My first slab

[redwood]

I've made a lot signs and stuff out of dimensional wood, but a client asked me to do something with a cedar slab he had.  The good thing was that it was dry and didn't have any major defects, except that it was cupped a good bit and rough.  The slab was 50" long by 20"+ tall.  I took care of the cupping and smoothing by making what seemed like a 1000 passes through my drum sander.  My AR Pro 6 did the rest.  The customer is going to finish it.


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[aluomala]

Nice work! I have been slowly collecting some nice slabs, live edge, burls, etc, and haven't decided what to do with them. It's not like they are basic planks from the big box stores: they have character, and you don't want to butcher them.

Is there a reason you didn't mill it flat with your CNC? I don't have a drum sander (yet) other than a home made one (I found plans online) that doesn't work as well as I would like it to (too much play when manually feeding, so it's not truly flat after passing through)), so I tend to use the CNC to mill it, but that also takes a long-ish time, with setting up toolpaths, etc, but it has the benefit of being automated (work on other things while the machine does the heavy lifting).

Regardless, looks very sharp! If you can, post picture after customer finishes it, so we can see the outcome.

Allan

[redwood]

I've flattened smaller round with my CNC, but this was longer them my CNC's limits and I wasn't sure how that would come out, especially since it wouldn't sit very flat. Though this slab was over 2" thick, it wasn't too bad to handle. By the time I was done flattening it, I had decreased the thickness of the slab by about 3/8".

I also have some misc. slabs that I don't know what to do with them. I didn't really know what I had until I sanded them. I have a Supermax 16/32 drum sander and I really like it, but it takes a lot of passes to flatten slabs like these.

[aluomala]

Oh, OK. I looked at the width of the slab, and not the length (since the longest any of the Axiom's can handle is 48", I should have clued in).

I used my CNC to mill a slab (that was longer than my machines capacity (I have the AR4Pro, and I'm looking at adding a AR8 to increase capacity in terms of production and work size), and I ran into issues immediately, now that I think about it. I didn't have a bandsaw at the time, which would have helped. In your case, I would have trimmed it down (not telling the customer) to 48" (assuming you have one of the **8 series machines (AR or Elite) and worked with that, but that doesn't help now.

I am likely going to buy the Superemax 16/32 when I improve my shop in the next month. Would you recommend it? I was torn between a Laguna bandsaw (14/12 model) and the Supermax (when I had some money to spend after a big project was finished) and I opted for the bandsaw (no regrets on that decision!), so I think the drum sander might be next on my list, along with the AR8Pro, laser engraver (stand-alone) and an upgrade to electrical system to handle all of this stuff.

Allan

[johnb]

Whether milling on the CNC or running it through a planer or drum sander, you can accomplish a LOT with warped/cupped/uneven thickness slabs by attaching sacrificial "rails" to each side and grinding down the whole thing (rails & all). Flipping it over top to bottom allows you to end up with two co-planar faces of either a "targeted" thickness or "the most you can get out of it (depending on when you "quit"). Seems to me you could put your index holes in the rails and tile it that way with minimal offset where one flattening toolpath stops and the other picks up. Leave the rails on and use the same indexing when tiling the pocket/letters (if it's bigger than the machine capability.)

When attaching the rails, you'll want them perfectly flat and (hopefully) parallel on the table. (Temporarily) shim the heck out of the workpiece and clamp it down (but not hard enough to distort it at all). When you have it shimmed properly, NO part of the workpiece will actually be touching the table and no part of the workpiece should extend above the height of the rail stock. You'll also shim the edges so that you don't pull a warp into the side rails when attaching them. Your first passes will be bringing rails (only) down to the height of the material, so don't make them too tall or you'll waste a lot of time doing this. For sure you want to keep your screws well away from any place the bit, blades, or sanding belt is planning to go. If the slab is "way ugly", you might start out by grinding down some of the really high spots with an aggressive grit on a belt sand before you do any of this.

