Slight crown in boards off the jointer
stevens
| Posted in Power Tools and Machinery on
I’ve had a Cutech (Wahuda) 8″ bench top jointer that’s been working well for a couple years. The time has come to replace the cutters in the spiral-style cutting head and to adjust the infeed and outfield tables. I’ve managed to get it set up pretty well…smooth cut, no snipe, etc…but there’s a tiny rounded hump in the middle of my boards running lengthwise. It’s slight. One or two passes with a finely set #5 and it’s gone. But, in an effort to dial things in better, I’m thinking that my outfield table is tilted front to back, while the indeed table is titled the other way, back to front. Any advice? Am I on the right track in the way I’m thinking about this?
Thanks,
Steve
Replies
yes take a long straight edge nd sure your infeed and outfeed tables are coplanar. There are articles and videos in FW so do a search. https://www.finewoodworking.com/2009/09/01/jointer-tables-should-be-both-parallel-and-flat
https://www.finewoodworking.com/2014/02/03/how-to-set-up-a-jointer
Non-coplanar tables will cause a banana board.
If you are getting a curved surface that is convex, the infeed table is a downslope relative to the outfeed, a concave surface the opposite.
If you are getting a little hump in the middle of an otherwise flat board, I am not sure what could be could be causing it.
Try running a piece of scrap across the tables several times. This will exacerbate any errors by multiplication and should reveal the problem more clearly.
The order of setup is:
1. Install blades.
2. If a planer-thicknesser, ensure that the blades are precisely parallel to the lower table (not an issue for just a jointer)
3. Make sure the outfeed table is level with the blades at maximum extent. For most machines, place a straight edge on the outfield table extending over the cutterblock. Rotating the block manually should pull the straightedge forward a little. How far is a matter of preference (I like 4mm) but it must be the same on both sides of the table. Adjust until this is so.
4. Make sure the infeed table is coplanar with the outfield table. Most setup problems with this occur either because the woodworker loses the will to live before the job is done, it being more than a bit fiddly on smaller machines, or having an imperfect straight edge.
To test your straight edge, lay it against a known flat surface such as your table-saw table (if cast iron) or jointer table. If this is too small, you can scribe a knife line on a flat piece of board - run the blade against your edge. turn the edge end for end so the same edge now abuts the other side of the line - if it matches up, it is straight enough for woodwork.
Maybe the hump comes when you lift off to change hand positions?
Thanks for the suggestions! Good comment about losing the will to live before the job is done. I'll keep at it with your advice.
If you didn't have this issue prior to the blade change I would start with setting the blades dead even with the outfeed table. I had a lot of trouble until I made a jig to help using 1x2x3 block and a gauge.
Hey there
It sounds like your blades are set too low. Contrary to what may seem like common sense, your blades need to be set above the outfeed table by just a hair.
Take a straight rule that's fat enough to stand on edge (like a rule removed off a combo square) and line it up a whatever measurement you want, then rotate the blade by hand it should pick up the rule and pull it back toward the infeed table about 1/8-1/4 inch. Just make sure that whatever measurement you choose you are consistent with it (all blades move 1/4" on the outside and the inside - in other words 2 measurements per blade)
If you say you had no problems with the jointer until you changed blades I would bet money that this is your problem.
Cheers
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