Thread: Edge Jointing Problem

Originally Posted by spartan

Many thanks to all for the advice so far. The hardest part about seeking help in this way is explaining yourselg accurately. Ive been a bit of googling and have come worked out that rather than describing the issue as a board with a 'slope', i should be calling it a taper.

Its not convex or concave.

Hi Spartan

I understood that you meant you have ended up with a taper. My comment was related to the cause for that. That is where the timber may be uneven to begin with such as being higher in the middle (convex) or lower ( concave). In these situations you can't apply all the pressure on the leading table as you have been doing.

Originally Posted by TP1

Hi Spartan

I understood that you meant you have ended up with a taper. My comment was related to the cause for that. That is where the timber may be uneven to begin with such as being higher in the middle (convex) or lower ( concave). In these situations you can't apply all the pressure on the leading table as you have been doing.

got ya...

I found this.....
Why a Jointer Tapers - NewWoodworker.com LLC

That is a very good link, but what NOTY was saying is correct.

The jointer fundamentally needs the cutters to be topping out level with the outfeed table, otherwise the relatively simple job a jointer does becomes a more complicated situation where the work is "resting" on the cutterhead in the cut. So - definitely worth checking.

I think you have a jointer/planer, so unless I misunderstand the problem the standard approach would be to jointer one edge, then use that face down through the planer to get the other edge parallel.

Apart from that 'though, given that it is giving you at least good straight edges, you can use this as a learning opportunity.

I suggest taking one of the tapered pieces and trying to get it closer to parallel (using the jointer) just for the practice. Nothing says you have to run the entire piece over the jointer, so you can either start with the wider end and put 6-12 inches over the jointer before removing it, then a bit more, then the whole thing - which will end up taking more off the wider end than the other.

Alternatively, depending on the grain, you would have the piece with the thinner end sitting on the outfeed table and lower the piece onto the blade to then joint just the last section, then last two-thirds, then all.

Have fun with it

Paul McGee

Originally Posted by spartan

got ya...

I found this.....
Why a Jointer Tapers - NewWoodworker.com LLC

Thanks for the link Spartan. However I do not accept , as it appears to be suggested in the article, that tapers are unavoidable. I take the view that if the sides were roughly parallel to begin with, any taper that results is due to technique. That is assuming the jointer is set up correctly.

Knowing this, I still recently managed to induce a taper along the edge of one shortish board which became useless as a result. That was with a perfectly set-up jointer. The board was originally a bit higher in the middle than along the edges and I realised I had used too much downward pressure on the outfeed table to begin with. The pressure at the front caused the jointer to remove timber too early. Now the taper could have gone the other way had I done the opposite with that board.

I am a lot more circumspect these days. I know some guys who rip a straight edge with a sliding table saw to avoid this issue.

Well, ive learnt a heap so far from this thread.
I pretty confident that the jointer/planer setup is OK, having run through the tests above - its pretty new Jet JPT 310. So I need to concentrate more on my technique.
I get the sense from has been posted im pressing down in the right place and right time (i.e, outfeed table) but probably too much pressure.

I've also seen on a couple of blogs people recommending fliping the board in two multiple (or even numbered passes).

There are heaps of videos on Youtube, and it can be good to watch as well as read about something.

I remember one on the jointer that I really liked, and I think put a link on th forum in a thread ... but I'd have to dig to find it again.

There are also videos in this forum ... (https://www.woodworkforums.com/f101/)
And a quick look, I saw:

https://www.woodworkforums.com/f101/s...r-video-62051/

and

https://www.woodworkforums.com/f101/g...-basics-40903/

Just on the first page.

Cheers,
Paul.

Not much to add. The jointers only job is to make things straight and flat ( can be made to do other jobs ), a reference point for the thicknesser bed or the saw fence. 3 or 4 20mm boards can be sent through the thicknesser on edge as a gang. Grip them all together at the ends as they go in and grip the other ends as they come out. Viola.!. S4S.

Also very good, even if he is American ... TheWoodWhisperer

[ame=http://www.youtube.com/watch?v=M-ZZ0dhbJYY]Woodworking #6 - The Jointer's Jumpin' - YouTube[/ame]

Originally Posted by pmcgee

Also very good, even if he is American ... TheWoodWhisperer


Woodworking #6 - The Jointer's Jumpin' - YouTube

Mate, is that a go at me? Don't worry, I'm heaps used to it. I've spent almost half my 64 years here. Aussie by choice, just a part of the multicultural warp and weft of the great wide brown land.

What an excellent thread, with years of valuable experience made available for us beginners to learn from.

I never knew you could push down too hard on a jointer - In my limited usage of a jointer, I always press heavily on the outfeed table just after the blade cuts the timber - I always thought that you would get the same thickness of cut along the length of the timber by doing this. I have seen nothing in the comments above to explain why this technique would cause tapering

Very timely thread, as I am about to have a go at edge jointing timber ( after I pass it through a jointer) for a round table to fit on a lazy susan. Will have to have a play and check for tapering on the 700mm long boards I will be using

Some more on the pressure thing.
When I take a piece of wood to my jointer I am attempting to change the shape of that piece of wood with the cutter blades and tables only. To do this successfully I need to present the machine with a relaxed, if out of true piece of wood. When completed the wood needs to be able to be used in that same relaxed, but now true, state. If I distort the wood as I work by applying pressure here or there I will not get a flat result as the timber will spring back, however so slightly, to that previous relaxed state.
Enough weight to feed and stop bounce or kickback is all that I need. Any more means dulling blades or cranky grain and that's countered by more pressure from the end of the board, not so much down. You play each piece as you joint it. I always work with the concave side down to avoid any rocking. Sometimes that can't be done (going round a fault etc). Then I start in the centre of the board and go carefully.
Grab some twisty scrap and practice. Then get some more and go again. After a while you may find that you are "seeing" the board flatten in your minds eye as you work and it will be. Your in tune with the jointer. Then you can pick up that piece of twisted figured maple in the corner and use it.
So I'd start lightly with the pressure.
Cheers, Tony.

excellent advice. thank you.

Thanks Tony, sounds excellent advice, will give it a go.