Opps, you mean not everyone on this forum is a professional woodworker? Wow, you learn something everyday.
Originally Posted by Bruce Benjamin
Why 20 inches? Simple! They are cheaper than the 12 incher porters. The ideal cat's meow machine for your average hobbyist woodworker is a 12 inch machine. As you move up to 16 in and 20 in machines, many folks are scarred silly to use the beastie. Also dialing in a wider machine becomes more difficult.
As an example. I have only seen ONE 12 inch porter 300 jointer in my lifetime. A buddy of mine restored it and sold it for $8000 dollars. This was about 5 years ago and the jointer was from about 1960. Granted it was in pristine shape and included a knife grinder. The price is very high but then again its a 12 incher.
I have written about jointers at extreme length in the past and I dont feel like repeating that diatribe here. Surfice it to say that there are advantages to a 12 inch or wider joitner over an 8 inch jointer. For example, this thread was begun on the premise of incorporating a helical head on an 8 inch jointer. I said it in the past and I will say it again, I PERSONALLY feel your wasting your money. The 8 inch jointer has way to small a head, to loose bearings and no true means of dialing in super precision so why deal with a super precision head.
Yah but boards are 8 inches are less.... yadi yadi yadi. This is true; however, I learned many many moons ago that one way to combat pagen grain hardwoods was to skew cut the stuff on the jointer. Most old iron jointers can skew orientate the fence. On some newer jointer, the fence is fixed and only moves in and out. So here I can skew cut an 8 inch board on a 12 or 16 or 20 inch jointer to mitigate blow out.
Lastly many 20 inch jointers are pigs and eat lots of space. The porter 20 inch 300 is not. IT is built on the frame of the 16 inch porter 300 and only the tables and cutter yoke are dedicated to 20 inches. Everything is identical to the 16 inch porter making for a nice compact design.
Ideally I would prefer to have a 12 inch jointer with a four knife head. But finding a porter 300 that is 12 inches wide with a four knife head that is actually reasonable in price is an adventure that eluded me so far.
Had the dog not stopped to go to the bathroom, he would have caught the rabbit.