Replies

1. 
   jjf | Jan 21, 2004 07:41pm | #1

   helical knives are a definit advantage for lower noise and less tare outs.

2. 
   VeniciaL | Jan 21, 2004 08:12pm | #2

   John,

   Once things are properly adjusted, you probably will be happy with the spiral knife setup.

   But I don't believe you will find a significant difference regarding tear out and other problems associated with a rotary cutterhead and problem grain. The spiral cutter will cut down on noise, mainly because knives are always in the wood and the loud component of the noise caused by the entire width of a straight blade hitting the tissue is reduced. I believe the tear out improvement is wishful thinking or mostly hype from the manufacturers. But some spiral heads may be better than others.

   Once things are properly adjusted, please let us know your experiences.

   VL

3. 
   toolpoor | Jan 22, 2004 05:18am | #3

   You raise an interesting question. Helical cutterheads are now an option on many jointers down to 6 inch, and on 15 inch and up planers. Some of the ads are claiming much reduced tear-out with these heads. The heads are expensive, running from $400 up to $1200 for small shop equipment. As I am now about to buy a new jointer and planer, and am seriously considering equipping both with these cutterheads, I would like to see some posts from those that are using them. The essential question is " Do they reduce tear-out in figured wood beyond that obtainable with 4-knife heads?". The cost of equipping a 15" planer with a shelix design head is within $200 of the initial cost of the planer. I do not want to find after purchase, that the surface finish improvement is not there, or is actually worse. Curley maple and birdseye are tough to finish free of tearout on a 3 knife cutterhead, even after back beveling the blades, and wetting the board slightly before planing a light (1/32) pass. I would expect the 4 knife heads are somewhat better, and the ads would have me believing the helical heads are better still. It would be nice to hear from those with experience with these, either good or bad. Thanks.

1. 
   VeniciaL | Jan 22, 2004 06:15am | #4

   Mainegywolfe,

   I have used a Grizzly 12" jointer with the Grizzly indexed cutter head. This is my only direct experience with such a machine, but I asked the same question you have of several owners of other spiral head machines.

   I have been working on a production of custom maple picture frames and have been very interested in eliminating tear out which has been a persistent problem.

   I had a chance to try out the machine in San Diego over the Christmas holidays.

   The advice I got from other spiral head cutter owners regarding reduction of tear out was I could expect a little improvement, but not that much to make a decision on that alone. The machine I used had an indexed head. I didn't get to test that feature but the owner told me the ability to rotate a new cutting surface into position was a big reason he uses the design. Each cutter has four sharp edges. When one edge is dull, a new one can easily be put in cutting position. This apparently saves a lot on down time for sharpening and setting knives.

   The machine was a dream to use. It just was so much MORE of a machine than my 6 and 8 inch models as to make them seem like toys. The cutting noise was VERY diferent from my straight knife machines. I don't know how much of the difference was due to the mass of the machine absobing noise or the spiral design. The sound was smoother, much lower in frequency than my machines. I can't really say it was lower in volume. But it was far less intrusive. The combination of the sound and the absolute mass and power of the machine made it seem like the wood was effortlessly being whisked away.

   I cut as much hard maple as I was able in about 15-20 minutes. Truth be told, the tear-out seemed no different than I am getting on my straight blade equipment.

   The owner said the machine was a "no brainer" and at less than $3500 had paid for itself immediately. It is marvelously productive. I watched his employee flatten 4/4 and 8/4, 13 footers, 6 to 10 inches wide. Boards that I couldn't even comfortably move around. Of course, that had nothing to do with the spiral cutterhead.

   VL

4. 
   dlwheel | Jan 22, 2004 06:48am | #5

   John,

   Is this the Byrd cutterhead? I'm very much interested in putting an 8" head on my jointer.

   -David

1. 
   john | Jan 22, 2004 10:42am | #6

   I am very interested in any equipment that can plane and thickness woods with wild grain such as curly maple, but I really can't see how a helical head is going to be noticeably better than a conventional head. The cutting action is still going to be against the grain half the time, and that is the cause of tearout. I'm not planning to use any woods of this type until I have a decent sanding machine

   John

1. 
   jjf | Jan 22, 2004 04:14pm | #8

   All blades lift the grain in the direction of the grainand it is this that causes tear-out.  Helical blades cut partially across the grain not directly with the grain so the forces are less likely to cause tear-out.  Also if they do cause tear-out the blades are only about 1/4 of an inch wide so if the some tear-out does occurit is not as wide and the portion not being cut helps hold the tear-out back and reduces it.  One negative factor of them is that since they are many blades across if they are not all perfectly the same height, ( blade repalcement on a head that has been used alot) you get slight iregularities in surface altitude which are easily removed with the first sanding.

