I have been having all kinds of problems attempting to join some 8 foot long oak boards together. My joiner is a Delta, with about 2 feet of infeed and 2 feet of outfeed tables.
What I generally find when I think the boards are completely flat is that are not! When I put them together, I find that they touch only at the ends, and have a gap that gradually gets wider toward the middles.
I think this happens because my table is not long enough to hold my stock, but would appreciate some ideas.
Is it possible my technique is wrong? What can I do to fix this?
I discovered that very same problem early on with my small jointer. Nowadays I use a Freud glue edge blade in my table saw to joint the boards. Also, it has been mentioned here on the WrecK that you can use a straight cutting bit with your router. Clamp the boards edge together(like they would be on the table top), establish some sort of straight fence and route along the crack between the boards. Even if the router cuts a little off, the joint will be tight, so we are told. I gave my POS jointer to Habitat for Humanity.
Larry's reply is a good idea - use a glue line rip blade on the table saw. Alternatively, I've been able to get good results using a carefully aligned roller stand on the outfeed side of the jointer. You have to make very certain that the stand is at the exact same height as the outfeed table. If you accomplish this, it makes jointing longer boards feasible.
IME, accurate jointing with a jointer is a combination of both technique and ratio of table length to board length. If your infeed an outfeed tables are each long enough to hold the entire piece, then your chances of accuracy are increased and the need for well practiced technique may be diminished accordingly, the reverse is also true
IOW, the longer the tables, the longer the boards that can be _easily_ jointed. The general CW rule-of-thumb is that you can joint up to twice the table length, but good technique can make up for increased table length to a point, and bad technique can mitigate longer tables.
Light and continuous hand-over-hand pressure (and sometimes NO downward pressure as the middle of the board approaches the cutters), on the outfeed side only, may help the bowing on longer boards for the particular problem you are noting, but you may find that you need another pair of hands to hold the board to the fence on the infeed side when edge jointing.
Short of perfecting your technique with lots of practice on the jointer (and wasted wood), the best solution is longer tables, or joint shorter pieces that can be easily accommodated by your jointer.
You can also use a well setup table saw effectively on longer boards.A Google search will get you some ideas on how to do this, as well as some neander methods of jointing with hand planes.
Practicing and carefully analyzing the results, then making changes, is the only way to effectively improve technique.
Ditto the comments on using the glue edge or very sharp cabinet blade. In addition to well adjusted roller stands, feather boards won't hurt. Also, make sure the stand rollers are aligned perpendicular to the blade and fence. They have a tendency of trying to guide a heavier piece of stock away from the fence - exactly what you don't need in this case.
I understand your pain. I have had a 1957 vintage 4" Craftsman jointer for about 20 years. It was manufactured back in the days when Craftsman machinery was built like a fire plug. Unfortunately, I became attached to it even though the table lengths are totally inadequate for anything larger than small projects - a lot of mine are not. I am currently trying to sell my baby and want to move up to a larger machine. My son-in-law just took delivery on a Griz G0500 and it is very nice. Ya know - the young'uns aren't supposed to have that kind of equipment before we old guys do. Are they?
|I have been having all kinds of problems attempting to join some 8 |foot long oak boards together. My joiner is a Delta, with about 2 |feet of infeed and 2 feet of outfeed tables. | |What I generally find when I think the boards are completely flat is |that are not! When I put them together, I find that they touch only |at the ends, and have a gap that gradually gets wider toward the |middles. | |I think this happens because my table is not long enough to hold my |stock, but would appreciate some ideas.
Have you verified that the tables are parallel? See:
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this is done, make sure that the outfeed table is at *exactly* the same height as the cutterhead.
| |Is it possible my technique is wrong?
Maybe. Here's what works for me.
When you introduce the leading edge of the work piece to the infeed table, you should hold it really tight to the table. You're going to have 6' of board cantilevered off the rear of the table; you need to push down with enough force to overcome this, otherwise your cut will be light at the leading end, get heavier as the work settles onto the table and then lighten up again as the opposite occurs on the outfeed side.
At the beginning of the cut, stand next to the infeed table and manage the piece. As the work moves through the middle stay there and guide it through until the work is about to exit the infeed table and then shift your weight forward to really push the work tightly down on the outfeed side. If the far end droops, the cut will lighten up and you have your problem.
A fresh coat of wax or Topcoat will help overcome the friction that you should be developing in holding the work down.
If you think your tables are too short consider that the longest jointer planes are less than 2' long.
Had a 4" Rockwell for years. You need prior planning and a strong arm, but it's doable.
First, sight the edge. If you have a high spot or two, take it off. Normally you'll curve toward the sapwood, so you can take both ends off the sapwood side by setting the piece on top of the guard somewhere near the middle and touching the infeed. Slide the guard aside and let the board contact the table, join off the end. Reverse and work until you're within a cut thickness of straight, then feed as normal, paying special attention that on the initial 6-8" you're flat to the infeed. Thereafter, keep all but guiding pressure downward on the first 8" of outfeed.
