Upgrading my 12" jointer to a Shelix head and testing it. Cut quality is improved, but there's more to it than that. The carbide shelix head is not a clear win. More about my homemade jointer: woodgears.ca/jointer/homemade....
The sound at 3:35 when the shelix head spins down is a damaged bearing somewhere. When new lubricated bearings are turned by hand there should be no noise at all, and absolutely no feeling of "bumpiness".
@@WikiSnapper Yes. I wonder if the bearing was installed by beating it on with a hammer, or if the assembly was dropped on to the bearing at the factory.
I can't lie, I'm actually really impressed by the low severity of injury on this one, I probably would have cut myself so often I'd bleed out before running the second test batch.
It's like when you become obsessed with getting your chisels and plane irons to ultimate sharpness, and they only need to look at you to draw blood. 😬 Either that or I am getting clumsy in my old age.
Those old bearings look to have a Metal Dust Shield (part number ending with Z or 2Z) the new bearing is a Rubber Seal (part number ending with RS or 2RS). Rubber seals will naturally create more drag.
More Drag - Yes. Like 500 Watts more drag? No. That would immediately melt the rubber completely off, or ignite it more likely. Its prob 50/50 Grease, Air resistance and maybe slightly missaligned bearings causing pinching.
@@marcoschwanenberger3127 I took his "more drag" comment to mean the difference between spinning freely and stopping themselves earlier. Not so much the power consumption.
@@Scoots1994 his old bearings definitely have zero grease left in them. Those things are bone dry. Even oil would stop free spinning. They're pretty low load so they might not even need grease, so that might be all the better for him to save on efficiency.
@@F0XD1E Problem with metal shield bearings and grease in wood processing machines is the dust - the dryer the better. Wooddust on grease ignites in a bearing easily once it is enough to increase friction - even worse with a wooden corpus. the dust-on-oil/grease is the reason why historic machinery was openly oiled twice a day in amounts to wash the collected dust to the outide of the bearing. A bloody mess and a problem for finished surfaces not yet coated, but the way to keep the machine running without going through bearings weekly. In this case here though I'd go for the alignment with Matthias' planer, because a dry, slightly worn bearing is way more forgiving than a new tight greased one.
@@manfredschmalbach9023 Bearings on some of the steam driven stuff I used to 'engineer' on, like the Riverboat at Disney had CONSTANT oiling from clear cups so you could see when they needed filling, and the tops had a pull and tilt to turn the flow off when not running, and a screw under that tilt do dad to adjust the flow. It made a mess if you had the flow set too high, and it seemed like most everywhere you had to get to wipe the mess off was hotter than H E double hockey sticks. These were mostly VERY low speed bearings, some of them like like 12 RPM,on the paddle wheel and nothing over about 150 RPM. They were mostly babbet type bearings, IIRC.
For the general hobbyist (like myself), perhaps noise and power consumption are secondary concerns to output quality and maintenance (including cost). For me, I love the result of my helical cutters and know that should I (lord forbid) cause my thicknesser any damage, it's a relatively minor cost to replace only 1 or 2 cutters rather than a blade. Love your tenacity and methodology as always! Cheers from Sydney, Dave
This is great information! I installed a similar head on my planer and love the results but never looked into the power consumption. That’s why these videos are great, they are always full of information that I didn’t know I was interested in!
The ATTENTION TO DETAIL in all aspects of all your videos! It's apparent that you know a ton about experimental design and the details that you include in your videos are highly educational and remind me constantly to be just as vigilant when designing and executing my own experiments!
There might be a problem with bearings or balance. I put a shelix head on my 6” jointer and the performance was night and day. Although almost noting can beat freshly sharpened flat heads for a smooth finish, I had to resharpen almost every day with heavy usage. The shelix cuts like butter, laughs at most knots, and is ~4 times quieter (I didn’t do tests but my ears and the people around are thanking me) and I haven’t even rotated a single blade in over a year.
Yeah there's really no replacement for sharp tools. Once you see what sharp tools can do then you always just want to use your tools when they're sharp. So what that ultimately means is you have to get really good at sharpening. It's a vicious cycle. I look at my tools under a microscope now to see how sharp they are. It gives another perspective on matters. Now I want a better microscope, of course. I just have a cheap USB one now. I was looking at saw teeth the other day with it. Very interesting.
