Comparing Insert Cutterheads
Do the differences in cutting tooth alignment between different brands of insert cutterhead matter? January 8, 2010
Question
We are in the final stages of make a planer purchase and trying to determine whether spending the extra money for a Byrd Shelix spiral cutterhead is worth the money over a typical spiral cutterhead. I understand the physical difference of the layout of the blade edge along the cutterhead cylinder but would like to know if the finish on the wood has a noticeable difference or is this just another marketing tool that doesn't improve the final result. Is there someone who would be willing to offer an opinion?
Forum Responses
(Solid Wood Machining Forum)
From contributor S:
What do you mean by a "typical" spiral head? I'm not sure I know all of the different types that are out there. My Byrd Shelix has small segmented carbide blades that are about 1cm square and can be rotated to get a fresh edge if one of the cutters gets a ding in it. It is my only spiral head so I cannot compare it to another but compared to a straight knife head there is no comparison. The Shelix runs much quieter, uses less power, increases the depth of cut, works smoothly on figured wood with no tearout and as an added bonus, creates small chips versus long ribbon shavings so there is less problems with plugging in the dust pipes and compacts more in the collection barrels so we spend less down-time changing dust barrels. I think any spiral head that uses small indexed cutters would give the same or similar results.
I think the advantages I found are from the fact that because it is a spiral, only one or two of the 1cm knives is in contact at a given time so the noise is much less and the power required to cut that one or two cm's is much less than compared to a straight blade that has all 12" or more in contact at a given time. Other brands of spirals that use small indexed knives would most likely give similar results.
As far as quality of finish, it is nearly perfect but does need a light finish sand to make perfect. There are very small lines that can form between the individual knives if not perfectly set but I find them to be less of a problem than the typical chatter marks created by straight blade knives. If you're really concerned about the finish quality, you should look for a planer that will also run at multiple feed rates - faster for roughing and slower for finish.
From the original questioner:
Thank you for your response. I was referring to "typical" as a spiral cutterhead where the inserts are square to the axis of the cylinder so the cutting edge of the insert does line up with one another and therefore, look stairstepped. In other words, the edge of the inserts stair steps down in a spiral parallel to the axis of the cutting head. In the Byrd cutting head, the inserts are cocked at a slight angle to the axis of the cutting head. When you look at the cutting edge of the Byrd inserts the line is straight, albeit helical, but still straight. The slight angle allows the cutting edge of the each insert to line up with the previous and next insert corner to corner and is supposed to allow for a shearing action as opposed to a cutting action of the "typical" cutterhead that I was referring to. If anyone could enlighten more, I would greatly appreciate it.
From contributor C:
To contributor S: I believe there are differences within spiral heads. Some are true spirals where the individual knives are set at an angle to the cut, and staggered knife heads where the knives are set parallel to the cut. That's all I know, I've never had the chance to compare the two styles. Maybe someone who has could shed some light on it as I would also like to see if anyone has found a discernable difference.
From contributor S:
To the original questioner: got it. I couldn't answer that because like I said the Byrd is my only spiral head. My guess is that the Byrd would cut better because the line is continuous if all be it spiral. If it were stepped I imagine it would tear more between the steps but that’s just a guess. Hopefully someone can answer it because I am considering upgrading to a double sided planer and the models I am looking at come in several spiral head types.
From contributor F:
See and I thought the other spiral being referred to was an actual spiral cutterhead, as opposed to a carbide insert head. I had a spiral insert cutterhead and it performs as others say. I traded it because the machine it was attached to was underpowered and couldn't keep up with the amount of work I wanted it to do. I now have the same size (capacity 20") planer but an industrial version with on board knife grinder, and I don't miss the insert head a bit. Oh and the other spiral type head has knives which spiral around the cutter-head. Never used one but haven't heard good things about them so good luck.
From contributor E:
I have run both. I have a Byrd Shelix cutterhead in my planer and I run Weinig spirals in my moulder. The Weinig's have the inserts set parallel with cutterhhead vs. the shear angle of the Byrd. I see no difference between them. I actually like the Weinig's better though. Weinig has the inserts set in a three sided pocket which assures that each inset is set properly. When I rotate inserts in the Byrd, there are usually a couple of inserts I have to track down that didn't get seated properly. Even though the Weinig's don't have the shear angle I still don't notice any tearout in my material being planed. Now if you're comparing the Byrd to some of the Chiwanse spirals, by all means go with the Byrd. Precision machining is still the name of the game when it comes to cutterheads.
From contributor I:
I agree with contributor E that the insert heads with the knife parallel to the cut is much easier to set. The Byrd head is hard to set up so that you do not see the pass of each individual knife. I have a Northtech insert head on my planer and much prefer to the Shelix head on my neighbors machine.
From contributor D:
I can't tell the difference and have been using these for about 7-8 years. I once ran a piece of rock hard gnarly crotch mahogany through identical planers, one with the Chinese spiral head, the other a retrofitted Byrd head at different angles. I couldn't see a difference.
From contributor S:
I am looking at purchasing a new double sided planer and specifically looking at Extrema. It appears to be about the same as the Bridgewood, Cantek, Lobo, Northfield, Silver, Sunhill, Northtech, Activa, and maybe others. All of them offer these spiral heads we are discussing but does anyone have experience with the different machines? Any advice toward or away from a particular machine?
From contributor F:
I can tell you the 20" Bridgewood is about the same planer as the Grizzly and it was certainly not worth the $4K it cost me. Northfield is some of the best equipment on the market and one of the last remaining made in the USA manufacturers. Not cheap though so be prepared for sticker shock. Also not in the same class as the other manufactures, these are machines that should last several lifetimes. I can't help you with the other companies as I haven't had and firsthand interaction with them.
