Shellix Head Question

[Chris Parks]

I was discussing and have been over the last few weeks the merits and shortcomings of both the Tersa Head and the Byrd Shellix type head on thicknessers, Eric from Minimax has taken the time to try and help with my stupid questions and I thank him taking the time to do that.

A question I have and it was put to me today was this...if a single carbide segment was changed an a Shellix head that had done a lot of work surely that new segment would be a different height and noticeable to the original segments. Has anyone got any thoughts, insights or experience with this?

The background to this is I am trying to decide between a Hammer A3-31 and a Minimax FS30 machine and the latter is nearly $2000 cheaper and $2000 will buy a lot of blades in my book. I can buy a 410mm wide Minimax for less than the Hammer (300mm) which is also appealing. I hate making decisions where thousands of dollars are involved. The reason for the price difference is the Hammer has a silent drive head and the MM has a Tersa head. Both give excellent results of course but I can't get away from the blade damage that inevitably results against the durability of the Silent Drive head.

[glenn bradley]

A question I have and it was put to me today was this...if a single carbide segment was changed an a Shellix head that had done a lot of work surely that new segment would be a different height and noticeable to the original segments. Has anyone got any thoughts, insights or experience with this?

I do have experience with this and my response will not be unique; a planer (or thicknesser) performs a task. This task is not to provide you with the final surface preparation of your blank. We would like it to be as smooth as possible but, even irregularities of a couple of thousandths of an inch will disappear at the first pass of a scraper, plane or sandpaper.

I am a big fan of insert heads and I know some (though not many) folks are not. They are less expensive over time, last a really long time between turning/replacement, are quieter and leave a wonderful finish on the curly and reversing grain woods I use. JMHO.

[Jim Andrew]

I have had 3 machines with the insert heads. Can't say I have seen noticeable wear on any of the inserts. The woodmaster I had, I bought the optional helical cutterhead, and it was a much larger diameter than others, and when a knot would come loose, it would crack an insert. Had to replace several in it. Sold it and bought a G0453px, and have not cracked a single insert in it. Only thing I have done is cleaned the cutters using the spray bit and sawblade cleaner, with a worn out toothbrush. The pitch does build up on your cutters. Have the Byrd cutterhead on my 12" jointer, really can't tell the difference from the Grizzly head. You really do have to push hard to flatten a wide piece on the jointer. They say a straight blade feeds slightly easier. But I didn't leave the straight blade in long enough to compare.
Only advice I would give is to get a big enough combo that you don't feel the need to move up. Costs money to move up. Sounds like the tersa blades are easy to change, with no adjustment, and the silent power cutterhead seems to use no more power than the straight cutterhead. I think if I were to get one I would want the widest I could get if I could afford it.

[Mike Wilkins]

If I could get a 410 MM capacity with the Tersa head, I would go in that direction. A planer is not a finish machine, although some machines can give a mirror smooth finish. I always run some type of sanding operation after planing, either hand-held or my double-drum. I have a 12" J/P machine, and after going through sharpenings and the eventual re-setting of the blades, I switched to the Dispo-A-Blade system of knives. Set up the knives to the outfeed one time, and you are set. And the blades are reversible.
I would love to get a 16" JP. Don't often find boards that wide, but I hate cutting down a wide plank just to get it through the jointing/planing operation.
My opinions are very low cost.

[Bill Orbine]

I do not notice anything of the cutting height when rotating a single (or a few) carbide inserts on a Byrd Shelix head on my 20" Powermatic planer. Even after having planed teak which is rough on tooling. For the most part, you should be fine with that as long as you do it right..... as some people reported having a little trouble seating the insert. Usually due to contamination like gum and dust.

Now.... try this on for size.... you can buy a Shelix for the FS30 from Byrd for about $1,150.00 and shipping. Something to think about.

[Chris Parks]

I do not notice anything of the cutting height when rotating a single (or a few) carbide inserts on a Byrd Shelix head on my 20" Powermatic planer. Even after having planed teak which is rough on tooling. For the most part, you should be fine with that as long as you do it right..... as some people reported having a little trouble seating the insert. Usually due to contamination like gum and dust.

