Troubleshooting Jointer Chatter

A chatter problem in a new jointer sets off a discussion of knife types and maintenance issues. December 26, 2006

We recently purchased a new jointer that has a Tersa cutterhead. I'm far from impressed with its performance. I've never heard anything but great things about these heads. This is why I'm wondering if we're doing something wrong. On our old traditional knife machine, you could joint a piece 8 feet long with one finger on the back of the board. Now pieces are much harder to push through. Also, there is so much chatter it is unbelievable! The pieces just bounce on the head if you don't apply enough pressure. Obviously, this goes against the whole concept of jointing. Any suggestions?

Forum Responses
(Architectural Woodworking Forum)
From contributor A:
Our Tersa heads are superior to almost any other tooling we use in our shop. If the knives are new, are installed properly, and the head is mounted on the spindle in the proper rotational direction, then I think you should look to the new jointer. If the new jointer is brand new from the manufacturer and is a 3 phase piece of equipment, could it be rotating the wrong direction? If the new jointer is a used piece of equipment, the possibility of a shaft runout comes into play. FYI, for our Terminus heads, we usually have purchased HSS inserts instead of carbide. But if you process massive amounts of lumber, you might prefer the carbide inserts.

From the original questioner:
Thanks for the response. The new jointer is brand spankin' new and most certainly is rotating in the right direction. It just has the tendency to be chattery and I don't know why.

From contributor R:
Unless the head's bearings are bad, it can't be the head. I can't believe Tersa would send out a bad one unless the one you have was made under license and was bad for some reason. I did have one with bad bearings, though.

From contributor D:
My Tersa experience is with a new planer. While the knife change is very easy, the Tersa knives have a very slight projection, working as a chop limiting design. Therefore, the feed rate is also limited. So a slight cut, slow feed - all relative - may be what you see. We certainly see our high powered planer labor to feed a board past the Tersa, with just a 1/8" cut. I think this may be due to EU safety standards.

I grew up with a Northfield Patternmakers 24" direct drive joiner (5" round head, 3 knives) that would face a 12" plank at 1/4" without much thought or pushing. One finger was all that was needed if the board wasn't too heavy. That is how we taught people to joint - one finger.

As a result of what I've seen with the planer, I would hesitate to buy a joiner with a Tersa. Would you mind mentioning the brand name?

From the original questioner:
The jointer is a Laguna 16". I'm not exactly sure who is making it for them, but a quick look at some of the European machines and you could probably figure it out. I really like the machine in every other aspect, however I guess the Tersa head is something to get used to.

From contributor B:
The fact that it is by Laguna could be part of the problem. Many purchasers of that brand, including myself, have complained loudly over the years both here and in other forums… as well as directly to them. They tend to be helpful in the support department early on. Speak with them, explain the problem, and see if you can quickly resolve the issue. If it drags on, though, without resolution, they tend to become less responsive.

From contributor D:
It may be worthwhile to repost in the Solid Wood Machining Forum. It would be best to get several more opinions on this. It would be most desirable to push some wood on a Martin, SCM, SAC, Panhans, or other Tersa equipped machine to see how it compares to your Laguna.

We have gotten used to the Tersa in the planer, but I don't like to have to change my ways for a machine that should be an improvement. Coincidentally, we started up a Quattromat at the same time as the Tersa planer. The Weinig has proprietary quick change heads similar to Tersa, but the machine just hums and can remove lots of wood fast.

I'm the opposite of a fan of Laguna, left over from a bad band saw experience. They have been using Eastern European castings, Isreali machining and electricals from god-knows-where. We had total electrical failure twice, and one almost started a fire at closing time with a melted capacitor jury-rigged to make a Euro motor run on American 3 phase. They were absolutely no help whatsoever on parts, advice, or help.

From the original questioner:
I have to agree with your assessment of Laguna. However, we purchased a shaper from them a few years ago and it is absolutely awesome. It is easily half the price of the big boys and works, in my opinion, better. The funny story is this - it came wired completely wrong from them. Luckily I have a great electrician and within a few hours, he had it up and running. Cost me about $300, still a lot less than the 4k or so more that an SCM or a Paoloni cost. That is why we decided on the Laguna, because we like the shaper so much (and the price).