Watch out for those knots. I put a pine board through my Dewalt thicknesser and the shelix head pulled out a loose knot which was so hard that as it bounced around inside the machine it completely wrecked the cutter head - not just the cutters - it bent back many of the cutter seats machined into the head, parts of them were torn and split. It didn’t do the thicknesser much good either. I managed to sort out the machine, but the head was a right off. It’s as it there had been a steel nut bouncing around in there.
@@1pcfred I recommend the Edge-On-Up sharpness tester - gives more quantitative information than a microscope image. That feedback helped me improve my sharpening a lot.
@@paulkolodner2445 what I did to improve my sharpening was just sharpen stuff for over 50 years. Maybe there's something else I can do to improve? I've an open mind. Just between you and me though I kind of doubt it. But we'll see.
I put a Shelix head in my Dewalt 735 planer and it made a HUGE difference both in terms of noise volume, finish quality and ease of use on my machine as I can take off more material easier. And if you do get a nick in a blade, you just rotate the one blade a quarter turn and keep on going. The carbine cutters last way longer than HSS.
That's awesome because so far my steel knives have lasted me 25 years. So way longer would be like lifetimes. Of course I sharpen my knives pretty often. I bought another set of knives but I've never used them yet. They're still sitting in a drawer.
@@1pcfred if your knives are that old, it's possible the quality of steel was better when they were made because a lot of HSS cutters now dull quite easily. I'd also like to know how often you're putting lumber through your machine as I read a review by one fella who said he's run over 5000 board feet through his shelix head on one project and they still cut like new.
@@krenwregget7667 I do not know if my knives are HSS. Maybe? I do know they take a sharp edge. I've passed some pretty bad wood through them too. Like pallet wood. Although that's not all the same. A board foot is a measure of volume, not area. So it is not easy to figure out how much surface 5,000 board feet really is. I used to run my planer more than I do now. I'll only break it out today if I have to plane a lot of wood. Which isn't too often anymore.
The bearings on your old cutter head appear to be metal shielded. The ones you're comparing it to are rubber sealed. Metal shields Don't make contact between the shield and the inner race like the rubber seal bearings do so they will spin more freely. That being said they probably shouldn't spin that freely. They also don't sound very good. It's not really easy or practical to repack metal shielded bearings because the metal shields usually get distorted / destroyed during removal. Best just to replace them
Cheers from Belgrade, Serbia i watched almost all of your videos, you have interesting take on wood and exhibitionist ideas, so its fun to watch, and you dont lose nerves when things goes badly, which is nice
Oh, COOL! The noise, surely you recognize that. It's the exact same effect as your homemade siren, the dust collector pulling air through is alternately stopped/passed as the blades close and open the gap between themselves and the bed. Paused @ 01:12, I bet the shelix head doesn't do that since the flow is never fully stopped.
I also recently replaced the straight blade cutter head in my planer for a helical cutter head. There's definitely something wrong with yours, or the installation, based on the sound. With my dust extractor running, I literally cannot tell whether the planer is turned on or off, it's that quiet.
For Canadian viewers, there's a Canadian company called Sheartak in Kitchener-Waterloo that makes custom helical cutter heads. They have tons in stock, and can make one for just about anything. Cheaper than Shelix.
I’ve got a Sheartak head in the 510 wide felder jointer. It’s amazing. They are not Canadian. Heads are made and shipped from China, but service is first rate and they are very responsive.
@@gl7662 Sheartak includes shipping, and also 5 free replacement cutters. Try completing that Shelix order, you will find that your total goes up to $608 before adding any cutters. Add another $45 for 10 replacement cutters. And add a surprise amount of brokerage fees when it arrives at your door from the US. In many cases the price difference is more dramatic. My order from Sheartak for a Shopsmith cutter head was $590, from Shelix it would have been about $1000.
I had a 6" helical head jointer with a 1.5hp motor. It clearly was underpowered and a pain to use on hardwood. I swapped it out for a 3hp motor and it was like night and day. Completely transformed the jointer from a pain to an absolute dream to use. I am not surprised therefore that you were using twice as much power with the new helical head, because that is exactly what my anecdotal experience says would happen.
I did a power comparison with the SHELIX and OEM knives in the DW735 planer. The SHELIX drew less power under no load (around 3 amps less), but more power under load (around 5 amps more).
maybe already said in comments, the most important variable to recognize is the comparison in cut quality between hss and carbide. when things are easy the comps might be similar, but when things are difficult a carbide anything is going to outperform hss because it’s harder and stays sharper longer. Great work, Matthias. I appreciate your unbiased approach and the interesting discoveries that result.
