Jointer Question

[callee]

Hey guys. Just a quick jointer question.

As I posted earlier, I recently received my Christmas present early -- a ridgid jointer.

I was pretty excited, particularly since I'd never had a jointer before.

I have a quick question now about performance.

When I read the manual before using it, I noticed that in the trouble shooting section it talked about how sometimes you might get "ripples" on the surface, and that the problem was likely one knife being set higher than the other. I doubted that this would be a problem, though, since all the reviews I had read had stressed how the ridgid came perfectly set up and aligned right out of the box.

when I ran my first batch of wood through, however, I was surprised to find a distinctly rippled surface.

I quickly discovered, however, that if I ran the piece through again, feeding it a lot slower, that the ripples disappeared and the surface was smooth.

I decided then that the problem must have simply been that I was feeding too fast.

But then latter I started to rethink (overthink?) it, and wondered if maybe one knife wasn't set too high after all, and by slowing down the feed rate I was simply giving that knife enough time to get back around and make the next cut; in other words, the surface was smooth because I fed slow enough to let the high knife do all the work.

My problem here is inexperience: I don't know enough about jointer performance to be able to tell if the problem is with the blades or my feed rate. Good thing I have your collectively huge pool of experience to tap into, right?

So please, help me out here, what's your thoughts?

[Mark in Ottawa]

I'd think one knife is too high, although you do have to use a moderate feedrate. Best thing I've found to do is use a dial indicator on a magnetic base and test all the knives - that way you know for sure that one isn't slightly higher than the other two.

There is a video somewhere on how to do just that...I'll go check for the link.

Edit - here's the link: http://video.google.com/videoplay?do...arch&plindex=0

Just my $0.02.

Mark

[Egon]

Suggest you check the blade height.

Did you use much down pressure?

[Al from Brooks]

With out doubt there will be ripples after running a piece of stock through a jointer or thickness planer. Even one finely tuned. The finish is good enough for a glue up, and you can use it for a finished surface if thats acceptable to your standard. If not, you still need to hand plane or sand.

I question the machine being "set up out of the box". Factory tolerences are not nearly as fussy as I would like, typically. And the set up guy at the factory could probably careless if it's out a tad. As tedious as it is, I'd reset the knives myself. First time you'll spend a good part of a day due to learning curve, but after that it will be faster. Besides, you will eventually replace for a sharp set.

Very best,

Al

[stevem]

i wouldnt depend on the factory setup at all, check the knife height carefully, at some point you will have to remove them for sharpening, so best to figure out the setup now anyway

its not difficult, just time consuming

i remove my jointer knives, hone them and reset them about once a month and it takes about three hours including honing

at one time you could remove the cutter head and ship it out for honing and resetting, but those days are gone!!

[Don Kondra]

It takes about two minutes to check the height of the knives.

Unplug the jointer and drape the cord over the infeed bed so it is clearly visible it is unplugged

Place a straight stick of wood on the outfeed table and rotate the cutterhead by hand, preferrably from the back pulley.

Ideally each knife will make a slight knicking sound as you rotate it past the wood.

No sound, too low. Drags the wood forward, too high...

The knives are relatively easy to adjust using the jack screws. Just back off the bolts till they are snug and use the allen key to adjust the jack screws.

Cheers, Don

[hwgill]

I got some new knives yesterday to install into my jointer, and these ones for some reason are not setting well. I finally have a height setting gauge from LV, and measuring from one side of a knife to the other, they are out (end to end) by 2.5 thou...I'm thinking that isn't close enough. How close is close enough? and how do I adjust for such a small amount?

[charlton]

Agree with Al. Think about how a jointer/planer work and you should see that you're ALWAYS going to get ripples. Whether those ripples are really detectable is another matter. How much ripple there is, will depend on your feed rate. If one blade is set too high, then it's going to take a bigger chunk out of the wood 1/3 of the rotational time (hence the ripples) and this would make the ripples even more apparent.

