slab flattening

xlogger · November 12, 2020, 04:19:35 AM

Got this wild idea about an easier way to flatten live edge slabs. Before I run one thru the planer I lay it on a flat MDF board to see if there is any rocking or if it will lay flat with cup up. If there is no rocking I usually run it thru the planer with cup up till I clean up the whole side and then flip it. If i was to get a electric hand planer and smooth the middle hump down somewhat then run it thru the planer it would save my back some and maybe some time. Anyone ever try this?

Dan_Shade · November 12, 2020, 06:23:21 AM

Are you planning to free hand the router to remove the hump?

Don P · November 12, 2020, 07:02:07 AM

I've done something similar with twisted timbers, hog off the offending wood with a power planer, some chalklines and winding sticks before going into the planer.

firefighter ontheside · November 12, 2020, 07:25:47 AM

How big of a planer and how big of slabs are you talking about? This might not be as much of a back saver as you imagine. I only have a 13" planer, but what I have done is use a piece of mdf as a sled. I hot glue shims under the twisted slab and then run it thru the planer until one side is flat. Then run it thru on the other side as normal.

WDH · November 12, 2020, 07:29:43 AM

I got one of the electric hand planers. Ok if you are working on that special slab for that special project. But, in my business, it is much too slow and inefficient when preparing that big pallet stack of slabs for sale.

doc henderson · November 12, 2020, 10:46:16 AM

I have used a Makita powered hand planer, or my jointer to establish a flat spot. for twisty wood, I cut oversized then put them back on the mill. I have done a big stump table with a router sled, but it took a long time. cupped is easier than twisted to fix by hand in my opinion. plan to try the sled idea some day. big planer maxed out at 20 inches.

xlogger · November 12, 2020, 01:47:29 PM

I've got a 20" planer. Just thinking on some of the slabs that might he easier to run in down the middle a couple quick times and save moving the slab back and forth thru the planer. I don't have a hand electric planer but watch a You tube on one this morning and it looks like it pretty fast.
I've got an Mdf board that I've used to shim and flatten one side if needed. Also I'll go back to mill if needed.

Ed_K · November 12, 2020, 02:04:29 PM

What do you do if it's twisted where back left side is sticking up and front right side is sticking up?

doc henderson · November 12, 2020, 02:16:41 PM

I would call that a twist. what ever you do, you have to shim under the high sides. I try to split the difference (shim each high corner equally) to get the most out of the slab. either on the mill or a planer sled. for a stump, I get the bottom setting the way I want it as I only "plane" off the top with the router sled. I had a thread where I showed how I did my engraving blanks with twist on a jointer. it is easy if it is narrower than the jointer. mine are not always. just need the bottom to ride flat on the planer bed. I have an 8 inch jointer.
I have felling wedges (plastic) I keep at the mill, but you can make wood ones, or look on the ground for a chunk of bark.

Don P · November 12, 2020, 06:44:25 PM

For twist in beams, and a slab would simply be a very wide beam, I set the beam on horses and shim it "level". That is splitting the difference in out of level so that at one end it is say half a bubble out left and at the other end it is half a bubble out right. Then draw a level line across each end from nothing at the one corner to whatever is level at the other. Then snap a line up the side from the nothing off corner to the level line at the other end. This will describe a shallow triangle of offending wood that needs to be removed from each diagonal corner. Grab the power planer and remove to the lines. You are using the planer as a jointer. It takes some finesse and sneaking up on it. This is basically what traditional woodworkers did with a scrub plane. You can check your work with winding sticks as you work.

I think xlogger is talking more about hogging the center hump off of heavily cupped slabs which is just running the planer down the hump to save moving the slab around so much. It will work but a power planer is small, underpowered and slow. They clog easily, I keep a flat carpenters pencil in my back pocket to stick in the chute to clear clogs and I've worn out 4 or 5 power planers over the years from that kind of heavy hogging work.

