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Proper use of a jointer? Help!

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Forum topic by ryno101 posted 12-11-2009 06:32 PM 2265 views 1 time favorited 10 replies Add to Favorites Watch
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ryno101

384 posts in 3132 days


12-11-2009 06:32 PM

Topic tags/keywords: question jointer

I’ve been struggling with using my jointer since getting it, I’m hoping you all can help!

I’ve got a 6” Jet JJ-6CS jointer, and I’m pretty sure it’s tuned properly. I’ve got the height of the outfeed table set to the height of the blades at the top of their arc, the gibs have been adjusted to make sure that the infeed and outfeed tables are parallel, the fence is square to the table, and I’ve got it set to make a 1/32” cut for the most part.

The problem is that as I feed stock (primarily edges, I haven’t tackled face-jointing yet!) through, I get about a 3 to 4” cut on the front, but as I continue to feed it through, applying pressure to maintain contact with the infeed table, the leading edge tends to lift up off the outfeed table, often by as much as 1/8 – 3/16 of an inch. If I apply downward pressure to the outfeed side to keep the stock flat there, it simply raises the infeed side to the point where I’m not getting any cuts.

I’ve tried to keep consistent pressure on both sides, one or the other, directly above the cutterhead, heavy pressure, light pressure, etc, and even when I do get consistent cutting along the entire edge, (usually with softer woods like pine/poplar) I end up with significant snipe along the leading edge.

Help? What am I doing wrong here? I’ve never actually seen a jointer in use, (other than on shows like New Yankee Workshop, The American Woodshop, or the Woodwhisperer) so I haven’t been taught how to properly use it.

-- Ryno http://shawsheenwoodworks.com


10 replies so far

View hammeredon's profile

hammeredon

7 posts in 2605 days


#1 posted 12-11-2009 06:40 PM

Try lowering (it might be raising) your outfeed table about 1/128 and see if that helps.

View PurpLev's profile

PurpLev

8523 posts in 3116 days


#2 posted 12-11-2009 06:45 PM

1. don’t apply pressure above the cutter – that’s the worst machine to get an accident on.

2. pressure should only be applied at the outfeed table after some (~12”) or material has passed the cutterhead. the pressure should not be heavy, but just to keep the lumber flat on the table.

3. if you are getting that drastic cut that it makes the lumber wobble between infeed and outfeed, I’d recheck the cutters are aligned with the outfeed table- which brings a question – how DO you check for that?

if you want, I can stop by sometime to look at it if you don’t figure it out on your own.

and Happy Hanuka!

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View Ger21's profile

Ger21

1047 posts in 2599 days


#3 posted 12-11-2009 07:18 PM

As was mentioned, only push on the outfeed side, not the infeed side. And make sure the edge your jointing is concave, not convex. A concave edge will always rest on the two ends of the board, and won’t do what you’re seeing. It’s much more difficult to straighten a convex edge.

-- Gerry, http://www.thecncwoodworker.com/index.html http://www.jointcam.com

View TomHintz's profile

TomHintz

207 posts in 2866 days


#4 posted 12-11-2009 07:28 PM

Also, keep the downward pressure to a minimum. You can take the bow out of a board while jointing it and when you release the pressure the bow comes right back.
I have a story on using the jointer with video at the link below. This has become one of the most popular videos on my site. The jointer looks so simple but it is VERY techynique dependent.

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

-- Tom Hintz, www.newwoodworker.com

View NBeener's profile

NBeener

4808 posts in 2642 days


#5 posted 12-11-2009 07:47 PM

With any luck, you may find some of this info helpful, too….

Jointer tuning article

-- -- Neil

View ChuckV's profile

ChuckV

2882 posts in 2995 days


#6 posted 12-11-2009 08:04 PM

All good points above. I would make sure one more time that the two tables are parallel. If the tables are low on the far ends, you would see what you describe.

Also, I set the outfeed table just slightly below the arc of the knives. With the jointer unplugged, I place a 1’ metal ruler on its edge with about 8” on the outfeed table. Then I carefully rotate the cutter head in the usual direction with my hand. I want the outfeed table set so that the knives lift the ruler just enough so that it slides 1/8” before returning to the table. This means that the outfeed table is a few thousandths below the knife arc. Also, doing this test on the two ends and the center of each knife is a quick way to check that they are all set properly. I redo this every once in a while as the blades wear.

-- “Big man, pig man, ha ha, charade you are.” ― R. Waters

View ryno101's profile

ryno101

384 posts in 3132 days


#7 posted 12-11-2009 08:21 PM

All,

Thanks… all good advice.

I think I might be pushing too hard?

Sharon: I’m laying my best straightedge on the outfeed table, and rotating the cutterhead to the top of the arc, and adjusting the table height up/down to where the straightedge just brushes the top of the knives.

Gerry: I hadn’t thought about that in particular, good to know.

Tom: Thanks for that link! I can’t believe I haven’t found you, your site is excellent, I’ll definitely be spending more time there learning.

-- Ryno http://shawsheenwoodworks.com

View Kent Shepherd's profile

Kent Shepherd

2718 posts in 2754 days


#8 posted 12-11-2009 08:23 PM

Without seeing it, it sounds like the infeed and out feed tables are not parallel. Maybe something came loose and shifted. If it’s lined up right you shouldn’t have to fight it to cut straight. it is critical that the outfeed side be perfectly in line with the arc of the blade. It’s easy to think it’s right, but be off a hair. This will cause snipe on one end or the other. That really doesn’t sound like your issue though.

-- http://shepherdtoolandsupply.com/

View PurpLev's profile

PurpLev

8523 posts in 3116 days


#9 posted 12-11-2009 08:27 PM

Tom’s site is very useful – read it. the jointer page is dead on.

sounds like you have the cutterhead positioned properly – make sure all knives are on the same height. ideally – when you place a block of wood (straight/jointed) on the outfeed table, and over the cutterhead, and you rotate the cutterhead by hand- it should pull the block of wood ~1/8” backwards…but not get stuck in it.

from the sound of it – I dont think it’s machine setup, I think it’s more learning to use that machine – postures, pressure points, and the motion in the ocean.

Enjoy the learning process :) it’s like riding a bicycle – at first, it’s all new, and nothing makes sense, but once you find that sweet spot – everything will make sense, and work on that machine might actually be fun !

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View Derek Lyons's profile

Derek Lyons

584 posts in 3036 days


#10 posted 12-11-2009 08:35 PM

Sounds like you’re having the same problem I did. The solution is practice, practice, practice… :) Unlike other (power) tools in our collective arsenals, a jointer has no fence or guides to do 90% of the work – it’s all in where and how much pressure you apply.

It sounds like you are applying too much infeed pressure and too much pressure overall.

-- Derek, Bremerton WA --

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