[redwood]

Feb 22, 2019 18:09:38 GMT -5 aluomala said:

Oh, OK. I looked at the width of the slab, and not the length (since the longest any of the Axiom's can handle is 48", I should have clued in).

I used my CNC to mill a slab (that was longer than my machines capacity (I have the AR4Pro, and I'm looking at adding a AR8 to increase capacity in terms of production and work size), and I ran into issues immediately, now that I think about it. I didn't have a bandsaw at the time, which would have helped. In your case, I would have trimmed it down (not telling the customer) to 48" (assuming you have one of the **8 series machines (AR or Elite) and worked with that, but that doesn't help now.

I am likely going to buy the Superemax 16/32 when I improve my shop in the next month. Would you recommend it? I was torn between a Laguna bandsaw (14/12 model) and the Supermax (when I had some money to spend after a big project was finished) and I opted for the bandsaw (no regrets on that decision!), so I think the drum sander might be next on my list, along with the AR8Pro, laser engraver (stand-alone) and an upgrade to electrical system to handle all of this stuff.

Allan

Actually I only have the AR6pro.  I occasionally kick myself for not going with 8.

I have a decent Shopfox bandsaw that I almost never use, since I got my Axiom, almost 3 years ago.

I had thought about a drum sander for a long time.  Only thing keeping me from getting it was the thought of parting with that much money.  I've done a number of tables that I struggled to get flat.  Nothing that anyone notices but me.  Anyways I had this slab and thought if I'm going to get one, now was the time as Laguna had it $100 off.  Someday I'll kick myself for not getting the 19/38.  Everything that I read, thought the Supemax was slightly better then the Jet, that was designed by the same people and sold to Jet.

[traindriver]

If you're going to do more than a couple of slabs, it would probably be worthwhile to make a sled like the one in this video:



There are several on Youtube.  I learned about them when I went to a class on making a waterfall table from a live edge slab. 

For drum sanders, I bought a Jet 16/32 before I bought my AR8 Pro, and it was a great addition, especially since I could easily clean up rough lumber, which is cheaper.  My only issue with the 16/32 is when I tried to sand stuff wider than 16 inches.  I don't have the patience to adjust the drum to the slight angle needed to be able to do wider stuff, and I kept messing the wide projects up, so I got the Supermax 25/50, which I HIGHLY recommend (as if my opinion counted for anything).  I actually haven't had a need to do anything wider than 25" since I upgraded, but a cool feature that the Supermax sanders have is a lever that will angle the drum slightly for stock wider than the drum, so you don't have to break out the wrenches.  Also, Supermax makes a great dust collector.

[gerry]

Feb 23, 2019 18:11:44 GMT -5 traindriver said:

For drum sanders, I bought a Jet 16/32 before I bought my AR8 Pro, and it was a great addition, especially since I could easily clean up rough lumber, which is cheaper.  My only issue with the 16/32 is when I tried to sand stuff wider than 16 inches.  I don't have the patience to adjust the drum to the slight angle needed to be able to do wider stuff, and I kept messing the wide projects up, so I got the Supermax 25/50, which I HIGHLY recommend (as if my opinion counted for anything).  I actually haven't had a need to do anything wider than 25" since I upgraded, but a cool feature that the Supermax sanders have is a lever that will angle the drum slightly for stock wider than the drum, so you don't have to break out the wrenches.  Also, Supermax makes a great dust collector.

The 16/32 has a builtin lever on the side that does a very nice job of getting rid of the center line problem of wide stick. It tilts the drum a tiny bit to fix the difference.

[redwood]

I knew about the technique of using a router and a sled to flatten slabs. I have plenty of routers, but I just didn't think of it at the time.

I smoothed out a couple of rough slabs that were wider then 16" and they came out fine. I would have loved to get a wider drum sander, but I'm running out of space in my shop and the cost difference is significant for me.