1. 
   JBD | Jan 22, 2004 06:05pm | #11

   Well it's about time someone posted the obvious (Jim)!!

   Haven't any of you ever used helical routerbits? Or even simpler, have you ever pared wood with a chisel or ran a jack plane across wood at an angle to get less tearout?  That is precisely the kind of cut a helical cutter is designed to do - to shear the wood fibers in an angular, slicing cut rather than a straight - on cut like standard knives.

   From a simple physics point of view, helical cutterheads HAVE to cut with less tearout.  If it does tearout with little difference, then the cutterhead is out of adjustment, not as sharp as it should be, or the helical twist rate is too shallow.  Be careful of some so-called "helical" heads that simply have staggered tooth, but straight cutters.  Its got to be true helical.   

   "The furniture designer is an architect." - Maurice DuFrenes (French Art Deco furniture designer, contemporary of Ruhlmann)

   http://www.pbase.com/dr_dichro

1. 
   Mackwood | Jan 22, 2004 10:33pm | #16

   Okay, I'll be the one to show my ignorance; what is the difference:

   1. "True Helical"

   2. "Grizzly" type helical (with the multiple square cutters)

   3. "Byrd" head

   4. Any others out there??

   I'll try a google for "Byrd Cutter Head" and see what comes up but your insights would be appreciated.  I am going to purchase an 8" jointer and am considering the "head" options.

   Thanks for your time and patience!

   Mack 

   edit:  Been to google and learned some things.  Now understand that "Byrd" = true helical = SHELIX.  Understand the concept.  Now the $$ question.  For a guy that does hobby WW and almost always hand scrapes whatever comes off the jointer and planer, is the helical head worth the investment?

   Thanks again!

   Mack

   edit again:  Grizzly has "spiral" cutter head, which I now realize is way different (in theory at least) than the helical or SHELIX as marketing by Byrd.  From reading the posts on this thread I get the idea that the spiral offers minor improvement over the straight knives and the helical offers a big improvement over the spiral as it really skews the cutting edge to the surface.  Again, any insights you might offer would be welcome.  Thanks!

   Mack

   Edited 1/22/2004 3:00:43 PM ET by Mack

   Edited 1/22/2004 4:47:15 PM ET by Mack

2. 
   rslatm | Jan 22, 2004 11:33pm | #18

   Some spiral heads just have the cutters in a spiral pattern and aren't angled for the shear.

   Oliver and I think Powermatic have a HSS shear cut head which is pretty new and innovative... http://www.olivermachinery.net/Products/4270-16Jointer.html

   Carbide lasts a long time but HSS yields a sharper edge initially. Carbide is usually used by shops that deal with woods like teak or epoxy glue-ups.  As far as is it worth it...that's up to you to crunch the numbers.  I get good cuts on wild grain with my straight knives and can change them in a few minutes so I'm not gonna spend the money.

   Edited 1/22/2004 5:33:30 PM ET by Rick at Arch. Timber and Millwork

2. 
   JMartinsky | Jan 22, 2004 04:15pm | #9

   Yes, it is the Byrd cutter head. It seems to be a very nicely machined product, but again, the results were less than spectacular. Hopefully the new head will solve the problem. On the up side, Byrd has been VERY responsive. No questions, no send us the old one back first, jusy we'll send you a new one. Not bad for a $350.00+ item, unless the problem is so common that they are used to it by now. We'll see. The fellow who posted about the "Woodmaster", I like em too, but they are pricey. Woodmaster is offering a spiral head now although I don't know what the upcharge is.

   Thanks!

   John

1. 
   dlwheel | Jan 22, 2004 05:10pm | #10

   John,

   I've got the 8" G0500 Grizzly with 4 knives. Does a nice job; tolerances are okay; I back beveled to handle some wild grain. Although it worked well, jointing was a lot more effort; and made the machine work harder. I recently resharpened the blades and spent way too long tweaking them; getting them set within .002". By the time I was done, I was ready to spend the money to get the Byrd head.

