Helical cutterhead difficulties

[Kevin Jenness]

I prefer Tersa carbide for jointer/planer. I get about 1-1.5 years from a set of knives.

Brian, why do you prefer Tersa for this application?

For comparison, I get about the same time between sharpening on my carbide jointer knives. Of course I have no idea of our relative volume. I would say I sharpen my hss planer knives 5 or 6 times more frequently.

[Brian Holcombe]

I prefer it for ease of swapping knives.

[Jim Eisenstein]

Thanks, Brian. I'm not really familiar with Tersa, but are these carbide straight knives retrofitted into a pre-existing machine?

[Joe Calhoon]

I ran about 500 feet of Teak for a contractor a while back with no noticeable wear on the carbide Tersa on my S4S machine. I would think carbide spiral would be the same. One Teak board will will wipe out HSS knives. With Tersa HSS will not last long in anything other than clear softwoods. M42 is a little better but will chip easy if any knots. Since I work a wide variety of material I use mostly coated HSS like the Kanafusa Tersa clones and carbide. I have not been totally happy with the Tersa brand of carbide. It does not seem to cut as well as Leitz carbide carbide clones I had in the S4S machine for a while. At the moment I am trying Rangate’s diamond coated Tersa in the planer. Too soon to see how they do. At first I did not think the coated Kanafusa Tersa were that good but after much use those hold up really well. I do run 2 knives in all my Tersa heads.
At least now with the Tersa patent expired there are several choices. I recently looked at a Martin spiral planer and jointer in a local shop and was pretty impressed with the finish off those and even though Tersa is pretty quiet these were really quiet.

I expect to get finished surfaces off my jointer and planer. Way back with straight HSS I always expected to have to sand most species after planing.

[Ronald Blue]

I installed a Grizzly insert head on my Jet 6" jointer a couple months ago. It had been returned and was in their scratch and dent room. It had a missing insert and a damaged one. I installed a new one and turned the damaged one. It leaves a glass smooth finish. I've not ran any exotics over it but can't imagine any different results. Post a photo or two showing your insert head. Something is wonky here.

[Jim Eisenstein]

Something is wonky for sure. Attached photo show 1 of 4 rows of inserts on the cutterhead. Other rows appear
the same. As bad as the scalloping looked in the previous photo (taken in oblique illumination), the scallops are
in reality only about 0.002" deep (via feeler gauge). Might be hard to detect this by eyeing the inserts.

inserts_IMG_6278.jpg

[Ronald Blue]

So if you hit the board with a sander does it "smooth" up quickly? Usually when you can see the irregularity it's bad enough to be an issue. Doesn't make sense especially since it was good in the beginning.

[Jim Eisenstein]

don't know, haven't tried. in general I would be heading to the planer for thicknessing after face jointing. the planer produces an excellent surface.

[Erik Loza]

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?

”No” to seating issues and “Yeah, probably” to the SCMI planer comment. In my experience, shops don’t really keep track of board-feet. They address it when boards start getting so streaky that guys are spending a lot of time sanding (assuming they don’t have a widebelt, which some don’t).

I have really never had major complaints with spiral heads. Once in a while you will get boards with tricky grain that cause problems. One of my local shops showed me a few walnut boards where the spiral cutterhead had lightly chunked out areas behind the eyes in the grain but I don’t think straight-knife would have done any better. I’ve seen Tersa do the same in white oak with similar character. The conclusion we came to was try feeding from the other end or angling the board if possible. Some boards are just tricky no matter what type of head you have.

Erik

[Mark e Kessler]

”No” to seating issues and “Yeah, probably” to the SCMI planer comment. In my experience, shops don’t really keep track of board-feet. They address it when boards start getting so streaky that guys are spending a lot of time sanding (assuming they don’t have a widebelt, which some don’t).

I have really never had major complaints with spiral heads. Once in a while you will get boards with tricky grain that cause problems. One of my local shops showed me a few walnut boards where the spiral cutterhead had lightly chunked out areas behind the eyes in the grain but I don’t think straight-knife would have done any better. I’ve seen Tersa do the same in white oak with similar character. The conclusion we came to was try feeding from the other end or angling the board if possible. Some boards are just tricky no matter what type of head you have.

Erik

Btw, i occasionally have a small area of tear out around Walnut knots, twisty turny interlocked areas and i just wet the trouble spots and no more tear out - most WW’rs probably know this bit thought i would mention it.

Also am amazed that i can take a .2mm pass on the ad941 with perfect results, no infeed/outfeed marks on hardwood being able to take that slim of a pass with constant results handles the tricky spots pretty good. If I am running a lot of pine for example i just take a little pressure off the infeed and outfeed rollers so it leaves no marks on a light pass

[Erik Loza]

Btw, i occasionally have a small area of tear out around Walnut knots, twisty turny interlocked areas and i just wet the trouble spots and no more tear out - most WW’rs probably know this bit thought i would mention it….

Ditto here. I think part of this Felder’s fault: Marketing Silent Power as some magical silver bullet for every board, every woodworker when the reality is that there are varying levels of experience on part of the operator, part of the board selection, and part of the expectation of results. All this being said, I still feel the spiral gives the ownership experience most folks are looking for more than any straight-knife system. Tersas are wonderful but I think we will see a day where your only option is a spiral head, from any manufacturer. We sell a mountain of jointer/planers and I can’t recall seeing any order that wasn’t spiral.

Erik

[Mitch schiffer]

I get a better finish with my powermatic jointer with their helical head which has about 1 inch long 2 sided carbide inserts then I did with my previous grizzly helical jointer. I was told by my dealer when I bought the grizzly jointer several years back to get the helical head (model g0858 i believe) then the spiral head (model g0490x). My understanding is the spiral versions that grizzly offers are much lower quality then the helical version.

[Alex Zeller]

If I had to guess I would say it's the inserts, not the head since the results change as you move/ turn the inserts. The inserts are mass produced at a very low price. I think I might try 10 of another brand and change then on just one side so when you run a board through the jointer you can see if that part of the board looks better than the rest. I remember that some of the replacement inserts through Grizzly were stupidly expensive. I think I would either try Carbide processors or Hermance (who I planned on checking with when the inserts on my 1033x need replacing). Both sell inserts made in Germany.