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In part 1 I looked back at the videos for Jet and Powermatic and the idea of including helical cutterheads in stationary woodworking machines in place of three-knife or four-knife heads. Also, the variations on noise levels were shown with changes in decibels readings.
Next, what about costs associated with each cutterhead? Let’s look at the Grizzly G0593 (with 40 carbide inserts in its head) compared to the G0586 (with a four-knife cutterhead). Both are 2hp machines with the only difference being the cutterheads. The additional cash outlay is $330 and that buys you the spiral-head machine. That might seem excessive, but I think it’s very reasonable if you look into the total costs over time.
Each insert has four sharpened edges, so in a sense, you would need three sets of knives (plus the set that comes with the tool) to gain equality with the inserts. The additional sets of knives are $50 per set or another $150.
If you would prefer to look at the process of sharpening the blades when they dull versus purchasing new sets, my local cost to have jointer knives sharpened is $5.75 per knife up to 18″. That’s $23 per set of four and the three additional trips to the sharpening service would be $69.
So, you think you’re way ahead? How about the fact that the knives are high-speed steel (HSS) whereas the inserts for a helical head are carbide? The HSS knives will dull much more quickly than the carbide inserts. I’m not sure how many more times you’ll need to sharpen the HSS knives. That’s going to depend on the amount of lumber you run over the tool. At Popular Woodworking we feel confident saying carbide last four times longer than HSS, so you’ll incur an additional $276 ($92 x 3) in sharpening fees. That puts the total invested in sharpening only at $345. And we’ve yet to discuss the value of your time in replacing the knives or trips to and from the sharpening service.
Next, let’s take a look at another difference. When a nick shows up in the knives, you loosen the locking screws, slide the nicked knife to one side then tighten those screws. All the while you’re hoping that you don’t change the height of the blade in relation to the other knives. With a nick in a carbide insert , outside of the trouble of simply finding that nicked cutter , you’ll loosen one screw, turn the insert 90Ã?º and tighten the screw. Time is a consideration here too.
In my opinion, the average woodworker who works in a home shop might never have to replace the carbide inserts. With the inserts staying sharp longer and rotating the inserts for three additional uses, this becomes a possibility , barring a catastrophe. If you do need to replace the inserts completely, the Grizzly G0593 that we’re using in this discussion has 40 carbide inserts. Total replacement costs for the 40 inserts is $80 (that’s less of an expense than having the HSS blades sharpened four more times).
Given the fact that a helical cutterhead is quiet, stays sharper for a longer period of time, allows for a quick fix of damaged inserts and is only higher in initial costs not long-term costs, if I were purchasing a new machine there would have to be a great deal for me to buy the old cutterhead design. I’ll choose the helical cutterhead with the carbide inserts. How about you? Is the supposed extra cost stopping you?
