New knives, new problems on 6" bench jointer

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Forum topic by mspain77 posted 03-28-2016 10:04 AM 623 views 0 times favorited 6 replies Add to Favorites Watch
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62 posts in 817 days

03-28-2016 10:04 AM

Topic tags/keywords: jointer

Hey guys,
I’m fairly new to woodworking and inherited my dad’s old Delta 6” bench jointer. I started using it about two months ago and noticed that while most wood was glassy smooth and flat, there was about a 3/4” raised section on every board. I noticed a very worn section on both knives in the same area and bought some new knives.
I just finished installing the new knives yesterday and I followed an article in Wood magazine to the tee. I made sure that both cutter heads would move a piece of MDF back about 1/8”, on both sides of the cutter head. My first few test pieces seem very rough when passing the wood through. Though most is smooth, there are some areas with a different look than before…hard to explain. I’ll add a picture and hopefully that’ll help.
I’m wondering if I got used to passing the wood through too quickly before and now the new knives are really biting a lot more or what? I tried to go slower and get the same. I also reduced the depth from 1/32” to even less than that (1/48”?) and it takes many more passes but seems smoother. I also have it on the lowest setting and follow the recommendations on the dial by work piece thickness, etc. The old setting was 1/32” for everything, recommended by The Wood Whisperer, and I would like to get back to that more efficient depth of cut. Anybody else have a similar experience? Is there such a thing as a ‘breaking in” stage with new blades? Seems like that would be ridiculous.
Remember, I’m new to this so be gentle, but any feedback would be much appreciated. Thanks in advance people!

-- It's a BEAUTIFUL day to cut some wood & build something!

6 replies so far

View Pezking7p's profile


3217 posts in 1677 days

#1 posted 03-28-2016 11:15 AM

Jointer knives are probably set too high. I think moving a piece of mdf 1/8” is too high. It should be more like you can hear the blade scrape the mdf, but it doesn’t move the mdf.

-- -Dan

View jdh122's profile


1018 posts in 2844 days

#2 posted 03-28-2016 01:23 PM

I’ve tried using low-tech methods of setting my jointer knives and only got increasingly frustrated (though some people seem to manage it). This video ( and the purchase of a dial indicator solved my problems.

-- Jeremy, in the Acadian forests

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1438 posts in 1824 days

#3 posted 03-28-2016 01:59 PM

Looks like you have one high knife.Try setting them with something hard like a metal ruler.I use a starret 12 inch rule.

-- Aj

View mspain77's profile


62 posts in 817 days

#4 posted 03-28-2016 04:41 PM

Thanks guys. After watching a few more YouTube videos and reading some posts on here, it seems that the knives should be parallel to the outfeed table top, or maybe 1-2 thou higher at the most. I lowered them and tried my best to get them even without a dial indicator. I tried using a magnet to hold the blades parallel at their highest point, but I had to move the table and magnet back to tighten the gib screws. The results are MUCH better, but I’m trying to mill up some dimensional lumber right now for a cheap table top and I’m having different issues. UGGHH!!
I appreciate your feedback. Please look for my next post about my current jointer issues, and I’d love to hear your feedback on that. Thanks again.

-- It's a BEAUTIFUL day to cut some wood & build something!

View pintodeluxe's profile


5705 posts in 2839 days

#5 posted 03-28-2016 06:14 PM

The Snapcheck is available at Chipsfly for a song. These help with setting jointer knives. I set mine on the blade and watch the indicator as I gradually tighten the gib bolts, making sure they don’t lift up.

The stick method usually got me within .007”, but that leaves a scalloped finish on your lumber. With the Snapcheck I can dial it in to within .002”.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View mspain77's profile


62 posts in 817 days

#6 posted 03-28-2016 10:08 PM

Thanks for the tip! I just ordered my Snap-Check. I saw something similar on TWW, but the one he used was around $150 or so, and I didn’t know there was anything this affordable around, so thanks again.

-- It's a BEAUTIFUL day to cut some wood & build something!

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