Hi All, need some help if it can be done I am trying to get rough sawn wood surfaced to and exact size,first side is no issue to get flat but how would I get the other side dead flat to say 23 mm each time with out having to measure with calibers.?This would be from irregular thickness boards.
I’m not sure I understand your question?
If you have a rough sawn board, flatten the first side. Flip the board over and set your Z zero at 23mm above your spoil board. Then use that as your “bottom of stock” and set your plunge depth/speed according to how much board is above the 23mm. If that makes sense. I does to me but because of my thought process which does not always translate clearly to other folks.
With rough lumber place it on the spoilboard and shim it if there are any spaces under the wood. I use wedges and hot glue plus any clamps to hold it in place similar to the tiger or gator clamps C3D sells. Lets say the piece is 12" x 18". Draw a rectangle that is 1" bigger 13" x 19" and zero on the highest spot. Then create a pocket and take off whatever you machine can handle. For my SO3 I take off 0.010" at a time. Run the pocket tool path inside the 13" x 19" rectangle. Put pencil marks all over the top of the wood. If you did not get the first side flat use jog and lower the router 0.010" and reset Z zero. Run the same toolpath again. Run over and over until all pencil marks are gone. Then you can flip the wood over and find the high spot and repeat until the second side is flat. You should have a flat piece of material of an even thickness. Because you flattened the first side it should be flat on the spoilboard when flipped over. Depending on how much variation you have you may have to run your pocket tool path over and over until it is flat. On an SO3 the 0.010" could maybe increased some but on an SO5 you could go much more. Just dont get overly confident even with an SO5. Some people like to draw zig zag pattern with 50% between lines of the surfacing bit you are going to use. Just overlap the edges with the 13" x 19" material size so you get all the edges trimmed down. The pocketing works but so does the raster zig zag pattern. The Shapeoko makes an adequate planner but if you have a large format planner a few passes through that will help even out the high spots. A planner does not really flatten wavy boards but does knock down the high spots. A jointer is the prefered tool to get one side flattened but most people dont have a jointer large enough to flatten a board on one side before passing it through a planner on the opposite side. So the Shapeoko can joint the first side and then plane it on the second side. Luckily I have a 20" Grizzly planner to remove the high spots on rough sawn lumber. Often on a saw mill the blade waves around on the surface giving you a roller coaster like effect.
Hi Tim,that’s what I trying to do,ask a stupid question where do I set the z at 23?In CM when I jog and set zero.I have had severe concussion and I get muddled up.
Thanks Guy,I have about 15 pieces I need to get to fixed thickness and dimensions for them is variable so if I could do the one side first and then set to only go down to 23mm?
The only stupid question is the one not asked.
One way is to cut a piece of small stock at 23mm and use that to set your zero with.
Another way is to have Carbide Motion units in mm’s and zero on the spoil board, jog up 23 mm and re-zero.
I’m sure the more experienced can provide a more efficient way, I’m fairly new to this game.
Once you chose a method that works, write it down for future reference.
See:
Basically you would surface until close, then finish off one side, setting the zero relative to the surface.