Planing with a router - which bit do you use?

[Bill McNiel]

Prashun,
My process to join two thick slabs using a tracksaw and router;
-Prelim cut the two edges that will be jointed (TS for max depth and then router with a pattern bit for the balance of depth of cut).
-Butt the two slabs together (level and true as possible)
-Recut the joint with the TS cutting both slabs simultainously (this creates a perfectly matched joint as viewed from the top/exposed surface)
-Router with pattern bit for the balance of depth of cut
-Use dominos for joint registry
-Drill and rout for coutertop connectors
-Apply finish
-For final install pull the slabs together (use bar clamps with padding to protect live edge as required) and then install Coutertop Connectors (they are really only used to keep the slabs together
-Mount on base

Hope this helps -

[Prashun Patel]

Thanks for all the help so far.

I'm going to start router-planing the bottom side first.

I had a chance to add cross braces and to level my rails today. That string trick is wonderful. I drilled 4 screws at opposite corners and wound cotton string clockwise. Pulled it taught and then drove the screws home. The screws tighten the string even further. It shows you immediately where the twist is. I shimmed the corners of the bed under the low string until the two strings kissed and it was level. The other trick is to shim the higher string up the width of the line such that when the lower comes up to kiss it, the two rails are actually coplanar - and not off by that width. It's hard to describe, but easy to get yr head around. The Wood Whisperer shows this technique really well. This whole thing takes a little time, but is straight forward and doesn't involve any guesswork.

Happy to report that after correcting the rails, the slab doesn't rock, so the top is already fairly flat! I got lucky.

Now time to build the router sled. The old one in the picture isn't good; the slot's too narrow for my new bit, and it rocks (in a bad way); I made the mistake connecting the bottom TO the sides instead of the sides to the bottom. This resulted in protruding pocket screws in the base, and doesn't allow the straight sides to pull out any bow in the base. What was I thinking ?!

[Art Mann]

I frequently use a 2" diameter, 1/2" shank diameter Magnate bit similar to the one in the link to resurface the spoil board on my CNC router. My experience is that it does a very smooth job on MDF rather quickly. I expect it would do well with hardwood using a frame supported router operated by hand.

[Prashun Patel]

Took about 45 minutes to get low enough for an even pass across the entire slab.
My rails are a little short, but the ends cleaned up easily with a hand plane.

I'm a little nervous about getting the two slabs exactly equal thickness.

I'm using a fixed router base for this. I like the idea of locking down the bit depth and not relying on the plunge mechanism to repeat exactly the same. (I know that sounds dumb). The other reason for using a fixed base is the lighter weight, and lower grip. This makes it more ergonomic to slide the router back and forth with one hand while gripping the sled with the other.

Of course, midway through my second surface, I got too comfortable. Big spark. Motor stopped. Thought I burned out the motor or hit some metal. No. I routed through the cord ( I know that sounds dumb.) Please say this has happened to you

That black streak on the bottom is from a nail I found buried inside. This will be the bottom. I'll book match on the left side, since it's more straight. The issue is that I want a little Georgia O'Keefesque gap in the center, but the sapwood and beveled edges create some issues for that; getting beyond the bevel may require removing all of the curve. Leaving some of the curve may leave too-skinny a sap band that could look unfinished...

[Jim Becker]

Of course, midway through my second surface, I got too comfortable. Big spark. Motor stopped. Thought I burned out the motor or hit some metal. No. I routed through the cord .

In the immortal words of Homer Simpson...

"D'oh!!!!!!!!!!!!!"

[Pat Barry]

Of course, midway through my second surface, I got too comfortable. Big spark. Motor stopped. Thought I burned out the motor or hit some metal. No. I routed through the cord ( I know that sounds dumb.) Please say this has happened to you ..

Thats a big reason why these things are double insulated. Good safety factor.

[Prashun Patel]

Ok, I've completed all four sides. I don't know if I will do this again (unless the slab is much smaller and can fit on a stable reference like my bench).

Here's what I liked: It was very good at removing most of the twist and getting to pretty flat.

Here's what I did not like:
1) Something was shifty in my set up. I can't tell if the bed was wracking under the weight of the slab even after squaring it. I tested for coplanarity halfway through and it fell out a tad. The slab did not rock either before or after the fix though. ???
2) It's hard to keep the bit depth perfect and to avoid tearout. This method is very fatiguing and it's too tempting to overdo the depth of cut. I got some cross-grain tearout in places that needs to be fixed with my plane anyway.

