Shim jointer cutter head or adjust individual knives

[Gabriel Marusic]

I have a Grizzly G0855 and just measured that my cutter head is off by .006 from each of its sides. It's a dovetail ways jointer so I'm measuring with the dial indicator on the infeed table as my reference. I'm wondering if the better method to correct would be to shim the cutter head itself or just adjust each of the knife blades individually. Thoughts?

[Randy Heinemann]

I'm a little confused about what the described problem is. However, when setting your jointer knives, the outfeed table is the reference point and must be flush with the knives. There is a great video showing an easy to use method for setting the knives on finewoodworking.com but I'm not sure whether you can view it without a current membership. Try YouTube and I'm sure there will be videos out there with similar easy methods.

[Andrew Hughes]

The simple answer is to set the knifes to the outfeed table. If the infeed and outfeed agree with each other you shouldn’t have any problems making flat boards with square edges.
If you had a insert head then one could still make flat boards but getting a square edges to a flat face would be difficult if not impossible.
If you suffer from ocd like me then you’ll need to shim the low side up. It shouldn’t be too difficult if the bearing blocks are bolted though the bottom of the casting?
Good Luck

[glenn bradley]

You want your outfeed to be your reference point. On a knifed machine I would reset the knives before anything else. Thank goodness you aren't one of those guys that starts adjusting his tables before he asks for help . If you have some scrap glass around and some rare earth magnets, a knife setting jig is a breeze. Old glass medicine chest shelves work great. The magnets suck the knives up against the glass which registers off the outfeed table surface.

jointer-glass-magnet.JPG

If there is no glass or thick plastic available you can use a well milled piece of hardwood. Of course if your jointer is on the fritz, how do you get a well milled piece of hardwood. MDF is pretty consistent and could be used in a pinch. With wood you have to recess the magnets into the bottom surface as opposed to just setting magnets on top of the glass. Ideally the glass would be an inch or so narrower than the knives. Grub screws can still tend to nudge the knives but, the magnets allow a quick recovery and re-attempt while loosening and tightening them.

[Gabriel Marusic]

You want your outfeed to be your reference point. On a knifed machine I would reset the knives before anything else. Thank goodness you aren't one of those guys that starts adjusting his tables before he asks for help . If you have some scrap glass around and some rare earth magnets, a knife setting jig is a breeze. Old glass medicine chest shelves work great.

jointer-glass-magnet.JPG

If there is no glass or thick plastic available you can use a well milled piece of hardwood. Of course if your jointer is on the fritz, how do you get a well milled piece of hardwood. MDF is pretty consistent and could be used in a pinch. With wood you have to recess the magnets into the bottom surface as opposed to just setting magnets on top of the glass.

So my infeed table is only adjustable by shimming which isn't practical to do since it's the side that gets moved up and down for cutting depth. That's why I'm treating it as a constant and my point of reference. The outfeed table is actually pretty good in reference to the infeed table but the cutter head is to neither. So I see my options as shim the cutter head (which I've never done before) or just adjust the individual knives. Thank you for the feedback on setting the knives first, that's likely what I'll do.

[Stewart Lang]

So my infeed table is only adjustable by shimming which isn't practical to do since it's the side that gets moved up and down for cutting depth. That's why I'm treating it as a constant and my point of reference. The outfeed table is actually pretty good in reference to the infeed table but the cutter head is to neither. So I see my options as shim the cutter head (which I've never done before) or just adjust the individual knives. Thank you for the feedback on setting the knives first, that's likely what I'll do.

I think you're going about this all wrong. The cutterhead has NO RELATION to the infeed or outfeed table. The cutterhead doesn't do anything related to the jointer's operation. The wood will never touch the cutterhead. Only the knives do, and only they matter, and they are completely adjustable and individually set to the height of the outfeed table. It sounds like you haven't touched them yet from the factory. Just loosen the the knives and adjust them. Easy.

[Gabriel Marusic]

I think you're going about this all wrong. The cutterhead has NO RELATION to the infeed or outfeed table. The cutterhead doesn't do anything related to the jointer's operation. The wood will never touch the cutterhead. Only the knives do, and only they matter, and they are completely adjustable and individually set to the height of the outfeed table. It sounds like you haven't touched them yet from the factory. Just loosen the the knives and adjust them. Easy.

Got it. Correct, I have not touched the knives from the factory. I've only set the tables with a straight edge and am now moving on to the knives themselves.