Now.... try this on for size.... you can buy a Shelix for the FS30 from Byrd for about $1,150.00 and shipping. Something to think about.

I can get it cheaper than that from Holbren in the US.....http://holbren.com they do smoking deals on them as I found when I bought my last one. I have already spoken to them and the shipping is $160. By the time I buy and ship it the prices are so close I may as well buy the Hammer. The other problem is that fitting a shellix head myself will understandably not do much for the warranty. Anyone wanting a quality European machine and not needing a segmented head would be silly not to buy the FS30. The Felder straight blade machine does not have a Tersa head on it so can't be compared. Thanks to everyone who has contributed to the thread, it seems my question has been answered.

[David Kumm]

On a jointer planer combo the build of the machine and the ability to return the tables to exactly where they should be trumps the cutterhead style. I have straight knife. Esta, ITCH. Bryd and Tersa. Each has advantages and disadvantages but if I only had one machine, Tersa would be first just because I run rough lumber. If I ran all clean hit and miss partially planed wood the insert head might be first. Dave

[Chris Parks]

David, I thought it would be the other way round, for rough timber use the segmented head due to the likelihood of blade damage.

[Chris Padilla]

I have that 16" (410 mm) Tersa journal on my MM J/P (FS41 Elite) and zero experience with the various "insert" journals. Tersa knives are double-sided and pretty easy to swap out and there are no adjustments to make. I was quoted a cost of around $1.2k for a Byrd shelix to replace the Tersa. I've been extremely happy with my Tersa head but like I said, I have zero experience with these insert heads. Haven't even seen one in person or heard or used one ever. My journal takes 3 knives. I think the new ones might have 4?

[David Kumm]

David, I thought it would be the other way round, for rough timber use the segmented head due to the likelihood of blade damage.

No, like straight knives you can shift a tersa in seconds or swap out to an old set in minutes for crap wood. Turning a few inserts, cleaning them, and replacing takes longer. I try to avoid the insert heads except for fine finish planing although a good tersa on a good planer is about the same. The knife heads do require a better machine and the spiral will compensate for a lesser one. If running heavy cuts or lots of bd ft the straight knife is better than tersa due to the size of the knife and its ability to dissipate heat. Dave

[peter gagliardi]

I have a friend who was running the Tersa system in his Martin planer, and jointer, and asked him how he liked it- I run Terminus in my non-Martin machines. Anyway, he echoed Dave's thoughts, great system, but knife life was "abysmal" at best. I think the Terminus system has a little more life per knife, as there is more stock to them, but none of them compare in longevity to the old style HSS blades. Compromises.

[David Kumm]

Peter, I've been told that heavy users with Tersa should go the carbide route. I'm a low user ( weak work ethic and lots of planers ) so M42 works fine for me. Now that the patent for tersa has run out there are several choices for blades too. I don't use enough to have a preference but suspect the commercial guys do. Dave

[Rod Sheridan]

I have a friend who was running the Tersa system in his Martin planer, and jointer, and asked him how he liked it- I run Terminus in my non-Martin machines. Anyway, he echoed Dave's thoughts, great system, but knife life was "abysmal" at best. I think the Terminus system has a little more life per knife, as there is more stock to them, but none of them compare in longevity to the old style HSS blades. Compromises.

Interesting, I'm running the cobalt knives in my Hammer J/P and they last longer than the steel knives on my General did............Rod.

[Erik Loza]

I'm going to tread lightly for obvious reasons but this is my 2-cents on the whole Tersa-vs. spiral-thing...

1.) If someone has a problem with longevity/durability of Tersa knives, buy some carbide ones. It's not that they are any more expensive than carbide insert teeth for a spiral head. It's just that you're used to getting regular Tersa knives at regular Tersa knife prices. Carbide costs what carbide costs. It just seems less painful because you are buying these little tiny teeth verus a single straight knife.

Out of curiosity, I priced out what the cost would be for another mfr's cutterhead. Their 12" machine has one continuous row of 72 teeth and a box of ten insert teeth is $58. So, I actually need to order eight boxes in order to effectively "change all the knives", which would be $464. Now, that gives me four fresh cutting edges, so my actual cost per fresh edge would be $116.

