Welcome to the forum, Nate! Your machine sounds like it's setup properly so that really only leaves technique. But if you've had this one a long time then I'm sure you know how to use it properly. What's the longest board you can run across the jointer and have it not twist?
Jointer doing the twist
My jointer is a 6" Central Machinery with a spiral cutter head (upgrade). I know how to setup a jointer, and I've had this one tuned nicely for a long time. Basically, joint two pieces of lumber, but them together, perfectly straight glue joint with no gaps.
My son and I have been building him a sturdy workbench out of white pine 2x4 lumber. Out of nowhere, instead of taking twists out of boards, it was making them worse! He was jointing the wide faces of 48" long boards, concave side down. His first board turned into a long twisted wedge. I was thinking the boards were too long for the machine and the flattened face fell off the front and it referenced back to the twisted face.
While troubleshooting, I began with a very flat piece of 1-1/2" thick butcher block that wasn't too long for the machine (5" x 18"). It put a twist in that too!
I went through the setup process on the jointer using a precision straight edge, and later a dial indicator. Everything looks spot on, like within a couple thousandths of an inch: Cutter blade height compared to outfeed table height withing a thousandths of an inch on both ends. Outfeed table height compared to infeed tabled--next to the cutters--within three thousandths of an inch front to back. Finally, precision straight edge shows outfeed and infeed tables are parallel and flat.
In my opinion, the jointer is as close to perfectly setup as possible, and I'd call .001-.003" deviation practically "perfect."
But I'm at my wit's end. Any ideas what might be causing twists instead of removing them?
Incidentally, we did get the 2 'x 4' x 2.5" top glued up and flattened, but I had to do it old school with a hand plane. That was actually therapeutic, the pleasing sound of thin layers of wood being planed off.
Thanks in advance for any ideas.
Nate
My son and I have been building him a sturdy workbench out of white pine 2x4 lumber. Out of nowhere, instead of taking twists out of boards, it was making them worse! He was jointing the wide faces of 48" long boards, concave side down. His first board turned into a long twisted wedge. I was thinking the boards were too long for the machine and the flattened face fell off the front and it referenced back to the twisted face.
While troubleshooting, I began with a very flat piece of 1-1/2" thick butcher block that wasn't too long for the machine (5" x 18"). It put a twist in that too!
I went through the setup process on the jointer using a precision straight edge, and later a dial indicator. Everything looks spot on, like within a couple thousandths of an inch: Cutter blade height compared to outfeed table height withing a thousandths of an inch on both ends. Outfeed table height compared to infeed tabled--next to the cutters--within three thousandths of an inch front to back. Finally, precision straight edge shows outfeed and infeed tables are parallel and flat.
In my opinion, the jointer is as close to perfectly setup as possible, and I'd call .001-.003" deviation practically "perfect."
But I'm at my wit's end. Any ideas what might be causing twists instead of removing them?
Incidentally, we did get the 2 'x 4' x 2.5" top glued up and flattened, but I had to do it old school with a hand plane. That was actually therapeutic, the pleasing sound of thin layers of wood being planed off.
Thanks in advance for any ideas.
Nate
1 - 20 of 34 Posts
I have zero jointer experience but if it's setup correctly and you know what you're doing, would the sharpness of the cutters be something to consider? I would think if one side or maybe random cutters throughout the head are really dull then it wouldn't be removing material consistently which might result in a twist. Again, I have no jointer experience so I'm just throwing that out there as the only thing that would maybe make sense to me without someone smarter telling me what the problem actually is.
Sometimes it seems the machine is screwed up but you can take a flat board and run it across the jointer putting pressure in the wrong places and have it come out with the face twisted.
I have found that a lighter touch is better than "muscling" the board over the cutters.
The first thing I do is sight down the board for twist and place it on a flat surface to see what pressure does on the corners.
Then I may run it only partially across removing only the "high" spots checking my progress each time.
You can "read the board" by scribbling lines on with a pencil if you can't see the difference from the pass.
