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milling squareness problem10/28
I keep encountering a problem that doesn't even seem possible. Any help would be appreciated. When I begin milling lumber I first mill a face on my jointer. Then, using that face as my reference, I joint one edge. (My jointer knives were set with a dial indicator to within four thousands of the outfeed table and my fence is square to the table.) Almost always these two jointed surfaces end up about 1/32" out of square. Next, using my planer I plane the 2nd face parallel with the first. Once the face #2 is planed I find it is perfectly square with the previously jointed edge. Now there is absolutely no relationship between that face and the jointed edge so why would they end up square when the 1st face and edge are out of square. What am I missing?
A couple thoughts in no particular order:
You need to allow time for the piece you are milling to relieve internal stresses. Try jointing one face flat, plane the second parallel and wait a few days. Repeat.
Your fence may be square to the jointer tables at the cutterhead, but twist and warping are very common in jointer fences. Check the entire length with a straightedge.
Glue line rip blades are so good these days that I use my tablesaw to get straight and square edges on my stock. Stock face on saw table is just much more stable than a narrow edge on the jointer table. Google " jointing with your table saw" and you will find lots of jigs that are dirt cheap to make and very accurate.
There are a bunch of other possibilities, but maybe these will help find a starting point.
Thanks for the suggestions Karl. I'm going to research glue line ripping. Think I'm already set-up for it blade-wise as I have a beautiful 10" 40 tooth Tenyru Gold Medal blade.
Facing and edging on a jointer is so simple and straightforward that the problem should be obvious. I'll bet lunch that the wood is not moving after being milled. That would be rare, and not in every piece.
Be methodical. Check your squares to insure they are dead square. Then your jointer fence - lay it on the jointer table to see if it is flat - and then make sure the two jointer tables are parallel across the width - 8", 12" or whatever. This is more simple than it may appear.
Not knowing you or your level of experience, are you sure your technique is correct and not at fault?
Have you gotten square lumber from this machine previously? Have you made square stock on another machine successfully?
I once got a call on a warped Walnut door - 42" x 96" x 2-1/4". I huffed and took off to the site to show those idiots how wrong they could be - opening was out, they hung it wrong, etc.
I was humbled - the door was warped by a stile that had about 1/16" out of square edge at the top rail. This threw the door into a 7/16" warp or twist. It was machine/operator error, as simple as that.
I agree with David, if your wood moves from the time you joint it to the time you check it for square, there's something very wrong in the world;>) No offense to Karl, but the edge is either square after jointing or it's not. Boards can move over time, but the square edge is not going to become un-square in a couple minutes, if ever.
Now as to your specific problem, I'm going to go with the square being the culprit. My thought process goes like this, if you have 2 parallel faces and one checks for square to the edge while the other does not.....it has to be your square. When you break it down to the simplest possibility, there's no other explanation. All the other information simply gets on the way. You cannot have two parallel surfaces with one being square to an edge and the other not!
Jeffd just solved your problem. You need to invest in a nice machinist square, beats the hell out of what is marketed as woodworking squares.
I agree. The basics are where it is at. A good machinists square - or two - is fundamental. No speedsquares, no combination squares, no reading a pointer and gauge. A solid, rigid, accurate square is required.
A quick look online had them from $4.00 to $69.00 (Starrett). Respect yourself and your work and get the better square if you don't already have one. It will be accurate beyond your ability to determine its accuracy - for life.
Besides a very high quality machinist square, and please don't buy a 4.00 one, invest in a nice dial calipers. Between the two you might spend 300.00. But the accuracy you gain will pay that back in no time at all. Just don't drop them! They are precision instruments.
Thanks to everyone for the input! I agree that IF the faces are milled parallel and one face is square with the edge then they both have to be square with the jointed edge. But that's not what I'm seeing. (I use a $65.00 Starrett square by the way.) Perhaps there is another possibility. Is it possible that my planer's knives are no longer parallel with its table? If so, maybe my planer is shaving off the just enough excess wood on one side of the face to eliminate the differential causing the out-of-squareness with the edge, leaving me with one face that is now square with the edge. Possible?
An improperly set up planer can cause the stock to be planed out of square.
There are two ways this can happen that I know of:
What kind of machines are you using?
Just an additional tip, if you don't have a decent dial caliper handy, (which you really should),.....take a board as wide as your planer can handle and run it through. Mark it with a triangle in pencil, (so you can keep track easier), then rip in in half and match the 2 outside edges. If it's off enough to show 1/32" on the square, it will be off enough to feel with your fingers, and most likely you'll even be able to see it;>)
I'd still prefer to use a dial caliper, but this will at least tell you if the planer is the problem!
Solved it! Turns out a couple of my jointer knives had slipped very slightly. Equally important, I noticed for the first time that when I adjust the set screw to square my fence with the table that the fence inevitably moves from that position a bit when I tighten down the large bolt that is used to lock-in the setting. Trial and error resulted in square fence. Fence, knives and table now in sync. David and Jeff thanks for the tips regarding the planer. I plan to do those tests.
Good news. I will add that I never had a joiner that would hold the fence at 90 degrees by the stop. In larger shops, I removed the stops so everyone would use the square instead of rely on the inaccurate stops. Except for the giant 18" Northfield patternmakers joiner with a hand wheel on the fence that was calibrated to move 1 degree with 10 turns. That was accurate no matter what.
when gluing up panels I run one face of the board against the fence and then the next board I run with the face away from the fence.
good luck ........nicko