straight knife vs spiral cutter head on a jointer

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Forum topic by dbw posted 12-25-2018 07:29 PM 1960 views 0 times favorited 15 replies Add to Favorites Watch
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318 posts in 2171 days

12-25-2018 07:29 PM

Topic tags/keywords: jointer cutter head spiral straight

Is it worth the extra $ to get a spiral cutter head on a jointer? I am looking at the Grizzly 0656 ($1095) and the 0656X ($1710). Is it really a pain in the rear to set straight knives even on a quality machine? Is the difference in the finish significant?

-- measure 3 times, cut once

15 replies so far

View Mike_D_S's profile


596 posts in 2749 days

#1 posted 12-25-2018 07:57 PM

I upgraded my old Delta to a spiral head so I have some direct experience with the same machine before and after.

Which I like about the spiral head:
1. The cutters stay sharper, but they are carbide vs the HSS steel knives I’m used to using so it’s not apples to oranges.
2. Though I’ve only had to rotate a few so far, it’s a lot easier and faster to just rotate one or two cutters than loosening al the knives and then sliding them left/right to offset the nick.
3. After checking that the head was parallel to the table top when I installed it, I just don’t have to worry again about height setting. I have occasionally face jointed a board into a wedge shape because I got one of the knives just a little high on one end.

Things I like about the straight knife head:
1. It’s cheaper. Even accounting for knife changes (I don’t sharpen my jointer knives) I would have to go a long time before I spent enough on straight knives to justify the conversion just on cost. The cost of the inserts is individually not that bad, but HSS knives are cheap as well.
2. Straight knives can be sharpened.
3. Straight knives take less power. I’ve had this discussion with several people online and in person, but my direct experience says that the spiral head bogs the motor down for the same cut depth as the straight knives did. So after the conversion I have to take a slightly smaller cut or the cutter rpms drop. This may not matter for the 8” since it comes stock with a 3HP motor in each head type, but for the 6” the straight knives come with a 1 HP motor and the spiral with 1.5 HP. My experience says this is not accidental.

I don’t think the cut quality of the spiral head is any better really than the straight knives generally. I don’t work with highly figured woods enough to say whether it would be better, but there are a lot of comments that say there is a difference. I will say that for aggressive cuts in something like african mahogany with the heavy ribboned grain I’ll get some tear out with both if I’m taking a heavy cut. They will both produce a good finish on a lighter cut, though the spiral might have a slight edge on where “light” is.

Hope that helps. I think it comes down to whether you are ok spending the money. If you have the money and buy the spiral, I don’t think you’ll be disappointed. But if you buy the straight knives and have trouble at some point, you’re probably going to assume the spiral would have been better.


-- No honey, that's not new, I've had that forever......

View MrRon's profile


5763 posts in 3778 days

#2 posted 12-25-2018 08:31 PM

It would seem to me that carbide cutters would not be as sharp as HSS, hence a rougher surface finish. Carbide is brittle, so you can’t get the same degree of sharpness as with a HSS blade. The same would hold true with ceramics; too brittle compared to HSS. I use carbide and HSS in my metal machining, and the HSS cutters give a finer finish. If I am wrong, please educate me.

View Aj2's profile


2529 posts in 2333 days

#3 posted 12-25-2018 09:38 PM

I have straight knives in my jointer and the Bryd head in my planer. I like the surface straight knives leave on wood. I’m done playing with tropical or nasty woods.
My jointer is very high quality over the planer so that might be a big difference. The jointer has a 5inch cutting circle and 38 degree hook angle. So it great for soft woods.
I also like trying different high speeds steels and getting them wicked sharp.
With a carbide insert you get what you get.
It’s not that hard setting knives just takes some practice and good setting tools. I recommend a quality dial indicator the cheap ones are too twitchy.
Good luck

-- Aj

View Mike_D_S's profile


596 posts in 2749 days

#4 posted 12-25-2018 10:02 PM

HSS knives give a very good finish initially and it might be better than the finish from the carbide inserts when the HSS knives are new. For me, I’m just finding that the carbide inserts are still providing an acceptable finish quality long after the point I would have expected to change the HSS knives based on my previous usage.

And I agree that setting the knives and keeping them sharp are not all that hard, but it takes a certain amount of time, practice and tools/jigs to do it reliably. For me carbide inserts are kind of like the easy button for jointer operations.

The question of whether the finish quality and having the easy button is worth $700 extra is a whole other thing. I’m cheap, so I got the Grizzly spiral head on sale to upgrade my jointer.

-- No honey, that's not new, I've had that forever......

