Carbide blades for handplanes?

[Steve Mathews]

Carbide has reached just about every cutting tool, both in metal and wood working. Is there a future in it for handplanes as well?

[Andrew Seemann]

Probably not. Carbide is really durable, especially under heat, but it is fairly brittle, doesn't get super sharp, and tends to chip at low angles, not exactly ideal for hand planes. The hand plane people have enough trouble accepting A2, I don't think carbide would go over well

[mike stenson]

I'd really hate to have to sharpen them. I sharpen my irons multiple times while in use. Unlike many, I'm OK with A2, although I really do prefer O1.. or maybe PM-V11. Put me in the 'would not buy' camp.

[Frank Pratt]

Carbide can't even be as sharp as steel when done with exotic factory equipment and a plane iron needs to be very sharp. Lots of guys even prefer some of the 'softer' steels because they take an edge so much better, even though it doesn't last as long. I've never used PM-VII, but I've read that it sharpens nicely & is very durable.

[Steve Mathews]

Sort of expected the answer would be that carbide can't achieve the same sharpness. So I'm wondering what's the hullabaloo over carbide tipped saw blades, planer blades, etc. when a better surface finish might be achieved with good steel and proper sharpening. I appreciate that in a commercial environment time is money and frequent sharpening might be an issue but for the hobbyist wouldn't we want the best possible surface finish?

[mike stenson]

I don't expect a finished surface from planers, jointers, or saw blades. I expect a finish ready surface after final planing.

[Roger Feeley]

I generally get a glue le finish from my table saw blades. My bandsaw is not nearly as good as I think it should be.

[Andrew Seemann]

Sort of expected the answer would be that carbide can't achieve the same sharpness. So I'm wondering what's the hullabaloo over carbide tipped saw blades, planer blades, etc. when a better surface finish might be achieved with good steel and proper sharpening. I appreciate that in a commercial environment time is money and frequent sharpening might be an issue but for the hobbyist wouldn't we want the best possible surface finish?

Planers, table saws, jointers, routers, etc have the horsepower to push the high angled carbide cutting edges through the wood. When you are spinning that fast, edge durability and heat tolerance start mattering more than initial sharpness. Holding a pretty sharp (or sharp enough edge) a really long time is normally more useful than a really sharp edge that dulls in 5 minutes. Even though, a hollow ground steel table saw blade probably can get sharper and maybe leave a better surface than tungsten carbide, a carbide surface is good enough for gluing and the edges last many times longer. Finished surfaces would be expected to be sanded, scrapped, or hand planed, whether the tool was carbide or steel.

What I remember from using steel table saw blades 30 odd years ago is that the surfaces were almost always worse in practice, probably because they didn't get sharpened often enough.

However, my jointer and planer both have straight HSS blades, and they work just fine. I occasionally touch then up with a stone or one of those diamond credit cards. I'm guessing they don't heat up as much in use as table saw blades and router bits, so the advantages of carbide on those isn't as pronounced. HSS router bits on the other hand are just plain awful

[Richard Coers]

I started woodworking 50 years ago, and that was before carbide saw blades. A carbide Forrest Blade was like discovery of the century. But then a few years latter cordless screw drivers came out and we could put away or Millers Falls push drills and drivers. No hullabaloo over carbide planer and jointer blades in my shop, I prefer HSS. No carbide turning tools either. So table saw blades are my only concession, but then again, I'm not a young woodworker.

[David Bassett]

... When you are spinning that fast, edge durability and heat tolerance start mattering more than initial sharpness. ...

What he said!

Being lazy, I just checked a circ saw blade: 7-1/4" diameter and 7000 max rpm. I don't think most saws run that fast, so I'll use 5600 rpm. Each tooth covers just over two miles each minute*. (Note that each tooth isn't actually in the cut for full revolution and then ignore it because lazy. Also, I think a table saw runs a little slower, but has a larger diameter blade, so I'll wave my hands and claim they're similar.)

If you think about more power driving that skinny little blade that far that fast and then pushing the 1 -2+" blade in the plane, I think it gives a vivid picture of the different demands on the blades.


(* Math:
(pi * D * RPM) / 12 = LFPM;

(pi * 7.25 * 5600) / 12 = 10,629;

10,629 / 5280 ft/mile = 2.01 miles / minute.
)

[Luke Dupont]

Totally unsuitable for handplanes.
I don't even like steels that include large carbides for handplanes (looking at you, A2).

Sharpness and sharpenability are of huge importance for handplanes, and even steels with large carbides tend to chip easily -- something that you really don't want in a hand plane.

It's completely different from a machine using a rotating blade or cutter traveling at 1000's of RPMs. Moving that fast, sharpness doesn't matter so much. And, moreover, people don't sharpen such tools.

A plane iron that can't be sharpened (or that no sane person would want to sharpen) and can't take and hold a fine edge, or one that is prone to chipping is, is, well, complete garbage and not something I would ever want to suffer using...

[Eric Rathhaus]

My ECE primus dovetail plane uses a carbide knicker. I'm hoping I never feel the need to sharpen the thing.

[John C Cox]

High speed steel plane irons are available if you poke around. Try one of those out.

[Luke Dupont]

High speed steel plane irons are available if you poke around. Try one of those out.

HSS will *work* for a plane iron and they are available. I have a few super cheap Japanese planes that use a HSS iron.

But, I wouldn't recommend them. They're a pain to sharpen. I mean, at least they are much more "sharpenable" than carbide, but...

There are much better steels for the handtool woodworker. There's a reason vintage steels, O1, PMV-11, and Japanese White and Blue Steels, among others, are so popular among handtool woodworkers.

[Eric Rathhaus]

Hi so the knicker on the dovetail plane is a small hexagonal wheel. Hopefully I won't need to think about it being too dull for many years because you can rotate the wheel and use all the corners. I always like to tune up a tool when I first get it but had to forgo sharpening this wheel. Workers fine but aggravates me no to be able to tune it.