Face jointing help please

Re: Face jointing

Mark Mandell - Gone Round In New Jersey

Don't know about the Robland, but were that showing on a straight jointer it would indicate to me a co-planer problem between the infeed and outfeed tables. I would check the tables with a good long straight edge and would expect to find either of the tables drooping to the end(s) so that the cutter sits at a slight peak relative to the ends of the tables. Adjustment is usually made to the infeed table to bring both surfaces co-planer along their entire length.

Just went through this with my Delta 37-190 after upgrading to a Byrd Shellix head.

Do you get good results when planing?

Re: Face jointing help please

Barry Irby

Do you have the manual? Or download one.

The in feed and out feed tables must be co-planer. Zero the infeed table and use a good straight edge to see if they are in a plane. Also, the cutters should just "snick" the straight edge when it is resting on the outfeed table. If the outfeed table and cutter does not match up perfectly you will get strange cuts.

That should get you started.

Re: Face jointing help please

John in NM

That is typically caused by your beds being out of plane. You should see that one or both ends are sloping away from the cutter head if you have a good straight edge and a feeler gauge.

How to correct it will vary with machine design, I'm afraid I'm not familiar with combo machines so I wouldn't know how to do it. There might be instructions in the manual however.

another explanation

Bill Tindall

The board may be bowed. Turn it over and try it.

Re: Face jointing help please

Dave Bair

Flip the board end-for-end after each pass. While the tables should be coplanar prior to jointing, the infeed table has to be lower than the outfeed table when actually jointing. Sometimes the cutter head has to be slightly higher than the outfield table to get a good joint and avoid tapering; it's .002-.005" on my machine, depending on how hard the wood is.

Re: Face jointing help please

Dick Coers

Lower the outfeed table. Place a straightedge on the outfeed table. Place it on one of the segments. Rotate the head by hand. It should lift the straightedge and pull it about 1/8” forward.

A question about your diagnosis

Bill Tindall, E.Tn.

If the outfeed table was too high would not the leading edge of the board jam?

I cut tapers on the jointer and to do so I have to start the leading edge on the outfeed table. No other way to do it.

I'm putting my money on a bowed board that is being jointed convex side down

Re: A question about your diagnosis

John in NM

I've seen the bow do that too - it just has to be long enough that the starting point is off the outfeed table before the other end gets cut.

I've never seen improper height cause a taper either, but I have found that when you have a very mild bed droop getting the outfeed height just so can help mask it.

Re: A question about your diagnosis

Dick Coers

I’m suggesting it’s just a few thousandths off. But it make a huge difference over several feet. I’ve also adjusted outfeed tables by going too low. You get a snipe of course. But the I raise it ever so slightly until the snipe disappears. Inveribly the outfeed table remains a few thousandths lower that the top of the cutter head arc. Second most common problem is the operator moving their hands back and forth from the indeed to the outfeed table. All hand pressure must be on the outfeed side as soon as possible, or error can be machined into the board.

Ify Bet

Mark Mandell - Gone Round In New Jersey

Howard stated " . . . many passes before the [trailing] end is cut."

If it were a bowed board, the head would cut the leading edge, skip the middle, and then cut the tail on each pass. With a straight board and pressure on the outfeed table, the trailing end would be slightly lifted off the infeed table surface. That would continue until the board conformed to the outfeed table plane relative to the cutter line with the described wedge as a result.

Re: Ify Bet

Bill Tindall, E.Tn.

"If it were a bowed board, the head would cut the leading edge, skip the middle, and then cut the tail on each pass"...agree if the concave side is down.

I am speculating the convex face in on the table. Easily diagnosed by jointing the other side where upon what you describe would be observed.

Re: Face jointing help please

Brian Holcombe

Is the resulting face flat?

Re: Face jointing help please

Ron in Sterling, CT

Has this situation always occurred, or is it something new? I don't have any experience with combo machines, but my experience with this situation on conventional machines has always been non co-planer infeed and outfeed tables.

Ron

UP-Grade Issue

Mark Mandell - Gone Round In New Jersey

I've always had my jointer dialed in to the proverbial gnat's eyelash. I never touched the outfeed table adjustments but rather set the knives to the "hop-skip" method Dick mentioned and then tuned the infeed table to that surface.

Didn't work when I upgraded the machine to a Byrd-Shellix cutter head. Since there was no longer a height adjustment to the cutting edges on the Byrd, I had to lower the outfeed table to get the requisite .0015" over the outfeed level. THAT threw the infeed table off so then that had to be dropped and reset for "0" to match the new outfeed setting.

I learned all this the hard way since the Byrd head didn't come with install destructions/constructions.

My first couple of test cuts produced exactly what Howard is describing. After everything was reset and brought back to coplaner at the "0" setting for both tables and the cutter sitting a thou or 2 above, the resulting cuts were impressive indeed.

Re: Face jointing help please

Keith Newton

Howard, before you run a board, do you sight down it, then put the bow up? If you do this, you can set down with the middle of the crown over the blade, and take some of the trailing half of the bow out first. You can then turn it around end for end, still crown up and do some off the other end before trying to run the whole length of the board.

If you don't sight down the board, and just happen to run crown down, then user error would produce what you describe if you start off trying to press the bowed up end down to the cutter, even on a perfectly setup machine.

A number of things to work through...

Howard Pollack

Thanks everyone, I will systematically work through these suggestions and report the outcome. -Howard

Step 1

Bill Tindall, E.Tn.

Determine if the piece of wood is bowed and if so were you putting the convex side down instead of the concave side? Easy to test, just joint the other side of the board and see if the problem is eliminate or persists.

Re: Face jointing help please

Pete in Holland MI

Jointers are designed to make surfaces flat, but not both surfaces parallel in both a is. You need a surface planer to do that. Expect only close using a jointer to plane both sides.