Jointer setup, poor cut quality

[Dave Westover]

Im setting up an older craftsman jointer and am running into trouble with the cut quality. I aligned the tables and installed new knives as accurately as possible. A few test cuts edge jointing pine and hard maple, and it seems to be either tearing out against the grain, or chattering with the grain. Im only taking 1/32 a pass. What would you folks suggest possible causes might be?

I will triple check my table and knife alignment tomorrow, but the cut quality is so bad Im thinking I might be missing something else. Bearings are ok and not too much vibration on the tables. The fence rattles like the tailgate on my pickup until I press the stock against it. Any thoughts?

Thanks for any input.

[Joe Jensen]

Please don't take this the wrong way, I'm just brainstorming. Are you sure the knives are facing the right way? Sounds like they could be in backwards?

Do you have a good step by step set of instructions in adjusting them?

[Dave Westover]

Please don't take this the wrong way, I'm just brainstorming. Are you sure the knives are facing the right way? Sounds like they could be in backwards?

Do you have a good step by step set of instructions in adjusting them?

Yep, pointy side out just like the picture :D

[Paul Atkins]

Were the blades sharpened? You said new blades, but not every new blade is sharpened well. Got to be able to shave with 'em. Take a smaller cut and see what happens. What is the speed of the head? Slow turning will cause what you are describing too. Is the belt tight? Is the belt shot? A bad belt could cause the vibration. One more thought - Are the pulleys tight on the shafts?

[Tom Hintz]

The jointer looks so simple but really is one of the most technique-dependent machines we use in woodworking. But, it has to be set up perfectly to start with, something that can be touchy on a good day.

You can get that kind of poor performance by one knife being a tiny bit higher than the rest, one or more knives not being level with the outfeed table or you feeding the stock in against the grain, something just about all of us have done by accident more than once.

I would start with your initial thought, going back over the knives. Sometimes taking a break and going back is the best thing you can do. If the knives are aligned right try reducing the cut depth just a tad but slowing your feed rate. You can get a ripple effect on the wood by just feeding it across the knives too quickly.

See the link below for a story I did on the basics of setting up and using a jointer that addresses the most common questions I get through my site. Don't feel like the Lone Ranger here, a couple hundred thousand others have been asking these questions over the years which is why I wrote the story in the first place!

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

[Dave Westover]

Were the blades sharpened? You said new blades, but not every new blade is sharpened well. Got to be able to shave with 'em. Take a smaller cut and see what happens. What is the speed of the head? Slow turning will cause what you are describing too. Is the belt tight? Is the belt shot? A bad belt could cause the vibration. One more thought - Are the pulleys tight on the shafts?

Sharp as my last set I guess, also from holbren. The speed is something I will look at tomorrow. It seems slower than my other jointer. The motor runs at 1720 but the drive ratio is higher. I havent measured the pulleys (surely not original) because Im not sure what it should be running at. I cant find any info on this jointer anywhere. OWWM has next to nothing. What speed should I be shooting for? Ive got a few pulleys I can swap but Id like to have an idea what speed is at least acceptable, if not ideal.

I checked the pulleys when I got it and they are fairly straight for steel pulleys, and tight. I will take the link belt of my ts and see if that helps.

Any suggestions on head speed is mucho appreciated.

Thanks

[glenn bradley]

How about a model number or a pic? I think we are all assuming a dovetail way jointer as opposed to a p-bed machine. When adjusting the tables for co-planer, what did you use for shims? Generally, brass sheet or even a cut up coke can is fine but tape or paper materials are not as they fail more quickly. If it is a DT way machine, this (http://www.taunton.com/finewoodworking/FWNPDF/011079062.pdf) may help even though it shows using paper as a shim(?).

[Rick Fisher]

The cutterhead should typically turn at 4500 - 5000 rpm. I would check that first.

Its probably something in the drive line, between the motor and the cutterhead.

[Jason White]

Hmm... I'm not convinced you've got them in there right either. Pointy side out is one thing, but which way is the bevel facing?

Can you post a picture?

Jason


Yep, pointy side out just like the picture :D

[Chip Lindley]

One more thought besides all mentioned (I think) so far. Although the bearings seem to run smooth, the journals they fit into could be worn. This would cause erratic behavior under load. Check for any slop where the bearings fit into the cast iron.

