Carbide vrs HSS blades

[larry merlau]

would like to get your opinions or experieces on the longivity of the two. is the differnce in cost between them cost comparable?
for instance $65-HSS vrs $241 carbide 15"planer blades
in jointer situations the no's are similar cost differntails. thanks for your opinions. hope this is in the right forum :confused:

[Gary Whitt]

HSS is what most use on planers and jointers.

Most knives have enough material for a couple of sharpenings.

I personally would not buy carbide for a jointer or planer; the chances of knots on rough lumber is too great.

[Jim Becker]

I'm with Gary. While carbide has some applications for knives on planers and jointers, most folks are best served by using one of the HHS formulas. They wear well and are less brittle than carbide. A better long-term investment might be the Esta disposable knife system which makes changing knives a snap. (This is something I really appreciate with the Tersa head on my MM J/P combo...it takes about 5 minutes to change the knives without bleeding on the floor...less if one is ok with cutting the you-know-what out of your fingers!)

[Charlie Plesums]

My new 16 inch takes chrome hardened steel, HSS, or carbide.

The cheap chrome knives that came with the unit are still producing super surface, so I haven't even tried the HSS that I also got.

Reportedly the HSS give a better finish, but don't stay sharp as long as the chrome. And the carbide cutters are more economical in a production shop where they are used "all day"

If you have the Tersa cutters, I heard about a shop that uses two blades in each slot - Say a 10 and 5 inch, to make up your 15 inch. In the next slot, put the two in the other order (5 then 10). Then if you get a ding, it is easier to hide the ding, and cheaper to replace the dinged blade.

[Jim Becker]

Charlie, the chrome knives are essentially sharper at first than the HHS, but will degrade faster. They are generally recommended for softwoods...but as you know, we all use them for "everything" since they came with the machine. When I use up my chrome knives (I still have another set in "inventory"), I'm going to go with the HHS. But I'll keep the chrome knives around, for that initial whack at rough lumber where dirt and grime can easily damage things.

BTW, there are two formulas of HHS available in Tersa format...regular HHS and M2. M2 is harder than the regular HHS.

[lou sansone]

larry


you would need to go to carbide if you were processing abrasive lumber like burmese teak. Teak will dull HSS / M2 ( jim I was under the impression that any decent HSS was M2 ) so fast you would not believe. Other than woods like teak and some other exotics, HSS is the material of choice.

lou

[Ian Barley]

Larry

Depends on your material and your motivations. Let me explain.

Cost of carbide is about 3-4 times as much. Cost of sharpening has about the same differential. That much you know already.

I do this for a living. I use hardwoods, mainly Oak and Iroko. With Oak a carbide blade will last about 6-8 times as long as HSS. That means I can get a full days work with Oak on the thicknesser before I have to change the blades (give or take). With Iroko carbide lasts about 3-4 times as long as HSS somewhere less than half a days work.

So if I use HSS with Oak in a day I might change the blades 4 times. Each swap costs me about 25 minutes from switch off to back at work. About 1 1/2 hours "lost" and I have to pay 4 sharpening costs as oppose to one for TCT. So with HSS my sharpening costs are about double and my efficiency is about 85% of the TCT alternative.

If I use HSS with Iroko I will change the blades about every hour or so. It takes the same amount of time so I can fairly easily "waste" 3+ hours of a working day changing blades and I have to pay about 6 or 7 sharpening costs. With TCT I would change the blades once - 2 sharpening costs which are about the same money value. But the killer is that I have lost about 40% of my working day to machine maintenance.

If I was using softwood I suspect that there would be a much less secure case to be made. If I wasn't costing my time that would also make it more confused. But in my situation the higher purchase and maintenance cost of TCT is very easily justified. When my current crop of planer blades passes away I will replace all of them with carbide because the extra money cost will save me a fortune in time cost.

[Jim Becker]

( jim I was under the impression that any decent HSS was M2 )Tersa knives come in two different HHS formulas and the "harder" on is M2. They are also available in the lower cost chrome steel and the substantially higher cost carbide. Some folks will keep various types in the shop and change them depending on the material they are processing...knife changes are so quick and easy with this system that changing to suit the job is quite practical from a time standpoint.

[John Renzetti]

Hi Jim, The tersa comes in chrome steel, HSS (M2) and HSS M42, and then Carbide. The M42 is a good compromise between the M2 and the carbide. It won't last as long as carbide but it won't cost nearly as much.
I have regular insert shaper profiles in chrome steel. They work fine for short runs, but you'll get about 3ft of use out of them on any man made material or tough wood species like teak.
take care,
John

[Jim Becker]

Thanks, John...I misspoke...trying to do three things at once...again!!

[David Dixson]

So where does one get the tersa knives?

[Michael Sloan]

The Tersa knives are available from a variety of sources. The cheapest prices that I have seen advertised are from Martin (but I have not ordered any from them). I ordered a couple of sets from MiniMax when I bought my equipment (which I am still using), and you can get replacement blades from them as well. I have also googled "tersa" and found a few other places that offer the blades as well.

Anybody else have a good source for tersa blades?