[Gabriel Marusic]

I'm a little confused about what the described problem is. However, when setting your jointer knives, the outfeed table is the reference point and must be flush with the knives. There is a great video showing an easy to use method for setting the knives on finewoodworking.com but I'm not sure whether you can view it without a current membership. Try YouTube and I'm sure there will be videos out there with similar easy methods.

Incidentally it was Grizzly's adjustment video that made me think about the ask. At just before 2 minutes in they start talking about adjusting the cutter head to the infeed table and I thought why not just the knives?

https://www.youtube.com/watch?v=3caxVqv3FyU

[glenn bradley]

Quick clarification. For a jointer to work correctly the infeed and outfeed tables need to be coplaner to within your accepted tolerances. If they are far askew I would resolve that (as twisted a web as that can turn out to be) before I adjusted anything else. Otherwise you will just chase the problem from one link in the chain to another. So, your target is tables aligned, knives even with the outfeed surface when at TDC, adjust your infeed, and away you go.

[Warren Lake]

sharp knives, set them all the same amount above the cutter head with a dial indicator with a big convex tip on it. That is your reference and starting point. My number .050 to the knife tip above the cutter head. Works perfect on my machines to chip clearance and not too much noise or poorer cut quality

set your outfeed to the knife tips top of the arc from there, I use a dial not wood blocks.

Then the relation of infeed. to the outfeed. Number of details between but those are my set ups.

If you have insert or the fancy snap in and out Terminus or the other one all of those tips are equal above the cutter head. Thats a given on all those knife systems and the same logic applies to high speed steel.

[Bobby Robbinett]

Ok so for starters you want to set your out feed side dead flat to the cutter head using a precision straight edge (around $125 for a 50” on Amazon) and feeler gauges (around $8 at Harbor Freight).

Once your out feed side is dead flat with the cutter head body, raise the out feed all the way up and set your in feed side all the way up and use your precision straight edge and feeler gauges to make the in feed dead flat and parallel to the out feed.

Once that is done your next step is to get a dial indicator with a magnetic base ($24 at Harbor Freight) and use it registering off the out feed side to set your knives just a few thou above the out feed. Once you do that, you are done.

[Gabriel Marusic]

Ok so for starters you want to set your out feed side dead flat to the cutter head using a precision straight edge (around $125 for a 50” on Amazon) and feeler gauges (around $8 at Harbor Freight).

Once your out feed side is dead flat with the cutter head body, raise the out feed all the way up and set your in feed side all the way up and use your precision straight edge and feeler gauges to make the in feed dead flat and parallel to the out feed.

Once that is done your next step is to get a dial indicator with a magnetic base ($24 at Harbor Freight) and use it registering off the out feed side to set your knives just a few thou above the out feed. Once you do that, you are done.

This is actually pretty much what I did down to the harbor freight magnetic base. I didn't do it at full height though, I did it with the tables pretty low. What does the full height do? I can only adjust the tables by shimming so moving after they're set could be tricky.

[Gabriel Marusic]

sharp knives, set them all the same amount above the cutter head with a dial indicator with a big convex tip on it. That is your reference and starting point. My number .050 to the knife tip above the cutter head. Works perfect on my machines to chip clearance and not too much noise or poorer cut quality

set your outfeed to the knife tips top of the arc from there, I use a dial not wood blocks.

Then the relation of infeed. to the outfeed. Number of details between but those are my set ups.

If you have insert or the fancy snap in and out Terminus or the other one all of those tips are equal above the cutter head. Thats a given on all those knife systems and the same logic applies to high speed steel.

I ended up using a dial indicator and magnetic base to set the blades which went well. I previously did the tables with a straightedge but should probably revisit that as well.

[Gabriel Marusic]

Quick clarification. For a jointer to work correctly the infeed and outfeed tables need to be coplaner to within your accepted tolerances. If they are far askew I would resolve that (as twisted a web as that can turn out to be) before I adjusted anything else. Otherwise you will just chase the problem from one link in the chain to another. So, your target is tables aligned, knives even with the outfeed surface when at TDC, adjust your infeed, and away you go.

I previously did the tables and they were with in .003 of each other though I should revisit that. I do wish my straightedge was a bit longer though; my jointer is 72" but my straightedge is only 38". Would that potentially have an impact? Not sure I can justify purchasing a longer straightedge though as I'd be looking at over $100 for something longer.

[Andrew Hughes]

Gabriel check out this instructional video.
Patrick does a good job of covering the basics https://m.youtube.com/watch?v=ob3V5S...&index=30&t=0s
Not trying to imply that the guys here don’t know and cannot give good guidance. It can get confusing because some procedures are hard to describe.

Good Luck