Jointer knife replacement

charlese · Post by **charlese** » Sat Jul 27, 2013 7:28 pm

Are there any vibrations without passing wood over the blades? So far we have been mostly zeroing in on vibrations while jointing. This usually is caused by uneven setting of the blades.

If vibrations happen while not cutting wood, I would suspect bearings. I have had a bearing problem in the past. Didn't know at the time, but the bearing closest to the headstock froze and actually wore down the drive shaft. Needed a cutting head replacement.

rdewinter · Post by **rdewinter** » Tue Jul 30, 2013 9:45 am

After running test pieces through the jointer, the vibration seems to have smoothed out. I got nice clean edges but the edge is not 100% square with the face. I guess this is due to the knives not being set exactly the same depth.
Bill, the reference you sent in your post does not show the sawdust session. Am I missing something? I still can't find the jointer pal knife setting jig either. Charlese posted an interesting knife setting jig using a piece of plate glass secured to the out feed table with a magnet and setting the knives up to the bottom of the glass. I'm going to try that method for now.

My latest problem is this...when jointing the edge of a board, the jointer actually slows down and even stops in the middle of jointing a board. My first thought was the coupler was slipping. I checked the grooves of the coupler and none of them were missing or damaged. What would cause the jointer to stop in the middle of jointing the edge?

WmZiggy...good points. Will try removing the blades and cleaning again. I have not honed the new blades yet. You mentioned jointer pals to help set the knives. But where do you find them?

rdewinter · Post by **rdewinter** » Tue Jul 30, 2013 9:45 am

After running test pieces through the jointer, the vibration seems to have smoothed out. I got nice clean edges but the edge is not 100% square with the face. I guess this is due to the knives not being set exactly the same depth.
Bill, the reference you sent in your post does not show the sawdust session. Am I missing something? I still can't find the jointer pal knife setting jig either. Charlese posted an interesting knife setting jig using a piece of plate glass secured to the out feed table with a magnet and setting the knives up to the bottom of the glass. I'm going to try that method for now.

My latest problem is this...when jointing the edge of a board, the jointer actually slows down and even stops in the middle of jointing a board. My first thought was the coupler was slipping. I checked the grooves of the coupler and none of them were missing or damaged. What would cause the jointer to stop in the middle of jointing the edge?

WmZiggy...good points. Will try removing the blades and cleaning again. I have not honed the new blades yet. You mentioned jointer pals to help set the knives. But where do you find them?

rdewinter · Post by **rdewinter** » Tue Jul 30, 2013 9:50 am

rdewinter wrote:After running test pieces through the jointer, the vibration seems to have smoothed out. I got nice clean edges but the edge is not 100% square with the face. I guess this is due to the knives not being set exactly the same depth.
Bill, the reference you sent in your post does not show the sawdust session. Am I missing something? I still can't find the jointer pal knife setting jig either. Charlese posted an interesting knife setting jig using a piece of plate glass secured to the out feed table with a magnet and setting the knives up to the bottom of the glass. I'm going to try that method for now.

My latest problem is this...when jointing the edge of a board, the jointer actually slows down and even stops in the middle of jointing a board. My first thought was the coupler was slipping. I checked the grooves of the coupler and none of them were missing or damaged. What would cause the jointer to stop in the middle of jointing the edge?

WmZiggy...good points. Will try removing the blades and cleaning again. I have not honed the new blades yet. You mentioned jointer pals to help set the knives. But where do you find them?

Dusty= there was no vibration before I changed the knives, but will remove the knives, clean and test for vibration.

jimthej · Post by **jimthej** » Tue Jul 30, 2013 10:15 am

rdewinter wrote:After running test pieces through the jointer, the vibration seems to have smoothed out. I got nice clean edges but the edge is not 100% square with the face. I guess this is due to the knives not being set exactly the same depth.
Bill, the reference you sent in your post does not show the sawdust session. Am I missing something? I still can't find the jointer pal knife setting jig either. Charlese posted an interesting knife setting jig using a piece of plate glass secured to the out feed table with a magnet and setting the knives up to the bottom of the glass. I'm going to try that method for now.

My latest problem is this...when jointing the edge of a board, the jointer actually slows down and even stops in the middle of jointing a board. My first thought was the coupler was slipping. I checked the grooves of the coupler and none of them were missing or damaged. What would cause the jointer to stop in the middle of jointing the edge?

WmZiggy...good points. Will try removing the blades and cleaning again. I have not honed the new blades yet. You mentioned jointer pals to help set the knives. But where do you find them?

Jointer Pal is a brand name. A search on Amazon yielded a half dozen hits of several brands.
On the bogging, The obvious points to check are the hub setscrews, the poly-v and motor belts. Most important would be to reduce the depth of cut to 1/32nd or less, and to slow the feed rate.
I took apart some 2x10 a coupe of weeks ago to get the cup and bow and wind (twist) out of it. Even with the Power-Pro, I never cut over 1/32nd and on the final passes it was probably in the thousandths. I still stripped the last 1/4 inch of splines out of a coupler that wasn't all the way on the headstock hub.

JPG · Post by **JPG** » Tue Jul 30, 2013 10:27 pm

The only thing I can postulate about the diminishing vibration is this. A blade was not seated against the vertical blade stop, and crept down against it. That blade was likely higher than the other two and created the vibration.

The jointer parts(stop screws, retaining screws wedges and head) are all usually well gunked up from debris. All these need to be thoroughly cleaned when either replacing or adjusting the blades.

Jointer(and planer) knives must be very securely mounted. There should be no possibility of the blades moving once secured firmly against the stop screws.

A jointer with improperly aligned blades is essentially useless for its intended purpose.

