Hi all,
Normally I’m over at BT, but I figured that this would be a better place for this question.
I have owned an 8″ Grizzly jointer for a year now. It’s a great machine, the one that’s Taiwan-made with the 4-knife cutterhead. I have had nothing to complain about except one little thing, and it’s irritating the crap out of me. The machine is on a mobile base and gets moved around a bit, and I think that may be contributing to my problem.
The problem is – the tables don’t appear to be coplanar when NOT set at zero. When the infeed table is dead level with the outfeed table and I put a straightedge across them, there is no gap. As soon as I drop the infeed table to make a cut, I can see and feel that the cutterhead is the ‘high point’ of the cut. What happens is, I get a board that is ever-so-slightly convex. In order to make a good glue joint, the boards need to be either dead flat or slightly concave (“sprung” joint). I can’t get that. I THINK I need to shim the outfeed table, but I have no idea if A) that’s indeed the problem and B) how to do it.
Now, the problem isn’t much. If I place two six-foot boards together, the centers touch and there’s maybe a 3/64″ gap at either end. That’s enough to bother me. What should I do about this little problem (maybe call Grizzly?).
Thanks.
Edited 7/21/2006 2:21 pm ET by JonE
Replies
The height of the outfeed table is adjustable.
John W.
Yep, I know the HEIGHT is adjustable, but that doesn't appear to be my problem. The problem is that the angle of the outfeed table is slightly different than the angle of the infeed table. By a degree or so. Best way to describe it would be - if I make a cut on a six-foot long board and stop the cut halfway through, so that there's three feet resting on the infeed and three feet resting on the outfeed. I have the entire piece on the infeed table, touching the table. The part immediately after the cutterhead is touching the outfeed table. The very end of the board at the far end of the outfeed table has a GAP between it and the table, enough that I can slide a couple index cards or three underneath it.
I agree the tables should be coplanar. I don't know that jointer so can't say what adjustments to the infeed table parallelism is possible.
However, technique can be of some help, in the interim perhaps. You should never have a gap between the wood and the outfeed table, since once the end of the board is clear of the knives the downward pressure should virtually all be over the outfeed table. That may allow adjustment of the outfeed table height to at least eliminate the convex cut.
Jon,
It's possible that the outfeed table is a skosh too high, relative to the cutterhead. The stock will make the transition to the table, but will be forced away from the cutter ever so slightly as it continues along the table, making the cut convex over the length of the board. This condition will occur as the edges of the knives get dull, making the cutting arc of the head slightly smaller than when new. Possibly, the outfeed (or the infeed) table is drooping as you describe, but try lowering the outfeed table by half a hair, and see if it doesn't help.
Regards,
Ray Pine
Thanks, I'll give that a shot and see if it works. It makes sense, because the machine was cutting perfectly with a slightly sprung joint when brand new.
I'll second joinerswork's remark. LOL!Cadiddlehopper
"Half a hair" - is that a Metric term?Frosty/Jerry
Frosty,
Not metric. It's a measuring system unto itself. It starts from "finer'n a frog hair, split four ways." Half a hair, that's relatively fine but not too little to see ;-)
Ray
I haven't heard "finer than a frog's hair" since I left Kentucky. Brought a smile to my face.Thanks for the definitions, I can tell you are of a scientific bent.Frosty
In order for the jointer to do it's job, you need to walk forward with the board and transfer you pressure to the outfeed table only. A common rule of thumb is to make the switch about one third the length of the board. Essentially, you are looking to have enough contact with the outfeed so that you can safely move your hands and keep the cut edge tightly referenced to the outfeed table. If you just keep pressure on the infeed table or close to the cutterhead, you will cut rockers.
To check your tables for twisting, you need a long straight edge. Cut a couple of feeler blocks, maybe 1/8" and 1/4" thick. Unplug the machine. Rotate the cutterhead so the knives are out of the way. Move the fence back. Hold the straight edge on the outfeed table, projecting to the infeed, and raise or lower the infeed table to match a feeler block. Lock the infeed table. Use the block to feel under the straight edge both front and rear as well as side to side. Do it the same with the different sized feeler. This will tell you if the table changes in different positions. No change, good fit everywhere, no problem.
The other factor with a jointer is setting the height of the knives. They need to be just a bit higher than the outfeed table. Sharp knives will dull slightly right away. I like using a blade from a combo square. On edge, line up 8", rotate the cutterhead so the blade moves 1/8". With this method you never need to move your outfeed table. Simple and surprisingly accurate. The pic shows what a test cut, with a straight board, should look like if you are set up correctly.
Beat it to fit / Paint it to match
Well, I'll check this thing over the weekend to see what is different about it. It worked fine out of the crate, and I did run through a whole series of setup and tests with straightedges, feeler gauges, dial indicators, etc. Every single knife was set 0.001 to 0.002 above the outfeed (according to the dial indicator). I suspect, as you all are telling me, that the knives are now below the outfeed by a couple thou. That would certainly cause my problem where none existed before.
Will report back, maybe it'll help someone else in the future.
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