Opinions on Carbide Planer/molder Knives

[Percy]

I have a Woodmizer MP360 and plane/mold alot of Yellow cedar. The yellow  has its way with the HSS knives and dulls them quickly. The Tormek T8 I have seems to sharpen the molding knives(side heads) reasonably quick but the planer knives is another story.  I bought a set of strait carbide tipped knives for the top and bottom heads. They seem to be holding their edge much longer than the HSS ones but it was 1000.00 for the set. I havent got any numbers yet on wether they are cost effective or not. Has anyone else tried/used these type of knives on their equipment and what were the results? Thanks

[farmfromkansas]

When I ordered my Grizzly planer, ordered the helical cutterhead.  Had to replace 2 teeth when rotating the blades last year, as those 2 were cracked, but the things last a long time.  Is there a helical cutterhead available for your machine? I do clean the cutters occasionally, as sap builds up on them, use some spray cleaner, and wash it off with water after scrubbing with a tooth brush, then turn on the machine and let it shake the last of the water out. Use compressed air first, and put cardboard on the table to keep off as much water as possible.

[Larry]

I run a Byrd Shellix carbide insert head in my planer and like it a lot.  In my jointer I'm running a Tersa which is another option.  With the Tersa head, knife changes might take 2 minutes if your slow.  Tersa knives are two sided, throw away,and fairly cheap.  They offer different knife steels along with carbide.

I run the Tersa M+ HSS which I think is M-42.  I have a friend running the carbide.  I get long run times with the M+ so never tried the carbide.

Besides fast knife changes, I think the Tersa gives the best finish of anything on the market, much better than off my Byrd Shellix.

Tersa Knives
And they are up in your neck of the woods.  I linked to the planer head page since you would have to change out.  No idea if it would be cost effective but I think the carbide knives would be a bunch cheaper than what your paying now.

[DWyatt]

We tried them on Dad's 20" planer before he switched to a helical head. I was not real impressed. If you're just hogging off a lot of material, they are probably fine and do hold their edge better than a HSS set. It seems they never get quite as sharp as the HSS set which caused us problems in hardwood and in figured soft maple. For us it just didn't work for finish planing, just too much chip out and don't forget that those expensive blades still chip like HSS and you've only got so much room to shift a straight blade to make up for a nick.

[Percy]

Thanks everyone for the input. My results so far are promising with the carbide knives. I have ran over 4500 lin feet of yellow cedar through the planer and they still perform the same as when they were new. I think the HSS ones are sharper when new or resharpened but that lasts only for about 200 lin feet in the yellow cedar. THen they deteriorate kinda quick like....These might be cheaper in the long run, especially if I can resharpen them. 

I studied my machine and I dont think I could easily switch to the Tersa heads but that system is awesome. Im sure some manufacturer will implement a system like that on their machines soon.

[Southside]

Had not heard of that system before, but just looked it up and tomorrow will be looking at my machines.....

[longtime lurker]

My experience is with both straight knives and Tersa knives.

Either way it's the same result... HSS definitely cuts sharper and cleaner while it's sharp, but it doesn't stay sharp for anywhere near as long as carbide. Carbide is never as sharp when it's sharp, but it stays half sharp for a whole lot longer. Carbide is great for a lot of things but if you want a super good finish, or the timber is really figured and prone to tearout... go HSS.

The economics of it: depends on the machine and how long it takes you to change out a set of knives.  I've never really priced up a set of carbide knives for my 4sider but suspect they'll be $$$ and worth every cent for what it does which is spot dress and/or DAR in volume. (The top and bottom heads run 36" knives, it's painful just buying HSS)
The smaller finish planer/thicknesser runs a Tersa head and I have run carbides on it occasionally before I had the 4 sider. They worked as above - stayed mostly sharp for longer - but now I dont need it for that kind of work and have gone back to HSS knives.

It varies all over the place subject to the wood but generally I'd say knife life between the two is maybe 4 or 5 times longer between sharpenings with the carbide.

If you're regularly using the equipment consider this a vote for the Tersa system... the ability to change out knives quick means they stay sharp. And sharp knives cut faster and cleaner as we all know. I do a lot of okay but not exceptional finish work with the 4sider just because with a crew of guys standing around I'll push the knives beyond "should be sharpened" at the end of the day so they are all off the clock when I change them out. With the little Tersa head thicknesser I can stop and do a knife change in no time... so I do.

[teakwood]

As you guys know, the only wood i work with is Teak. HSS knifes 1h to get dull, Carbide 2months. everything on my machines had to be changed to carbide.
20" planer i  upgraded to spiral cutter head about 5 years ago and the jointer i did 1 year ago, costly but i would never use straight blades again in my life.

[WDH]

20" planer i  upgraded to spiral cutter head about 5 years ago and the jointer i did 1 year ago, costly but i would never use straight blades again in my life.

You could give me free sharp HSS knives for life and I still would not use them.  The spiral head with the carbide 4-sided inserts are so superior.  

[teakwood]

and not just the superior cutting performance, less noise, less power consumption, less effort to push them thru, it's  the installation process of new blades! straight blades needed 1-2 hours of tightening and loosening and adjusting height and they where never right. if you got one tenth of a mm higher on one blade that's the only one that cuts.
spiralcutter just clean them and rotate them, also time consuming but after tightening they all sit at the exact same height.  

[Percy]

Yes, those spiral heads are the best.  If I had a 5th head on my molder(MP360) I would definitly purchase them. Unfortunatley in my case, the spiral heads would not allow any shaping on the top or bottom of the board. Swapping heads looks like a big job on the 360.