Face jointing is a bit difference than edge jointing in that the wider surface gives you more to read.
And there is far more material needed to remove to get it flat.
I have switched over to a table saw with a straight line rip jig for my edge jointing. especially for boards over 3 ft long.
The first thing I do is sight down the board for twist and place it on a flat surface to see what pressure does on the corners.
Then I may run it only partially across removing only the "high" spots checking my progress each time.
You can "read the board" by scribbling lines on with a pencil if you can't see the difference from the pass.
Face jointing is a bit difference than edge jointing in that the wider surface gives you more to read.
And there is far more material needed to remove to get it flat.
I have switched over to a table saw with a straight line rip jig for my edge jointing. especially for boards over 3 ft long.
As woodnthings said, light constant pressure. Once the front of the board the infeed, both hands should be feeding from the outfeed table. On longer boards you can keep an hand on the infeed side, but no pressure. Too much pressure, or pressure in the infeed and outfeed side can prevent a board from flattening, or make it worse.
One more thing to check setup wise is whether there is deflection happening on the infeed or outfeed wings. There are ways the wings can come out of alignment with pressure. Test adding a paint can at various places on the bed and ensuring the entire surface is still flat.
Also ensure the cutters are tight and not damaged.
Barring setup though, the only thing it leaves is technique
Also ensure the cutters are tight and not damaged.
Barring setup though, the only thing it leaves is technique
Jointers are not a matter of running a board and keeping it pressed against the outfeed. It require techniques and tricks.
I’ve found the best way to remove a twist is the set the cut fairly thick ans keep down pressure just in the two low corners. Feed slowly and as the wood exits to the outfeed, avoid the tendency to push the board down flat. Sunsequent passes will remove the twist.
Push blocks can be a source of problems especially on longer boards with a bow. If you’re not removing the bow, the reason is you’re pushing the board flat, essentially mimicking a planer - bow in/bow out. Use a shoe with a hook or heel and a handle, reach back and “pull” the board with minimal down pressure, focus on down pressure only on the leading edge - do NOT keep the board pressed flat against the outfeed.
On severely bowed boards, just take partial passes on both ends until you can here the blades contacting about 1/3 the distance.
Long boards are a challenge, and smaller jointers have short beds which makes it even more challenging.
In your project there, you don’t really need to worry about perfect boards since minor twists or bows can be clamped out. After the top is glue up, you will flatten anyway.
I’ve found the best way to remove a twist is the set the cut fairly thick ans keep down pressure just in the two low corners. Feed slowly and as the wood exits to the outfeed, avoid the tendency to push the board down flat. Sunsequent passes will remove the twist.
Push blocks can be a source of problems especially on longer boards with a bow. If you’re not removing the bow, the reason is you’re pushing the board flat, essentially mimicking a planer - bow in/bow out. Use a shoe with a hook or heel and a handle, reach back and “pull” the board with minimal down pressure, focus on down pressure only on the leading edge - do NOT keep the board pressed flat against the outfeed.
On severely bowed boards, just take partial passes on both ends until you can here the blades contacting about 1/3 the distance.
Long boards are a challenge, and smaller jointers have short beds which makes it even more challenging.
In your project there, you don’t really need to worry about perfect boards since minor twists or bows can be clamped out. After the top is glue up, you will flatten anyway.
Thanks everyone for the responses. I really don't think I'm applying too much pressure. I'm not leaning on the board, just applying pressure with my left hand on the outfeed table while pushing it through with my right. Besides, how much deflection could I have caused in the 1-1/2" thick piece of butcher block I mentioned in my original post?
I like the idea of only running the long boards through about 1/3 of the way. I didn't think of that.
As SomeDudeOnline suggested, the cutter heads could be more dull on one end compared to the other. I've been edge-jointing boards almost exclusively, and I realize I always put the fence on the backside of the cutter heads. I rarely face-jointed a wide board. So, it is possible that the cutter blades are more dull on that side, especially because a few of my projects involved bubinga and zebrawood.
