Art Davis
01-23-2007, 6:39 PM
I posted a question/gripe about milling a couple of days ago and got good advice---to get some relatively inexpensive wood and do some sawdust generating---and I am acting on it.
In the meantime, I decided to play around with some scrap in my shop. I took a badly bowed two-by-four and cut it into two four foot segments. (Wanted to see if four foot lengths could be jointed well on my 6 inch jointer.)
I followed the procedure I had acquired by searching here and reading the mags. Put a wiggly line on one edge, placed the tips down (inverted U) and ran it through the jointer until the wiggly line was gone, then made a few more passes until the edge look straight when held up to the light. I made sure I didn't press down hard, thereby distorting the natural shape. Then I did the same to one face. Looking good. Ran it through my planer, and guess what? It was pretty badly bowed again! Ran it through the jointer several times again until one face was flat.
Then I went to my table saw and ripped it to a couple of inches in width, keeping the jointed edge against the fence.
Uh-oh!!! The ripped piece had acquired a remarkable curve side-to-side (forgot what this is called---I think bow is relative to the flat sides, no?). I guess the stresses rearranged themselves inside the wood and distorted it.
Well, how about a piece of hardwood? Took a small piece of redoak, about an inch wide, 3/4 stock. Jointed one edge and one face. Both looked great. Then, on to the planer, where I ran it through several times. Huh-oh! Now it was bowed (flat side to flat side) again! Of course I could flex it back into shape by twisting it by hand.
Okay, so apparently the wood has a mind of its own. Am I doing something wrong? If I keep up this process, I'll be left with nothing but toothpicks? And even if I am finally able to get a stable end product, how much oversize do I have to go to get a particularly thickness and width?
There is clearly some major and fundamental point I am missing, but---Heck! I don't know what!
Can you help?
Sleepless in Shady Cove,
Art
In the meantime, I decided to play around with some scrap in my shop. I took a badly bowed two-by-four and cut it into two four foot segments. (Wanted to see if four foot lengths could be jointed well on my 6 inch jointer.)
I followed the procedure I had acquired by searching here and reading the mags. Put a wiggly line on one edge, placed the tips down (inverted U) and ran it through the jointer until the wiggly line was gone, then made a few more passes until the edge look straight when held up to the light. I made sure I didn't press down hard, thereby distorting the natural shape. Then I did the same to one face. Looking good. Ran it through my planer, and guess what? It was pretty badly bowed again! Ran it through the jointer several times again until one face was flat.
Then I went to my table saw and ripped it to a couple of inches in width, keeping the jointed edge against the fence.
Uh-oh!!! The ripped piece had acquired a remarkable curve side-to-side (forgot what this is called---I think bow is relative to the flat sides, no?). I guess the stresses rearranged themselves inside the wood and distorted it.
Well, how about a piece of hardwood? Took a small piece of redoak, about an inch wide, 3/4 stock. Jointed one edge and one face. Both looked great. Then, on to the planer, where I ran it through several times. Huh-oh! Now it was bowed (flat side to flat side) again! Of course I could flex it back into shape by twisting it by hand.
Okay, so apparently the wood has a mind of its own. Am I doing something wrong? If I keep up this process, I'll be left with nothing but toothpicks? And even if I am finally able to get a stable end product, how much oversize do I have to go to get a particularly thickness and width?
There is clearly some major and fundamental point I am missing, but---Heck! I don't know what!
Can you help?
Sleepless in Shady Cove,
Art