Even if the insert cutter performs the same with higher power consumption, the increased longevity will be a big benefit. Also, it might be easier to rotate those inserts than to change out the old blades.
Good stuff! I can’t argue with your measured results, so I won’t try. I installed a Lux spiral cutter in my Dewalt 735X planer several months ago. I always wear eye and hearing protection since the planer and dust collector make so much noise together, therefore I don’t really notice a sound difference. I do see a dramatic increase in cut quality, however. My dust collection has seemed to improve with the smaller cuttings, which I appreciate. The Lux head was very expensive, but I would do this upgrade again.
Setting aside bearings and noise, the cut quality was not the unambiguous, major improvement I was expecting. Thanks for the comparison (round 1 I suspect).
Yeah and Mathias didn't even sharpen the steel knives either. While he put them up against brand new carbide inserts. Plus with the heavy cut that's worst case for the steel knives too. It favors the inserts more.
I really appreciate this video. My jointer came with a spiral head, and I have no interest in changing that out, but I have been on the fence on changing the head for my planer. I like how the carbide heads don't need replaced as often but using more juice makes me hesitant because my shop struggles with that already.
I'm still running my original knives and they're decades old now. Of course they've been sharpened countless times between then and now. They still got life left in them too.
Are your power consumption concerns related to cost, inadequate service or both? I occasionally trip a breaker, but never have given a thought to the cost of running my planer or table saw for any given project.
@@marshallmurrell4583 I have 3 outlets in my entire shop, and so I have power bars with breakers in them that all of my tools are plugged into. It's not ideal but my shop isn't large and I do hobby wood working not professional work. The breakers in the power bars pop under too much load. I only ever run 1 tool at a time (and my dust collector which has its own breaker because it pulls all the juice).
First off I absolutely love your videos and have been watching them for many years, but I do have to say that homemade jointer is the most terrifying thing I’ve ever seen, my solid steel jointer is terrifying and it’s solid as a rock, but those heavy, razor sharp blades spinning up to a thousand or more rpms is just beyond scary, it’s truly amazing that those two small pieces of birch ply have kept that thing from seriously hurting you or even killing you buddy, as always stay safe truly. I’ve made some dumb mistakes as all true woodworkers have and have seen even more had have to say the worst are always jointer and table saw with routers close thereafter, I’ve witnessed someone mutilate their hand on a jointer after hitting a knot( which they should have paid attention too before even beginning) as well as my self loosing the top of my right ring finger after a board took off like a rocket! Please stay safe Matt
Yeah I don't trust those wooden bearing blocks whatsoever, there's a lot of energy in that cutter. Would be nice if a machining channel made him some steel or alloy bearing blocks that he could properly bolt down rather than using deck screws.
I love your way of thinking and how you try to deal with engineering challenges through experimental measurements. I think that the best way to measure the efficiency of each planner head is to measure directly the cutting force under constant feeding speed and load (as you did), not the power consumption. Bearings have increased power loses when rotating under load. If you know the forces acting on a bearing then you can estimate the power losses with a simple calculation. Most bearing manufacturers provide rolling resistance (friction) factors for their products.
I grew up with that old style blade head and it was always very loud but a friend of mine got a new planer with a Shelix head and it was so quiet we could have a normal conversation over it running. Even with the new head cutting it was quiet enough you could still loudly talk without having to shout.
Hey, great video. It has never occurred to me to make a shop built planer, and you have done a nice job of it. I'll be checking your old videos in a bit to see if you covered it. I really don't think you can regrease sealed bearings, and if they are noisy and that free running, they need replacing. It's not like they are super expensive. We used to have a DeWalt thicknesser at my Menz Shed that had HSS blades. It was so noisy I couldn't consider getting one for my home shop. We now have a cast iron 15" Macma thicknesser with helical heads which is _much_ quieter. It also doesn't clog the dust extractor when used with damp wood. It does still leave slight lines across the timber, but not as bad as the DeWalt, and I didn't fit the inserts and, sad to say, some of the Shed lads are not flash with their workshop practices.
Something to explore swap the cutterhead bearings side to side to see where the vibration may be coming from. I found a bearing issue by mounting a dial indicator to outfield table ( mine is magnetic 😉) with the probe over each bearing cap. Shows up very quickly.
