Why Pivot the Way Tubes Both Ways

[nuhobby]

Well, what do you know. I was just doing a drill-press job with my Shopsmith 510. I wanted my 2 opposing holes each 22.5 degrees away from perpendicular to the (somewhat wide) board. I got by with some flipping and extending and such, but if I had a 180-degree trunnion I would have been happier....

Oops, I meant I wanted a 360-degree trunnion! I think 180 would not have quite got me what I wanted. OK, I'm stumped.

[JPG]

Oops, I meant I wanted a 360-degree trunnion! I think 180 would not have quite got me what I wanted. OK, I'm stumped.

The180 degree range only makes sense so as to provide 90 degree in both drill press and under table shaper modes. Kinda difficult to drill when table is past 90 degrees from perpendicular(you would be looking at the bottom of the table!).

[nuhobby]

To answer part of the questions: The reverse motor direction operation allows one to mount a shaper cutter upside down so as to cut on the underside of the workpiece rather than the top. In order for that to work, the spindle must also reverse direction. It also allows one to do under the table cutter mounting without any additional device(speed increaser), and also has the desired speed without it.

Reverse sanding - not sure?

With the grain cuts - Not a clue!

I just read a reible post over on http://www.ssug.org. "With the Grain Cuts" - Aha!!
Imagine the typical Jointer's operating instructions. A given direction of wood feed will be better than the other opposite direction, respective to the wood grain, for smoothness of cut. Now imagine you are edge-Shaping a piece of wood. Again, one given direction should be smoother than its opposite direction. Can you always achieve the optimum direction? With a Router, no. You are stuck with one cutting direction (assuming you don't want to climb-cut). With a Shaper, you can find the optimum way. You can reverse the shaper's orientation on your shaper spindle as needed, and change motor direction as needed.

[dusty]

I just read a reible post over on www.ssug.org. "With the Grain Cuts" - Aha!!
Imagine the typical Jointer's operating instructions. A given direction of wood feed will be better than the other opposite direction, respective to the wood grain, for smoothness of cut. Now imagine you are edge-Shaping a piece of wood. Again, one given direction should be smoother than its opposite direction. Can you always achieve the optimum direction? With a Router, no. You are stuck with one cutting direction (assuming you don't want to climb-cut). With a Shaper, you can find the optimum way. You can reverse the shaper's orientation on your shaper spindle as needed, and change motor direction as needed.

Your solution presents one of the fears that I have. Being somewhat absent minded now and then, I just might feed the stock into those whirling blades backward. This is just one more safety item to be ever so mindful of.

[pennview]

Imagine the typical Jointer's operating instructions. A given direction of wood feed will be better than the other opposite direction, respective to the wood grain, for smoothness of cut. Now imagine you are edge-Shaping a piece of wood. Again, one given direction should be smoother than its opposite direction. Can you always achieve the optimum direction? With a Router, no. You are stuck with one cutting direction (assuming you don't want to climb-cut). With a Shaper, you can find the optimum way. You can reverse the shaper's orientation on your shaper spindle as needed, and change motor direction as needed.
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This isn't always the case and depends on the profile of the cutter and what latitude you have in cutting your profile.

Cutters with a symmetrical profile (like the tongue/groove, 3-bead, or jointer cutters) allow you to profile the edge of a board cutting with the grain. If you're cutting against the grain in one direction, simply flip the cutter, reverse the motor direction, and run the board in the opposite direction.

If on the other hand, you're using cutters like the cabinet door lip, combination quarter round, and ogee, you can't simply reverse things because you've generally selected the face or show side of a board and can only run it against the cutter in one direction. If you can't cut with the grain in the normal cutter rotation, you can't cut with the grain when flipping the cutter and reversing the motor direction because you must also flip the board and then you're still cutting against the grain.