One friend of mine says that in the wrong hands a power planer is about the quickest way to make a crooked board out of a straight one :D

low_48 · November 12, 2020, 11:06:59 PM

If you want to use a planer like a joiner, a rigid sled under the slab allows for shims to even it out. Then send the slab and sled through the machine. https://www.woodsmithplans.com/plan/double-duty-planer-sled/

xlogger · November 13, 2020, 04:33:04 AM

Don's correct on how I was planning on using the hand planer. Just trying to figure out a way to take some of the work out of it. Danny goes back to his mill, going to try that and see how much time it takes. I'm going to HF soon and get a hyd cart to help, not had time lately just to much going on now.
If you use wedges on mill how well do they stay in place. My mill cuts 30" but the clamp is not near that to hold slab still. Would you use a Mdf board on mill and then slab?

WDH · November 13, 2020, 06:56:45 AM

When flattening on the mill, I have not had any issue with the wedges staying put.

Ed_K · November 13, 2020, 07:15:20 AM

I went to that woodsmithplans site that's a pretty involved sled ;D.

olcowhand · November 14, 2020, 04:54:41 AM

Quote from: doc henderson on November 12, 2020, 02:16:41 PM
I would call that a twist. what ever you do, you have to shim under the high sides. I try to split the difference (shim each high corner equally) to get the most out of the slab. either on the mill or a planer sled. for a stump, I get the bottom setting the way I want it as I only "plane" off the top with the router sled. I had a thread where I showed how I did my engraving blanks with twist on a jointer. it is easy if it is narrower than the jointer. mine are not always. just need the bottom to ride flat on the planer bed. I have an 8 inch jointer.
I have felling wedges (plastic) I keep at the mill, but you can make wood ones, or look on the ground for a chunk of bark.

X2 with shimming the corners on my Slabbing rack/ Router Sled......

xlogger · November 14, 2020, 06:10:51 AM

Didn't Customsawyer get a Slabmizer? Wonder how that working for him?

Larry · November 14, 2020, 01:16:52 PM

A couple of months ago I got to watch a Slabmizer at work. Last Saturday I watched a Wood Wizz from Baker. Both are similar machines, a router on steroids running a 4 or 5" cutter.

Both are better than a router bridge but at the same time seem painfully slow. Especially for a $17,000 plus machine.

Has to be a better way to flatten slabs.

Don P · November 14, 2020, 05:39:46 PM

A few Byrd heads riding the rails on a 4 post carriage?

Stephen1 · November 14, 2020, 06:45:47 PM

I have used a carbide blade on the mill to flatten a slab. It worked very nice. You almost do not need to plane the slab, it is pretty smooth.

Larry · November 14, 2020, 09:27:23 PM

Quote from: Don P on November 14, 2020, 05:39:46 PM
A few Byrd heads riding the rails on a 4 post carriage?

Your on the right track Don.

WM and Wood Wizz are putting a head onto the shaft of a motor. Cheap and not much engineering required. The problem is the cutting geometry is wrong and they don't have enough power. They are cutting straight into end grain.

This is the head on a Wood Wizz. The Slabmizer is similar but I don't think I have a picture of it.

If they had a Byrd positioned like in a planer it would eat the wood. I have a 3" Byrd head on my shaper I use for pattern work. It will take a 3/8" cut all day at a rapid pace.

Of course my solution is going to be a lot more expensive to build.

I have to give both the Slabmizer and the Wood Wizz credit for one thing. When they are done you can start in with something like 150 grit using a ROS and finish the slab.

Don P · November 14, 2020, 09:56:58 PM

That's the same way the planer head on the Lucas works, I think about 9" dia with inserts. It is happy with about 1/8" deep x 3" wide cuts. I've thought about ganging up 16 power planers on the rails :D

xlogger · November 15, 2020, 06:16:17 AM

On the carbide blades do you have a different wheel on the WM 250? Do they sharpen well and how long do they usually last? Also I've been using Kasco blades wonder if they sell them or what other choices you all use?

DR Buck · November 17, 2020, 05:06:42 PM

I have an 18" planer that I have used with wedges under the piece going through as already explained in previous posts. I also built a small 24" wide router sled to flatten slabs. It worked OK, but I was not thrilled with it. So, I ended up buying a commercial built router sled for slab flattening. Here's a link to the one I bought:

Live Edge Wood Slab, Casting with Metallic Epoxy. - YouTube