$Finished$*Updated w/ pics*Ever wondered how to flatten a slab without massive equipment?

[SubGuy]

This is how I do it:

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This one is a one run design and proof of concept. That slab is 3.25" thick and 26" to 29" wide. I will post pics of the project once I get it finished. I am working on a sketchup design for a more fine tuned version for flattening slabs. The sled is a simple router sled you can see leaning against the DC. Comments, questions and critiques welcome.

 

[junquecol]

Re: Ever wondered how to flatten a slab without massive equipment?

I would add some vertical rails to side of router bridge. This is to prevent sagging over middle of span. If you can snag a set of bed rails, these would do nicely, without adding height to bridge.

 

[SubGuy]

Re: Ever wondered how to flatten a slab without massive equipment?

They are on there, just hard to see at that angle, I will post another pic of it tomorrow. It's 8" high 1/2" Baltic Birch ply kind of like a gutter design. I have thought to trim it in half and double it up, but it hasn't really presented a problem.
Also a very helpful thing I found was to lube up the track the plate runs on with some bowling alley wax. It's a dream to move in the slot now.

 

[Roy G]

Re: Ever wondered how to flatten a slab without massive equipment?

Zach, it looks like you have a nice set up to do the flattening. How big is the bit you are planning to use? I did something similar years ago but only had a 1" diameter bit, so it was a long process. You will definitely have some chips to dispose of after you are finished.

Roy G

 

[Bas]

Re: Ever wondered how to flatten a slab without massive equipment?

I have found that one of these is indispensable when working with large slabs:



Doesn't take up that much room in the shop either.

 

[junquecol]

Re: Ever wondered how to flatten a slab without massive equipment?

Wipe base plate of router with dryer sheet, makes it like sliding on ice. I do this with my dado jig for cubbies. For bit, to flatten slabs, I use $5 Woodcraft (now a lot more $) rabbeting bit. Removed bearing, and ground off bearing stud. I originally bought rabbeting bit just for bearing to be used on another bit. Double the pleasure at half of the price.

 

[SubGuy]

Re: Ever wondered how to flatten a slab without massive equipment?

I am planning on 42" x 12ft working surface, but I am trying to figure out a way to make it modular/expandable. That is attached to my assembly table/bench with some Spax bolts. I made sure they are all equal height from the floor (which is not level) as my table was built equal leg height. If I make all my measurements using the floor contact with the table posts and work up to make it equal, it will come out level. Right now, I have a 3/4" Grizzly pattern bit (1/2" Shank)I am working with, it's slow going, but I have more than enough router to do the job (Freud FT2000, 3.25hp VS Plunge). I have a 1.5" surfacing bit and a 2" surfacing bit coming from Magnate. I read some really good reviews on Amazon and it looks like a great price. I will post a review when I get them and use them. So far, I am seeing chip/dust problems and have to stop every pass to vacuum off the piece. My plan for the final design is to make some sort of gantry like a CNC Machine and have a 4" DC hose attached to the jig. Still working on that. I have looked at a few other designs and find them lacking in DC. I have tons of thoughts on it and will expound when the ideas are fully developed.

Zach, it looks like you have a nice set up to do the flattening. How big is the bit you are planning to use? I did something similar years ago but only had a 1" diameter bit, so it was a long process. You will definitely have some chips to dispose of after you are finished.

Roy G

 

[CrealBilly]

Re: Ever wondered how to flatten a slab without massive equipment?

Drag it up and down the road behind you pickup?

 

[farmerbw]

Re: Ever wondered how to flatten a slab without massive equipment?

Zach, when I was working on a maple cookie I followed FredP's advice and used a bowl bit similar to this and had good results. I think the idea is that the sloped edge eases into the wood a little better than a straight bit. :dontknow: I just know that it worked in my case and as usual Fred's advice was right on the money.

FWIW.
B

 

[SubGuy]

Re: Ever wondered how to flatten a slab without massive equipment?

:nah:

Drag it up and down the road behind you pickup?

 

[SubGuy]

Re: Ever wondered how to flatten a slab without massive equipment?