I think the bearings are out. or something. if you can, protect your hands, push hard on the bearings, and roll the cutter. It should roll silently, and have no play. I would not be surprised if the cutters bearings got damaged 'cause shipping decided to play kickball with the crate
The helical head (lux cut, a shelix clone) vibrates noticeably more than the original straight knife head in my DeWalt planer. Overall I'm not in love with it. I *do* love the shelix I installed on my jointer though.
You could also stick some of this sound dampening material which is used in cars on the inside of the jointer to get rid of some of the noise. They prevent that the wood could start to swing and act like a resonance body
I've noticed on my own jointer that I can often use it without dust collection for shallow cuts and can turn on dust collection after to dispose of the chips stored in the dust port. Perhaps you can test a reduced amount of airflow to see if that helps with the noise. You might find that you don't need such powerful suction to achieve perfect results. After all, planer chips aren't the dangerous super-fine dust anyways, so you might find the noise to be more pollution than a small pile of chips to be swept later.
Great comparison video! I've always wondered: Would it be a good idea to make a jointer with an oblique cutter head? I mean: the traditional one but installed in a diagonal. Maybe it pushes wood laterally? Maybe it's a great uprgrade. And obviously should have both tables modified (in and out). Hope to hear you opinions!
I wonder if you redesigned your dust collection orifice, by adding some baffles and maybe taper it away from where the cutter head meets the planer bed. Seems like you have created a chamber the wants to amplify the sound and pumping action of the air flow around the orifice/blade. Food for thought.
I just took delivery of a Shelix head I ordered 50 weeks prior for a Dewalt planer. Nothing against the company, they were up front about lead times when I ordered. They are popular and therfore the line is long.
Suggestion: you could install a spring to pull the guard back over the spinning head once you finish the cut. A few years ago Jamie from Perkins Builder Brothers channel found out how unforgiving an unguarded jointer is ...
i put one of those on my dewalt planer.. it was like a whole new machine; no longer did it blow the breaker, even with heavy cuts, and it cuts MUCH cleaner than the stock cutterhead that it came with. if you there is one single thing you can do to your planer to upgrade it, it's getting a helical cutterhead for it.. can't reccomend it enough. When I bought a new edger, I specifically looked for one with a helical head on it...
Yay, helical heads take more power, but run smoother and way quieter cutting. There is something up with that head you have there. Been running a LuxCut in my dewalt planer and its unreal how much better and longer lasting they are! Do a LOT of reclaimed 200yr old oak and the stock knives would go dull and be useless after 6-8 runs.. havent changed the lux cut blades yet, they really are better!
I just mentioned this in another comment. Our HSS bladed thicknesser used to clog the dust extractor port when using less than perfectly dry timber. The helical head thickness does not have this problem because the shavings it makes are small chips rather than long strands. The finish is better and the thing I personally like best is that it is way quieter. Not even as loud as a table saw. The DeWalt thickness we used to use was so loud I couldn't possibly have bought one for my home shop.
The carbide inserts have a grade tolerance on the edge position relative to the seat, not sure if those are tight or loose tolerance, so not sure if the lines can get better or not. I suppose in madness you could get a bunch of loose ones and fit it to each seat measuring edge alignment.
The noise that matters to me is when you're actually planing. With my DeWalt the shelix is much quieter (with the straight blades you could hear it a few blocks away). However, I'm unhappy with the finish quality of the shelix.
I would definitely pursue this further. Seems like it needs a wee bit of tweaking lol. My company is still a strong believer in the standard straight knife cutter heads and doesn’t want to shell out money for spiral carbide cutters. We run everything through our wide belt to clean up the material but it’s never perfect. All they’re more expensive I still think this is the way to go
The difference is quite huge. Especially when one does hit a nail and you have to turn an insert versus change/sharpen the blades. Also Carbide stays sharp a very long time compared to STeel.
I replaced my 8" jointer head with a Byrd Shelix Cutterhead. It had 40 cutters on an 8" head. The difference was night and day. Quieter, smoother cut and to sharpen, just rotate the heads and there's NO OUTFEED TABLE ADJUSTMENT NEEDED! Yay!!!!!
I wonder if the layered sawdust on the outfeed had become almost a part of the build over the tears. It's as if the machine ended up making things function with the sawdust present. I had a similar issue after removing the dust from the nooks and crannies on my old pantorouter cabinet. (It gives me an excuse to redesign it with linear rods lol.)
