What am I doing wrong when using a jointer
Hobbyist86
| Posted in Power Tools and Machinery on
As you can see in the attached picture either end of this ash rough cut lumber, is thinner than the middle. This is an issue I keep running into. Has anyone run in to this problem and how do I change my technique In order to prevent this.
My technique is I do a pass through and I turn the piece so the end that was last cut goes through first. My idea is that would cancel out any errors am I wrong?
Replies
No photo... and it sounds like you are talking about a planer?
i added the photo, it is a planer I'm using its a craftsmen one from the 90's everyone seems to have.
I think you probably are referencing a jointer sold by Sears in the 90's. Though I am seeing no photo of the machine.
Is this what you have?
That is the one.
This thread is getting confusing. Is it a planer or a jointer they are two vastly different tools and accomplish different tasks but are most useful when used together.
The picture I see appears to be a board that was edge jointed and you seem to be cutting uneven. Since you were turning the board on each pass(not a good practice) we don't know if the leading edge or trailing edge is cutting deeper. Regardless the problem probably lies with you machine setup not your techniques.
More than likely your tables aren't co-planer. Since I'm not familiar with your jointer I can't help you with the procedure but I'm sure you can find some help in the archives. There are three key settings you need to maintain on jointers, tables need to be parallel, the fence needs to be square to the tables and the knives need to be set to be at the height of the outfeed table when at top dead center. I tend to buy professional tools but my feeling is hobbyist level tools like Craftsman tend to be more prone to coming out of adjustment and will need to be check more frequently
You tables are not co-planar.
The free end of the infeed table is above the cutter end of the infeed table, from the perspective of the outfeed table.
This means you push the end of the board into the cutter, digging a piece ot of the corner, then that end rides on the outfeed table, feathering out the snipe. Repeated cuts slowly exacerbate the issue.
If you get a dip in the middle of your boards, the infeed table is 'drooping' a bit.
How to fix this will depend on your machine, but will like as not take some considerable time - make sure that you set a couple of hours aside!
https://www.finewoodworking.com/2018/07/30/ep-3a-machine-setup-jointer-part-1
Good luck.
Not all is lost. You now have a nice clamping caul.
There could be a few reasons why this is happening.
1. Least likely, but also still entirely possible (and most difficult to remedy depending on your jointer...) Your tables are not coplaner - meaning that they are out of level with each other. While the infeed is obviously a bit lower than outfeed, they do still have to travel in parallel with each other. If one is out slightly, it'll throw off the ability to make straight passes, and you do end up with those bows. This can be shimmed or adjusted depending on what kind of jointer you have.
2. Second most commonly, your knives are too low. I have have come across this on multiple machines. It's easy to spot if you know what to look for though. In the worst cases, the knives are below the outfeed. If this is the case it's easy to feel because as you slide the wood along you'll feel it make contact with the outfeed. More often people assume that their knives need to be dead level with the outfeed table, but in reality they need to be just a bit higher. Not alot, but enough that if you laid a ruler from a combo square on it's edge and spin the cutter that the ruler will get picked up and moved about 1/8-1/4" forward before dropping back down. There's lots of information online you can find about how to do this trick.
3. Most commonly, your technique is off. Always make sure that you're putting the pressure on the outfeed side of the table. Once you have one end past the cutter you need to start using that as your reference face. Not pushing down so hard as to flex the board, just firm enough that you keep that end flat on the outfeed side. If you are putting more pressure on the infeed side you'll get that arc. Especially if you're going from pressure on one end to the other back and forth during the cut, as can often happen as your adjusting hands to push the board across the jointer.
Also, I don't recommend swapping end to end across your passes... You want to joint with the grain and stick with it. Also, when edge jointing it is important that you have a flat, jointed face. That face needs to reference off the fence in order to get a true square edge. That's another reason not to be flipping the board. You're going to get inconsistencies. I don't think that's the reason why you have such cupping, but it's not helping and certainly could be exacerbating it.
It's also likely that you have more than one of these things going on! First thing, check your knives height. Try the ruler method on there and make sure they're high enough. Check to make sure your tables are coplaner. And check out some videos on proper jointer technique. Chances are that if you're not sure you're doing it correctly, then there's a good chance your not. A jointer is a simple tool, but it still requires proper technique otherwise you will not get the desired results!
Good Luck!
In the interest of trying to help a new woodworker learn the right way. I am going to disagree with some of the advice you have given based on my 40+ years of Woodworking both as a hobbyist and professionally.
First the tables being non parallel is the most likely cause of his problem not the least likely.
Second setting knife height before determining that your tables are parallel is a waste of time.
Third while you are correct about the ruler trick, if you ruler is moving 1/4" your knives are way too high. I aim for somewhere between 1/16"-1/8" of movement when setting the height of my outfeed table.
Lastly as for technique, you are correct he should not flip the boards on alternate passes and grain should be the only determinate of which direction to go, but the fact that he did implies a misunderstanding of what a jointer is designed to do. A jointer does not make opposing faces parallel, that task is reserved for the tablesaw and planer, all a jointer does is flatten faces prior to planing and straighten and square edges prior to ripping. It is a tool design to true wood for finishing on other tools. Given the small size of that particular jointer it also is very limited even in doing that. A good rule of thumb is a jointer can straighten boards no more than twice its length so with that jointer maybe 5'. There is a reason profesional jointer are so long because only long tables can truly flatten long 10' boards. That brings me to another point you made regarding putting pressure on the outfeed side, that is probably 60% true, but going back to what a jointer does, straighten boards, if I have a board with bow I will take several passes where I will not remove any wood for a foot or two as I joint out the bow not putting any pressure on the outfeed table until I hear the blades engage the wood for at least 6 ". If I were to rush to apply pressure on the outfeed side I would simply be cutting the same bowed profile along the length of the board and it would take much longer to achieve a straight edge.
The reason i suggested checking knife height first is that it's the easiest thing to look for, and I have seen it not set properly on multiple machines. I agree though that if your tables are not coplaner then it's a moot point. Just that I've seen the knife height issue a lot, especially on this smaller hobby jointers, and like i said... it's easy to spot and fix as a starting point. Not saying not to check for coplaner, just start with the easiest thing to diagnose and fix.
In regards to the ruler method, that's a matter of personal preference although it is pretty common practice to fall within the 1/8 to 1/4. Higher than 1/4 is too much of course... I would agree that 1/16 is tolerable but that's getting a bit low to account for spring back.
As for technique, I think we're pretty much in agreement there.... I certainly did not state explicitly about not doing this until you start getting contact, but you are correct. Nevertheless, I DO think that this is the most common problem when starting out at the jointer, which is why i suggested following up on proper jointer technique online in videos where he can get much better and clearer advice than can be given on a forum.
Cheers!
I'm still not convinced it is a jointer. He says "pass through" in the OP.
Please post a photo of the machine for us?
its a jointer, maybe I should have said pass over the cutter head.
I don't believe Sears sold a planer in the 90's. The jointer they sold during that time was referred to as a jointer/planer ( picture in my earlier post).
Furthermore, I thought posts on this forum regarding jointers were not allowed.
Good advice by Eideann.
One last thing.You also must be sure the two tables are in the same plane as to their width.This can be checked with winding sticks or running a dial indicator along one table with the point running on the other table
Yes unfortunately you are very wrong about this whole idea. I would stop woodworking immediately if I were you or you are going to really hurt someone.
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