I'll rotate the cutter blades, run a 5" x 18" piece of perfectly flat 1-1/2" thick butcher block through it and see if it stays flat. If it does, I'll see if it takes out the twist it put into the other piece of the butcher block.
I'll report back my results.
I like the idea of only running the long boards through about 1/3 of the way. I didn't think of that.
As SomeDudeOnline suggested, the cutter heads could be more dull on one end compared to the other. I've been edge-jointing boards almost exclusively, and I realize I always put the fence on the backside of the cutter heads. I rarely face-jointed a wide board. So, it is possible that the cutter blades are more dull on that side, especially because a few of my projects involved bubinga and zebrawood.
I'll rotate the cutter blades, run a 5" x 18" piece of perfectly flat 1-1/2" thick butcher block through it and see if it stays flat. If it does, I'll see if it takes out the twist it put into the other piece of the butcher block.
I'll report back my results.
Good to be here! Well, it put a twist IN a previously flat piece of butcher block countertop that was 18" long. I didn't try shorter boards.What's the longest board you can run across the jointer and have it not twist?
I think I'll build such a jig. I've got every issue of Shop Notes. There's got to be one in there somewhere.I have switched over to a table saw with a straight line rip jig for my edge jointing. especially for boards over 3 ft long.
@Nate-dust
I had a similar problem 3 years when using the jointer instead of a planer that I did not have at the time.
portion of the blades that were never getting used under the guard we're very sharp when I moved the fence over to that section that seemed to have made the problem go away.
mahogany seems to eat planer and jointer knives fairly quickly. I was doing about pieces 3 in wide pieces and it always seemed like it was doing pretty good job till I laid it out on the layout table and saw that I had acquired twist unexpectedly just doing the job totally wrong. what dull knifes can do for you.
wood working is a never ending learning curve. some part get easer with time and practice. and do not forget to
observe what other Woodworkers are doing whether it be by videos or in person at some of the woodworking demonstrations
there are a lot of good Craftsman on this forum that you can provide some good answers.
Welcome to the group
I had a similar problem 3 years when using the jointer instead of a planer that I did not have at the time.
portion of the blades that were never getting used under the guard we're very sharp when I moved the fence over to that section that seemed to have made the problem go away.
mahogany seems to eat planer and jointer knives fairly quickly. I was doing about pieces 3 in wide pieces and it always seemed like it was doing pretty good job till I laid it out on the layout table and saw that I had acquired twist unexpectedly just doing the job totally wrong. what dull knifes can do for you.
wood working is a never ending learning curve. some part get easer with time and practice. and do not forget to
observe what other Woodworkers are doing whether it be by videos or in person at some of the woodworking demonstrations
there are a lot of good Craftsman on this forum that you can provide some good answers.
Welcome to the group
You can build one from this thread I posted, see post number 4:I think I'll build such a jig. I've got every issue of Shop Notes. There's got to be one in there somewhere.
Straight Line Rip Jig
I've recently aquired several BF of white oak, that has been face planed, but not straight lined. I found this link for a simple jig, http://www.popularmechanics.com/home/reviews/4283497 Just wondering if anyone has any advice on a better one, or if anyone has used something similar and had...
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Something that I thought of last night. You might try pulling a string across the table. Anchor it on one corner and pull it tight and site down the table. It is not a bad way to see if there is any twist in the tables.Properly done it is very effective and simple too.
Second thought, what condition are the blades in? Last time they were sharpened? Level with the table? Might have moved. I can see no reason for this to happen other than something wrong with the blades if the machine was working and suddenly isn't working right.
Second thought, what condition are the blades in? Last time they were sharpened? Level with the table? Might have moved. I can see no reason for this to happen other than something wrong with the blades if the machine was working and suddenly isn't working right.
I rotated all the cutter blades 90 degrees to fresh edges, but that didn't help. I still can't get a 5" wide x 18" long section of butcher block countertop perfectly flat. I made sure to hold down the high corner, too.
