Jointer tune up

[Phancy]

I have an 8" Jet jointer that I bought new about 17 years ago. I am an avid intermediate woodworker that wants to advance my quality of work and make things easier. Not knowing the tolerances of my jointer in the past but checking them recently my infeed table is .015 high on the infeed end farthest from the cutter head, 32" away from the knives, side to side measurements are within a few thousands.
        Will I notice much of a difference of the quality of cut if I correct the tolerance to a few thousands? Is it much of a job to lower the end of the table? I do have good measuring tools and a 8' precision straight edge.
         Thanks for your input,
          Phil

[woodhead]

so what's that, like a 64th of an inch?

0.015625 

Al

[Phancy]

so what's that, like a 64th of an inch?

0.015625 

Al

Yes a 64th of an inch which may cause a convex curve in the center of a long board. That is my question is it worth while to get the table into the recommended manufactures tolerance.

[Phil Thien]

So you used a 5' or 6' long straight edge, clamped to the outfeed table and extending to the end of your infeed table, and have determined that the end of the infeed table is .015" closer to the straight edge than the front of the infeed table is?

The first question I'd have for you is, is your straight edge certified straighter than .005" per foot, because .015" over 36" is .005" per foot and a lot of lower-end straight edges aren't any straighter than that.  OTOH, I know Lee Valley makes some aluminum units they state are straight to .003" over their entire length and aren't all that expensive.

The next question I'd have for you is, if you joint two 6' long boards and place them next to each other, do you have gaps at the ends, and have you measured the gaps with a feeler gauge?

I did have a jointer with a fixed outfeed table (an Inca) and had trouble with a drooping outfeed, which resulted in some problems.  Asked about it here and the resident jointer authority told me it was me (technique), not the machine.  I did find factory instructions for adjusting the outfeed, though, and got better (perfect?) results after the adjustments.  Mine was easy, though, the table was only about 20" long and aluminum.  I literally flipper the unit upside down, loosened two bolts, slipped a couple of shims in, snugged the bolts and I was golden.

Yours is going to be a bit more work, I'm afraid.

[Phancy]

So you used a 5' or 6' long straight edge, clamped to the outfeed table and extending to the end of your infeed table, and have determined that the end of the infeed table is .015" closer to the straight edge than the front of the infeed table is?

The first question I'd have for you is, is your straight edge certified straighter than .005" per foot, because .015" over 36" is .005" per foot and a lot of lower-end straight edges aren't any straighter than that.  OTOH, I know Lee Valley makes some aluminum units they state are straight to .003" over their entire length and aren't all that expensive.

The next question I'd have for you is, if you joint two 6' long boards and place them next to each other, do you have gaps at the ends, and have you measured the gaps with a feeler gauge?

I did have a jointer with a fixed outfeed table (an Inca) and had trouble with a drooping outfeed, which resulted in some problems.  Asked about it here and the resident jointer authority told me it was me (technique), not the machine.  I did find factory instructions for adjusting the outfeed, though, and got better (perfect?) results after the adjustments.  Mine was easy, though, the table was only about 20" long and aluminum.  I literally flipper the unit upside down, loosened two bolts, slipped a couple of shims in, snugged the bolts and I was golden.

Yours is going to be a bit more work, I'm afraid.

Yes the straight edge is certified at .002 over 8', I borrowed from where I work. it is used to calibrate a 4' wide 8 head wide belt sander. 

Yes you understand how I measured the .015 

No, I have never measured the gap. Some of the boards will mate perfectly no gap, others do have a gap that clamps will pull them together, sometimes will more force than i am comfortable with. So none of my glue joints have failed that I know about.

Not sure how difficult it will be to get back in tolerance and if the result will be worth the trouble.

[Phil Thien]

Not sure how difficult it will be to get back in tolerance and if the result will be worth the trouble.

If it were me, I'd be looking for videos on Youtube to see how involved the adjustments might be.

[barryvabeach]

Phancy, many will tell you that perfect it's the enemy of good, and you have good so leave it alone.  If you get a slight Gap in the middle, and it closes with clamps, that is pretty good.  Much better than having it touch in the center and gaps at both ends, in fact that is referred to as a spring joint.   If your machine has dovetailed ways, and you do decide to mess with it, you will need an aluminum can and some scissors to cut shims, or a set of shim material.   It is usually preferable to insert the shim on the outfeed  table, since that is not adjusted as much as the infeed.  If you have parallelogram tables, there are usually a set of bolts or screws that are adjusted to get the tables parallel, and once that is done, you will have to reset the height of the outfeed.   Plan on spending a few hours if you start messing with it, and perhaps using a bunch if cusswords.   Again, it may not be worth the effort based on the results you are getting.

[Strokes77]

I would phrase it this way, hopefully not too harsh...  You've worked for 15 years without a problem.  But now you have a fancy 8' strait edge, and you are finding problems you didn't know you had.

I guess it's up to you if it's worth spending an afternoon chasing this "problem".

[Phancy]

I would phrase it this way, hopefully not too harsh...  You've worked for 15 years without a problem.  But now you have a fancy 8' strait edge, and you are finding problems you didn't know you had.

I guess it's up to you if it's worth spending an afternoon chasing this "problem".

I always knew I had a slight problem but never measured it
This is exactly what I was considering is it worth while to fix,
The WW and others tune there jointers to within .005 or less as specs suggest for best results

[fredhargis]

I'll have to look at mine (same model and age) later, I think there may be 2 bolts under the table that adjust that so it might be easier than you think. But it's cold and i haven't been out to the shop yet. Check your manual, it may show an illustration for those bolts. That said, if it's been working for you all these years there seems to be little reason to screw with it.