Jointer question

Re: Jointer question

John McGaw

Have you checked the rest of the alignment? For instance, are the tables co-planar when the infeed table is elevated? I'd imagine that a sagging infeed table could cause the problem you describe.

lower the outfeed table

Dick Coers

The easiest method is drop it too much and get a snipe. Then raise it until the snipe just exactly disappears. No measuring, no fixtures. It usually hits the mark very well with this technique.

Tables must be co-planer

Thats it exactly

John in NM

Up til snipe, down til it just disappears.

Keep pressure on the outfeed side.

another thought

Bill Tindall, E.Tn.

If the outfeed table is too high the leading edge of the jointed board will catch and stop. I think the problem is pressure distribution on the board. I find it ever so easy to not remove a uniform thickness when face flattening.

Pressure Distribution

Joe in a Cleveland suburb

As the board moves across the infeed table and more on to the outfeed table, don't you apply more pressure on the outfeed side?

Re: Jointer question

Don Stephan

When I experienced this problem I bought a good straightedge from Lee Valley and brought the infeed and outfeed tables co-planar. Problem went away.

Re: Pressure Distribution

Bill Tindall, E.Tn.

I have a notion that application of force differs for face flattening vs edge straightening. I think the greater lifting force when face flattening requires more pressure over the cutterhead and to the trailing board end as the board end approaches the cutterhead. (a notion is a conclusion weakly supported by experimentation) I think a jointer makes a poor thickness planer for this reason....in my hands.

Fact: if your edge jointing is correct it isn't any jointer set up that is causing your problem face flatening.

Re: Jointer question

Rick Christopherson

Your outfeed bed isn't too high, it is sagging. You can try lifting the far end of the bed and then adjusting/tightening the dovetail gib screws. If that doesn't work, you'll have to shim the dovetail ways.

Re: Pressure Distribution

Barry Irby

I tend to agree with bill on this.

Use a good straight edge to check and see if the outfeed table has drooped. Zero the infeed table and check to see if the the tables are coplanar. If the out feed table has drooped you will need to adjust the dovetail gibs or otherwise bring it back up. Both tables could have drooped. Maybe necessary to adjust both.

Poor technique could have an effect. A dull cutterhead makes getting a fat surface harder. Keep very firm pressure over the cutters. Use push blocks for safety. (Imagine where would my hands be if the board instantly disappeared.) If the stock is not too gnarly you might be able to reverse the board on every other pass and cancel out the effect even if you don't know what causes the effect. That's a work around and may allow you to ignore the problem.

And, a jointer is not really a planer or thicknesser. Use the jointer to flatten one side and a planer to make the other side parallel. If you have a planer does it really matter if the flat surface is not perfectly parallel to the original rough surface?

Re: Pressure Distribution

Brian Holcombe

I get best results when applying light pressure to the front half of a board and maintaining that position until the board has a good amount on the outfeed. At that point I will use hand over hand until the board is finished.

I joint the convex side first, which is not how beginners are taught, so I’m very careful about positioning. In this case I put pressure in the center of the board and avoid rocking.

I work thin stock or very wide boards commonly and so I remove material from the convex side. The convex side is usually the stronger side, so removing material there encourages the board to relax as it is worked. It’s not as intuitive as jointing the concave side first.

Jointing the Convex Side First

Steve Elliott

To end up with a straight board of maximum possible thickness jointing the convex side first is very helpful.

Most solid wood ends up with at least some case hardening, which means the outside of the board is in compression and the center is in tension. This is why most boards will tend to pinch the blade as they are ripped down the center. Removing stock from the convex side makes the board straighten out a bit.

After one face is flat, removing the extra stock from the thicker ends hardly changes the straightness of the board at all. If the concave side is straightened first, removing stock from the middle to get parallel surfaces makes the board become a little curved again.

Maybe...

John in NM

I used to assume that all jointer problems were lack of coplanar beds and spent a lot of time fussing with the adjustment and measurement on a couple of wedge bed jointers (what most of us have). More often than not, I found that height of the outfeed was the real problem - when the last inch or so hardly cuts at all, the outfeed is too high.

Is it too high because the beds are coplanar and it's just above the tangent line of the cutter head, or because the outfeed sag moves it's plane away from that tangent? Doesn't matter - for either one you need to lower the outfeed. Keeping pressure on the outfeed side makes it possible to avoid problems with slight bed misalignment, so long as the outfeed height is good.

Now other problems may come with severe sags, but I think those are quite rare - I've never seen one.

For the most part, I've found that beds don't sag a whole lot. The reason for the success of the ubiquitous wedge bed jointer is that its relatively easy to build compared to a parallelogram or other multi-point bed, and if it is set up to be coplanar it tends to stay that way. A possible exception is a jointer that someone tried to adjust and got off in the weeds, thinking a long aluminum straight edge was more accurate than a big cast iron bed.

I certainly don't know everything about jointers, I only know the mistakes I've made before. One was assuming that the solution to this very problem wasn't simple. Try the simple solution before tacking the complex one - there is no downside to approaching it this way. Just my 2 cents.

