Shopbot as a plotter

[sparker]

Is there a pen attachment which can be placed in the shopbot so it may be used as a plotter.

I design boats and before cutting panels I do a 1/10 model first.

Seems it would be a very simple attachment.

[billp]

Larry,
I know of one person who took a pen and "threaded" the outside of the barrel with a standard tap/die. He then formed the mating internal threads into a piece of hardwood. Then he simply attached the block of wood to his Z axis and by adjusting the pen up/down (by turning the barrel) he was able to get the exact height he was looking for.
I suggested to him that he might also want to add a "set screw" into the side of the hardwood block so he could lock that position in place.
Seems simple, and accurate...

[hespj]

Hi Larry, I design the occasional boat too, and I have made scale models of some of those hulls. But I haven't plotted them, I've just cut them out of a block of wood. Not sure why you'd want to plot.

I've done a lot of "plotting" too. Well, not really plotting - I've never drawn on paper, only onto plywood or MDF. Initially I made a pen and a pencil holder, but these didn't work very well. Since then I've used a Vee bit to engrave boards with drawings. Usually 0.5mm (say 1/50") deep.

[hespj]

Interseting post Bill. Initially, before making a pen holder I just put a 1/2" dia pen into the router. Having a pen at a fixed height wasn't very good. So I made an attachment which let a pen slide up and down (a tube). A firm contact was maintained by having a weight on top of the pen. The weight was attached to the top of the pen so that when the router was raised the pen didn't slide out. Better, but not brilliant. I think the idea could have been made to work well, but I decided engraving was best for my purpose.

[billp]

Larry,
I think John and I will both agree that any method you attempt will ONLY work if your table is really flat and true...

[hespj]

Yes, unless the pencil is able to slide up and down as I described. And if you're drawing on sheet material like MDF you might (will) find that it's not a consistent thickness, resulting in no lines in some places and a snapped pencil in others.

I also remember drawing on a painted surface with a fixed pencil (not sliding). A little nib of paint broke the pencil.

[rhfurniture]

Could you set up a single nozzle ink-jet? Maybe it's a way of utilising your old printer.

[bill.young]

Back in the ShopBot "Stone age", when we didn't have any toolpathing software and a very rudimentary DOS preview, I used to draw all my files on a sheet of tileboard with a dry erase marker so that I could (in theory at least) see my mistakes BEFORE I started cutting the expensive imported marine plywood!

Here's a picture of one of panels from Marc Pettingill's "Sweet Dream" canoe (I think).


26957.jpg

Bill

[norm]

Larry,

Check with Ron Varela. I think he used to have a spring loaded pen attachment he used on the Bot. I was going to use something like that to draw stained glass patterns. Worth a try.

Norm

[myxpykalix]

Thats where i saw it! I knew i just saw it the other day. He took a brass tube, stuck a spring inside the tube, then the sharpie. I assume to apply downward pressure to keep the tip on the material. When i tried this long ago I recall that because of the nonlevel surface it pushed the tip of the marker up into the barrell. So try to get a marker that is designed not to be able to to that.