What's your opinion of this cut? The difference in lengths indicates to me that the two ends might be off in height a little, but the cutter head just might be canted a little with respect to the tables. This is a twenty year old machine, but certainly the Taiwanese machining had to have been tight. I had to do considerable shimming with this spiral cutter head upgrade. I didn't have shim stock, so I used an aluminum can.
What kind of precision does one need to get good, consistent results?
![Ruler Rectangle Office ruler Wood Line]()
What's your opinion of this cut? The difference in lengths indicates to me that the two ends might be off in height a little, but the cutter head just might be canted a little with respect to the tables. This is a twenty year old machine, but certainly the Taiwanese machining had to have been tight. I had to do considerable shimming with this spiral cutter head upgrade. I didn't have shim stock, so I used an aluminum can.
What kind of precision does one need to get good, consistent results?
I guess it's more accurate to say that "I suddenly noticed" because we were face jointing boards, something I rarely do.I can see no reason for this to happen other than something wrong with the blades if the machine was working and suddenly isn't working right.
More often than not it’s technique. There’s a bit of an art to using a jointer.
Are the tables coplanar? Parallel to head?
Why do you rarely face joint? All boards need to be face jointed.
Are the tables coplanar? Parallel to head?
Why do you rarely face joint? All boards need to be face jointed.
The cut you posted could be a result of not having the fence at 90 degrees to the cutters.
Here's what to do:
Raise the bed(s) enough to clear the cutters and then using a 4 ft aluminum level, lay it across the beds adjusting until the level is laying flat on both beds.
Some older inexpensive jointers only have an adjustable infeed bed, the outfeed is fixed.
Once the beds are leveled (If possible) you need to check if they are co-planer. Co-planer means like pages in a book, they all lay parallel to one another.
If one table is tipping down at the end, you will need to shim it up. there are instructions and You Tube videos for that process.
The cutter head, and the tables must be co-planer. The arbor of the cutter head can also be shimmed to bring it parallel to the table surfaces.
Here's what to do:
Raise the bed(s) enough to clear the cutters and then using a 4 ft aluminum level, lay it across the beds adjusting until the level is laying flat on both beds.
Some older inexpensive jointers only have an adjustable infeed bed, the outfeed is fixed.
Once the beds are leveled (If possible) you need to check if they are co-planer. Co-planer means like pages in a book, they all lay parallel to one another.
If one table is tipping down at the end, you will need to shim it up. there are instructions and You Tube videos for that process.
The cutter head, and the tables must be co-planer. The arbor of the cutter head can also be shimmed to bring it parallel to the table surfaces.
Probably because I buy S4S lumber and billets that are already flat.More often than not it’s technique. There’s a bit of an art to using a jointer.
Are the tables coplanar? Parallel to head?
Why do you rarely face joint? All boards need to be face jointed.
From my initial post:
"I went through the setup process on the jointer using a precision straight edge, and later a dial indicator. Everything looks spot on, like within a couple thousandths of an inch: Cutter blade height compared to outfeed table height withing a thousandths of an inch on both ends. Outfeed table height compared to infeed tabled--next to the cutters--within three thousandths of an inch front to back. Finally, precision straight edge shows outfeed and infeed tables are parallel and flat.
In my opinion, the jointer is as close to perfectly setup as possible, and I'd call .001-.003" deviation practically "perfect."
"I went through the setup process on the jointer using a precision straight edge, and later a dial indicator. Everything looks spot on, like within a couple thousandths of an inch: Cutter blade height compared to outfeed table height withing a thousandths of an inch on both ends. Outfeed table height compared to infeed tabled--next to the cutters--within three thousandths of an inch front to back. Finally, precision straight edge shows outfeed and infeed tables are parallel and flat.
In my opinion, the jointer is as close to perfectly setup as possible, and I'd call .001-.003" deviation practically "perfect."
1 - 20 of 34 Posts
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