Knife wear important

Bill Tindall, E.Tn.

As knives wear the height of the outfeed table gets higher...well not really, but the result is equivalent. Frankly I adjust as John suggests, entirely empirically.

I begin new jointer knives with the fence far right ( I mostly do edge jointing). As this area gets dull I move the fence left an increment. It often takes me several years to march across my 8" machine to where I have to sharpen. I have noticed that sometimes I need to slide fence left and the board does not feed, because I have outfeed adjusted for dull knives with the fence right. So knife wear is significant for table adjustment.....empirically.

That said, if the jointer works for edge jointing and there is a problem face jointing, I'll bet the problem is pressure issues when feeding face surfaces.

I should add...

John in NM

I'm not saying that Rick is wrong per se, just that there is another cause of this kind of problem and the easy solution for both is the same - height and technique.

Some would say that using a technique to get around sagging tables is not as good as fixing the sag, and they would be right. There are a few of us woodworkers who want all their machines perfect, and there are a few others who couldn't care less as long as they can get the results they want by whatever means it takes. The bulk of us are somewhere in between, and accept work arounds when they aren't too burdensome.

I suppose the trick is to have a clear view of one's own goals, and take offered input (such as Rick's vs. mine) at face value, understanding that our goals may well be different, hence the differing advice.

Too low is better than too high

Steve Elliott

With outfeed table height, a few thousandths of an inch make a significant difference. Bill is right that knife wear is enough to affect whether the jointer gives the desired result.

For most stock preparation an outfeed table that is a little low is better than one that is a little high.

A low outfeed table leaves a slight snipe at the end of the board, which is hardly a problem at all if the board is still overlength.

An outfeed table that is too high won't cut straight. The board is lifted slightly by the outfeed table as it is machined and either the trailing end of the board lifts off the infeed table (when feeding pressure is kept on the outfeed table) or the leading edge of the board lifts off the outfeed table (when pressure is kept on the infeed table).

For short boards the effect may not be enough to notice but for longer boards, especially when taking a shallow cut, an outfeed table that is too high is a real problem.

Sometimes when preparing edges for glue-up even a small snipe is a problem and in those cases I raise the outfeed table just enough to ensure there is no snipe. When I go back to general stock prep I often find I need to lower the outfeed table again to get good results.

Re: Jointer question

TomD

You say, Joe, that you have noticed this result. Is it happening with a new to you jointer, or is it happening as your jointer has gotten older, or the blades duller. If it is something that is changing rather than the condition of a new to you tool, I would sharpen the blades first if they are anything other than pretty darn sharp.

I would also measure the tables to ensure they are flat and coplaner. When I bought my jointer, I took a machinist's straight edge, and measured all these different machines I was looking at, and out of about 12, only one had flat tables. Coplaner has been mentioned, but good flat tables, no twists, just perfect are a help.

Re: Jointer question

Joe in a Cleveland suburb

Thanks for all the replies as always.

Regarding coplaner. As far as I can tell the tables are. But I don't have an expensive straight edge to verify. Just 3 different long levels. The outfeed table might have a very slight sag to it. I'm going to look closer at that. I'll have to find something to shim with.

The blades should be sharp. I'll try the trick of lower the outfeed table until I get slight snipe, then raise it back up.

TomD wondered if it was a new jointer. No. I dug out the manual for it and I had the receipt attached to it. I bought it 18 years ago new. So, I have been regretting buying a 6" jointer instead of an 8" jointer for 18 years...

I don't know why I have been having so many woodworking issues lately. Maybe because I am getting older and can't remember from day to day what I'm doing.

Thanks again.

I don't understand the significance of the problem

Bill Tindall, E.Tn.

What is this jointer problem preventing you from doing successfully?

My typical use of face jointing is to get one face planer. Not cleaned up, just planer. If I started the board on the outfeed table so as to purposely cut a taper I don't see how the result would adversely affect the ultimate outcome after thickness planing- a board flat, uniform thickness and cleaned up.

When facer flattening I frequently switch ends, start end up on outfeed table, change where pressure is applied and maybe other alterations to wind up with a planer surface ready for thickness planing. I can not vision any deficiency of jointer set up that would significantly impede this goal.

Edge jointing is another matter. The result is critical. If you are not having edge jointing problems your jointer set up is adequate and look elsewhere to solve what ever the problem is that I don't understand.

The problem is not cutting a wedge because there is no need to plane so much from a face prior to thickness planing that a wedge can become significant. It is not even important that the trailing edge be touched by the jointer if what is in front registers on the planer bed.

Re: I don't understand the significance of the pro

Joe in a Cleveland suburb

I'll re-evaluate what I am doing.

Maybe I'm just over thinking it.

Thanks.

@jonny,

Jonny, welcome. I'm assuming you're referring to hand-held electric planers, like this...

All three brands you mentioned are good ones.

Ellis Walentine