Jointer alignment -- tangled in knots

[Ken Cohen]

Hi --

I need some common sense advice -- and apologize for the long post.

I was "lucky" enough to find a lightly used Grizzly G0656 at a great price as my first jointer -- but I am unable to make it do its job either through alignment error, operator error or both. I have read everything on SMC, tried many things and can't seem to make progress. It's times like these where I wish an experienced SMC hand lived down the block who would probably sort things out in 10 minutes. Lacking that, I would welcome some advice on the best plan of attack to bring this beast to life.

I'll avoid all the details, but key symptoms and"fixes" follow:

1. FWIW, jointer seemed to work fine on inspection -- 90 mile truck ride to my house (properly secured, I thought) may have undone that

2. Once home, tried edge jointing and flat boards became bowed. Bought a good 3' straight edge and found infeed/outfeed not conplanar on two axes. Visible to naked eye, not a matter of a .001. Studied this forum, call Grizzly tech support and learned about shims.

3. Spent 1/2 day trying to shim to coplanar state. Unfortunately, infeed side was apparent source of side to side error (vs. cutterhead as reference), so "violated" rule and place shims on infeed side. Improved situation, but never got it dead on. Exquisitely sensitive to gib screw settings. Not stable when raising, lowering. Result: less bowed boards, but still bowed.

4. Knives: next target. Won't bore you with the tale. Had them sharpened. Used the video (forgot name) technique to align with dial gauge. Knives generally .006 lower in center than edges. Tried to force parallism to outfeed by carefully setting screws. Etc. etc (including piece of wood alignment technique). I think knives are close, but not dead on at this point (a couple of thousandths). Still need work??

I'll stop at this point. Bottom line is limited progress. Short boards joint perfectly, Long boards not true (vs. reference and vs 2 jointed boards). I am pretty sure I'm making things worse, not better -- and lack the judgment/experience to fix this.

My question: What is the best sequence to work my way out of this self induced mess? Candid feedback about the possibility of operator error is welcomed.

Glad to answer any questions if that would help. As always, appreciate the help and encouragement of this community.

Thanks.

Ken

[Chris Tsutsui]

If you are only having trouble with long boards do you know if your technique for longer boards is different than with short boards?

Did you use any work support for the long boards because I know my 6" Delta bed wasn't long enough to easily joint 8' boards.

[Steve Jenkins]

First question is where are you. there may be someone close who can help out.
Check to make sure the knives are straight. I had a set sharpened once that during the sharpening got ground down about 1/16 in the center and there is no way to correct that except by resharpening.Take the knives out and lay them on a table cutting edge to cutting edge. You will readily see if the are straight or not.
to check tables use your straight edge and lay it on the infeed table parallel with the table and near one edge (say at the front) with one end above the cutterhead. check the gap between the straightedge and the cutterhead. move to the back of the same table and check the gap. they should be the same. Now go diagonally and do the same. You may have to do some shimming to get things even. To check the gap don't use a ruler. either feeler gauges or if you have a very small gap you can put a light opposite the way you are looking and eyeball it really close. Feeler gauges are better though.
Now repeat on the outfeeed table.
All the above can be done referencing to top dead center of the cutterhead rather than the knives.
Now you can set the knives.
I don't know how you are doing that but it can be one of several ways.
Good luck and don't hesitate to ask more questions if necessary

[John Coloccia]

How are you trying to joint them? It works best to put it with the cup down, i.e. the ends are touching the table and the middle is raised. Then you true the other side on the table saw and joint a nice straight piece if you have to.

Also, don't push down on the infeed table. That will definitely screw you up on longer boards.

Anyhow, that's my experience. YMMV. :D

[Ken Cohen]

Thanks to all for the advice. Seems that bed alignment is the proper first step.

Using my 3' Veritas reference edge and feeler gauge (my "low cost" jointer suddenly more costly), I carefully (1) mapped the beds and (2) tested their alignment to the cutterhead. Three key results:

1. Both beds had well defined dips on the fence side in the mid-bed area of .002 to .005. I don't think this makes a difference on performance.

2. To my great surprise, the outfeed bed -- right at the cutterhead -- is bowed high in the center by ~ .002 -- enough that the straightedge rocks slightly when placed across it. This one potentially concerns me. It's obviously a critical spot -- question is does it matter?

