"Man is a tool-using Animal ... without tools he is nothing, with tools he is all"

True helical cutters from Byrd Tools
(Powermatic 15HH planer)

Published: Feb 16, 2011

Helical vs Blades

Can you actually save money by spending money, all while getting a better tool?

In December 2011, Fine Woodworking makes pretty much the exact same argument as I do, just 10 months later. What a bunch of copycats :)

One of the most common questions out there seems to be: Are helical heads worth the money?

Most people would agree that jointer and planer heads using carbide inserts instead of high-speed steel (HSS) blades provide a quality advantage. They run much quieter and can produce a better finish, especially on wild grain. Some complain that the helical heads produce a "wavy" finish. This isn't surprising, given the simple geometry of the tool: you're using a blade that's rotating in a 2-3" arc, so it has to remove the wood in a "scooping" motion and leave a rounded depression. However, the exact same geometry applies to straight blades, but they remove the scoop in one continuous cut across the board and it might be less noticable. Both heads would produce a less wavy surface if the feed rate is reduced, allowing the scoops to overlap. And, in either case, it's pretty unlikely you're going to use the board without sanding, which will quickly remove the miniscule waves. In fact, the multiple small ripples from the helical head would theoretically be easier to remove, in my mind, than the longer ripples from the straight head.

And don't forget that helical carbide cutters will handle materials that HSS won't, such as MDF. I sometimes need to tweak the size of a plywood panel and the jointer is a perfect tool, it'll cleanly shave off a hundreth of an inch with no problem.

 

In general, most people only balk at the helical head models because of price. For example, right now the Grizzly G0453Z is $1669 while the G0453 is $1194 (including shipping). These are identical except for the "spiral" cutterhead of the G0453Z (see "Helical vs Spiral" in the sidebar), so we're paying a premium of $475 for the spiral head.

Helical vs Spiral

The terms helical and spiral are often used interchangably but they can mean very different things.

A true "spiral" blade cutterhead uses a curved HSS blade. Instead of slamming the blade straight into the wood the blade engages only a small section at a time as it turns, "slicing" the wood off. This allows it to deal with wild grain with little to no tearout.

A helical head imitates this action with a series of small cutterheads arranged in a spiral pattern. Each cutter is rotated slightly, so that one corner hits the wood first, then the rest of the cutter shears off wood as it moves forward, mimicking the shearing motion of the spiral blade. However, turning a square cutter makes the edge rotate in different radii (imagine it turned 45°, the corner would protrude further, digging a diagonal groove). To solve this, the cutters must have a curved edge so that all points on the cutter edge are the same distance from the center of rotation. "Byrd" head cutters follow this design.

The Grizzly "indexable spiral" heads are a mixture of the two technologies. While the cutters are arranged in a spiral pattern, they're simple square cutters set perpendicular to the rotation of the head, i.e. each cutter acts like a miniature straight blade. Grizzly claims this simpler arrangement is as effective as the true helical head cutters, while others claim the true shearing action of the Byrd design is superior in difficult woods. Grizzly also sells true Byrd heads for retrofit into their jointers and planers.

Ignoring the qualitative advantages of the helical heads, let's just look at the economics. Quite simply, carbide inserts stay sharp far longer than HSS blades. A very conservative estimate would be that carbide keeps a sharp edge three times as long and I certainly wouldn't argue with you that fives times is unrealistic. When you include the fact that the carbide inserts have four edges, a set of carbide cutters is equivalent to between 12 and 20 sets of HSS blades.

A typical price for a set of three 15" HSS planer blades is $50. If you purchase fresh blades each time, you're looking at between $550 and $950 for HSS blades (you get one set with the planer, so you only have to buy 11 or 19) during the life of one set of carbide inserts after saving $450 on the original planer. Replacing the 74 cutters would only cost $234, so the savings of carbide vs HSS would be even more during the second set of carbide cutters.

You could, however, get the knife blades resharpened if you have a shop nearby. The closest place to me is over an hour away and charges $5 per knife. So now we're only spending between $165 and $285 vs the original $475 savings, assuming you can even have a blade resharpened that many times. The ultimate cost of just sharpening may be more or less than the carbide in the long run, depending on the actual carbide life you get. However, don't forget to factor in the cost of driving or shipping your blades to the sharpener, the expense of backup blades to keep working if you have to ship them, and the value of your time spent swapping planer blades in and out (if you buy a gizmo like a set of Planer Pals to make blade changes easier, you've just spent $100 that could have gone towards that helical head).

You could get a machine to sharpen your own blades, but even an inexpensive Tormek is several hundred dollars. And the planer blade jig is an additional $175! And don't forget, once again, to factor in your time in all this.

Realistically, I seriously doubt you can resharpen a planer blade 20 times, so you're really going to end up with a mixture of buying new and resharpening to minimize your cost.

Speaking of setting planer blades and the value of your time, let's say you get a nick in your blades. It doesn't need to be a nail or staple, I've seen a good hard knot take a chunk out of an HSS blade. Yes, you can shift one blade slightly to overlap the cuts, but it's definitely a time-consuming hassle. Not only are carbide inserts more resistant to knicking, you can merely rotate the cutter to a fresh edge in less than 30 seconds (not counting the time to remove the planer top, which you have to do with the straight head also).

So, I think the answer is pretty clear. The monetary savings of HSS over carbide are small at best. Unless you assign a value of $0 to your time in blade replacement and travel time, the carbide cutterhead is less expensive in the long term. When you factor in non-monetary advantages of helical heads over HSS (noise, finish quality, etc) getting the helical head version is clearly a better choice. The only situation where the HSS model is better is when you simply can't affford to get the helical model right now, because a straight-blade machine is clearly better than no machine at all. I initially bought the HSS version of my Grizzly jointer and upgraded it later to a Byrd head. The cost of the upgrade vs the original price difference was only about $25 more plus 30 minutes of my time to do the swap, so that's always an option for the cash-impaired.

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