

I agree with Dennis that you've got an original sled design there with the screed plaster bed. Any idea what the sled weighs?

Also, how long is the steel bar you use in the t-track when edge jointing?
Gale's Law: The bigger the woodworking project, the less the mistakes show in any photo taken far enough away to show the entire project!

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SteveMaryland
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Re: Router Sled for Lumber

Post by SteveMaryland »

algale wrote: Sat Nov 13, 2021 4:45 am I agree with Dennis that you've got an original sled design there with the screed plaster bed. Any idea what the sled weighs?

Also, how long is the steel bar you use in the t-track when edge jointing?

Router sled weighs about 60 pounds. Heavy. I have to pick it up using two plywood-grabber handles. Stowed in the garage. Definitely an outdoor tool and process considering both the table size and the huge amount of shavings.

Two steel bars, each 4 feet long. 3/16" thick. Would rather have one 8 ft piece. I attach these to the board with small brads. Yes it mars the wood but that is the tradeoff.
Mark V, Model 555510, Serial No. 102689, purchased November 1989. Upgraded to 520
br549
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Re: Router Sled for Lumber

Post by br549 »

Nice job, and something I could see as very useful.

A few other ideas for truing edges. Rather than attaching 3/16" bars with brads and using table saw to straighten first edge:

1. Use a track saw, or circular saw with long straight edge, or

2. Use router with straight cutting bit. The 3" x 3" aluminum angles would make great guides for the router to slide against. Use same bolts to hold wood steady in sled against edge you are not routing, and use sacrificial wood wedges to steady side you are routing. Raise the stock you are truing off of the plaster bed slightly to avoid routing into the plaster, or

3. Use a circular saw while stock is still in sled. Use 3" x 3" angles as edge guides. Add wood strips as fillers between aluminum angles and saw base as required for positioning blade where you want to cut. Raise stock off of plaster bed to prevent circular saw blade from damaging plaster.
edma194
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Re: Router Sled for Lumber

Post by edma194 »

Cool project! How wide is the router bit you use? Are you planing one side of a 12" board in 5 passes?

I still have plastic material and aluminum angle from decades past when I used them for similar router motion control. No bearings either, just sliding. Interesting idea to attach a miter bar to straight cut one side of the board. I did the same kind of thing recently by screwing a piece of aluminum extrusion onto the top of a board to hold against the fence for the first cut. But using a miter bar turns the board into it's own ripping sled, I might do that in the future.
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