Router sled for surfacing slabs

[Crusarius]

you definitely optimized your space very well. are those kinda separate from the shop and vented outside to keep dust down?

[tule peak timber]

Yes, like a low volume wind tunnel.

[Crusarius]

you have fans or does it just act like a chimney and pull the air out? That looks like a perfect dust less setup.

[tule peak timber]

Yes on the fans and heat, yes the room naturally ducts air flow ( lucky !)

[mike_belben]

   smiley about 29 rpms

Yeah but look at the torque!  We will just have to gear it up a few notches wont we?
I always wondered what a floor buffer with a sanding disk would do to a piece of rough lumber.

[Crusarius]

I would expect sawdust

[doc henderson]

or the square buff type?  floor sander

[DWyatt]

I got it all put together this weekend and did a test run on a slab 8) overall I am pretty happy with how it works, one thing I will be changing is adding extensions to get the 80/20 bearings further apart from each other. Currently the bearings are mounted about 6" from each other which made the sled bind every once in awhile. making them about 12" apart should remedy this problem. The main rails are 96" long and should be able to process 7' material easily and about 45" wide. We also added the option to make it narrower in 6" steps as well (set at the middle set of holes in the picture below.


 

You can see the bolts in this picture where the bearings are mounted to the box. I need to space them out more to make it less temperamental.


 

And here's a few picture of the slab. Since it was a tree crotch with 3 branches it moved a lot during drying so I took 2 passes at 1/4" each. to get one side flat. We shimmed the slab and I shot screws through the sides that I know will get removed during further processing.

Here's pictures of what I got done yesterday, one side flat.



 

Wear a good mask, hearing protection, and safety glasses. Nothing can prepare you for the mess it makes :D



 



 

In the last picture you can see I tested going back and forth across the grain. I much preferred to go with the length of the slab. It definitely doesn't leave a perfect surface but everything should clean up nicely with 80 grit.

[Crusarius]

Looks good. you are 100% correct about the dust and the mess. I also found going with the grain was much preferred. It left a smoother finish and was less work. With the setup I have played with going with the grain left me less to clean up as well. What I found works best for me was to make a full pass in the normal cut direction then shift the router towards the smooth side about a 1/4" then return to beginning making a climb cut then move to the uncut side and make your next path. this left me very little uneven if any. I will have to post come pictures of my latest Frankenstein creation. I have one more slab I need to smooth for my drill index part of my machining tools cabinet build.

[DWyatt]

One thing I will note is that the D-Handle on the router is a big nuisance here's a picture dad sent me that he took while I was running the router. One hand on the body of the router, one hand on the other side of the sled. I tried to run it with a lighter grip on the router, NOT advised. I was taking nearly 1" wide cuts x 1/4" deep in both directions. While the surface isn't perfect, its flat and sandable.




 

[Crusarius]

I had to remove the handles from my router to fit in my track. 

[doc henderson]

I use my big porter cable plunge router.  You could also make a base for the router that is a sled inside the sled, but if every thing gets thicker, you have to extend the bit further and it becomes less stable.  I still only cut in one direction so the cut is pulling router in.  If you wanted to could move to each end and cut in both directions, but easier in my opinion to just pull it back across not cutting. If you can lock the cross sled in position for a cut, there is less to hold.  If the sides of you cross sled were shorter it would make your handle work better.  but you may need the c-channel effect to support weight going across a wide slab.  the bottom of my cross sled is only 3/8th inch thick so I can extend down a ways.  My plunge router has steps to drop by about 1/4 inch at a time.

[doc henderson]

 


my set up made to fit my router, designed for this one project.  your sled looks great.

[doc henderson]

It looks like you could set it up on a lower bench or the ground.  That will be good for thicker, wider, longer stuff so you can reach all the way across and still control the router.  My project was end grain so direction made no difference

[doc henderson]

If you will be doing slabs with the grain and can surface the long way, I would make a router base that can lock in place, then you just can push the whole sled down the track.  keep the router base and sled base thin so the shank of the huge router bit does not get too much stress. i.e. the thicker all of the bases are, the further you have to extend the bit and or have less of the shank in the collet.

[doc henderson]

maybe you could rig double screws or cables to pull your sled equally on each side.  this would decrease binding from torqueing the sled inside the rails and could operate with one hand and drink coffee with the other!!!    .  sorry could not find a cup of coffee.  We will have you thinking like an old man soon enough. 8) Might even want a remote on/off switch to start and stop, esp. if the stuff hit the fan.

[mike_belben]

I dont know if metal work carries over at all here but if i was mowing a quarter inch off an aluminum billet and wanted it fairly clean in a single pass it would be a pretty stout two flute end mill and only climb milling.. In the case of wood id be trying to climb with the grain.  If its browning the wood the feed rate is too slow. If its tearing and peeling the wood grain then spindle speed is probably two slow gi en a sharp endmill.  Should be big crescent chips flying off with no heat coloring.

  Ive only milled woodblocks a few times in the bridgeport (which is what a router sled is sort of trying to mimic except in flying gantry format rather than fixed head cutter) but that feedrate and chip output is what youre looking for when doing it on a vertical mill.

[doc henderson]

I agree with mike and your final pass after all is flat, might be a thin pass to get better finish, less sanding.

[Crusarius]

Definitely agree with mike. and all of doc's rambling  I guess since fixing my mast issue is not working the way I want I will setup my router sled and get some good pictures and show everyone what I am working on.

[Crusarius]

Finally 12 hours later the video is done uploading. I hate frontier!

Router sled surfacing spruce slab - YouTube

I will have more later. not trying to upload from home again.

[Crusarius]

here is another video.

Router surface 1 - YouTube

[DWyatt]

Yours is much smoother than the one I made. Some of which may be a function of the depth of cut, but I definitely think the actual linear bearings you're using are the ticket. A couple questions.What size of bit are you using and with what router size? What is the base that your router is on that fits in the groove of the extruded pieces? What is your depth of cut your taking and how wide are you in between the rails?

[Crusarius]

That slab is about 14" wide I think I was 18" between the linear bearings. The plate on the router just happened to be the plate for my router table. It fit perfectly in the grooves. 

The bit is either a 2" or 2 1/4" 1/2" shank carbide 2 flute cutter. I don't remember which one I had in it. 

At the deepest cut I was probably taking 1/16" off. I have done quite a bit more than that but (around 1/4" maybe?) was trying to keep that slab as thick as I could for the project I am using it for.

I think the router is a 1hp. I wasn't even using the big porter cable I have.

What I do have sometimes is the router chatters because the plate is not tight in the grooves. But my technique / pattern that I use seems to take care of any issues. The slabs come out smooth enough I could get away without sanding but usually just do a quick 80 grit rub down on my DA.

[Tom the Sawyer]

Crusarius,

We, too, have very slow internet service.  I have found that when I need to upload a large file, like an HD video, it is much easier to save it to a laptop, or tablet, and then drive to our local branch of the county library.  They have free Wi-Fi that works not only in the building, but out in to the parking lot and you can even park in the lot near the building, after hours, and upload large files in minutes instead of hours.

[Crusarius]

thats not a bad idea. I doubt I have anything like that around me but maybe. I just bring it to work and upload from here. the second video I uploaded to less than 2 minutes the first one took 7 hours.