benchtop jointer

[Mike Erickson]

To the best and brigthest on Sawmill Creek,

I have a 6" Delta benchtop jointer, when I try to plane a flat surface such as a 4" board the planed surface is planed at an angle.ex:one side is 1 3/8 the other side is 1 5/16 I know this is a small difference I have checked the knives and they seem to be at the same height although I did not check them with an indicator I just layed my scale on the bed. Am I being to picky or is this normal.
Thanks to all who answer
Mike Erickson

[Travis Johnson]

Mike, I am in no way the best and brightest on Sawmill Creek, but I will still try to answer your question.

If your knives are off 1/16 of an inch from one side to the other, that is indeed a problem. In fact 1/16th of an inch is a large amount. If you have to make multiple passes, then with each pass that difference is muliplied.

The key thing to keep in mind is, as woodworkers, our joinery can be a bit sloppy, after all we can plane a sliver of wood off here, or tweak a dovetail fit there, so measuring in thousanths of an inch is not required. Machine set-ups though are far different. When it comes to that, woodworkers have to turn into machinists.

Fortunately with jointer knives, only one machinist tool is needed, while a simple holder to hold that tool is easily made in the shop. The tool is of course the dial indicator. All that is need to be known about this tool is that it measures range, not a specified distance. With jointer knives, I strive to get them to be set within .007 of an inch of each other. That is, height wise, and side to side.

Now this should answer your initial question, but if you would like more information, you can check out this thread. I hate to send anyone off of here, but there was some great discussion about how to set up a set of jointer knives that I would really hate to re-type. Here is that link:

http://dgroups.woodmagazine.com/n/pfx/forum.aspx?nav=messages&tid=7827&webtag=toolsandbuying

[glenn bradley]

Definitely adjust the knives. I connot imagine the beds being that far off. It is pretty straight forward; loosen the four knife retention screws, adjust the cam-like adjustment screws while checking against a straight-edge referencing the outfeed table. The recommended method is to do the fence side of the knife first, then the outer side. the procedure is in your owners manual. Enjoy.