Disappointed with (Byrd etc) cutterheads...

[Mike Palmer]

I have had both types. I can say without exception that the spiral is much quieter and provides a better finished cut. I have a Casadei J/P with a cutter head that has two spriral knives that shear the wood. It is a different design from the segmented type but the concept is the same.

[Andy London]

Andy,

Do you have the Byrd shelix or another spiral brand? And on what brand jointer if I may ask. I'm interested in the specifics because I'm thinking of buying one and have considered the Sunhill on sale at Amazon for $199.

Thanks a lot, Rick

It is the Byrd on a very old Delta.

[Jack Easton]

There was also a review in the August 05 issue of Woodshop News, "The Cutting edge" or something like that, where the reviewer compared the spirals to tersa to standard. When I get home, I'll see if I can find it. He tested three catagories, and the tersa won all three. I have worked with both in a production environment (we had the spiral - pretty sure it was a Byrd - in the SCMI planer, and tersa in the Martin planer) Both planers worked equally well, but the tersa head offered more options, like being able to change knife types (from HSS to Carbide - or we generally kept 12" of the head HSS and the other 12" carbide and would use the side of the planer that was more appropriate), and knife changes, in general were easier. The spiral was a little quieter, but in a big shop you couldn't really notice. I had been talking about this for years, but the spirals seem to have caught on as a silver bullet in the last couple of years, so I kept my mouth shut. Don't get me wrong, the byrd head worked fine (just hope one of the screws don't freeze), but when I started my own shop, I sought out and got a planer with tersa head. Take that for what it is worth. For the average guy, coming from standard cutter heads, either system would be a joy to move to.

[Dev Emch]

Bear a few facts in mind.

1). A true helical cutter head has a continous spiral or helix shaped cutting edge. Northfield and others have made these knives and they are a royal pain! A second version has shown up via schmidt in NJ that uses a series of one sided inserts to achieve the same affect.

2). A standard helical insert head uses industry standard four sided inserts. Pockets are machined along a helical sprial or lead angle. One side of the insert is facing the wood directly as the planing process occurs. In other words, the centerline of the insert retaining bolts are along a helical arc but the cutting edge of each individual insert is parallel to the axis of the main cutter cylinder.

4). SHELIX heads are identical to standard helical heads with but one exception. The pocket for the insert is cut at a positve angle between the cutting edge of the insert and the axis of the cutter cylinder. This produces the same affect of skew cutting a board on your wide jointer. It is a shearing cut which is better suited to heavy figure. You also see hand tool guys planing wood with a smoother at a slight angle and not straight on. Same thing. Its a shearing cut.

5). ITCH heads are only available or were only available for oliver machines. It is an alternate approach but not necessarily the best approach.

6). TERSA heads are straight knife heads. Clearly they can complete with most straight knife applications in which new knives are installed and dialed in. But there is no way they can complete head on with a heavy duty machine using a full bore, in place, knife grinder. The reason is simple. During the final grinding stage, a stone is run across the head with the cylinder running. This stone is held on the traverse ways of the grinder and this joints the top of the knives to be identical. In this case, all knives are cutting.

No one else is jointing cutter head knives with but one exception. In extreme high speed moulder operations, the moulders are running at such an insane speed that it is required to joint each cutter head. Here, you will find jointing stones shaped to the exact profile of the cutter head. This sets the cutting circle to the exact height and allows wood to fly through these machines. Needless to say, these stones cost some coin and profiles subject to this treatment will be run for extremely long runs to justify the tooling costs.

7). I do not know much about the Newman head. But, many of these companies did borrow ideas (and employees) from each other all the time. So surfice it to say that if the newman head is insert based, it will most likely resemble the ITCH head. Newman and later Newman Whitney were known for some of the huge lumber yard planers where ITCH type heads were heavily used.

8). ITCH stands for Individual Toothed Carbide Head. So playing it really loose, I guess we can call all these heads including the shelix head ITCH heads.