[dutchie1979]

It doesn't matter if all the knives are setup perfectly to within .001" of each other the ripples will always be there. It all comes down to how fast the board is fed through, and this will determine the chip lead on the knives. The higher the chip load, the faster the board is fed the bigger the ripples. This principle is the same when it comes to metal machining, when we are roughing the finish does not matter so the chip loads are high, and when we want to finish the part and make it look good, we reduce the chip loads to make it look pretty.

Hope this is clear as mud, but in the end the knife height will not effect the ripple effect you are getting, but as the other people suggested checking the heights wouldn't be a bad idea.

[Tom Hintz]

We have dealt with this very question a bunch of times and even spoke with jointer designers. It can be a high knife, or too fast of a feed rate or some of both. The fact that the ripples went away when you slowed the feed rate down kind of limits the high knife theory but check them anyway. Being sure about the knive settings is a very good habit to get into. If they are all at equal heights, work on your feed rate. As you have seen, slowing it a little can get rid of the ripples.

I have a story about the jointer at the link below if a bit more info might be of help.

http://www.newwoodworker.com/basic/usejntr.html

[Blaine in Kitchener]

I agree that with the situation you describe it is most likely feed rate. I tend not to worry too much about the feed rate and ripples on the face since the faces will be run through the planer which seems to do a better job of leaving a smoother surface (likely because of a constant feed rate and higher RPM on the cutter head). Where you do have to be concerned about ripples and feed rate and depth of cut is edge jointing. I like to do my final passes before glue up with a small depth of cut and a very slow feed rate to get the smoothest surface possible to get the best glue line possible.

Blaine

[astewart]

I think that this one was posted before (maybe by me ) but I use it and it did solve some issues on my 8" on surface flattening.

http://www.finewoodworking.com/ToolG...e.aspx?id=5294

I use a pretty slow feed rate (it isn't a race) but also notice the feel of an aligned jointer is smoother and when a knife is off it has a vibratory feel.

Good luck (and hope this helps a little).
Alex

[Gene45]

My jointer does not have any jack screws so setting is a bit more difficult. I use a steel straight edge, adjust the tables to the same height, and rotate the cutter head by hand. If the blade does bit reach the straight edge, it is too low. If it moves the straight edge, it is too high.

[hwgill]

I always wondered what those screws were for on the cutter head...now I know, and was able to adjust my knives to within .001".

[Grillzy]

Callee- slow down! Just feeding too fast. If you push way to fast then you will get big ripples which will bump up and down on the lower rollers of the planer and then the planer head will leave the same ripples
Grillzy

[callee]

Thanks for the advice everyone! I checked my blade heights as described, and they both appear to be perfect, so I agree, it must have just been my feed rate. I was doing some milling last night and I went nice and slow, and the results were perfect, so I think I'm all good!

Thanks!

[dan]

thought you wern't supposed to open that till xmas, wife couldnt get to sleep with all the whining

[callee]

ha! actually, she told me I had to make shelves for the baby room!

[stevem]

you'll like having a jointer callee, its far easier than fiddling with planer sleds for jointing rough lumber and the knives are far easier to sharpen

i rarely run rough lumber through my planer, the knives are way too pricey and cant be sharpened(DW735), i joint an edge, saw to width, joint flat, saw to thickness, then off to the planer with nice clean lumber

there was an excellent series in popular woodworking on various power tools a while ago, including an article on safety, usage and maintennce of jointers, an excellent read. if you cant find it, i can for you

[hwgill]

I usually do the same (I like the 735, and it's ease of changing blades, but $70 for knives and they can't be sharpened...it is expensive). Joint the edge, flatten if it's 8" or under (over 8", rip to rough width and then flatten), then plane only one side. I'm now on the first side of my second set of knives, and have had the planer for just over a year...but the cedar really killed the knives. I had always wondered why such a soft wood as cedar was so harsh on blades and knives, then when I found out why, it totally made sense.