What should I expect for cast iron tolerance on new Grizzly 76” jointer tables?

Hey there,

I’m curious if what I’m seeing is below a reasonable level of tolerance on the outfeed table (just the cast iron, not involving cutter heads).

From front-left to front-right on the outfeed table (away from the fence) I get a .002” variation, which is great. From back-left to back-right I get maybe .005”, which I guess isn’t awful? But from front-left to back-right I see a roughly 0.011” scoop in the middle.

Measuring with a 36” straight edge that should be within .002.

I got the outfeed edge within .001 with the cutters from front to back (well, the cutter body, challenging to do on a helical head) using a dial gauge. It’s pretty flat for maybe the first 8-12 inches, then some of that scoop in the middle variance kicks in. I’m not sure how much I should worry about this.

You won't see any difference in any of those tolerances. And since you only know what your straight edge tolerance should be, the measurements might be off a couple thou.

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Originally Posted by Richard Coers

You won't see any difference in any of those tolerances. And since you only know what your straight edge tolerance should be, the measurements might be off a couple thou.

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Ok thanks. I had heard others seeing their tables having .002 tolerances all the way through so I was concerned.

I wouldn't worry about those numbers. I seem to remember something about jointer tables being around a hundredth for tolerance.

I knew some folks who owned a local shop that sold wood machinery (now retired). They said that most of the people that fiddled with new jointers to make them "more accurate" usually ended up making them worse than what they stared with, to the point where sometimes they would have to send someone out to fix them.

Does your jointer have adjustable gibs? You might be able to adjust the gibs to take out some of that dip.

Those tolerances are way off of what I personally consider to be acceptable. Most offensive is the .011” dip. I have a SCM jointer/planer that is flat to less than .002” over the whole surface.

The question to ask is, does it work? If it doesn't work, what can you do about it?

Start by setting the outfeed table even with or just below the knives. Joint a pair of flat 1x4s as long as the outfeed table and offer up the jointed edges to each other. Do that at the right, left and center of the machine. Can you get a tight joint? If not, adjust the outfeed table height in minor increments. If you can't get the results you want, beg, borrow or buy an accurate 6' straight edge and check that the tables are in plane. Adjust them as close as you can if needed and try again.

If you truly can't make the machine do what it is supposed to do, document your findings and talk to the seller. If it is out of their stated tolerances they should replace it. Grizzly has a decent reputation for customer service, but I suspect your machine may be within their standards. In my opinion .011" over 36" on a jointer table is pretty horrible and not likely to result in accurate work, but the proof is in the pudding.

On my grizzly, I'm within about .002 everywhere I can tell (I won't pretend I'm an expert at feeler gauges and a straight edge). I did however find the back left side of my outfeed drops .005 or so. When I'm edge jointing a glueup, I'll usual slide the fence to the middle to avoid that drop, since I generally have to check and resquare the fence every time I edge joint. That said, I've never noticed anything bad from my .005 drop, and I've found more issues are created from bad technique - if I'm not careful about how much (well, little is probably a better word to use) I can end up with a non-straight edge joint, but if I'm careful to just barely guide the wood through the machine and not push on it more than I absolutely need to I get better results.

Why do you think your straight edge is accurate? HAs it been stored correctly so it has not lost that accuraqcy?
Bill D

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Originally Posted by Bill Dufour

Why do you think your straight edge is accurate? HAs it been stored correctly so it has not lost that accuraqcy?
Bill D

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Yeah it’s been hung on the wall in the mountable storage it came in. Also checking against other flat surfaces (cast iron tops and granite countertops) I only see about a .002 degree of variance.

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Does your jointer have adjustable gibs? You might be able to adjust the gibs to take out some of that dip.

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I don’t know what those are to be honest. So I’m not sure if it does. This is the G0858.

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Originally Posted by Kevin Jenness

The question to ask is, does it work? If it doesn't work, what can you do about it?

Start by setting the outfeed table even with or just below the knives. Joint a pair of flat 1x4s as long as the outfeed table and offer up the jointed edges to each other. Do that at the right, left and center of the machine. Can you get a tight joint? If not, adjust the outfeed table height in minor increments. If you can't get the results you want, beg, borrow or buy an accurate 6' straight edge and check that the tables are in plane. Adjust them as close as you can if needed and try again.

If you truly can't make the machine do what it is supposed to do, document your findings and talk to the seller. If it is out of their stated tolerances they should replace it. I think Grizzly has a decent reputation for customer service, but I suspect your machine may be within their standards. In my opinion .011" over 36" on a jointer table is pretty horrible and not likely to result in accurate work, but the proof is in the pudding.

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Sure, I can try that. But for $2500, I have a certain level of expectations. I think I will give Grizzly a call and ask them about this.

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Originally Posted by Myles Moran

On my grizzly, I'm within about .002 everywhere I can tell (I won't pretend I'm an expert at feeler gauges and a straight edge). I did however find the back left side of my outfeed drops .005 or so. When I'm edge jointing a glueup, I'll usual slide the fence to the middle to avoid that drop, since I generally have to check and resquare the fence every time I edge joint. That said, I've never noticed anything bad from my .005 drop, and I've found more issues are created from bad technique - if I'm not careful about how much (well, little is probably a better word to use) I can end up with a non-straight edge joint, but if I'm careful to just barely guide the wood through the machine and not push on it more than I absolutely need to I get better results.

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Interesting. I’ve seen advice to put pressure on the outfeed side once it passes over the cutter head. I’ve not heard people explain to put minimal pressure on that side, although that does make some sense so you aren’t forcing the wood into a position it doesn’t naturally want to be in. I have used that technique with some thin boards on my little bench top jointer I had.

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Originally Posted by Bob Spryn

I don’t know what those are to be honest. So I’m not sure if it does. This is the G0858.

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That is a parallelogram style jointer as opposed to a design with inclined ways with gibs. Each table is supported on four adjustable points so it is possible to make the infeed and outfeed tables coplanar and parallel to the cutterhead. One can twist the tables slightly in this way, but adjusting out a major dip in the length of a casting is not going to happen.

Joint two four foot pieces of wood on edge near the back of the jointer.

Put the two jointed edges together, if you have no gaps, or a few thou gap in the middle, you are good.

Repeat the test in the middle of the jointer and agin near the operator position, if the above is true, no need to start fixing something that isn’t broken……Regards, Rod