Been looking forward for this to come out after you mentioned getting it in, so long ago it seems! Hope those quirky issues you have get sorted and it performs better. The increase in power is a common observation, as instead of taking two intermittent cuts, it's under a constant load from the staggered teeth. The power increase while not cutting doesn't make as much sense, as that'd be either a difference in air resistance on the carbide knives versus two steel blades, or bearing issues.
Did an 8 inch shelix head on a Delta jointer. Should have done that years ago, won't be going back to straight knives. Quieter, smoother and have yet to rotate the inserts.
The drastic increase in planing power consumption can be attributed to a continuous cut. With your conventional head, you're only cutting for a fraction of every revolution...the knives are only hitting three times per revolution even though the contact area is higher in comparison. The shelix head is basically always guaranteeing that some part of a cutter is in contact with the wood (with the contact area lower) so the motor is always under load and doesn't have time to do any kind of speed recovery that would help with cutting momentum. I run a Shelix on my 735X and have noticed how uncomfortably warm the plug gets now. I wouldn't say that it leaves a superior finish per se, it just leaves micro waves that are much easier to sand and blend than what I might deal with with straight knife gouging...or worse, chunks missing out of a knife.
This actually does not make any sense, physics wise. If anything the continuous load should use LESS power. It is probably the cutter geometry. The shelix is probably making smaller chips or doing more damage to the chips than the straight knife.
@@NGinuity Compare it to router bits with a straight flute vs spiral cut. A straight knife is going to briefly impart a very large force since it's cutting the entire width of the board, whereas the helical cutter only has a very small cutting edge in contact with the wood at any time. However the helical cutter has a new edge going into the wood continuously, where the straight knife head has a relatively large gap between cuts. Power consumption might average out - small continual force, vs large intermittent force. But I would make the argument that the intermittent cutting is less efficient because of all the vibration it creates.
My Dewalt 735 with a Shelix cuts so smooth, it is like I don't even need to sand after. I take shallow cuts so maybe that is it. No problem with little snipes with each carbide insert either.
How hard do you think it would be to add an indicator gauge calibrated with the infeed table to show how much material you're removing, or is it easy enough to use a gauge that it wouldn't be worth it?
That helix head is way out of balance, interesting because of all the balance holes. Lol Those bearings on your old head should be replaced, 11 years is a good life and no amount of regreasing will make up for any minor damage done to the internals. They probably should be replaced with 2rs (rubber sealed) bearings rather than the ZZ that are on it, better for high dust applications. I also think new bearings on the head would bring the idle power up to similar to the helix, and running the bearings in on both will bring it down a bit. I think one of the main advantages of a helix head is longevity, the carbide stands up way better to abuse not just nails but dirty wood, paint etc. And if it gets dull you can flip all the bits a quarter turn for a fresh cut. There was a good Frank Howarth video where he showed this by jointing about a km of old painted benches. I wonder if it's the same as metal working where carbide works better with a higher chip load (about10 times high speed steel)? Either higher RPM or deeper cut, would be interesting to see. Anyway great video!
You have to find that problem! My shelix is whisper quiet in my jointer and much louder in my yellow Dewalt planer. That thing is dangerous.(I think, I don't actually know) Also! I didn't think I had a miss aligned cutter in my planer and I thought I bent something. I'll go take a look next time and maybe I just shifted a cutter on the pallet garbage I was running thru there. I was afraid to look.
A thought about getting the fairest comparison: would not splitting a board on the bandsaw and then planing each half of the book matched pair on either planer give the most comparable result?
Is the Shelix head heavier than the old head. On my DeWalt DW735 planer, I think the default head was aluminum and thus a lot lighter than the Shelix I replaced it with.
Sounds like the ball bearings are trashed or have no lubricant. Trouble may be the bearing supports are out of line. Loosen the bearing block screws a little while you hand-turn the motor pulley. Keep the belt on. Smear a little finish on the wood to see the cross-marks. You really shouldn't be supporting that high-speed spinning blade with wooden supports! If either of them failed, you would have "raging cat claws" in the shop.
The pulley retention nut removal process had me screaming at the screen! I thought you would lose a 1.2mm layer from your leg if that mamma jamma went flying. The head vibration is scary. I am curious if your bearing blocks are not co-linear and cause you excess friction. Twist on the bearing races could be causing the shaft to cam over or Lean the outer races. Good luck and keep sharing your Mad-Scientific-Methodologies with your grateful masses! -CY Castor
@@matthiaswandel But you removed them and it appeared you re-installed them (or tried to) in the old screw holes. I think that might have caused some misalignment that you would not have had with a metal base, metal blocks and bolts.
