Setting Planer and Jointer Knives
Shop owners discuss instruments, jigs, and shop methods for measuring and setting knife heights. October 28, 2005
Question
What planer or jointer knife setting jig works best for you?
Forum Responses
(Furniture Making Forum)
From contributor A:
We have a number of people using the Mag-Set knife setting jig for both planers and jointers. It is easy to use and very accurate. It is available through Wood Tech Tooling. Others use Planer Pal or Jointer Pal. We even have some customers that still prefer to use the old Hammer Sets, or Crow's Feet.
From contributor B:
I set my knives on my jointer for many years with a short straight edge. Then I bought a used jointer and the seller threw in a knife setting jig that I really love. It has a foot that rests on the knife that causes a pointer in a little window to show how many thousandths of an inch the knife is high or low. For me, knowing in measurable terms exactly where the knife edge is in relation to the outfeed table is gold. I don’t know where you can buy one as I got mine used, but mine was made by Inca.
From contributor C:
Powermatic made one like the Inca jig but it was not very accurate. A $15 indicator, 1/2 button tip and a block of wood is far better for jointer knives.
From contributor B:
To contributor C: Can you explain what you mean by that? What is a button tip? How is it used with a block of wood?
From contributor C:
A button tip is a larger size tip than is typically found on an indicator. I use a 1/2" (button) slightly convex, and the indicator could simply be mounted in front of a heavy block of wood that sits on the outfeed table. Bridgewood has some nice looking knife setting jigs. An indicator is a more accurate gauge than the Inca. I've used it.
From contributor B:
I can tell when my jointers are set well by the feel and also by jointing a couple long stiff pieces of wood and looking for light to shine through the two edges when they are held together. I check my 16" planer by measuring with calipers the thickness of boards run at various points along the knives while the planer is set to a single elevation. That’s all it takes for me to get the performance I need for my work.
From contributor E:
You can use a tool called a Multi-Gauge. It is a piece of cast iron that has been precision ground on three sides for reference surfaces and the fourth has a clamp to hold a dial indicator. It is available from Garret Wade tool catalog and many other tool catalogs. It runs about $80 bucks.
From contributor F:
I use a straight edge for my jointer. Most important is the blades parallel to the outfeed table. For my planer I use a dial indicator with a magnetic base. I have a Powermatic 15" planer so I can set the knives from above. Its quick and I can get the knives well within .001".
The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).
Comment from contributor G:
I use a plate of aluminum to set planer and jointer knives. Set the machine or tables so the lowest knife just hits and skims the surface. With the other knives snug, not loose or tight, I rotate them until they touch the plate. If the knife sticks out too far, I just tap it with the aluminum plate until it touches. When all are set, I tighten them and re-check the setting. I found I can easily set all the knives within a thousandth of an inch. The plate I use is 6 by 12 inches by 1 inch thick. The aluminum does not damage the finest honed knife. I found that on the planer, with the knives snug, all I have to do is rotate the cutter head until the knife contacts the plate, and then continue rotation, pushing the knife in until it passes the plate. Then tighten all and go to work.