   What problems did you experience with the head? Out of round; inserts not aligned?

   -David

1. 
   rslatm | Jan 22, 2004 06:30pm | #12

   What are using to set the knives? With my set-up I can zip right through a knife change. I did a 3 knife 12"  DJ30 and a 4 knife 20" planer in half an hour within .001" just the other day. Of course doing it professionally meant I perfected the technique.

   Edited 1/22/2004 10:32:31 AM ET by Rick at Arch. Timber and Millwork

1. 
   dlwheel | Jan 22, 2004 06:56pm | #13

   Rick,

   Well the machine comes with a "jig" that sets over the knives and against the housing; springs are used to provide "feed-back".

   The knives can be adjusted w/o the springs, as well, using jack screws.

   I don't have any problem getting them set to tolerances... but when i tighten up the gib bolts, i'm no longer within tolerances... very frustrating... so i use the jack screws and "anticipate" the amount of movement the tightening will cause. If i didn't have to do that, yes, i could be done in 30 minutes, rather than 2 hours.

   I know this is a lower end unit; no where near the quality of my SCM planer w. tersa head... but when it is set, it does what a jointer is supposed to do.

   What am i doing wrong?

   -David

2. 
   rslatm | Jan 22, 2004 08:12pm | #14

   I tighten the end screws just a bit and push them down slowly. I usually go .005" in at each side until I get to within .005 of where I want them to be then nudge them a few thousandths at a time. I typically have them just tight enough where I can still tap them down with a block of wood and a small hammer. I also know how much they will move when I do the final tightening.  Most of the time I've got the tension judged right so it doesn't move when I tighten the screws. I use dial indicator with a special base and a 1/2" convex button tip. I have a small tripod and indicator for smaller head planers. I typically always start the knives high and bring them down. Many heads don't have adjusters so I don't bother with them even if the head has them. 

   
3. 
   dlwheel | Jan 22, 2004 08:35pm | #15

   Rick,

   Thanks for the feed back. Your setup tools are better than mine. I have a Starrett magnetic base with dial indicator and a couple of other dial indicators but i need to get a better tip; but my problem is not the tip; but obviously my technique. The way you describe it, is about the way i ended up doing things. I'm done with it for several weeks; i'll do a better job next time... but the shelix byrd head may still be the way to go.

   Thanks again,

   -David

2. 
   JMartinsky | Jan 22, 2004 11:16pm | #17

   You have the machine I think that I should of gotten. The problem I am having is that I am getting "railroad tracks" down the length of the peice after jointing. They are not real pronounced, but they are there just the same. Byrd said that this not uncommon and that look is to be expected with a spiral, but I can feel them and they said that is NOT normal and will send me a new head. At this point, I am pretty sceptical of the whole spiral thing. With the stock knives on the PM, I barely had to sand, right now I DEFINITELY have to sand. I don't consider that an improvement. So, if that is the case I'd rather find out on a $350.00 6" head than a $1500.00 20" head. Do you use the "Dispoz-a-Blade" or stock knives?

   John

1. 
   dlwheel | Jan 22, 2004 11:34pm | #19

   John,

   You are right about the "railroad tracks" being associated with spiral cutters... but even with non-byrd cutters you shouldn't be able to "feel" it; something must be wrong. Everything I've heard about them is positive, both service and product. I think in the end you will be satisfied.

   I've talked to them about a cutterhead for my planer and that is NOT a small number.

   I think the G0500 jointer is one of the best values around; but do i wish i had a 12" jointer?... you bet!

   Good luck,

   -David

5. 
   creekwood | Jan 22, 2004 03:00pm | #7

   I don't know about the new heads, but I read with interest the posts on them so far. I have a 15" planer with a regular head, and have the problem with tearout on figured wood. I had a job a while back that called for curly maple. I called around and found someone with a thickness sander to help me out on the rough lumber, but he also had a Woodmaster. He took the infeed speed to just creeping, and the maple ran through with NO tearout. Came out as smooth as the proverbial baby's butt. So, that is the machine on the top of my wish list.

   Just a thought.