For the first time in months, I got a chance to get back into my shop over the weekend. Boy was it nice. I was able to complete a piece for a customer that had been promised a while back. (Thanks for being patient and understanding.
I chose the rough lumber, cut it into manageable sizes, and then rolled it to the jointer. As I pushed my first piece over the three-knife cutterhead, I was amazed at how loud the operation sounded. I was caught off guard and wondered if the machine was not properly tuned to work.
Then I realized that the sound was loud because over the past few months, all my woodworking has been in the shop at . The helical head of the magazines jointer is included. It is noticeably quieter.
Jet and Powermatic both added helical cutterheads on a few machines. I returned to our AWFS Coverage Page to view the videos. This cutterhead was installed by Powermatic on its new planers and jointers (click the video to view), while Jet used a helical cutterhead to the jointer/planer combo machine (click the video to view). Now my curiosity was piqued and I decided to see if helical cutterheads were best.
The loud sound is what garnered my attention. I decided to start there. The next day I grabbed the sound-level meter and took two readings at the 30 cm Bridgewood jointer in the PW shop. The meter read 86dBAs while it was idle. Next, the reading was taken while cutting a piece 4/4 mahogany. This number was 94dBAs. The difference between running idle and at full work with a helical cutterhead equipped machine was only 8dBA.
After work, I packed the meter with the mahogany board in the truck and drove straight to my shop. There I have a 30 cm Delta jointer. I ran the same tests. This time the three-knife head moved the sound level meter to 89dBAs. Thats only a difference of three decibels over the helical head, big deal. But when I jointed that piece of mahogany, thats when the difference appeared , big time. While cutting the 4/4 material, the decibels jumped to 112dBAs. This is a substantial increase. A helical cutterhead is quieter.
The surface thats jointed is the telltale sign of a good set of knives. Each jointed surface was examined under a magnifying glass light and I found no difference in the resulting cuts. Yes the three-knife head left small almost indiscernible ridges in the surface that are easily sanded smooth. The helical knives also left ridges. They also were very small and easily smoothed with a sander.
So far, the only difference Ive found is the sound level. And with hearing protection, is that an issue? On Wednesday, I’ll examine the cost differences. We know that the out-of-pocket costs for the helical are higher, and I will reveal if I discovered that one cutterhead was better than the others. (Care to make a guess?)
If youre interested in reading more about the Jet Jointer/Planer Combination or the Powermatic Thickness Planer shown in the picture above, click on the PDFs listed below.
,Glen D. Huey
