Shelix vs Tersa

[Sam Babbage]

The shop I work in is currently trying to work out what style of jointer head we want to go with. I thought I might try and see what you fine folk think about it. The primary requirement is minimal tearout in the primary wood we work in, Lacewood. Consumable costs and blade change times are also important.

With fresh knives the Shelix would certainly have the edge, but what happens when the Shelix knives are heading south but still fine for non-figured wood? Is the reduction in tearout still present, or would it be outweighed by the speed of swapping in fresh Tersas then swapping them back to finish off the original knives on secondary timbers etc?

Also, the durability of HSS or M42 Tersa blades is also a concern, how do they stand up compared to well sharpened standard HSS knives?

Either way, the head will be going into a large 510mm European jointer, SAC, SCM or Martin, probably. Head diameter would range from 115mm to 125mm.

EDIT: Lacewood is a medium density hardwood with pronounced medullary rays when sawn on the quarter, I suppose the closest American wood would be QSWO.

[Jim Becker]

I really haven't worked with lacewood, but I love the Tersa knife setup on my MiniMax FS350. Excellent results; long knife life including slight adjustments to deal with the inevitable nicks and fast knife changes when needed...with zero realignment. I tend to work the work skewed for more of a shearing cut, but lacewood may or may not benefit from that due to the "interesting" way the grain comes and goes.

[Joe Jensen]

I had three diffferent heads in a PM60 jointer. First the stock head and bimetal PM knives circa 1990. Those knives stayed sharp quite a while. I upgraded in about 2000 to a Terminus (tersa clone). When I owned it they only had HSS and Carbide knives. The HSS lasted only 1/4th as long as the PM bimetal but they had two sides. Cost was a little more than sharpening, but no downtime. I'd saw when sharp, both the Terminus and Stock straight knives were ok on figured wood. In 2004 I put a Byrd head in the planer. WOW, huge improvement over the straight knives. With 6 months I ordered a Byrd for the PM60. When I upgraded the PM60 an SMCI with straight knives I upgraded that to a Byrd as well. I can't comment on life of the carbide knives on the Byrd, but as a serious but not high volume hobbiest I have yet to rotate a carbide cutter on the Byrd. With the same kind of usage, I had to sharpen the straight knives in the planer at least twice a year. That's 10 sharpenings for the Bimetal knives in the PM planer and still the same side on the Byrd carbide cutters. Tearout is still zero.

[Rick Fisher]

I have a Helical head in my planer, and a 12" Griggio Jointer with a Tersa head..

The tersa head is great for most woods but when cutting Maple or some other hardwoods, it really shows it inferiority.. The Helical head in the Planer leaves a superior finish..

Having said that, Jointing Oak or Fir, the Tersa head is just as good.. Its just the figured woods, or woods that tear out easily..

[John Harden]

I really haven't worked with lacewood, but I love the Tersa knife setup on my MiniMax FS350. Excellent results; long knife life including slight adjustments to deal with the inevitable nicks and fast knife changes when needed...with zero realignment. I tend to work the work skewed for more of a shearing cut, but lacewood may or may not benefit from that due to the "interesting" way the grain comes and goes.

I've worked with Lacewood. +1 on Jim's advice. Tersa makes darn fine knives and most importantly, their zero adjustment cutterhead design ensures perfectly aligned blades.

You don't get any quicker for blade changes and they will last quite a long time. They're reversible too as a bonus.

Regards,

John

[Sam Babbage]

Thanks for the replies... Seems either option is plausible.

[Dan Forman]

I've had both, the Byrd will have less problem with tearout in figured wood. The cutters last a looong time, and then you just rotate to the next sharp edge (which I haven't had to do yet). The Tersa knives chipped on knots, the Byrd laughs at them. I'm glad I made the switch.

Dan

[Larry Edgerton]

I have a SCMI520 with a Tersa head and I run M42 knives. I can plane old reclaimed birdseye without popping any eyes, changes are fast, shifting is faster, and the ability to switch to an old set of knives in a couple of minutes to clean up rough stock is a bonus. The finish @ 16fpm requires almost no sanding. I am happy with my investment, and will buy a Tersa head in my next jointer.

The clone knives that are out on the market are crap. They package them like the originals but they are not worth the bother, buy original Tersa knives. I have not had the chipping on knots with my machine running M42's that someone spoke of.