I have my jointer lower, so that I can pass things over the tablesaw and they will clear the jointer fence, so it's a bit easier for me to work a board than if the jointer was up higher.
The rule of thumb is a board maximum of one and one half times the length of the table. In exceeding that length what happens is that the board cams over the ends of the table as you feed it through the cutters resulting in the condition you are having.
Too he good suggestions you've had already let me add that the fastest way I have found to get the job done is to remove the high end of the bows at the ends with a hand plane then feed the board through the jointer to clean things up and establish the 90 degree edge too face relationship.
Only touching at the ends? I'm no expert but, did you edge the planks before jointing with the TS? If you have a crooked board that long the jointer might not fix it by just running it through. You have to edge it first with a good TS blade or I have seen people joint a few feet then turn the board around and joint other side.
Well, I read all the responses in this thread and not one of you Norm wannabees mentioned a hand plane :-).
For the original poster: clamp the two boards bottom to bottom and use a hand plane to joint them. You won't get it perfect, but it won't matter because the two will be complementary.
And there's NO length limit.
BTW, a very slight concavity, a few thousandths of an inch, is suggested by some woodworkers as a way to put extra pressure on the ends so they won't separate over time. Are they right? I don't know. If you do it, take a single pass when you're done with the blade set so the shaving is almost tranparent. Just skip a few inches at each end.
lay your board flat on the table and lay a straight edge on top of it. line up the straight edge and mark a line where you want your cut edge to end up. take the board to the jointer. note that you don't have to pass the whole board over the blades every pass.
A "lot" of folks don't own the correct plane or have any idea of how to use it to joint a board of "any" length perfectly flat and straight. While it sounds great, your suggestion is much harder.
A table saw and a piece of plywood as a carrier will get much quicker and staighter results.
YES!! I thought I was going to have to say it! This is one place a RAS shines. I have an 8' table and when I use an 8' carrier I get good results. The fence and carrier must both be straight, of course. I use the factory edge of a piece of 3/8-3/4 plywood for my carrier. ABout a foot wide is good for most things. I screw up through the carrier with a sheetrock screw into the BACK of the workpiece. You can get fancy and make clamps to hold the work to the carrie if you can't allow the two little screw holes.
No one mentioned it, but you CAN do this with a CS, IF you can find a good enough straight edge.
How wide is the gap in the center? Sometimes, a very slight bow is GOOD, as it'll keep pressure on the ends as the wood moves. Tage Frid mentioned this in several writings.
Barry: I would have been happy with a gap of about 1/32" or so, for the very reason you mention. But it was starting to get closer to
1/8"! That just seems to be no good!
Thanks for all the great replies, guys! Some of the ideas are what I ended up doing and trying, and I was eventually able to get a pretty good joint. Sadly (or maybe fortunately), I still have to make 8 more boards at about this length, so I should get pretty good at it by the end!
I tried aligning rollers precisely, but couldn't get them exact (my basement floor is kind of wavy, which didn't help.) What ended up working best was running just the ends of each board through the jointer once or twice, set on a very slim cut. After knocking the ends down a bit, I ran through the jointer all the way through a few times from each direction, checking the boards against each other each time.
I think it worked -- I guess I'll know better when I take the clamps off tonight!
I might have to try the idea with a straight router bit through the edges sometime, though I see some logistical difficulties with that, too.
Thanks again, and by all means keep the suggestions coming!
Excellent idea! Problem with me is I have had no one to teach me the correct way to work with handtools. Hand tools to me are the ones you grab with your hands like a router, jigsaw, etc. hehe.
Don't know if you idea is the normite solution but I will defintely log it in the ol' noggin for my future reference.
Just be aware that the results with this method may not be quite as "excellent" in practice as it sounds is theory - particularly when doing edge jointing on long boards - and the technique likely requires as much practice with a hand plane, if not more, as when using a jointer.
As with the jointer, should you put a bow in the boards with either method, in either direction, you compound the error by a factor of two when the two edges are put together. If you are going to use this method with a hand plane, and on boards as long as were mentioned, it helps greatly to use a "shooting board" of some type, or edge guide, for the sole of the plane to ride on.
Also, the only "complementary" component mentioned with this method will be in any angle deviation from 90 degrees between the two adjacent edges and the faces when joined.
When edge joining boards destined for glue ups with a jointer, you can get the same "complementary" angle of the faces and edges of two adjacetn boards by simply alternating the faces which go against the fence of the jointer ... IOW, alternate the top face of one board, and bottom face of the adjacent board, against the fence.
After you've done your initial grain match with the boards, and have them oriented the way you want them, you can make this easy to remember by marking each adjacent face on top with a pencil or chalk with an "I" for the face that goes into against the fence, and an "O" for the face that goes out/away from the fence.
... with either method, and as bridger said, practice, practice, practice.
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