@@matthiaswandel Slightly worn, bone dry metal-shielded bearings are way more forgiving in terms of alignment than brandnew rubbersealed tight ones. It can also start self-energizing cycles depending on amount of disalignment and rounds per minute with "whipping" tendency of the cutterhead once every factor's maximum should come together in a "shit hits the fan" moment. We once had a cracking cutterhead (spiral blade, dead-stop emergency brake allegedly saved us from complete disintegration of the head) in the first sawmill/planing factory I worked. Later assessment showed too worn-down bearing-holders in combination to an imbalance of the cutting head, after all was bent in place again and counterbalanced on an industrial balancer. Bearings were still in spec, their holding blocks weren't any more, single digit grams out of balance was enough to wreck it with the whipping tendency.
That nut spinner or whatever it was that kept edging closer to the running head due to vibration was driving me nuts. Also some tight metal pins to locate those bearing caps would help with that problem, as you said, screws or bolts are LOUSY locating devices, especially wood screws. Big stuff out of spec, like you are talking about is frightening, the kind of stuff that can end careers, and on rare occasions, even lives. Some of the 'safety features' on tools any more make the damned things far more dangerous. Not necessarily even bad design in some cases but horrible sticky flimsy crap. I just took the one off of my table saw because trying to start a board through it was absolutely risky. Some safety stuff is designed exactly as it should be, usually on high end or industrial tools.
@@MrJdsenior I worked as a selfemployed boatbuilder for over 30 yrs and rented machine rooms near my very work sites/customer's boats over that time. It got worse over those years, in terms of "safety": often I had to remove "safety features" in the way of my work for two or three hours - and put it back on after I was done cutting, thicknessing, planing and routing my strips'n boards, curves and rounds, when I was technically ready to leave. It became so bad I finally built a mid size boatbuilder's workshop in a trailer I could completely open, both sides became the awnings to work out of the weather in and on both sides of that thing, just to not have to mess around with "legal safety devices" making a lot of my work undoable on "legal" machinery anymore. You gotta know pretty well whatcha doing and have to keep Your regular as the irregular loads in sight and checked. You can only do that as long as there aren't any employees or even apprentices working with You. That makes safety and safety devices such a nuisance: You gotta make anything as vandal-proof as You can imagine vandal idiocy of Your employees, and then the deciding little sum of vandal idiocy more You couldn't even imagine yourself in a delirious stupor.
I always thought that the carbide blades were susposed to be more effecient cutting because of the angle they cut at and they slice at the wood rather than slap it. But maybe because there is more cutting surface it does take more energy, even at no load because of air resistance.
Yep. The wood mounting, being less rigid, would allow a small out of balance to swing out by centrifugal force and become a larger amplitude of out of balance. In other words the flexibility of wood increases the amount of vibration. I think his jointer is unique in having an all wood mounting system for the rotating blade. Not much experience to go by.
MW what was the source of your shelix head/ size and cost carbide square count and type (some are wedge edged and use a corner). Would a higher quality sample make a big difference and best quality bearing are the absolutely parallel.
I’ve heard/read that the reason that the Shelix head consumes more power is because there are cutters in contact with the wood at all times because of the spiral design. That’s not the case with straight cutters. I’m not sure if that argument holds water but it’s a possibility.
I'd be interested to see a new set of knives vs new shelix, and then perhaps over time you can keep track of hold long it takes before the shelix heads start losing cut quality, and need rotating. I think it's pretty accepted the Shelix is better, on some level, but the up front cost is huge, and replacement cutters are expensive, so it'd be interesting to know the durability, to compare cost over time.
I think people prefer the helical carbide cutters better because they're just too lazy to sharpen steel knives. They want to avoid the whole work aspect of woodworking as much as possible.
The bearings are mounted in a wooden holder which is mounted on a wooden frame. This may permit much higher amplitude vibrations. In other words the shelix needs a very rigid mounting system. All metal. On the other hand, it may be seriously out of balance compared to the knives. Still an open question.......
I saw when you inserted the new cutter-head and bearings in your bearing blocks, it seemed to get in pretty smoothly without any force (at least the first one). On your bandsaws I remember the fitting had to be tight, in order to prevent it from working loose. Am I correct, that in this plander configuration the bearings are not prone to work themselves loose so easily as on a bandsaw?