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Jointer Knife Adjustment Jig

Aligning jointer knives doesn't have to be difficult. Using an inexpensive dial indicator, a shop-made holder, and these six simple steps, you can achieve perfection in under 30 minutes.

Jointer Knife Adjustment Jig

Jointer Knife Adjustment Jig

Adjusting jointer knives is a shop task often misunderstood and too often neglected. This doesn't have to be the case. Many methods and jigs exist (some very involved and others quite expensive) to help you set jointer knives.

Like most woodworkers, you probably don't want to spend a lot of time or money on tool maintenance. If your jointer's cutterhead has jackscrews here's how to get the job done in no time with an inexpensive dial indicator (less than $20) and a shop-made holder. Begin by making the holder (at right), and then follow these steps.

Step 1: With the tool unplugged and the knives removed, clean all dust and debris from them, the gibs, and the cutterhead slots. Lightly coat the parts with a light machine oil to help make adjustments easier and to keep parts from freezing together. If the knives need sharpening, take them to a professional. Note: during tool start-up, any excess oil will quickly fly off the cutterhead and not contaminate your work.

Step 2: Place the knives in the cutterhead, making sure they sit below the outfeed table height. Snug the gib bolts to hold the knives in place. Do not tighten yet.

Step 3: With the dial indicator mounted in the holder (as shown in the top photo) and positioned over the outfeed table, turn the dial's outer ring until it reads zero.

Step 4: Position the dial indicator foot over the knife, centering it on the cutting edge. The dial should read less than zero. Note: A flat foot on the dial indicator makes locating the edge center easier, but an indicator's bullet tip also works.

Step 5: Using an Allen wrench and the jackscrews in the cutterhead, raise the knife until the dial reads zero along the entire length. Tweak each end of the knife to reach the desired height.

Step 6: Gradually tighten the gib bolts in this order: Start with the far bolt, as shown, then the near bolt, then the far inside bolt, and finally, the near inside bolt. This so the knife won't creep upward and need readjusting. Recheck the knife height, and repeat Steps 5 and 6 on the remaining knives. Check all bolts and guards before turning on the jointer.

If you like this project, please check out more than 1,000 shop-proven paper and downloadable woodworking project plans in the WOOD Store.


Comments (7)
zmaker wrote:

l_emmons Check Step #6 of the instructions for the gib tightening sequence. This sounds like a pretty good process and process description to me.

3/1/2012 06:45:35 PM Report Abuse
Gnugs wrote:

Same question; what's the gib tightening sequence since it's NOT shown?

11/23/2011 03:28:37 PM Report Abuse
cmonroj1 wrote:

I mounted indicator on the end. To locate unit same place each time, have two nails out the bottom 1/16" but a wood piece better. Calibrate indicator zero with foot slightly depressed to read as the blade approachs zero. Many indicators can swap wider foot. Remove drive belt & rock cutter head to measure top of travel.

11/23/2011 01:10:15 PM Report Abuse
rjrutter wrote:

They should make clear that the knife EDGE must be at top dead center

11/23/2011 11:23:38 AM Report Abuse
l_emmons wrote:

What is the sequence for tightening the gib bolts ? All the picture shows is using a wrench on the inside bolt. Do you tighten from inside to outside or is there a special sequence ?

11/23/2011 09:34:22 AM Report Abuse
Dave at WOOD wrote:

hsg_charliec, that's just not true. You may have to register on the site, but not subscribe to the magazine.

11/15/2011 01:58:58 PM Report Abuse
lowes toolan wrote:

Great info and excellent reminder for everyone! Safety first and always. Just checking to see if I missed anything for our first class at our store.

10/30/2009 07:59:23 PM Report Abuse

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