Anyway, I was hesitant to mention the name because I am fully aware of their reputation and didn't want to get people judging my question based on the brand. A jointer is probably the most basic of all the big power tools. Two beds and a spinning head. There's not a lot there to be a problem. The head spins with no wobble and also seems to be very true. I've checked it all over with a dial gauge. The beds are perfect as well as the fence, even though it is insignificant to our discussion. I'm convinced that it is due to the minimal knife protrusion.

Can anyone out there with a Tersa on their jointer tell me that they can take a 1x4x8 and run it over the jointer with just a finger at the back and not get any chatter? We used to be able to do this with our old traditional knife Delta (to a degree).

From contributor M:
I have a jointer with a Tersa head in it and it wouldn't be a problem pushing a 1x4x8 with a finger when the knives are sharp. A possible source for your problem, especially if it's brand new, is that the heads are shipped with the cheapest knives they make and are only good for a few hundred feet before they get dull and get chipped edges. I run the carbide ones in mine and don't have any issues keeping a board flat on the table. On a recent run of poplar, I was taking 5mm off the faces before going into the planer without any problems. Also, the lack of projection of the edge doesn't limit the depth of cut, either. I have taken 8mm at times, although I wasn't using one finger to push it.

From contributor T:
We have a 20 inch Martin jointer with a Tersa head and 24 inch SAC planer with a Tersa head. They both work like you would want them to. We also have an SCM Sintex 4-side planer with Terminus heads. The Terminus head knives last a lot longer than the Tersa knives. We use M42 steel in the Tersa knives.

From contributor B:
Another thought. Have you checked the head mounting bolts? If they aren't fully torqued down, you could be getting chatter in the head under load.

Also, contributor T is right about the Terminus knives. I can't believe how long they last in my Powermatic 8" jointer. I'm actually almost embarrassed to admit how long it's been since they were changed. They just keep cutting clean and sharp, though!

From contributor M:
One last thing to check. Not all Tersa cutterheads are the same diameter. In the old Inca jointer/planers, I think they were around 78mm. In the Minimax and Felder machines, they are 87mm. The one I have is a 125mm. If you have one of the smaller ones, that would explain a lot. There is no way you can feed a board easily with one of the smaller diameter heads.

Also as an aside, I have never been pleased with the life of the Tersa HSS knives. I once had a Terminus salesmen explain that because they are so thin, there is a harmonic setup that causes them to wear out fast. He did say that the Tersa carbide lasts as long as theirs, but not the HSS. Take it for what it's worth - it was a Terminus salesperson that was telling me that.

From contributor L:
I have Tersa heads in our Martin jointer, planer and S4S. We never experienced the problem the questioner describes, and it is possible to take a 10mm deep cut on any of the machines if we needed that. Contributor M is right - if you have the chrome knives, they will be trash after just a few boards. We run 2 knives in all the 4 knife heads on the planer and S4S for the sake of economy and the cut seems about as good. For difficult or figured wood, we can slip in the other 2 knives if needed. 2 are easier on the dust collection, also. With the jointer being a hand feed machine except for power feed facing, it is a little different. Hand feeding or edging, you can feel the difference in pressure between 2 knives and 4. Our jointer is set up with 4 knives the first 100mm operator’s side and 2 knives the rest of the head. That seems to be a good compromise.

Like contributor M, I have been disappointed in the life and chipping of Tersa HSS. It is due to the thinness and knife angle. They make a flawless cut at first, but go downhill fast. If you only ran CVG fir, they would be great. For the past year we have been running Leitz clones in the S4S. Kanefusa is going to have a clone also. The Leitz are good - we ran the S4S 6 months on one set and now have their carbide in. The Leitz HSS is a little thicker and little different knife angle from the Tersa. The first cuts are not as good as Tersa, but stay consistent for a long time. They are less prone to knife chips from knots than the Tersa. The Leitz carbide seems about the same as Tersa.