Some are worn so badly that shim stock is needed to fill the *gap*. TiteLoc bearing compound can be used to afix the bearings with or without shims.

[Jeff Duncan]

There's a lot of good advice here but I would say start out with the most likely which is the knives. There are mechanical things that could be the culprit, but I think that's jumping the gun a bit. Make sure your knives are installed correctly and in good alignment. Tables and/or fence being out of whack shouldn't cause the problem your describing so don't go messing with those yet. It's either a knife problem or less likely a bearing problem.
I also don't think it's speed related as if that was the case simply slowing your feed rate would improve the quality. So again, before you start calculating pulley sizes and trying to re-engineer an entry level machine, make absolutely sure your basics are covered....the knives:D
good luck,
JeffD

[Dave Westover]

Thanks for all the input folks. Knives were ok, tables ok, belt wasnt a factor, and Im out of time and patience. Im not at all happy with it but slowing the feed rate waaay down produces a good edge. All I can think is dull knives or its "geared" too low?

I might have the knives sharpened after this project Im on. Or not. If I dont deserve a new jointer, who does? ;)

[Tom Hintz]

If you are jointing just the narrow edge, move the fence to different positions across the knives. Very often one spot will be much duller than other places across their width because people tend to leave the fence in one position and essentially wear out the knives in that spot.

With what you have discovered so far, I also would think about changing the knives out or having the current one sharpened by someone that knows what they are doing.

The gearing thing would be very odd though not impossible. I have seen some "expert" advice on forums that said reversing the pulley positions would improve performance somehow. As you might suspect, the folks who design and build jointers have a whole different take on that bit of advice....

[Dave Westover]

If you are jointing just the narrow edge, move the fence to different positions across the knives. Very often one spot will be much duller than other places across their width because people tend to leave the fence in one position and essentially wear out the knives in that spot.

With what you have discovered so far, I also would think about changing the knives out or having the current one sharpened by someone that knows what they are doing.

The gearing thing would be very odd though not impossible. I have seen some "expert" advice on forums that said reversing the pulley positions would improve performance somehow. As you might suspect, the folks who design and build jointers have a whole different take on that bit of advice....

I didnt feel or hear it bog down, but i wonder if its a power issue? Im surprised to find new knives cutting poorly so it makes me think the problem is elsewhere. Either way, I will have the knives sharpened after this project and go from there. Not knowing where the problem is truly aggravates me. Thanks again.

[CPeter James]

Are you sure the knives are not in backwards? All of you symptoms point to that. The bevel should be on the top as you turn the cutter head. If they are reversed, the action will be a scraping, not cutting and give exactly the results you are getting. They should look like this.

CPeter

http://home.metrocast.net/~cpjvkj/cutterhead.jpg

[Tom Hintz]

I didnt feel or hear it bog down, but i wonder if its a power issue? Im surprised to find new knives cutting poorly so it makes me think the problem is elsewhere. Either way, I will have the knives sharpened after this project and go from there. Not knowing where the problem is truly aggravates me. Thanks again.

I just got it through my head what kind of jointer we are talking about. The key issue would be the age rather than being Craftsman, though poo-pooing it just on the nameplate is more fashionable.... I wonder if the motor isn't just tired. I have seen a few older machines that while not used heavily, suffered from the years of sitting around to the point that new motors were needed to "freshen" them up.

Before you do anything, check the knives against the diagram CPeter sent. You would not be the first to find them in backwards.

[Kyle Iwamoto]

My .02.

The fence rattling "like the tailgate of my pickup" would indicate to me that either or both of the bearing sets are toast and wobbling/vibrating. If that were the case, you could have a helix cutterhead and still get tearout. In that case, no matter if the knves are dull, broken, razor sharp or backwards. You won't get a good cut.

How old is it and how much do you have invested? Ridgid has a great cheap 6" jointer for about 400 bucks. No, it's not as good as a Delta or PC, but the price is low. I can't balance a nickle on edge, but it's pretty smooth.

[Jason White]

Is it wired for 110 or 220? Might do better with 220.



I didnt feel or hear it bog down, but i wonder if its a power issue? Im surprised to find new knives cutting poorly so it makes me think the problem is elsewhere. Either way, I will have the knives sharpened after this project and go from there. Not knowing where the problem is truly aggravates me. Thanks again.