3. Using the infeed as the reference (i.e. straightedge on infeed), the outfeed bed was level at the cutterhead (save for my bump) and low by .006 near the fence (but OK on the other side) over 14". This one seems fixable with a shim to the lower fence side gib.

So, I shimmed the lower outfeed gib, first with my Coke can -- and when that didn't work, a .002 feeler. Result is fence side is dead on, other side has a <.002 gap in the center when straightedge is stretched across both bed. It was late, so I decided this is good enough.

One caveat on the outfeed adjustment: a tiny, tiny turn of the upper gib screw was necessary to get close -- or lose the setting. Should such small changes in the gib screw produce such a big change (raises question of whether these settings will hold)

First, for those who have made it to this point, thanks for your interest and patience. Questions:

1. Am I there (enough with the thousandths)?

2. The .002 "bump" in the outfeed bed at the cutterhead: does it matter? (And, ugh, what would I do?)

3. The sensitivity of the gib screw adjustment: normal? Does it matter?

If all is well, off to knife alignment -- and hopefully some jointing.

Thanks.

Ken

[Barry Vabeach]

Ken, I think you are either there or pretty close. I have seen manufacturers say that the table is flat to .003 ( or maybe even .005 ). I wouldn't worry about any dip less than that. On the outfeed table, I wouldn't be happy with bump that caused the straightedge to rock noticeably. Try using a smaller straightedge so you can precisely locate the hump. If it is in a fairly concentrated area ( say 2 inches by 2 inches ) I would use sandpaper or files to grind it down to level. Again, I am not sure you would have to do that to get good results, but I would do it so I don't run into problems with my straight edge getting tilted one way or the other due to the hump.

[Steve Jenkins]

I wouldn't be too concerned about the slight dips in the tables, just be sure that when jointing don't put downward pressure at that spot on the outfeed table.
The hump I would concern myself with though.
Your point three doesn't address the most critical issue and that is the relationship of the tables to the cutterhead. Put your straight edge on the outfeed table with the end just over the cutterhead not on the infeed. It should be parallel. Same for the infeed. It looks like the way you did the measurement you can't tell if it is the infeed table height ou the outfeed that is throwing you off at the fence side

[Ken Cohen]

Steve --

Thanks for your interest and help. Sorry I didn't mention it, but I used your method both initially and after shimming/cajoling.

After the shimming, the outfeed bed is as close to parallel as I can measure (no gaps across the bed less than .0015) vs. the cutterhead.

The infeed side seems very slightly tilted. With the bar referenced against the cutterhead near the fence, the .0015 feeler gauge slips between the bar and cutterhead in the last 1" of the cutterhead (away from the fence).

In all measurements, I checked to make sure there were no gaps on between the bar and the bed.

This seems consistent with my measurement showing a small (.002) gap with the bar stretched across both beds near the operator side of the cutterhead. And, your technique would indicate that the infeed side is now the culprit.

Hope this helps. I guess the ? is whether it is worth tinkering with the infeed side (shim?) to work out the tilt? And, I'd welcome your thoughts on the "hump" -- whose impact is now below my ability to measure (though it showed up as a .002 dip in the center of the cutterhead in my initial measurement)

Thanks.

[Chuck Wintle]

i am wondering if it would be too costly to have the beds ground flat. The other thing are the gib screws seems way too sensitive in their adjustment sensitivity in my opinion.

[Steve Jenkins]

Ken, bottom line on any woodworking machine is how well does it cut wood. I think you are good to go to set the knives and see how it works. If that slight hump causes a problem then you will have to deal with it but if not it can be ignored. Sounds like you are getting a good understanding of how your jointer is put together which is a good thing.

[Ken Cohen]

To Steve and others: thanks.

I worked on the knives today and got everything pretty close. Initial test passes (what really matters) seem very good, much better than before.

Someway or another, I've introduced a new problem: Jointed faces are perfectly flat except for a repeatable ~3/8" ridge about 2" from the fence. The ridge is a slightly raised, almost corrugated surface. I looked at the blades and nothing obvious jumps out.

Back to the blades for a closer look when I have some time.