Helical cutterhead difficulties

[Bob Falk]

I put a helical head on my Woodmaster 18" planer and have planed hundreds of feet of hardwoods and softwoods. I have yet to rotate the cutters and it still cuts beautifully. Love the fact that it is lower noise.

[Erik Loza]

…Do carbide inserts last any longer than carbide Tersa knives? A hobby user might never wear out their first inserts, but a commercial shop certainly would…

No idea! I never actually talked to a hobby customer who ended up splurging for a head full of carbide Tersas. Once they heard the price from Simantech or whoever, that conversation was over!

…Here's Sam Blasco's opinion. https://www.elitemetaltools.com/arti...expert-opinion…

Sam didn’t write that. I did. Probably around 2012, when I sold for SCM. It was from a page on my sales site….

5FDD92E8-CBF4-4318-A98C-D96FDD0A0782.jpg

Sam might have inserted a little testimonial in the middle but rest is direct copy-and-paste from my site. That was when I was trying to sell Tersa against Felder Silent Power. I still stand by all those statemements: Tersa is awesome and has many advantages over spirals but having sold (and used) a good spiral head for several years now, I do think it is what most ww’ers are truly looking for in an ownership experience. There must be something to this, since both SCM and Martin now offer their own spiral heads in addition to Tersa. By the way, I can order any Felder machine with a Tersa head and gladly do that but it’s simply not a request we ever seem to get.

Carbide spirals have Kryptonite?

Warren even better: Dust, ground from the bones of angry old woodworkers.

Erik

[Andrew Hughes]

Teak has sand in it. So you are saying that the carbide tersa didnt last and were replaced with the carbide spiral? Carbide spirals have Kryptonite?

Sand and oils it’s a double whammy. I’d wager a box of Daniel Webster cigars most run the carbide insert past the point of sharpness. I would like to know what super tungsten knives are like. My machine has a badge says they were offered 60 years ago.
I had a set of hss street knives that had a black oxide coating on the face they were very long lasting. But they were not the proper thickness for my machine to stopped using them. Through them out so I wouldn’t be tempted .

[Warren Lake]

im old Erik but not angry, I am blunt and there is enough nonsense on enough posts. I never joined the rat race.

[Kevin Jenness]

im old Erik but not angry, I am blunt and there is enough nonsense on enough posts. I never joined the rat race.

Blunt, but never dull.

[John Lanciani]

Seems like a fair comparison would be between carbide Tersa and carbide inserts. Four carbide knives from Tersaknives.com cost $548.80, or $224.40 per knife change. https://tersaknives.com/products/car...nt=14070872646 108 Byrd inserts for a 16" cutterhead replacement for a Powermatic 160 cost $4,482, $1,120.50 per changeout. https://byrdtoolexperts.com/checkout Are other brands of inserts less expensive? Do carbide inserts last any longer than carbide Tersa knives? A hobby user might never wear out their first inserts, but a commercial shop

I think I recall that Joe Calhoon runs 2 carbide knives and 2 dummies in his Tersa jointer.

Here's Sam Blasco's opinion. https://www.elitemetaltools.com/arti...expert-opinion

I have no horse in this race. I have a 16" jointer with carbide straight knives and a Powermatic 160 with an onboard grinder. I have a 10* face bevel on my planer knives for diminished tearout. I know from limited experience that the helical heads are far quieter, easier on dust collection due to smaller chips and better on highly figured woods than straight knives.

You added a zero to the price of the Byrd inserts; they are priced per 10, not $41.50 each. Big differrnce.

[Warren Lake]

I like teak. I let a friend use my shop over 40 years ago and he trashed my knives with Teak. Letting him use the shop was a good thing as he worked in a top shop and info was shared.

[Kevin Jenness]

"Do carbide inserts last any longer than carbide Tersa knives? "

Do

No idea! I never actually talked to a hobby customer who ended up splurging for a head full of carbide Tersas. Once they heard the price from Simantech or whoever, that conversation was over!


Erik

It seems like a question that I would want answered if I were contemplating Tersa vs helical.

Since you have sold numerous insert head machines, do you have an answer to the original poster's question?

[Warren Lake]

The machine I priced a tersa for think was about 7k canadian without the knives. Ive never not been able to do a job so far on old school stuff.

If you asked me to run 500 feet of teak then for sure im not set up for that and would have to figure it out if I wanted to take the work. Esta has the drop in knives but dont think they have carbide. Combo machine wont have a head replaced when a saw is on one side and a mortiser on the other end of the shaft.

[Kevin Jenness]

You added a zero to the price of the Byrd inserts; they are priced per 10, not $41.50 each. Big differrnce.

