Jog to Position Still a Mystery ?

[DickB]

Jog To Position simply offers other options regarding where to place your project on your actual board when your actual board is bigger than your project board (project board being the one that you designated in Designer).

First let's look at the mechanics of how this works; then we can look at why we might want to do this.

Let's consider the case of a 12" x 6" project board in Designer.

1. Suppose we load an actual board that is exactly 12" x 6". I'm sure we all know that in that case, we have no choice as to how the project will be placed on our real board. (We are going to ignore any option that would result in Scaling, as we have all been advised many times to avoid that option for various reasons.) To avoid scaling, we must choose the option Stay Under Rollers - No.
2. Now, if we load a board that is 19" x 6", exactly 7" longer but no wider than our project board, we do have the choice to either Stay Under Rollers or not.
   
   1. If we Stay Under Rollers, the project will be centered on our actual board, with an extra 3.5" on either end. (This is probably what most of us would do, but that gets into the "why", so let's leave that as is for now, and let's continue to look at our options even if they might be ill advised.)
   2. If we choose not to Stay Under Rollers, we would be offered more options.
      
      1. One would be to Center the project on the board. If we chose that option, we would end up with the same result as if we chose Stay Under Rollers - the project would indeed be centered on our board.
      2. Another option would be to Place On End. In that case, we would have 7" of unused board at one end.
      3. Finally, we have the option to Jog To Position. This would allow us to place our project anywhere along the length of the board. We could put it in the center, as before. We could put it on the end, as before. We could put it 1" from the end, or 2", or whatever. So, with Jog To Position, we have more choices in where to place our project on the board.
   
   
3. Next, what if we load a board that is 30" x 6" - longer than 7" longer than our project board?
   
   1. If we Stay Under Rollers, the project will be located 3.5" from the end of our actual board, with an extra 14.5" on the other end.
   2. If we choose not to Stay Under Rollers, we would be offered more options.
      
      1. One would be to Center the project on the board. If we chose that option, the project would indeed be centered on our board, with 9" of space on either end of our board.
      2. Another option would be to Place On End. In that case, we would have 18" of unused board at one end.
      3. Finally, we have the option to Jog To Position. This would allow us to place our project anywhere along the length of the board. Again, we have many more choices than the ones described above.
   
   
4. I am going to leave the case of a loading a board that is both wider and longer as "an exercise for the student".

Now let's discuss the "why" a little. Why use Jog To Position? Let's look at Case 3.

If we chose Option 3.1, we stay under the rollers (desirable) and minimize board waste. Option 3.2.1 keeps us under the rollers, but wastes a lot of board. Option 3.2.2 conserves board, but does not keep us under the rollers (not desirable). So our best option is probably 3.1. But what if we have a defect in our lumber 4" from the end of the board? That defect will show up in our project. We could avoid the defect by choosing Option 3.2.1, but at waste of board. If we instead chose Option 3.2.3, we could place our project just past the defect - say 4.5" from the end of the board - and minimize board waste.

There is more to consider when using a sled, and the choice of using Jog To Corner versus Jog To Center, but I have to run. I can explain more later, but for now, see if this helps with the basics regarding Jog To Position.

[jakab]

I looked up the 2011 T-N-T and created a pdf.
It takes four mpc files to work as designed.

I really need to go over it again to see if commands have changed.

Thanks DocWheeler, I'll read this today.

...Peter

[jakab]

Thanks DickB, that certainly explains a lot and clarifies many of the grey areas.

One more question: When you Jog to Position, are you designating the 0,0 position of the design? or just the X position?

Thanks.

[DocWheeler]

Specify both X and Y positions.

[DickB]

Thanks DickB, that certainly explains a lot and clarifies many of the grey areas.

One more question: When you Jog to Position, are you designating the 0,0 position of the design? or just the X position?

Thanks.

You designate both X and Y, and you have a choice. If you select Corner you are designating where 0,0 of your project will be placed on the actual board. (Use figure 17 of the manual to see which corner is 0,0 and how it is oriented in the machine. I have a copy of this figure right at my machine for reference!). If you designate Center you are obviously jogging to and designating where the center of the project will be located on your board. I machine a lot of wheels (large gears) for my clocks, and find jog to center often useful. For example, I make blanks out of hardwood wedges to orient the grain somewhat radially. These blanks are typically not perfectly square, so they do not align the same way every time in my sled. By using jog to center, I get the project center - the center of my wheel - aligned with the center of the blank where the wedges converge every time.

[jakab]

Thanks again DickB, that really clarifies the issue.

Now, there is also Jog to Touch, which I understand can be used to measure the board thickness at a predetermined spot on the board, correct? For example when using a sled where the workpiece does not occupy the whole void in the sled, correct?

Very useful information.

...Peter

[ronboley]

Ok...I'm still being lazy and not testing this....so the lower left corner of the board, sled or whatever is being physically being loaded and measured is the "origin" of board measurements on the machine per page 17 of the manual...but this is NOT the 0-0 "origin " of the virtual board as viewed at the lower left corner in the designer software ???...so how does the machine/software relate these two "origins"?? Obviously the lower left corner of the virtual board in designer is the upper right corner as viewed from the keypad side of the machine with a board loaded...so the two are not the same point...so in jog to position or jog to corner (or jog to end) what point in the designer view of the virtual board is being jogged to what point on the physical board?

My assumption would be that the jog to center would jog the center of the virtual board (both x and y centers) to the point you pick to jog to on the physical board, just upside down and backwards....

So which "corner" in the virtual board is being used to jog to which corner of the physical board?

[DocWheeler]

See page six of the pdf I posted.
Virtual board coordinates are top-left.

[ronboley]

Ok so here's how I blow a Sunday afternoon. After going back thru "TNT April 2008" and DocWheelers "Positioning the Carve and Jigs Revised" unpublished (thank you by the way, publishers and unpublishers of this fine material) ....this is what I get....the three sketches attached to this...the origin of the virtual board is at the upper left hand corner (not lower left)...the jog to position is relating the center of the virtual board to the center of the real board/sled combination (or whatever it physically measures), the real board/sled combination measurements are from the lower left corner (origin), the X and Y inputs the machine is expecting when "jog to position" is used is the distance from the origin to the virtual board center line.

That being said the main lesson is to set up the virtual board, carving, sled and real board to use only "center on board" or face brain damage.

If the powers above would look at the three sketches and let me know if I finally got it right....THANKS!

[DocWheeler]

You are indeed making it difficult for yourself.
What you are positioning on the real board is just the Virtual Designer board, not the carving.
To try to juggle the Real board, Virtual board, and the Carving is unwarranted.

The TNT that I wrote in 2011 had four objectives: 1) to help the reader realize that it was only the
virtual board that was being positioned on the real board, 2) the four position options explained,
3) that the "Y" measurement works with seeing only the rails, and 4) how the sensors work so
that the various schools of thought about sled "filler" length could be better understood (whether 3.5",
4", or some other number was "best") - to understand that only about 1.375" is really necessary.

The TWO jog to position options, to center or to edge/corner, are positioning of the Virtual board
on the real board. If you want to center a star on a real board at X,Y then you simply enter those
coordinates after selecting the correct positioning options.

Take a piece of scrap and try it - that is a better way to learn than your present course IMHO.