Now, if I go to W Moore Profiles' site, 12" carbide Tersa knives are $82 each. I need three of those to do a complete knife change on a 12" J/P, which would be $246 and since Tersa has two edges per knife, my actual cost per fresh edge is $41.

So, it costs roughly 3X as much to replace the knives of a spiral head than it does with Tersa.

2.) Just like bandsaw blades, a lot of people obsess too much over "finish quality" of the board that comes out. As if it should be finish-ready all the time, every time, no matter the species of wood or the board-feet. Just like bandsaws, where everyone wants that one magic blade that gives you a finish-ready cut on green wood, dry wood, soft wood, hard wood, etc. Be realistic in your expectations.

3.) The whole point behind Tersa is speed and consistency/ fool-proofness of knife change. For shops, time is money and sometimes, the labor is less-than skilled at working on the machines. How many hundreds of board-feet could that flooring shop have run in the time it took them to rotate all the teeth on just one row of the head of a spiral 24" planer, for example? When lines start showing up in the boards, would he rather take 30 seconds to just scooch one of the knives over a bit or start hunting for the bad insert tooth? Does it help the owner's insurance rate when there is no possible way for a knife to installed incorrectly or fly loose of the head?

Be a smart consumer is all I am saying.

Erik Loza
Minimax USA

[Peter Quinn]

I'm going to tread lightly for obvious reasons but this is my 2-cents on the whole Tersa-vs. spiral-thing...

1.) If someone has a problem with longevity/durability of Tersa knives, buy some carbide ones. It's not that they are any more expensive than carbide insert teeth for a spiral head. It's just that you're used to getting regular Tersa knives at regular Tersa knife prices. Carbide costs what carbide costs. It just seems less painful because you are buying these little tiny teeth verus a single straight knife.

Out of curiosity, I priced out what the cost would be for another mfr's cutterhead. Their 12" machine has one continuous row of 72 teeth and a box of ten insert teeth is $58. So, I actually need to order eight boxes in order to effectively "change all the knives", which would be $464. Now, that gives me four fresh cutting edges, so my actual cost per fresh edge would be $116.

Now, if I go to W Moore Profiles' site, 12" carbide Tersa knives are $82 each. I need three of those to do a complete knife change on a 12" J/P, which would be $246 and since Tersa has two edges per knife, my actual cost per fresh edge is $41.

So, it costs roughly 3X as much to replace the knives of a spiral head than it does with Tersa.

2.) Just like bandsaw blades, a lot of people obsess too much over "finish quality" of the board that comes out. As if it should be finish-ready all the time, every time, no matter the species of wood or the board-feet. Just like bandsaws, where everyone wants that one magic blade that gives you a finish-ready cut on green wood, dry wood, soft wood, hard wood, etc. Be realistic in your expectations.

3.) The whole point behind Tersa is speed and consistency/ fool-proofness of knife change. For shops, time is money and sometimes, the labor is less-than skilled at working on the machines. How many hundreds of board-feet could that flooring shop have run in the time it took them to rotate all the teeth on just one row of the head of a spiral 24" planer, for example? When lines start showing up in the boards, would he rather take 30 seconds to just scooch one of the knives over a bit or start hunting for the bad insert tooth? Does it help the owner's insurance rate when there is no possible way for a knife to installed incorrectly or fly loose of the head?

Be a smart consumer is all I am saying.

Erik Loza
Minimax USA

I think your math is a little off? $82/knife=$41/edge multiply times 3 per head= $123 per complete knife change. So more than inserts, no? Marginal, but more.

My take? Hit a staple with a spiral....change a few $5 chips, costs you $25. Hit a staple with carbide tersa....costs you the edge or you live with the damage, so $123 per booger. Doing a whole head change....about the same. Cost per lineal foot, ALWAYS cheaper with carbide long term, but my paycheck and cash flow doesn't exist in the long term, it exists today. Might be nice to have the cheaper. HSS to act as mine sweeper for rough lumber....I bought a wire brush instead. Surface quality? Neither is a finished surface, point is nearly moot. As others have said make your decision based on the mechanics of the two machines or price, head is less important factor. I prefer spiral on a jointer, no preference on planer, but on a combo you have to pick!