John, thanks for the correction. That would make the material cost of swapping out the inserts $112.05 vs. $274.40 for 4 knives in a Tersa head, a significant difference. If one ran two tersa knives in a jointer the difference would be halved. What would the relative labor cost be at let's say $75 per hour? Two minutes for tersa and an hour for inserts? Then there is the question of longevity of inserts vs Tersa, which I can't answer.

[Erik Loza]

…It seems like a question that I would want answered if I were contemplating Tersa vs helical.

Let’s put it like this: I see every every spare parts order that goes through my sales territory and rarely see orders for replacement inserts. Now, to be fair, probably 80% of the machines in my area are in hobbyists’ garages, so you might never actually need to buy replacement inserts under that level of usage (which actually I suppose is a selling point in and of itself, since we took orders for Tersa knives left and right during my Italian days…) but the larger message is that spirals definitely require less “involvement” from the ownership standpoint than Tersa.

I recently placed an order for a complete set of replacement inserts for a local pro shop on their 16” machine. 60-something inserts, it was several hundred dollars. He works only with domestic hardwoods and his machine was around five years old. Way more board-feet through that machine than a hobbyist would ever see. This was the first time he actually purchased any new inserts and just wanted to do it all at once. I’ve never actually run the numbers but just off the top of my head, it could easily be 4X-5X the costs over the life of the machine if carbide Tersas. If you hit a nail with a spiral head, it will fracture one insert but if you hit a nail with a carbide Tersa, that knife goes in the trash. Again, this is not sales schtick. There’s probably a pretty good reason why Martin (the most die-hard of die-hard Tersa flag bearers) came out with a spiral head.

Erik

[Kevin Jenness]

Let’s put it like this: I see every every spare parts order that goes through my sales territory and rarely see orders for replacement inserts. Now, to be fair, probably 80% of the machines in my area are in hobbyists’ garages, so you might never actually need to buy replacement inserts under that level of usage (which actually I suppose is a selling point in and of itself, since we took orders for Tersa knives left and right during my Italian days…) but the larger message is that spirals definitely require less “involvement” from the ownership standpoint than Tersa.

I recently placed an order for a complete set of replacement inserts for a local pro shop on their 16” machine. 60-something inserts, it was several hundred dollars. He works only with domestic hardwoods and his machine was around five years old. Way more board-feet through that machine than a hobbyist would ever see. This was the first time he actually purchased any new inserts and just wanted to do it all at once. I’ve never actually run the numbers but just off the top of my head, it could easily be 4X-5X the costs over the life of the machine if carbide Tersas. If you hit a nail with a spiral head, it will fracture one insert but if you hit a nail with a carbide Tersa, that knife goes in the trash. Again, this is not sales schtick. There’s probably a pretty good reason why Martin (the most die-hard of die-hard Tersa flag bearers) came out with a spiral head.

Erik

Thanks, Erik. Have you ever fielded any complaints about insert seating like the one that started this thread? If I were buying new I would lean toward spiral/helical but for that worry. The typical minor "ghost lines" I have seen would not bother me.

The shop I used to work at first swapped out the inserts on their new SCMI planer after several hundred hours of use. Would you say that is a fair average for domestic woods?

[Jim Eisenstein]

Well, this thread has evolved well beyond my experience and expense level. It seems to me that a hobbyist machine
like my Grizzly 8" ought to be able to produce decent results without the user having to be a NASA engineer. I am
in fact a retired professor of physics with *lots* of experience with equipment far more complex than a jointer. And
yet there it is; I've not been able to get the thing back into decent shape. If and when I do, I'll repost. In the meantime here's a photo
of a typical recent result from my jointer on poplar. It ain't acceptable to me.

ridges_IMG_6277.jpg

[Frank Pratt]

Well, this thread has evolved well beyond my experience and expense level. It seems to me that a hobbyist machine
like my Grizzly 8" ought to be able to produce decent results without the user having to be a NASA engineer. I am
in fact a retired professor of physics with *lots* of experience with equipment far more complex than a jointer. And
yet there it is; I've not been able to get the thing back into decent shape. If and when I do, I'll repost. In the meantime here's a photo
of a typical recent result from my jointer on poplar. It ain't acceptable to me.

ridges_IMG_6277.jpg

I was about to post a reply about how people should not expect a finish ready surface right off the planer or jointer, but that board is pretty awful. It would take more than a couple of light passes with a sander to get that out.

[Brian Holcombe]

I would contact the manufacturer. I use a lot of insert carbide for machining and they are always easy to reinstall.

I prefer Tersa carbide for jointer/planer. I get about 1-1.5 years from a set of knives. I generally do not run exotics, there is a local shop near me that runs a lot of exotics and I’d be amazed if spiral knives actually do last longer since their knives always seem perpetually worn out. Teak and sandy woods just beat up cutters.