|Forum topic by David Craig||posted 11-09-2012 06:08 PM||1137 views||0 times favorited||3 replies|
11-09-2012 06:08 PM
Ok, part of this is an admission to stupidity or at least an admonishment to myself to use the resources available to me to do some research before using something I am unfamiliar with.
I have done a small amount of scroll sawing, but mostly with cheap blades and not usually the ones recommended by authors of projects. I had a collection of blades from the local HD and just used those to get familiar with the machine. I ordered some reverse tooth blades from an online company (blades are Flying Dutchman). I was told, once, by a friend, quite awhile ago, that he didn’t worry about how he mounted the reverse tooth blades because they are the same in either direction.
Ha. Ha. Ha.
I noticed some burning when trying to saw through some fairly thick maple. I attributed much of this to the size and thickness of the wood and played with the feed, speed, and tension. The project didn’t go very well (7r was the blade size, btw). My eye sight is not what it used to be and I had a hard time seeing hook angle by the naked eye so I decided to research a little further under the usb microscope.
Here is the hook angle change -
Here is where the hook angle changes -
Obviously not the center :)
So the reason for the burn was because only about an inch of the blade is actually going down into the wood while the rest of the blade was going in reverse. There was just enough cutting force to indicate the blade was cutting, but enough going in the wrong direction to impede smooth cutting.
Two words of advice. Pay attention to your hook angle and visit scrollgirl's site as she has a nice little break down of the different blade types.
-- There is little that is simple when it comes to making a simple box.