[Prashun Patel]

I ended up completing the flattening by hand (bless the Veritas BU Jointer, it's a joy to use).

I have an EZ Smart guide but it only goes to 100". These are 108". Also the base makes the depth of cut just too shallow.

I made my own straight guide and removed the EZ base, but the saw is hard to dial into 90. I think I'm going to suck it up, rip it as well as I can, and then edge joint it by hand (the Veritas edge jointing guide is really nice to use too!)

Figuring out how much of the middle to rip is tricky. Looking for some symetry of the sap wood, but have to work around the alternating bevels. Also leaving some of that center sap band will result in a very wide 45" table. I may rip it all off. The grain matches fairly well along the rest of the length. Design critique welcome!

[Kent A Bathurst]

Personal choice. Me - I don't like the sapwood contrast. Outer edges mutch more aesthetically pleasing to me than sapwood down the center - looks like a racing stripe on a SuperBee. Your call.

On ripping for center match:
1. pick a common grain ref point both ends, both pieces - somewhere you know the grain matches.
2. Measuring from those ref points, rip inside waste, but leave 1/4" + extra waste.
3. Now you can butt them together, and start running the blade down the common seam, as suggested way earlier. Will take 2+ passes.
4. Keep it up until you have a perfect match.
5. Slip/slide the 2 pieces to get the book matching correct.
6. Glue it up.
7. Trim the ends.

[Jim Becker]

Honestly, I'd love to assemble the table exactly how your slabs are pictured in post #38...with the groove and some creative splines to reinforce and add some splash. Given the length, the 45" wide wouldn't scare me one bit! I would like that proportion. (And have a room it would fit in very nicely) That said, it would also likely look very nice if you had to do the center rip, but you could still leave a 1/2"-3/4" wide open groove down the middle to make for an interesting table that hints at a bookmatch.

[Prashun Patel]

Thanks for the opinions, Guys. I'm on Kent's side of the fence on this I think. I like trying to find that line between organic and refined. A 2 slab table (while SO appealing for the ease of construction) just feels 'rustic' to me. Kent, I take your point about getting rid of the center sap line altogether. While it may take more time, I might just nibble away at the edge until it feels proportional and right.

Off the circular saw, the cut is a little ragged for my taste - even with a guide providing zero clearance on the good side. Also, like I said, the blade doesn't make it through all the way. I think I have to tediously: flip, cut good-side-down, complete with a handsaw, flip, flush trim with a router.

Given that I'm planning to make several cuts to sneak up on the final width, if anyone has a more efficient method, I'm all ears. Boy, if I could JUST put an 8 1/4" blade on my saw.

[Prashun Patel]

Here's the first nibble...
I think if I try to get rid of all that center sap, it'll remove maybe too much of the straight heartwood grain at the bottom and top.

Kent? Rip more?

[Prashun Patel]

More trimming.
I was able to rip the slabs and complete the cut with a pull saw.

I used this Veritas jointer plane to smooth it. Man, what a joy! This wood and this plane just made it so easy for someone like me. The edge guide is fantastic. I couldn't figure out how to stand the boards on edge since my bench space is too small, but I was able to shoot it pretty square. I'll find out on Monday if the glue line is straight enough...

There's still a tiny bit of sapwood in the middle Let's see how it looks when the boards are side by side.

["Felix Marti"]

Thanks Guys. I did not realize that shank was 1/4". I definitely would use a 1/2" shank bit.

Scott, the slabs are each 22-24" wide. I am SO tempted to rip them down the center and then run them through the planer. But I think I'll have more issues re-gluing them perfectly.

John, do you have a picture of the sled you used?

The other issue I have is that the slabs are over 100" long. So making straight rails for the router is an issue; I'll have to bricklay a couple 8' sections and then joint the rails, I guess.

-----------------------------
Hello Prashun.
I believe the Wood Whisperer did a video on the exact task you have before you (http://www.thewoodwhisperer).
The length of rails you need to construct is no challenge. If there were a means of talking I could talk/show you the process.
Felix

[Mike Heidrick]

I use a yellow import 1.75" dia 1/2" shank one from Ebay but I am only surfacing MDF on my CNC table.