Jointer tolerance

[Phil Thien]

Have you tried moving the outfeed table up/down, clamping/unclamping it, and testing again? I wonder how consistent that .003" is as you move the outfeed table up/down.

If it is very consistent, then I'd be inclined to add a shim (if the design of the jointer will allow it) under the side that is low.

I'd be inclined to use a single layer of aluminum tape, or some brass shim stock from the hardware store. But I really like that tape.

[Chip Lindley]

Tom, if you look at a Shelix cutter head, each carbide insert is held in place by an allen-head set screw. The screw registers the insert. There is no other adjustment other than the tight tolerances built into the design and machining of the head, carbide inserts, and set screws. A cutter-full of bolted-on inserts has no adjustment other than to be shimmed exactly to be parallel with the outfeed table.

As Chris explains above, on a conventional cutter head, we assume the cutter head has been shimmed parallel with the tables at the factory, or after a rebuilding. When mounting knives, each can be raised up/down with jack screws to a desired height, parallel with the table.

Old jointers (before the marvelous jack screws) relied rather on trial and error, even with knife setting gauges pressed down on a spring-loaded knife to achieve exact (sorta) height. Then, the jib screws were tightened to secure the knife.

Very OLD cutter heads had no springs and relied strictly on trial and error to set the knife height! Those MagnaSet gauges are somewhat useful in holding those knives at exact height before tightening the gibs.

During all this knife-setting activity, shimming the entire cutter was not indicated. Only upon initial manufacture, or perhaps after new bearings were mounted, was the cutter head shimmed parallel with the table. Suffice it to say, the cutter head is shimmed (adjusted) only Once! The knives are adjusted every time they are sharpened and inserted.

[george wilson]

Can you put shims under the housing that holds the bearings on one end of the cutter head?

When I bought a new Grizzly 8" jointer for my job before I retired,I noted that the bearings were held in round holders on each end of the cutterhead. There was 1 large screw holding down each of these bearing holders. Very easy to loosen one of the bolts and put some shims under it. However,the grizzly was perfectly aligned already.

I am not familiar with the Lagun. Can it be adjusted like that? I would not want .003" out across the table. That is enough to cause sniping on 1 side of the table. A piece of typing paper is .005".

[Chip Lindley]

Yes George, under the bearing journals is where any shims would go. Different thicknesses, .001" .002" .003" and .005" (shim brass (from a hobby shop) or shim stainless steel (auto supply store) can be cut and placed either side of the bolt hole to raise the offending low journal. It's all trial and error. Sometimes just tightening down the journal bolts will change the height a *thou* or two!

[William Harrison]

Thanks for all the information.

I am a little impatient so I have shimmed one side with brass shim material. When I measure now it's at most .001 off. So I am happy with that. I need to wait for a long straight edge from LeeValley to measure the specs from end to end. So for now a shim works. I will have to wait for a reply back from Laguna to see what they have to say. I am supposed to get a new manual with more guidance on specs and adjustments.

[Jeff Duncan]

If I may jump in and try to help....with a straight knife jointer as long as your infeed and outfeed tables are in perfect alignment, the knives can be set to the outfeed table so that the cutterhead itself doesn't necessarily have to be perfectly parallel to the tables. On the shelix style heads you cannot adjust a knife to make up this difference. So to make the fix one would need to shim the cutterhead itself, or shim both infeed and outfeed tables (not ideal solutions).
If both tables are accurate to each other which is what it sounds like, the only realistic option to me would be to shim the cutterhead. This isn't something I would do on a new machine. Now the caveat is that .003 may be within the allowed tolerances of their machine. This is a very small amount out and not exactly a top of the line machine. Only Laguna can tell you what's acceptable to them. Having said that my 16 jointer is out .002 - .003 along it's length and t doesn't adversely affect anything. See what Laguna says their tolerences should be, then go from there.
good luck,
JeffD

[Rick Lizek]

Tom, if you look at a Shelix cutter head, each carbide insert is held in place by an allen-head set screw. The screw registers the insert. There is no other adjustment other than the tight tolerances built into the design and machining of the head, carbide inserts, and set screws. A cutter-full of bolted-on inserts has no adjustment other than to be shimmed exactly to be parallel with the outfeed table.

