Budget spiral cutterhead upgrade for 6" jointer

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Review by Mike_D_S posted 06-20-2017 03:44 AM 4186 views 2 times favorited 8 comments Add to Favorites Watch
Budget spiral cutterhead upgrade for 6" jointer Budget spiral cutterhead upgrade for 6" jointer No-picture-s Click the pictures to enlarge them

Short story: Fits Delta 37-190, easy to install. Only put about 20 bf across it so far, but cut quality is very good. I’m giving it five stars due to the cut quality, but the instructions were marginal but usable.

Long Story:
I’ve been wanting to upgrade my jointer to a spiral head for a while, but couldn’t bring myself to drop the nearly $400 on my older Delta 37-190. The Delta is a quality machine and with a few minor tweaks around adding a port for dust collection, I’ve been very happy with it. Good flat, heavy cast iron tables, fence that stay set.

The only downside is that sometimes getting the blades set to the correct heights and level is a chore. One time I’ll knock it out in 15 or 20 minutes and the next time I’ll fight it for an hour.

So when I saw the Grizzly spiral head on sale for $215. Looking at the head, it has the ‘shear’ style set to the cutters and at that price, I decided to pull the trigger. Only trouble was that none of the Grizzly heads were listed as fitting the 37-190. But after doing some research, I figured that the T27698 head seemed to be the one that fits the ‘generic’ 6” jointer and the specs i could find made me think it might be a fit for the 37-190. So I ordered it figuring that if it fits, great and if not I can return it.

I ordered the head in mid-April, but they were listed as back ordered. Finally last week (mid June) it arrived. Unpacking the head, everything looked good. I disassembled the Delta head and pulled out the calipers to compare the two. I was quickly able to figure out the Grizzly head was an exact match for the Delta 37-190 head.

So with a little effort and the help of a gear puller I had the new head ready to go and about an hour later I had confirmed the head was level with the outfeed table to less than 0.005”, so no shims were needed. I set the outfeed table height quickly and went to making test cuts.

I face planed some 5” stock in cherry, sapele and oak as test pieces with no issues. Then edge jointed the same boards with good results. Then I prepped a bunch of 8/4 walnut and maple I’m preparing for cutting boards. All of the cuts were good quality and ranged from from ‘wave the sandpaper at it’ basically finish ready to only needing a few quick light passes with 220 to be ready to finish.

Average quality wasn’t any better than the best I have gotten with good new knives on the 3 blade head, but was noticeably better than the average quality I get out of the 3 blade head.

One thing I didn’t see was any evidence of waviness or light lines reported by some people when switching to spiral heads. But maybe my eyesight isn’t as good as some other people? I did notice that the head did seem to require more power on average. Making the 5” face cuts, I could definitely hear that the motor rpm was down a bit for what I felt was my normal feed speed. But the cut quality didn’t seem impacted an subsequent passes with a slightly slower feed speed didn’t seem to bog the motor at all.

So I admit that I haven’t put all that much wood across it, but given what I’ve seen so far, I give it a thumbs up. At $215, it’s at a price point where I didn’t have to feel guilty about putting new money into the old jointer.

Hope this info helps someone to make a decision if they are looking at these heads.

Edit June 27: Adding the measurements from the head to the review, will fill in remaining later
short end bearing shaft: 0.590” (15mm nominal)
pulley end bearing shaft: 0.665” (17mm nominal)
pulley shaft: 0.620” (16mm nominal)
Cutterhead cutting edge diameter: 65mm

Specifically for the delta 37-190, the bearings were a 6202 and 6203. I got the 2RS rubber sealed.

Update October 23: I now have a few months using the new head and am still happy with it. Just finished surfacing a bunch of cherry and it still seems to be cutting just like new. I’m not at production volumes, but this is approximately 150-200 BF of mixed cherry, oak, sapele and walnut.


