Jointer coplaner with gibs & what knife angle is best

[Frank Rotondo]

I'm having a problem with my shopfox w1684 Jointer. I'm not getting a satisfactory cut with this machine as I did when it was first in operation (taper instead of a flat face and a lot of chatter when the cutter contacts the blades). I started doing some checking using a Oneway fixture with a spherical ball attached and the Veritas 50" straight edge. I am using T-1 HSS Titan blades bought from an on line supplier.

The axis of the cutter head is .002 low on the op. side but the blades are all within .000/.0015+ (total) of parallel with the outfeed table. Using the straightedge what I found was that the tables are out of plane. It appears that the end of each table is up from the center. When I have the infeed table up .010 from the outfeed and have the straightedge on the infeed and set to cover most of the outfeed I can get .010 under at the cutter but as I move out it gets tight and I can't get .009 under the far end. When I run .009 under the straightedge from the cutter out you can hear it snap out from under the end of the s'edge. When I reverse that operation and set the infeed .010 lower than the outfeed I get the same results on the infeed table at the end away from the cutter.
Now here is the mystery part. When I have the infeed and outfeed set at zero with the dial indicator and lay the straight edge equally across both tables they appear to flat and on the same plane. I say that because I can't even get .0015 (thinnest I have) under any part of the straightedge.
I think what I have to do is shim the outfeed table under the gibs nearest the cutter so that it is on the same plane as the infeed table. I say I think because I'm looking for some reassurance I'm reading this right.

Finally what is the best angle for Jointer knives? 45 degrees? Or is there a best angle? I have read some pieces that some use different angles for different wood. I mostly run rough sawn soft maple and cypress and joint and plane to thickness.
Any help will be appreciated!

[John Lanciani]

.001" over 25" (half the length of the straightedge) is far under the tolerances of both the jointer and the straightedge you are using to measure it. If you're getting chatter you most likely have dull knives, sharpen or replace and reset them to be .002 or so higher than the outfeed table and go from there.

[Frank Rotondo]

Thanks John for the reply.
Knives are newly sharpened by outside vendor.
Any thoughts on knife angle?

[John Lanciani]

45 deg. might be a little blunt but it depends on the geometry of the head. What does Shopfox recommend? Did the problem start when you installed the freshly sharpened knives?

[Mel Fulks]

T1 is good, much better than the most widely sold stuff. If you have not already adjusted (or MIS -adjusted ) the tables it is possible that the knives have dulled a little and even have some nicks. Both of those things ,in effect, make the out feed table too high: less steel in knives ,more wood on new surface of wood, then out feed table is too high even though it has not moved. Having the knives a little higher than out feed is sometimes done intentionally and stops your current problem.
But makes the machine a little less accurate. First thing I would do is look for sharpest spot on the knives ,move the fence to that point. Objective is to see if two boards jointed there will fit together along entire length. If they do ,your knives need sharpening.

[Mel Fulks]

Slow typer here. I see knives are newly sharpened. If two jointed boards touching at edges are hollow in middle your table is too high. If they touch at center and are slightly open at ends then table is too low. Most of the time ,in my expirience ,
the out feed table needs adjustment when knives are changed. Failure to understand that is the major reason guys start "adjusting" everything out of alignment.