Jointer making me crazy!

[Dennis McDonaugh]

I used to worry a lot about aligning my jointer knives and tried both jointer pals and a dial indicator. I have finally settled on a very unscientific method of adjusting the knives by jointing a board. I use the jig that came with the jointer to set all the knives the same height in the cutter head (this is the most important part, but not really that difficult). The jig works well and only takes a few minutes. Then, using a sorta straight edge I raise the outfeed table until its about even with the TDC rotation of the blades. Takes something like 30 seconds. Next I raise the infeed table until its just below the outfeed table (another 30 seconds). Now I face joint a board and look at it. I need to be jointing most of the face. If I need a bigger cut I lower the infeed table a little. After that, its a matter of adjusting the outfeed table until I get a little snipe then raising the table until the snip is gone.

[Chris Damato]

After further inspection, I have noticed that one of the knives is slightly lower than the other 2. I guess I am going to have to attempt resetting them using a straight edge for now. My jointer did not come with a knife setting jig so I will attempt it with a square.

Most of my jointing is edge jointing and face jointing oak, maple, poplar and cherry. Will I notice decreased quality by moving to the Byrd cutterhead as opposed to the straight knives?

Thanks,

Chris

[Joe Grout]

Chris put the straightedge away you are going to knick those knives.

The suggestion that you use a straight stick for setting the tables and the knives is the best solution there is.

I post this elsewhere, and it is the way I teach others to set jointer knives Hope it helps

1.If you do not have a top dead center mark on your fence you can find TDC by setting the stick on the outfeed table. Make a reference mark on the stick right at the edge of the outfeed table on the stick. Now with the jointer unplugged, hold down the stick with gentle pressure and rotate the jointer head by hand. As you do the knife will catch on the knife and move toward the infeed table. Let it do so and when it stops moving forward make another reference mark on the stick. This distance represents the distance that the knife is set above the outfeed table in an arc which makes it appear to be much more than the .001 or .002" is really is above the table. This clearance is necessary so that when you joint board the end doesn't catch on the outfeed table as you push the stock across the jointer. Now make a third mark on the board halfway between the two existing marks. This is going to represent the TDC of the cutter arc and so you should try and get as close to the center as you can. Set the stick back on the outfeed table and align the mark with the outfeed edge of the table. Once again using the same knife as you did to find the length and in about the same position on the knife rotate the knife until the center mark is aligned with the edge of the outfeed table. Stop the rotation and hold the cutter head in this position. Now make a vertical mark on the fence that aligns the edge of the knife to the fence. I actually scribed a line on my fence with a scribe so I always have this reference to work off of anytime I have to change knives. This is the reference point that determines all future work in changing knives.


Pull out ONE knife and mark the cutterhead as # 1. Clean out the slot and clean up the gib and the screws so that foregn material has no effect on the gib and the knife. If the head uses springs to lift the knife make sure they are all still there. They are small and get lost occsionally so it pays to look.
Now I set one fresh knife in the slot and put the gib in to and run the screws out just for enough to just touch the knife. Roughly set the knife so it aligns with the witness mark on the fence Tighten the screws a little at a time working form the center outward. Tighten a little move to the next screw, tighten, move,tighten move etc.
After you have the screws all tightened down, put your stick back on the outfeed table. I usually start with the stick near the fence. Make a new reference mark on the stick perferablly on a different side of the stick. One thing to remember here is that these marks are the ones you are going to use to set the other knives and so make sure they are accurately located. Once again, rotate the knife head and when the stick stops make another mark. Now, move the stick across the width of the jointer and align the first mark with the out feed table and using the same light pressure on the board rotate the knife again.
If the board stops at the second line then the knife is parallel ACROSS the width of the blade and probably does not need any more adjustment. You can check the knife in a couple of more places and I would on jointers wider than 8" to make sure the knife is not being forced higher or lower by the gib screws.
If the marks do not align then the distance the mark is from the second line will tell you what is wrong with the alignment ( if the board does not reach the line the knife is set too low , if it goes past it, it is set too high)loosen up the knife and reset it.
Once you get the first knife aligned go through the process again with knife #2 . After you get to the knife set and tightened in then put the stick on the outfeed table again over toward the fence and rotate the head as before. If the knife pulls the board to the second lineagainst the fence and on the outside then the #1 and #2 knives are in the same plane and you can move on to the #3 knife
Once again the same process and if all stays put because you have tighten all the gib screws equally and paid close attention to the stick you should be able to confidently straighten and flatten boards with no or very little ripple
I usually run two boards at this point to assure that all the work I have done is indeed right.



I just spent 30 minutes describing the process outlined here and I can set jointer knives using the above method on a 20 " jointer in about the same time. I consistantly change out knives on 6 and 8" jointers in about 15 minutes. I have been doing it on a regular basis for about 15 years now following this procedure and I think I have had to go back an reset knives maybe twice in that time (once because a knife slipped after I installed it due to sawdust between the gib and the knife and once because I didn't do it right

Joe

[Chris Damato]

Thanks for the reply Joe. I am a little confused about the TDC. I don't know if my knives are adjusted properly to begin with, therefore if I measure for TDC with the setup I have now, it will be incorrect. How do I approach doing this in a situation where everything is probably out of whack and none of the three knives are equally set?

Also if anyone could answer this for me I would appreciate it. Most of my jointing is edge jointing and face jointing oak, maple, poplar and cherry. Will I notice decreased quality by moving to the Byrd cutterhead as opposed to the straight knives?

[Frank Chaffee]

Chris,
Top Dead Center will be in the same place regardless of how high or levelly a knife is adjusted. A higher knife will produce two marks on your stick that are further apart than the marks made from a lower knife, but the mid-way point between those sets of marks will always indicate the TDC of the rotation of the cutterhead.

Joe, thanks for sharing the step by step knife setting process with us. I have saved it into my woodworking folder.

Frank

[Joe Grout]

Chris

It is going to make you pocketbook lighter that is for sure.

I do not promote the use of Byrd heads on machinery due to the cost of the initial investment, futhermore while it creates a better overall finish it does not actually make you a better woodworker.

Smooth finishes are the product of planers, sanders , and elbowgrease whether by scrapeing the final product or just plain handsanding.

Jointers are for flattening stock and straightening edges. They are highly acurate machines when set up and need little real maintenance and when it does need it, you should be able to do so with the information given here.

I have operated machinery with Byrd style heads over the years, and the general consensus amongst most of the owners of this machinery is the payoff is a long way down the road in financia terms. Even in practical usage, it does not fully preclude maintainance issues.

JMO

Joe