Minimize tear out on tiger maple

[John W Johnson]

I have a fairly new set of carbide teeth in my jointer/planer (I just rotated them maybe a hundred bf ago), but I keep getting tear out on this batch of tiger maple. I ran an earlier batch thru on older, more worn teeth and it came out fine. I've read somewhere that wetting the wood will help minimize that, but I can't remember what was used, how much, how long before planing, etc. And since I have no recollection of where I saw it, I'd rather hear or read it here before I tried it.

[Rich Enders]

You will get some improvement by dampening the surface of the wood, but HSS instead of carbide would provide a substantial improvement. Possibly that is not an option for your set-up, so hopefully a spray bottle for water misted over the board just before machining will do the trick.

[Loren Woirhaye]

I wipe with a damp sponge when I do that. I wipe each board individually prior to feeding.

I haven't done it often. Your cutterhead precludes back-beveling the knives, which is the most reliable way to address this issue.

[Josh Rudolph]

You will get some improvement by dampening the surface of the wood, but HSS instead of carbide would provide a substantial improvement. Possibly that is not an option for your set-up, so hopefully a spray bottle for water misted over the board just before machining will do the trick.

Rich,

Forgive my ignorance, but can you explain how the HSS would provide improvement over the carbide setup? Typically the HSS setup is a straight knife wheras the carbide "teeth" are setup in a spiral fashion. The straight blades has the entire length of the blade contacting the wood at once, wheras the carbides contact surface is roughly 3/8" wide. My thought process would lead to the ability of HSS to be sharper than carbide. But that would also only work for a pretty fresh set of blades. I would think it does not take long for the HSS to dull to the point of the carbide teeth at which point minimizing contact area would be beneficial. Not trying to contradict your statement, just want to understand why HSS is a better option for the figured wood in this instance.

Thanks.

[Andrew Pitonyak]

I am interested in Rich's answer, but, since he has not yet answered, I will guess.

You can obtain a sharper edge on HSS than you can on carbide. Carbide, on the other hand is harder and will hold that edge for longer.

Carbide is composed of very fine particles that are compressed (or something) into the desired shape. The finest edge that you can obtain is to take the edge down to those particles (and you cannot sharpen those particles). Steel particles (or grains, or whatever) are more homogeneous and can be shaped / polished / honed to a finer edge on a microscopic level. So, when fresh, the steel is probably sharper, but, you will need to sharpen the steel before you need to mess with the carbide because it will maintain a workable edge longer. As such, you would not want a carbide edge on something that you want to have very sharp (such as a chisel or plane blade).

I think that carbide is also more fragile (fractures / shatters more easily), but I could be spreading incorrect information there (this is off the top of my head).

[Josh Rudolph]

I am interested in Rich's answer, but, since he has not yet answered, I will guess.

You can obtain a sharper edge on HSS than you can on carbide. Carbide, on the other hand is harder and will hold that edge for longer.

Carbide is composed of very fine particles that are compressed (or something) into the desired shape. The finest edge that you can obtain is to take the edge down to those particles (and you cannot sharpen those particles). Steel particles (or grains, or whatever) are more homogeneous and can be shaped / polished / honed to a finer edge on a microscopic level. So, when fresh, the steel is probably sharper, but, you will need to sharpen the steel before you need to mess with the carbide because it will maintain a workable edge longer. As such, you would not want a carbide edge on something that you want to have very sharp (such as a chisel or plane blade).

I think that carbide is also more fragile (fractures / shatters more easily), but I could be spreading incorrect information there (this is off the top of my head).

Yep...that is my current assumption also, but was curious about his statement. I can understand if the blades were freshly sharpened versus fresh carbide. But as John said he rotated them a hundred bf ago. So my assumption would be that the HSS steels would have "dulled" to the same sharpness of the carbide by then (maybe a bad assumption?). By then I think minimizing contact surface area would help minimize the tearout along with dampening the wood.

[Chris Padilla]

Some woods just tear out no matter what you do. If possible, consider sanding down the boards instead of cutting them. I'm guessing the tear out is when you are face-jointing and/or planing the wood? Try brand new sharp blades. Try the wetting. Try flipping the board around...might tear-out less in one direction versus the other. Try taking lighter cuts.

For jointing, I would just rip the offending material off on the table saw with a sharp ripping blade and then sand the table saw marks off.

And yes, HSS can be more sharp than carbide but it wears much faster. And further yes, carbide is more brittle than HSS.

[Loren Woirhaye]

Another approach is to do the best you can and use a high-angle plane to do the last bit. A 10 degree back bevel on a standard pitch bench plane yields cutting angle of 55 degrees, which should be sufficient to plane the interlocked grain without tearing it out.

[Ira Matheny]

I do a lot of work using highly figured wood. My solution...Skip the planer. I use 50 grit in the Lobo wide belt sander. After reaching near the desired thickness, I switch to 100, and then to 150. I have worked with 220 grit. No tear out but you must be careful as some wood [maple is one] will burn when sanding.

[Rick Lizek]

Pushing the board slower on the jointer minimizes tear out. I've seen different planers that gave mixed results on figured wood. The ones with the lower feed speed give better results.

[Rich Enders]

Josh,

Sorry for the delay. It looks like others have answered the HSS question you posed. One thing I would add is about the durability of HSS. For sure it is not as durable as carbide, but it is not so bad either. My 12 inch MM jointer/planer is seven years old and I have only changed the HSS blades once. I normally only use the J/P about 5 hours per week, but at one point I received and four squared about 1,000 BF of white oak.

[peter gagliardi]

The best thing you can do is to take heavy passes. Like an 1/8" or more. This will limit tear out to the point that it is almost a non issue. Leaving that extra "ramp" of wood in front of the cutter is what works best. Almost all my work in a commercial shop is tiger maple, curly cherry, or some other figured wood.