Minh Tran
07-25-2016, 10:15 PM
I recently purchased a Grizzly G0452 and have been using it on Douglas Fir 2x4s. I've already prepared the jointer by making sure that the outfeed table is leveled with the tip of the blade when it is at its highest point. Afterwards, I made sure that the depth of cut is zero-ed and when a non-zero depth-of-cut is set, that the outfeed table and the infeed table are displaced in parallel by the set amount. I get mixed results in cut quality but I'm mostly having trouble fixing bows on surface joints and crooks on edge joints.
The Problem
The first milling operation that I perform on a piece of lumber is surface-jointing. The DF 2x4s I pick out are usually flat and straight. Those that are in good condition to begin with usually surface joint and edge joint easily to a square.
Occasionally, if I exert to much downward force at the beginning and end of a face joint and the cut depth is somewhat heavy (when cut depth is set between 2/32" and 3/32"), I end up with a bow.
What I've Tried
When trying to fix a bow, I noticed that I slowly worsen the bow if I support the board at the start of the joint, 3-4 inches from the board's edge. The error increases dramatically if I set the depth of the cut to 3/32". Which makes sense because I'm pushing the already shallow end of the board deeper into a cut.
I then tried to identify where the bow begins and ends and marked those region around the board (this reference helps me identify where my cuts are being made when I position my push block at a certain location). I decrease depth of cut to 1/32" and sometimes to as small as 1/64". I noticed that if I position my push block *after* and in between the bow as I feed the board through the cutterhead, the bowed region gets cut. This slowly fixes the bow.
Now ... the bow is about 1/16" proud, so if I set my cut-depth to 1/32", 2 passes should fix the problem. But after passing the board 4-8 times through, the board is still not flat! This confuses me.
I then increase depth-of-cut to 2/32" and push the board through on the bowed region but I over-cut and recreate the bow. @#$%@#$%!!!!! This meant the bow was <1/16" proud before depth-adjustment (but it was still noticeable).
What I'm Planning to Try
I'm thinking that I might get better results if I start from where the bow is less than 1/16" proud, plane it with a thickness planer, and then resume surface jointing. Maybe I should better stock than DF 2x4s. Do some species of wood surface joint/plane better than others?
Thoughts/tips?
The Problem
The first milling operation that I perform on a piece of lumber is surface-jointing. The DF 2x4s I pick out are usually flat and straight. Those that are in good condition to begin with usually surface joint and edge joint easily to a square.
Occasionally, if I exert to much downward force at the beginning and end of a face joint and the cut depth is somewhat heavy (when cut depth is set between 2/32" and 3/32"), I end up with a bow.
What I've Tried
When trying to fix a bow, I noticed that I slowly worsen the bow if I support the board at the start of the joint, 3-4 inches from the board's edge. The error increases dramatically if I set the depth of the cut to 3/32". Which makes sense because I'm pushing the already shallow end of the board deeper into a cut.
I then tried to identify where the bow begins and ends and marked those region around the board (this reference helps me identify where my cuts are being made when I position my push block at a certain location). I decrease depth of cut to 1/32" and sometimes to as small as 1/64". I noticed that if I position my push block *after* and in between the bow as I feed the board through the cutterhead, the bowed region gets cut. This slowly fixes the bow.
Now ... the bow is about 1/16" proud, so if I set my cut-depth to 1/32", 2 passes should fix the problem. But after passing the board 4-8 times through, the board is still not flat! This confuses me.
I then increase depth-of-cut to 2/32" and push the board through on the bowed region but I over-cut and recreate the bow. @#$%@#$%!!!!! This meant the bow was <1/16" proud before depth-adjustment (but it was still noticeable).
What I'm Planning to Try
I'm thinking that I might get better results if I start from where the bow is less than 1/16" proud, plane it with a thickness planer, and then resume surface jointing. Maybe I should better stock than DF 2x4s. Do some species of wood surface joint/plane better than others?
Thoughts/tips?