Jointer Problem?

[william_hunter]

Hey all, first post, hope you can help me out here.

I have an older (1955 ish) Craftsman router with cast iron tables and stand. Its a solid machine with some issues, like a bad gouge on the spindle where the pulley rides, but that I can manage. What I want to know is: how do you get a smooth, flat, non tapering planed wide face on a piece of rough cut stock?

The scenario: I am building a fun little chair for my 4 year old, for his birthday. I used rough cut red oak, nicer wood than I probably should have used for this, but it was here and handy. I have tons of it, actually. I got the technique for straightening the edge down and got nice straight edges using a combination of the jointer and my table saw, then used my chop saw to square the ends. Now, one piece has a little bow in it and I was planning on using the jointer to straighten that bow then run it through my planer to get nice parallel sides. My main issue? I can't get the jointer to cut a wide side flat. Each time I have tried with a practice piece of bowed wood, I end up with a tapered piece. It appears that the blades are not evenly cutting the wood, though I am using a wide pushblock to hold it down and another to move it across the tables.

Am I putting too much pressure on? Why am I getting tapered boards? Help!

[william_hunter]

I had a few thoughts about why this might be happening, so just for completeness' sake, I will share what I did to check the machine.

1. Check infeed and outfeed tables for being level. Check. Both are. When the infeed table is set at 1/16" the entire width of the outfeed table is exactly 1/16" above that.
2. Check blades for being square to table top. Check. Looks good on all blades.
3. Check for twist in table. Check none that I can find.

Seems like it is indeed technique based, not equipment. I'm not really surprised by that revelation. Any advice?

[jackellis]

You may be applying uneven pressure. I assume you're trying to flatten the faces rather than the edges. If so, you want the concave side down and the convex side up. It takes a little practice to flatten unevenly warped boards.

When face jointing concave boards, I try to push from the end with one push block, hold the board against the fence with the other push block, and avoid putting too much downward pressure on the board that might cause uneven cutting.

Once you have one face flattened, put the board through your planer, flattened side down. There's no reason to flatten both sides on the jointer.

[LCHIEN]

On my delta JT360 jointer, I find if I make repeated cuts it tends to taper the wood. However, this is not necessarily a sign that things are bad...your goal is to flatten one side. Then use the thickness planer to make the sides parallel. I suppose it it were really bad then you would loose a lot of wood. But you didn't say how much tapering per pass you have? I generally take off about a 32nd per pass. Unless its really warped a couple of passes does it. If I have to take off more and don't want to taper too badly, I might reverse the feed direction on successive passes to even up the taper. I know this goes against the advice to plane with the direction of the grain... but if it doesn't create any tearout and it controls the taper...

[cabinetman]

Since you said your tables are both level, check to see that the knives are even with the outfeed table. Hand pressure on the stock should be mainly on the infeed table until the stock gets about half way onto the outfeed table, then a balanced pressure on the outfeed table, with minimal pressure on the infeed table. Basically a jointer setup is for whatever the knives are set up above the infeed table, what's remaining after machining is supported by the outfeed table.


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[william_hunter]

I put a big right angle square on the outfeed table, long edge down, and slid it front to back. The blades are just barely in contact with the square along the entire length at every point on the outfeed table. I think its pretty well aligned there too. I guess I need to work on technique here.

Thanks for the responses folks, I am hoping to work this out by Thursday, since the boy's birthday is being celebrated Friday. Be nice to have his chair there on time.

[william_hunter]

Now if I can just get my planer to start up. -sigh-

Seriously, this project must be cursed. The switch on the planer was missing the lockout tab, so I got a new switch assembly from PartsDirect, plugged it in but forgot to put the hold-down ring on. It started and ran just fine. Took the switch off and put that ring on, put switch back on and no joy. Looks like I will be planing on the jointer, both sides, unless I can work out that issue.

[Pappy]

A jointer is one of the simplest machines, yet one the hardest to master. Keep practicing and don't get TOO frustrated. Once you hit the sweet spot in technique, you will wonder why it was so hard to find.

As C-Man said, make sure you're knives are even with the outfeed table.

I also feed with pressure on the infeed side until the knives quit cutting into the bow. Then I move the pressure point to just past the cutter head. This keeps the front of the board in contact with the outfeed table and keeps the back of the board from wanting to lift off the table/knives.