As Chris explains above, on a conventional cutter head, we assume the cutter head has been shimmed parallel with the tables at the factory, or after a rebuilding. When mounting knives, each can be raised up/down with jack screws to a desired height, parallel with the table.

Old jointers (before the marvelous jack screws) relied rather on trial and error, even with knife setting gauges pressed down on a spring-loaded knife to achieve exact (sorta) height. Then, the jib screws were tightened to secure the knife.

Very OLD cutter heads had no springs and relied strictly on trial and error to set the knife height! Those MagnaSet gauges are somewhat useful in holding those knives at exact height before tightening the gibs.

During all this knife-setting activity, shimming the entire cutter was not indicated. Only upon initial manufacture, or perhaps after new bearings were mounted, was the cutter head shimmed parallel with the table. Suffice it to say, the cutter head is shimmed (adjusted) only Once! The knives are adjusted every time they are sharpened and inserted.

I've been adjusting and repairing machinery for 25 years and the older machines were the ones with the jack screws along with the machines without jackscrews, Oliver and Crescent, to name two without jackscrews. The spring loaded heads are a much more recent development, SCMI, Delta and many others have this. Setting these heads with the proper tools isn't a matter of trial and error at all. With my Dial indicator and special base I can rapidly, easily and very accurately set knives within .0005'. Some machines had knife jointing capabilities which are even more precise. Some of the high speed moulders have this feature built in. I've measured knife projection of magnaset jigs and those are pretty iffy, easily off by .005' or more depending on the care and experience of the operator.

Nothing wrong with the spring loaded knives on SCMI machines. They were pioneers in making knife setting simple and fast for the average woodworker so they could focus on woodworking and not machine adjusting. The Tersa knife even simplified things more. Dispozaknife is a simple retrofit for older heads to do the same. Insert tooling has been in the industry for years and only in the last few years has it come down to the hobby woodworker.

[Danny Burns]

Thanks for all the information.

I am a little impatient so I have shimmed one side with brass shim material. When I measure now it's at most .001 off. So I am happy with that. I need to wait for a long straight edge from LeeValley to measure the specs from end to end. So for now a shim works. I will have to wait for a reply back from Laguna to see what they have to say. I am supposed to get a new manual with more guidance on specs and adjustments.

Can you let us know how things work out in the end?

Thanks.

[george wilson]

Chip,I am a very experienced machinist. The picture below is a surveyor's compass I was commissioned to make for the late David Brinkley,newsman.I did not know if this model had the ability to have the bearing housings shimmed. I got a Bison 5C collet chuck to run to .0001" after machining a backplate for it in place on the lathe.Then,just by selectively tightening the already very tight 6 socket head cap screws that were holding it on,I got the chuck to run this true. It was about .0003" out when I just press fitted it to the backplate and tightened the screws. The interesting thing was how tight they already were before I tweaked it some more.

William: If you have a decent steel rule,you can tell if the cutterhead is parallel.Put the rule on 1 side of the table on edge,and set the outfeed table so the cutters just graze it enough to move it some when they are slowly rotated. Check the distance the rule is moved on each side of the outfeed table. Adjust the shims until the rule is moved exactly the same amount. If necessary,glue a small block of wood to the end of the rule that is not over the knives to make it stand on edge. As said above,you can get it more parallel probably without adding further shims.

.001" is not much,and you may be satisfied with it if you don't see noticable snipe when you edge joint a board on the inboard side of the table,then move the fence to the outboard side and repeat without moving any other adjustments.

[Simon Dupay]

Use the machine and see if there is any wrong before making ANY ADJUSTMENTS! You may make it worse then it is now. You may not even be measuring right .003" is not very much I use a jointer at work way more out then that and still will give you a good enough edge.

[george wilson]

I just advised him how to make practice cuts.

[William Harrison]

Wow lots of replies. So I am happy with the .001 and would have not made a stink if I had the tolerances for the machine. Since the machine was new I just wanted to know what are the tolerances. So far no call back from Laguana even though I have been told they would call me back and have an email sent to me with the specs. Very annoying that I don't get any calls back. However one nice aspect of Laguana so far is I get a human every time I call, which I have been doing. It's amazing how each time I call they tell me "I was just going to call" or "I was just working on it". Anyway I did not call them back the last 2 days because I wanted to give them some time. I will call them back for more information on Monday.

I like the idea of using a ruler to measure the cutterhead. I will do so this weekend.

thanks again everyone for the education.