A jointer with inadequately secured blades is a disaster waiting to occur.

I do not wish to alarm you, but do research the blade replacement procedures thoroughly. In the distant past, I encountered the same issues as you. Hard lesson, but never forgotten.

The easiest 'mistake' to make is the 'far' end of the blade raises off the stop screw as the 'close' end is being adjusted.

I have determined that a slight snugging of the wedges will prevent that, but will require occasional backing off to allow the blades to be 'raised'. That and downward pressure of the blade against the stop screws. Then after 'getting the height set', loosen the wedges, snug a little tighter, and recheck. :DRepeat as required!:D

Clean. Aligned. Secured. Sharp. The secrets to a 'smooth', accurate jointer.

rdewinter · Post by **rdewinter** » Wed Jul 31, 2013 10:52 am

JPG
Thanks for the tips and info. I'm gettiing frustrated with the alignment of the jointer knives. The latest problem is this...when I removed the blade and the wedge. I totally cleaned the screws, knife holder, knife and wedges. I reset the height screws back to zero (screwed height screws all the way in so I started at the knife being at its lowest level). I reset the knife and wedge and put the locking screws back in (slightly snug), then using a straightedge I slowly raised each side of the knife until it slightly touched the straitedge just like the manual suggested. The problem is the knives are to high and they hit the bottome of the outfeed table. I started all over and set the height just high enough to miss the outfeed table. After securing all screws tightly, as you recommended, the jointer still does not perform correctly. I'm getting snipe and ripple . I think all of the knives are not cutting the board.
Getting very frustrated with this jointer!!!!!!!!!!

nuhobby · Post by **nuhobby** » Wed Jul 31, 2013 12:16 pm

I'll just mention I had got a new SS Jointer in late 2007. After my first blade-change and adjustment some months later, I could manually rotate the cutter and see the blades trying to hit one of the table castings slightly. It was toward one side or the other of the length of the blade, I can't quite recall. Anyway, I took a file and slightly removed a spot of cast-iron to avoid this interference.

JPG · Post by **JPG** » Wed Jul 31, 2013 2:42 pm

rdewinter wrote:JPG
Thanks for the tips and info. I'm gettiing frustrated with the alignment of the jointer knives. The latest problem is this...when I removed the blade and the wedge. I totally cleaned the screws, knife holder, knife and wedges. I reset the height screws back to zero (screwed height screws all the way in so I started at the knife being at its lowest level). I reset the knife and wedge and put the locking screws back in (slightly snug), then using a straightedge I slowly raised each side of the knife until it slightly touched the straitedge just like the manual suggested. The problem is the knives are to high and they hit the bottome of the outfeed table. I started all over and set the height just high enough to miss the outfeed table. After securing all screws tightly, as you recommended, the jointer still does not perform correctly. I'm getting snipe and ripple . I think all of the knives are not cutting the board.
Getting very frustrated with this jointer!!!!!!!!!!

When the blade 'just touches' the straightedge, it IS the cutting edge at the highest point as it is rotated ONLY? Also the straight edge IS flat on the OUTfeed table? As the head is rotated, each blade should just nip the straight edge and move it horizontally less than 1/8" or so. A straight piece of wood can take the place of the straight edge. That movement should occur regardless of the direction the head is rotated.

I assume the snipe is on the trailing end? If so, the knives are too high.

When starting a pass, the leading edge of the workpiece should move on to the outfeed table with minimal clearance(zero is perfect).

Start a pass and retract it just after moving onto the outfeed table an inch or so. Shut it off and take a close look at the workpiece leading end clearance to the outfeed table. A gap means the blades are too high. If the workpiece wants to bump INto the outfeed table, the blades are too low.

BTW pitch(crud) can build up on the outfeed table casting inside the cavity.

Ripple(if I understand your meaning correctly) is caused by the workpiece rocking as it is passed through the jointer. That implies the work piece is not being held tight to the OUTfeed table. If the blades are high AND the workpiece leading end is pushed down, the infeed table end of the workpiece will rise above the table. Upon noticing the trailing end 'flying' the operator pushes it back down to the infeed table(and causing the leading end to raise above the outfeed table;)) the workpiece rocks on the cutter edge of the infeed table and the blades gradually take a deeper cut as the workpiece lowers onto the outfeed table as the cut gets deeper(ripple?). Upon noticing the 'flying' leading end attention is shifted to pushing down the leading end(which again causes the trailing end to 'fly' and the cutter takes a shallower cut! . . . . . . . .

FWIW keeping the workpiece tight against the outfeed table is nigh impossible if the blades are cutting too deep(set too high). The leading end can be pushed down tightly, but the cutter end is held high by the infeed table until the end clears the infeed table. Then the workpiece drops creating the snipe.

rdewinter · Post by **rdewinter** » Thu Aug 01, 2013 10:03 am

My jointer problems have been fixed!!!!

The problem with the jointer stopping or slowing down in the middle of the cut was caused by the lower hub ( that drives the coupler) was loose and was slipping causing the jointer to slow down or stop. Simply tightening the set screw was all that was needed.

The biggest problem was setting the jointer knives. And I owe a big thank you to Rob Diggs (sdsmith51) who realized my frustration with setting the knives and diagnosed the problem. After setting the knives properly, he noticed that the problem with the knives hitting the out feed table was the cutter head had moved slightly toward the out feed table. He aligned the cutter head and the problem was fixed. After tightening all the cap screws, a pass over the jointer yielded a very nice square edge.

Thank you Rob. It sure is nice living in the same area and having such a nice thoughtful person as Rob nearby. Rob also passed along some jointer knife sharpening/honing tips. Rob really epitomizes that we all our really a ahopsmith community and willing to help each other out when in a bind or just have a question.