Spiral/Helical cutter heads: quality??
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Those of you who have used jointers with spiral or helical cutterheads, how do the results stack up against straight knives? The advantage of being able to rotate (or replace) individual inserts in these cutterheads is what the companies tout, but I’m seeing in a recent review that they might result in a surface pretty different from what the straight blades produce — prominent ridges in some cases. Even the “helical strip knives” such as found on the Sunhill CT-204L seemed to do this.
Wood Magazine is the first I know of that has presented information on the surfaces produced by these cutters, and I was surprised by their results — What’s your in-shop experience??? Especially with non-figured wood.
forestgirl — you can take the girl out of the forest, but you can’t take the forest out of the girl 😉
Another proud member of the “I Rocked With ToolDoc Club” …. :>)
Replies
I have the Grizzly G0543 jointer with 40 carbide inserts. I have not noticed any tracks when using this tool. I recently built some knife storage blocks and after the glue up I ran the laminated side on the jointer to true it up. I then trimmed the other side with a TS. I used birds eye maple and cherry and the jointer did a nice job on the laminated side without worring about what way the grain was going.
Life is what happens to you when you're making other plans .
FG,
Great question. I hope you get some more responses. I've seen several reviews of jointers and planers, and while everyone discussed the theoretical pros and cons of the insert type cutter head, no one has given them a real test except for the one article you referenced.
Hi Forestgirl,
I have the Byrd head on my 8" Grizzly jointer. It's a real nice cutter head, it makes a very acceptable finish. I don't notice any difference when sanding.
Figured wood and straight grain cut just as well.
It's really quiet.
I don't get the "glass smooth" finish that sharp, fresh knives give, but that only lasts for the first few boards anyway.
Grizzly is now selling retro fit cutter heads that use a different brand of insert, it doesn't have a radius but it's less expensive too. I have no experience with those.
Bill
Thanks to Bill and Jerry. Others who have these cutterheads, please add your comments. If you have a chance to look at the Wood Magazine review, you could let us know if you see similar surfaces when you face-joint. As BD mentioned above, Wood seems to be the only magazine that has done a comparison of surface. It's be curious if their results don't match anything WWers are seeing in their shops.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
I'm sort of selfishly posting to keep this thread at the top. I too am interested in more information about the advantages of a helical cutterhead over straight blades. In FWW's recent review of jointers, there was a sidebar about helical cutter heads. I'll try to find it, but the short version is that the reviewer didn't think there was enough improvement in cut to warrant the difference in cost. Beyond that, I have to wonder about how the segmented helical cutter head will work out over a longer term. It's great that you can replace just a few of the segmented cutters if you nick them, but the recently replaced (new) ones will be less worn than the remaining (old) others. Seems to me this would create some inconsistency in the cut. I think I've read every thread on this subject and it seems like for every post of praise, there's one of someone complaining of "railroad" tracks in the cut. As FG said, more input would be greatly appreciated.
One thing that I really like about the carbide cutter head is that I can join glued edges. If I ran glued edges on a HSS cutter head I would have nicks on the knife where the glue joint was. This has not happened with the spiral head. If I do nick a cutter or two I can just rotate the bad cutters. I have not had to do this in the year and a half that I have had the G0543. You do have to be very carefully when rotating cutters. Make sure both mating surfaces are spotless as even a film of oil could cause the cutter to be higher and cause tracks.
Life is what happens to you when you're making other plans .
"I'm sort of selfishly posting to keep this thread at the top." Why not? There's gotta be more than one or two people out there with these cutterheads, one would think.
For those who haven't seen the Wood article, they took cuts with the different styles of cutterheads (straight, helical strip, square inserts, radiused inserts), testing with curly white oak, lacewood, and bird's-eye maple, plus regular hard maple. They used a feed rate of "about 1" per second." They state that the surfaces looked smooth, but did not all feel smooth, so they rubbed chalk over the jointed faces. The chalk "revealed ridges -- some wide, some narrow -- on the spiral-cut samples" which sanded away easily. They provide color photos in the article.