I looked at bowl bits, but I ultimately went with this. It's not completely flat on the bottom, but I intent on taking overlapping passes anyway so the slight angle will be easy to sand out and shouldn't be that much different that what I am dealing with now with the variations in the 2x6 surface. Ultimately, I want to go with this, but not ready to take that $$$ leap yet. I will wait until I have a few more projects on the bench that need it so it will pay for itself. It will also require some upgrading to the sled design and the X rail design to make it worth the accuracy. Once I go down this route, I am hoping to eliminate a few grits and several hours of sanding, which is becoming problematic with my possible shoulder impingement I have been experiencing on and off lately. I attribute it to the stroke sander and the manual pads I use. I really need to replace the graphite cloth, but haven't had the time and when sanding a lot, it has worn out my shoulders. It's probably an old injury I have forgotten about.

 

[farmerbw]

Re: Ever wondered how to flatten a slab without massive equipment?

That Amana one looks like a hoss for sure!!! Don't think I've ever seen one with replaceable cutters like a helical cutter head. I'm betting it'll take a lot of power to spin that one, but if you take shallow passes you'll probably be ok.

B.

 

[SubGuy]

Re: Ever wondered how to flatten a slab without massive equipment?

I got the power to do so. If I ever get around to getting it, I will post a review and observations with it. I wanted to go right to getting it, but it didn't seem reasonable for only one project. If I get two more similar projects (looking very probable right now) I will go ahead a buy it. But that is about 2 to 3 months out now. Only reason I wouldn't get it would be that the Magnate bits I have on order work so good that I don't have the need to get it. They also make a 1/4" shank version, but I like 1/2" shanks.

That Amana one looks like a hoss for sure!!! Don't think I've ever seen one with replaceable cutters like a helical cutter head. I'm betting it'll take a lot of power to spin that one, but if you take shallow passes you'll probably be ok.

B.

 

[mquan01]

Re: Ever wondered how to flatten a slab without massive equipment?

Zach, when I was working on a maple cookie I followed FredP's advice and used a bowl bit similar to this and had good results. I think the idea is that the sloped edge eases into the wood a little better than a straight bit. :dontknow: I just know that it worked in my case and as usual Fred's advice was right on the money.

FWIW.
B

+ 1

 

[SubGuy]

Re: Ever wondered how to flatten a slab without massive equipment?

I did some more work on it today. Those chips were after one pass. They were about 1-2" deep. And as promised, a better picture of my sled. Simple, but effective. Also it's made of 3/4 Baltic Birch Ply vice 1/2". Total so far, I have taken of between 1/2 to 3/4". I have 2-3 more passes to make and it will be ready to sand. I won't be doing the bottom, because the metal fabricator is making it to fit, but I may end up machining some flat spots for mounting and slightly recessing them.

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Even though you can clearly see the bit marks, the grain is absolutely beautiful. I am stoked to get some finish on this thing and let it pop!

 

[Danny Batchelor]

Re: Ever wondered how to flatten a slab without massive equipment?

What kind of wood is the slab?

 

[junquecol]

Re: Ever wondered how to flatten a slab without massive equipment?

But the Amana comes with free shipping.

 

[FredP]

Re: Ever wondered how to flatten a slab without massive equipment?

you can save a bunch of time and wear and tear on your router by plowing out 2 or 3 channels 3/4" wide and just deep enough to support some support strips. you route the length of the slab on both sides [and in the middle if the slab is really wide,] cut some 3/4x 3/4 strips to fit in the channels, flip it over and run through the planer. then flip it over and remove the strips or simply plane them off and finish planing to thickness. clear as mud eh?:icon_thum

 

[SubGuy]

Re: Ever wondered how to flatten a slab without massive equipment?

American Elm

What kind of wood is the slab?

 

[SubGuy]

Re: Ever wondered how to flatten a slab without massive equipment?

Oh you have a 30" planer I can borrow? When should I expect you to come by in the flatbed with the forklift that has snow chains?I have 3ph power, but we may need to move the PM180 out the way. Bring some friends, say about 4 so we can move it..... LOL Fred. Your funny.:gar-Bi

you can save a bunch of time and wear and tear on your router by plowing out 2 or 3 channels 3/4" wide and just deep enough to support some support strips. you route the length of the slab on both sides [and in the middle if the slab is really wide,] cut some 3/4x 3/4 strips to fit in the channels, flip it over and run through the planer. then flip it over and remove the strips or simply plane them off and finish planing to thickness. clear as mud eh?:icon_thum