A user wrote me and asked what he could make such that he could draw to paper the gcode for an image using his mill.

Here  are pictures of my pen holder that I use.
A holding plate to mount the holder to the mill was made and an extended handle was added for fine manual adjustment of the pen to the paper.
The ball point pen was modified using the original parts. Just reversed the pen in the holder and changed how it was held in the pen body.
There is a 1/4" of spring travel so it's very easy to just bring the quill down and then manualy adjust the pen tip into the paper some .005" to .010" or so. Works great and frankly travels quite accurately.You don't have to worry about Z backlash but make sure you allow a proper Z change in the gcode to lift the pen tip away from the paper.
BTW, purchase a few extra pen refills or pens. Not fancy, but for a couple of buck's, it does the trick. 

RICH

Nice jig there, Rich. I had been meaning to make one for myself for a couple years now. We have one on our EDM machine at work for back plotting. They really do come in handy. I finally made one a couple weeks ago, and quiet by accident discovered a super duper ultra mega simple way of constructing one. I do like the heavy springs on those pilot pens, and they do have a shorter ink tube than the regular pens. I made mine from one of those cheap freebie pins you often find. Mine only has .125 travel, and has two settings for spring tension. I will get the pen at work tomorrow, take some pics, and post the method. 2 options are better than one, right? I like how yours has an adjustment knob. That's pretty slick.

Sam,
Post some pics.The more examples the better. I thought someone had already posted something, maybe it was in a different thread.
RICH

Here is the pen I made.
Step 1. Order something from Winford
Step 2. Take the free complimentary pen, shown in fig 1 and dis-assemble it as shown in fig 2.
Step 3. Measure about half the distance of the spring, on the opposite end of ink tube.
Step 4. Crimp some little tabs into the ink tube for a spring stop.
Step 5. Assemble back into pen tube.

You should now still be able to click the pen, resulting in two spring tensions. Low tension, this particular pen travels 0.28in (7.1mm) High tension travels 0.15in (3.8mm)

Step 6. Insert pen into a tool holder.
Step 7. Plot!!!

You can trim the pen and ink tube down in size, to achieve whatever length of pen you want. I also had to remove the clip on the clicker end.

Video

Way to go Sam and even a video.
RICH 

I agree with Rich, that's brilliant Sam. Certainly the simplest solution I have ever seen.

If Winford knew about this I bet they would have sent you the free pen without you even having to place an order.   

Tweakie.

I cut a pencil stub, drilled out the back side and spring loaded it on a dremel bit for my mill. I use the dremel as my spindle. I need to make a better version for my machine but it works for now.