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

View Mike_D_S's profile


605 posts in 3018 days

8 comments so far

View runswithscissors's profile


3107 posts in 2828 days

#1 posted 06-20-2017 03:56 AM

I has been noted by others that spiral or helical heads do take a bit more power. One LJ compared amperage draw with knives vs. helical, and it did take more juice. I surmise that there are constantly cutters engaging the wood, with no “resting” period that the motor gets with 3 knives making intermittent cuts. Not that those periods of no-load would be more than a micro second.

I have the Jet 12” jointer-planer combo, with helical head, and would not want to go back to straight knives.

I’m glad it is working out for you.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

View robscastle's profile


7237 posts in 3007 days

#2 posted 06-20-2017 11:15 AM

Hello Mike
Looks like a good sales pitch for the upgrade, and at possibly around 50% dixcount its a real no brainer.
Setting the knives on a jointer has got to be one of the most time consuming maintenance activites of all the woodworking suite going.

I think I have spent hours when I cannot get the required result first up, and even then have concerns to everything being at the same level.

The “Uses more Power” hype has been a talking point for a while, I personally believe its not supportable and it may be the result of the helical head working so well its removing additional material than the fixed blades were.

Regardless the advantages outway the disadvantages by far.

I had a look at your pictures and i assume there is four rows of inserts I can see 7 inserts visible in your pcture and assume the next row is staggered and has 8 inserts in it?

-- Regards Rob

View jonah's profile


2123 posts in 4102 days

#3 posted 06-20-2017 11:49 AM

Anyone heard of someone installing the 8” version of this on a Powermatic Model 60? At ~$260, it’s a lot more palatable than a $450 Byrd head.

View Mike_D_S's profile


605 posts in 3018 days

#4 posted 06-20-2017 11:52 AM


Yes, four rows with staggered cutters. I’ll post a few additional pics this evening. That’s not an ideal pic as it doesn’t show the end cutters. One each end of the head, there is an end cutter with a square set to the rotation plan, which I’m assuming is to insure the end of the cut is flat for sure.

I never took current readings on the old jointer, so a measurement now won’t mean much, but I never really take heavy cuts. Heavy for me is 1/16” as I’m usually quite happy to make multiple passes. So I don’t think cut depth is the cause of the perceived load.

While it’s counter intuitive if you think about blade contact, from the little use I’ve had it does seem this head is a bigger load. I think it’s likely a combination of things. I’d have to measure to say exactly, but I think the diameter of the body for the spiral cutterhead is a little smaller than the 3 knife head, so less rotational momentum. Then we’d have to think about belt stretch where I would expect the 3 knife head intermittent contact to potentially not reduce the motor speed as much correspondingly. The spiral head would be stretching the belt, but with the more continuous contact, the belt stretch would tend to be more consistent meaning the load on the motor would be steadier.

Conceptually, I can rationalize the spiral head drawing more power for the same cut.


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

View Kelster58's profile


759 posts in 1343 days

#5 posted 06-23-2017 04:56 PM

Thanks for posting this. You have imagination and skill. This will be a big help to many!

-- K. Stone “Tell me and I forget, teach me and I may remember, involve me and I learn.” ― Benjamin Franklin

View Mike_D_S's profile


605 posts in 3018 days

#6 posted 06-23-2017 05:27 PM

While I’d like to take credit for being imaginative and skilled, really the only risk I had was the restocking and return shipping costs.

If it hadn’t been a drop in fit, I wouldn’t have tried to make it fit.


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

View russde's profile


108 posts in 3643 days

#7 posted 06-27-2017 05:47 PM

Any chance you could measure and post the specs? I’ve got an old Atlas 6001 that would really benefit from an upgrade like this.

View Mike_D_S's profile


605 posts in 3018 days

#8 posted 06-27-2017 06:23 PM

I added the measurements I had above and will fill in the rest when I get home tonight. I also listed the generic bearing sizes.

Actual dimensional information is very hard to come by online and even calling Grizzly doesn’t get you much more than what is in the manual. We should have a thread for people to put in their measured dimensions from these heads for others to use as a reference.


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

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