So, in theory these cutterheads may not produce the same quality surface as a straight knife does, but in practice, does it matter? Need the folks using them in their shops to answer that question.
One last tidbit: "Manufacturers of the tested spiral-cutterhead jointers weren't surprised by our findings. Grizzly's Bill Crofutt explained that a difference of as little as .0005"...in the size of an insert (or its pocket in the cutterhead) can create a slightly uneven surface. 'Even a layer of machine oil can cause that, so you need to be meticulously clean when installing inserts,' says Crofutt."
Doesn't seem like there's any doubt that they do a superb job on figured wood.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-) Do unto others as you tell them they should do unto you....
I recently bought the Grizzly G0593 8" jointer with the spiral cutter head. I set it up 2 weeks ago and have only run maybe 50 bf through it so far- poplar, red oak, some soft woods and a little bit of birdseye maple. The jointed surface is quite smooth, although I'd probably scrape it or smooth it before finishing. No real tear out, even with the birdseye.
I saw the article in Wood, but my experience doesn't conform to their remarks about the spiral cutter head surface. I also don't think the jointed surface needs to be flawless- it needs to be flat and the face and edge need to be true. I got the spiral head because I think carbide is a better choice for jointing, its more durable, and easier to change the heads. You can set up HSS knives and hit a knot the same afternoon and you're back to square one.
My 2p,
Glaucon
If you don't think too good, then don't think too much...
I have the insert head in my 25" planer. The folks at Woodmaster were quite up front when I bought the head and told me that I would get some lines on the stock when using this head. I don't have a problem with this on my planer because I am going to hand plane or sand these surfaces, however the surfaces coming from my jointer are the ones I depend on for glueing and I don't want uneven surfaces in these situations. Besides I can change my jointer knives in 30 to 45 minutes, planer knives are a whole different story and I was glad to be rid of that chore.RonEdited 1/26/2006 11:49 pm ET by Ronaway
Edited 1/26/2006 11:50 pm ET by Ronaway
FG,
I have a j/p comb and have a Tersa head in it. I have the choice of using HSS, Chrome, M42 and Carbide knives. I have been using HSS and get very good results. The best part of a Tersa head is the speed of knife changes, the knives are self aligning, and the knives are double sided. The knives are held in by three wedges. You tap each wedge down and then slide out the knife. You can either flip the knife over and use the other side or slide in a new knife. Now you repeat this procedure for all the knives and then turn on the machine. The wedges are forced to the edge of the head and the knives are locked in, thats it. Now the HSS knives i have are extremely sharp and will slice your finger open with just a glance (don't ask me how I know) give glass smooth results and can be changed in a breeze.....I do not know why anyone would want anything else. The idea of spinning all of those little cutters does not intrigue me one bit
Forest girl,
I've been debating this whole issue for a long time, and can't justify the cost yet. maybe if i was in a production mill planing wood for other people all day long. One other thing i considered was carbide insert straight blades. I've found them for $290 for my 20" planer. THis is a big difference between the new insert head. What gets me is how easy honing planer and jointer knives in the head is. I think most people don't know about doing this, but i seem to be able to do it about 4 times before actually removing the blades, which is after a mountain of wood, maybe 2,000+ bd ft run thorugh mulitiple times. What i bought, that makes a big difference, is grizzlies cheap 20" knife grinder. Its tricky, but for less than $200 you don't send your knives anywhere. you have to be careful with it b/c it runs too fast, and doesn't use water, so it burns real easy. There is some crappy plastic parts in the assembly that holds the massive cast iron blade guide, which i've been meaning to rebuild myself with steel, or weld it in place. Once this is set up for your knives, sharpening HSS is easy, quick, and resetting the knives shouldn't be that difficult.
