Update on adjusting jointer knives

I fooled with that thing for several hours. I have two blades adjusted to about .002 above outfeed table. One blade is at 0. SHould I try to get that last blade to .002 also or knock down the two at .002 to zero. It is very hard to get everything exactly the same on three blades.

Or will the difference be negligible the way it is?

Reply to
stryped
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Seems to me that adjusting one blade to match the other two would be easier than adusting two blades to match one....

Reply to
Locutus

Reply to
stryped

Why not give it a go and see how it works? Might find it "good enough".

In general must agree w/ Locutus it's easier to fiddle w/ one than two...I reiterate previous recommendation that w/o the adjusting screws it will undoubtedly by easier if you've tightened them down to bring the one back up a little high and tap it in than get it out by only a thou or two.

The thing about the height relative to the outfeed table is, yet again, the point in having the height adjusting screws on the cutterhead itself. Get the knives consistent, then make some test cuts and, if and only if needed, then adjust the cutterhead height. Again, this is how the manual instructs.

Reiterate yet again, however...woodworking isn't machining, and obsessing over precision isn't productive. The point in having the machine should be to use it (although there are those who seemingly never do get around to actually ever making sawdust---you may be one. Whether that's your objective, I don't know).

Reply to
dpb

hey, go for it. get them all the same.

now, whether your machine will cut straighter at 0 or at +.002 only you can determine, and only by careful testing. so, with the machine as it is, make a pass on a known straight board. label it 0,+.002,+.002. then adjust the 0 blade to +.002, make a pass on a known straight board and label it +.002,+.002,+.002. then set them all to 0, make a pass on a known straight board and label it 0,0,0. for significant results, you will probably need to make multiple samples at each setting to average out for variations in the stability and density of your boards. also,make boards of different lengths....

now set up an accurate test station to determine straightness. if you get meaningful results, including things like (no difference),(high blades cut concave),(high blades cut straight),(low blades cut convex),(low blades cut straight),(other), let us know.

now, go get going, now....

Reply to
bridgerfafc

Rather than go for "ideal/perfect", run a few boards with the set up you have. If the results look good to you then you're done. If not, THEN adjust the one that's 0.002" off the other two.

Keep in mind that the joiner and planer are for creating reference surfaces and edges for subsequent parts making. Glass smooth edges and surfaces aren't necessary. And while making and assembling parts, your going to get smudges, pencil marks and stuff on the surfaces which you'll remove later with sand paper and/or scrapers.

Realize that 0.002" is less than 1/256ths of an inch. After you run 20 or 30 feet of stuff the 0.002" high knife edges will probably be closer to the Zero knife anyway.

While it's good to know if your machines are set up correctly, and assuming an out of ideal specs isn't dangerous, it's the results that are important - not the theoretical perfection.

Don't sweat the small stuff unless they significantly affect the big stuff.

charlie b

Reply to
charlie b

LOL!!! That's just plain mean :-)

Reply to
Dave Bugg

Negligible? Depends...2 blades will be taking off 1/500 (plus or minus) more than the third. Is 1/500 of an inch significant with wood? Not to me...

Reply to
dadiOH

Reply to
Dave W

charlie b wrote: After

What type of wood are you running though your jointer that takes off 2 thou in 30 feet?

Dave

Reply to
David

"Dave W" wrote in news:FvidnQJX3Lic7rzYnZ2dnUVZ snipped-for-privacy@suscom-maine.net:

Stryped,

This reminds me of an incident that happened some years ago to a company that made mid-sized lawn and garden equipment. The garden tractor they made was nice machine. One day they started getting calls with transmissions failing. The transmission had been in production for years with never a problem and suddenly they were seeing hundreds of failures. What had happened was that the various shafts in the transmission were specified to be +.001 -.002. Well they had bought new machines to replace their old ones and the machinists set the new machines up the same way as the old ones which was at +.001. The new machines held that tolerance instead of randomly cutting things up to .003 shorter. All of those .001 added up and they would up in a situation where there was now a .001 interference fit and the shafts would burn due to a lack of oil. They changed their specs to +0 -.002 and all was well again.

So tell me how many passes are you going to take on the board and have it be .002 out and what is the cumulative effect? Lets say you have one board. It has two edges. You glue up 3 boards. That is 6 edges. 6

*.002=.012 Make two passes on each board? You could be out .024 inches. 1/64th = .0156

I leave the choice of whether or not to chase after that .002 up to you.

Did you watch the google video on setting jointer and planer knives?

I trust you have a dial indicator and a base.

Reply to
R. Pierce Butler

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