View ArtMann's profile


1441 posts in 1351 days

#5 posted 12-25-2018 10:26 PM

I had a planer with straight knives for more than a decade before I upgraded to a planer with a segmented spiral cutter head. On stock with a non reversing grain and no figure to speak of, the straight cutters did a slightly better job. Sharpness doesn’t matter. The moment you start trying to plane stock with reversing grain direction or heavily figured wood, the value of the spiral segmented cutter head becomes obvious. There is some wood that you simply can’t plane without ugly tear out with straight knives that comes out nice and smooth with a spiral cutter head.

The difference is not subtle or of just marginal value. The difference in results a is usable versus non usable finish.

View Andre's profile


2826 posts in 2341 days

#6 posted 12-25-2018 10:33 PM

Have had both and Carbide all the way! The type/Quality of the head makes a difference as will the wood you run through/over the machine! After you pass a plank of wood that has some grain that changes you will never regret the choice. IMHO

-- Lifting one end of the plank.

View Bob5103's profile


147 posts in 1368 days

#7 posted 12-25-2018 11:12 PM

I have had a spiral head in my DW735 planer for about 4 yrs and really like it, and I swore when I replaced my jointer it would had one too. A year ago October I bought a new jointer from Grizzly, all they had in stock was a straight knife model. But they did have a Shelix spiral head in stock, so I bought the jointer and spiral head separately. I put the spiral head as I was setting up the jointer and it is great! Another plus is it was cheaper to buy them separately. I just checked and the same would hold true for jointer you are looking at, it would be about $1435, vs $1720. (not counting shipping) Almost a $300.00 difference. It was really easy to replace the cutter head and I highly recommend doing it this way.

View Phil Soper's profile

Phil Soper

25 posts in 336 days

#8 posted 12-26-2018 12:03 AM

About four years ago I shifted from a straight knife planer to a Powermatic with their spiral head. Quieter and better finish on boards with reversing grain direction. I liked it so much that I soon changed my jointer to one with a spiral head. I will never go back

View TheFridge's profile


10859 posts in 2021 days

#9 posted 12-26-2018 12:43 AM

The HH in a jointer is where it’s at. I friggin hate setting knives. Worth every penny.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

View tacky68's profile


89 posts in 1962 days

#10 posted 12-26-2018 01:38 AM

^^^^ What Fridge said. I had mine converted last year-WORTH EVERY PENNY!!! I will not ever set a jointer knife again. It was an exercise in frustration. Good luck.


View Fred Hargis's profile

Fred Hargis

5796 posts in 3028 days

#11 posted 12-26-2018 11:38 AM

Setting those knives is one of the more frustrating things you will ever have to do in a wood shop, there’s no way I’d go back. I put a Shelix in my Jet jointer and couldn’t be happier. I looked at the jointer you mentioned (it’s out of stock, so who knows if you can actually buy one) and then the price of the cutterhead. You can buy the jointer (maybe) and put your own cutterhead in it (a 30 minute job) and save money….at least that’s the way it looks to me. Oops, I see Bob already stated that above. On eother thing: the jointer will be quite a bit quieter with the insert head.

-- Our village hasn't lost it's idiot, he was elected to congress.

View dbw's profile


318 posts in 2171 days

#12 posted 12-26-2018 01:01 PM

Sounds like the consensus of opinion is the HH. the truth is wood working is not about taking the time to set jointer knives. Wood working is about making things out of wood. In addition it sounds like setting knives is a frustrating task which requires special tools/jigs. Thank you for your help.

-- measure 3 times, cut once

View Blindhog's profile


135 posts in 1583 days

#13 posted 12-26-2018 02:26 PM

I’ll echo the positive comments regarding spiral cutter heads. I replaced the cutter head on my DW735 with the Shelix and have been very pleased with the performance. Did the same to my 6” Jet jointer and have had great results as well. As others have noted, the spiral head produces a much cleaner cut on highly figured woods.

-- Don't let perfection get in the way of plenty good enough

View Aj2's profile


2529 posts in 2333 days

#14 posted 12-26-2018 04:11 PM

Setting jointer knives is not that hard. If you buy good hss and don’t run dirty wood on your machine they will last plenty long enough for the weekend warrior.
The steel knives that come with cheap Chinese machines are not a good example.
Save your money for hh planer.

-- Aj

View Andybb's profile


2148 posts in 1138 days

#15 posted 12-26-2018 06:21 PM

^^ I’m a weekend warrior and just can’t justify the cost. Good sharp straight knives in a jointer work just fine. My biggest knife issue is trying to put figured wood through the planer. That’s the application that tempts me but a hand plane and a drum sander usually work then I forget about it until the next time.

-- Andy - Seattle USA

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