One thing on Carbide straight knives, i can't sharpen, and they want $1.50 per inch on my 20" four knife machine, thats $120 to sharpen! Not gonna happen. You can buy much higher end HSS knives as well. I have yet to do this, but Grizzly told me the ones that come in there machines (like all the tooling that comes in their machines) is much softer than some of the harder HSS knives they sell seperately. Sounds worth a try. I know steel makes a huge difference in bandsaw blades, so might as well get the best in a planer blade!Let us know what you find out. How about the difference between Grizzlies cheap insert head and their byrd? Which one comes in their lower end machines?
I haven't seen the article. I have the a Grizzly 12" jointer with their spiral cutterhead. No "railroad tracks" here. Actually, I got one once, and found out one of the inserts was loose. The surface probably isn't as smooth as that done by just-sharpened knives. The same can be said of HSS router bits vs. carbide-tipped, but hardly anyone uses HSS router bits anymore. After the first sanding with 80 grit with the ROS, it doesn't matter.
Apparently some of the Shelix "shear cut" heads come with inserts with square sides, and some with inserts with radiused sides. The square inserts will cause ridges when they are tilted to get a "shear" cut, it's just basic geometry. To get a smooth cut, all the cutting edges of the cutterhead must lie on the surface of an (imaginary) cylinder. That's impossible for straight edges if they are not parallel to the axis of the cutterhead.
Just got the new Oliver 4240 10" Jointer this year with the Byrd Shelix Helical Cutterhead and the Carbide Inserts.
Absolutely love this machine!!!
I've noticed that the Byrd Shelix Helical cutters are arranged in a "true" helical shape. If you look at the carbide inserts on Grizzly jointers, you will notice that the blade is positioned at a 90-degree angle to the stock. The Byrd carbide inserts have a slight skew to the angle and actually form a more noticeable spiral around the cutterhead.
What difference does this "true" helical shape make in the cut? I haven't seen a side-by-side comparison so I won’t speculate.
In terms of the overall impact of carbide cutters on jointers/planers . . . the easiest comparison would be the impact that carbide has had on:
Router Bits, Circular Saw Blades, Band Saw Blades, Drill Bits, etc . . .
Is the surface glass smooth and ready for finish? No!
I am positive that a Spiral HSS blade would make a much smoother surface. However, that ability only lasts for a very short period of time. Eventually those blades will wear and the inevitable nick lines will start appearing. Then re-sharpening . . . and re-setting . . . and re-sharpening . . . and re-setting . . . and, well, you get the point.
As for the benefits that I have personally seen from the use of Carbide Inserts, I can include the following:
Longer life on the cutting edge . . . even after hitting a few random pieces of metal in some air-dried walnut slabs.
An unbelievable ability to avoid tear out in the nastiest figured woods . . . forget running your hand along a board to feel which way the fibers are lying before face jointing a board. The ability to reduce tear out has to be experienced first hand in order to believe it. The time you gain by not having to fix tear out will far surpass the extra couple seconds you spend making up the difference between the "glass" HSS Knife surface and carbide cutter surface.
Unbelievably quiet . . . the 10" jointer actually makes less noise than my 6" jointer with straight HSS knives.
I have yet to rotate the carbide inserts and I have recently heard stories about issues that may arise on surface quality when resetting the inserts. I will gladly post more information once I have undergone that experience . . . but with the longevity of these carbide inserts . . . that post may be a while.
- dsperling
FG, Are you drawing any conclusions yet?
Hmmmmm, conclusions? Well, we haven't had a huge number of people reply yet. But so far, it seems like whatever lines or ridges or whatever do appear on the stock, they're easily taken care of by sanding that would be necessary anyway, so the practical impact would seem next-to-nill.
One question I forgot to ask is whether one must take much less stock per pass than with straight cutters -- that's another thing I've heard, somewhere.
Having had my first maple experience recently, I can see the attraction the spiral or helical cutter heads might have, for sure.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-) Do unto others as you tell them they should do unto you....
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