Of course, you have to have the Tersa cutterhead before you can use the Tersa knives.

Mike

[Jim Becker]

David, there are a few sources for Tersa cutter heads and knives. (yes, you need a whole new cutter head to use them!) Martin is one source in the US. Do a Google search on "Tersa". You should also look at the spiral heads for comparison...neither option is inexpensive, but both have advantages...different ones, however.

[Byron Trantham]

Ok guys, what's a Tersa? Sounds interesting.

[Jim Becker]

Ok guys, what's a Tersa? Sounds interesting.
Byron...good diagrams and information at: http://www.woodtechtooling.com/TERSA/TersaCutterSystem.html

[Chris Padilla]

Byron,

I believe all Minimax machines use a cutterhead (i.e. a planer or jointer or j/p combo) that accepts Tersa blades.

It is just a style of cutterhead. Blade changes are a breeze and there is absolutely no "setting" of the knives. It is done automatically through centrifugal force of the cutterhead spinning. It is kinda cool.

[Byron Trantham]

Gee, I wonder if they have a replacement for my Jet? ;)

[Chris Padilla]

Bah, why do I bother posting when Becker's around.... :rolleyes:

[Byron Trantham]

It's ok Chris, you still answered my question.... :D

Argh!!!! $400-$800 for a new cutter head?! I don't think so Tim. I'll continue using my TS Aligner Jr., thank you very much. My whole jointer cost about $400. :p

[John Renzetti]

Jim Becker wrote, Byron...good diagrams and information at: http://www.woodtechtooling.com/TERS...tterSystem.html
__________________
----
Hi Jim, Now you're in trouble you posted a link. :)

I know the feeling about doing 3 things at once.

Right now Martin-USA has the best prices on the Tersa knives. I think the thought process must be "well you've got the Tersa knives now how about $24,000 for this T-54 planer to go with the knives."
I believe Tersa is a Swiss company that developed the Tersa cutterhead. It's probably the best known of the insert type cutterheads. I don't think Tersa is actually making the cutterheads now, they license other companies to manufacture the cutterhead. An Italian company makes most of them for companies like MM,SCM, Felder. Martin makes their own using their own patented process.
I've heard that the Tersa patent has expired so beware that there might be others coming on the market with a "Tersa" cutterhead. I think I saw an ad for Powermatic where they said the machine had a "Tersa like" cutterhead.
If you see specials for the tersa knives coming from a company you don't recognize, I'd be careful, especially if the patent expired and anybody was allowed to make the knives. In order to work as advertised these knives, as well as all large insert knives, have to be made to extremely tight tolerances.
take care,
John

[Jim Becker]

John, I was not posting a vendor recomendation, only a page that had a good picture of what Tersa looks like. As always, buying the "real deal" is a good idea!

[mike lucas]

Carbide should always last much longer, in fact, if the carbide is from good quality micro-grain stock, it will last 7-10 times longer. However, high speed steel is easier to sharpen, and will be 20%-40% sharper when new, but it will not how the edge near as long as carbide.

With the likely hood of nicks in blades on jointers and planers, carbide is not worth the price difference for most.

[Charlie Plesums]

Charlie, the chrome knives are essentially sharper at first than the HHS, but will degrade faster....
Jim, you are usually right, but I saw several posts (over the last year or so) that suggested the HSS gave a smoother surface (implying sharper) but that the HSS dulled faster than the chrome. Intuitively, I would have come to the same conclusion that you did. Is there a test that you are aware of?

I have both chrome and HSS, but the chrome give such a good surface (it is hard to tell if I have sanded) that I haven't even tried the hss yet.

Unfortunately Martin-USA sells the knives in sets of 2, and my unit takes three. Not a big deal unless I go for Carbide at $297 for two blades:eek: .

I found a post for a lower cost source of Tersa knives - one of those companies without a web site - but I can't find the 800 number at the moment.

[Jim Becker]

Charlie, "my understanding", and that could be wrong, is that the chrome knives tend to be keener, but last the shortest time and are generally recommended for softwoods where the extra sharpness is a plus to avoid tear out. Here is a table from one provider I have bookmarked:

Chrome: Softwoods only.
HSS: Best for all around use. Recommended for pine, oak, maple, cherry, etc.
M42: For tougher applications. Less likely to chip the cutting edge than HSS.
Solid Carbide: Most durable, reduced finish quality, recommended for hickory, exotic hardwoods, laminated woods, dirty material, glue lines.

But even this is "interesting" relative to their recommendation of carbide for "dirty material"...given that carbide edges can be quite brittle when they engage stone and metal! Sheesh! Who to believe?

[Charlie Plesums]

Since some parts don't make sense, as you note, I will keep looking.

At least from Martin-usa, the HSS and M42 are VERY close in price, so why would I choose "ordinary" HSS rather than M42. (And chrome is half as much as the M42, Carbide is 6 times as much)
I probably have 10 or more trash cans of chips on the first side of my chrome blades, mostly oak and ash, and some walnut (just based on projects in process, not on a test). And no sign of dullness (roughness or tear out)