New Sharpie Holder Design

[EricSchimel]

28697

Hey all, a friend of mine and I designed these sharpie holders for the ShopBot. It's a spring loaded piston that you chuck into your spindle/router. The Sharpie is held in by a set screw. You get over .5" of travel on the spring so this lets you push it against the material you want to draw on.

The spring is very light so it puts just the right amount of force down for the marker or a pencil. We're considering doing a run of these soon. The next version will have 3 set screws so if you want to use something smaller like a pencil you can center it up and lock it in place.

Here's a video of it in action:

https://goo.gl/photos/ntDwMrxrwLh63Jxf7

I'd love to get some feedback!

[Ken Sully]

Very Nice! Does it use a standard size sharpie? Any idea how much they will be?
Now the stupid question...how do you zero the Z?

[Dana Decker]

Now the stupid question...how do you zero the Z?

what I do is place a piece of paper like a receipt on the spoilboard and lower the sharpy till it touches. then lower it a few thousand more and z zero it.

[EricSchimel]

Zeroing is exactly what Dana said. Since this is spring loaded you just drop the Z down until you see it compress a little and zero it there. The spring is really light so you've got some leeway.

You'll be able to use just about any marking device (pen, pencil, etc) with the three set screw version. There will be three set screws equally spaced in a circle and you just put anything in the end if it, tighten down the screws and you're good to go.

As far as cost, I think we'll be able to keep it reasonable. I wanted to gauge some interest here first. Depending on how many we make in the first run will determine the price.

[myxpykalix]

the most important questions is....price?

[EricSchimel]

Probably a little more than this guy:

http://www.widgetworksunlimited.com/CNC_Plotter_Pen_Bit_Thick_Line_p/cnc-pltr_pen_thick.htm

But not much more, I should have final pricing really soon.

[knight_toolworks]

the only issue I see is the length if your trying to draw on a 2 or " material you may run out of room. but the other pen holders have this issue or my laser. my biggest problem with pen holders is if there is a gap or you run off the edge of material you break off the tip. I have never worn out a pen I always break the tip off.

[Chuck Keysor]

Eric, thanks for posting.

I have long had a medium interest in getting a pen tool for my Bot. However, I noticed in your video, that when each letter/vector was closed, that the pen did not align with the start of the letter/vector. I know that when I engrave a fine closed vector with a V bit, that the ends align perfectly/imperceptibly. So I would GUESS there is some lash (?) in your assembly. But maybe your design is better than everyone else's.

Have you evaluated the other pen tools? (I have not ever seen one in action, so I am asking a genuine question..) Do they exhibit the same condition of the ends of closed vectors not meeting?

Has anyone else evaluated other brands for this characteristic? The things I would want to draw would be detailed line images/art, where the ends of closed vectors would need to meet without any perceptible error.

Thanks, Chuck

[EricSchimel]

Great observation Chuck, here's what's going on:

The marker drops and the ink gets sucked into the surrounding cardboard that's why you're seeing that. When the line finishes off the marker retracts right away so there's no "puddle" that's built up. To alleviate this all you need to do is set a ramp move (which I didn't do in this video) so the marker doesn't drop down, hang out for a second and then continue to move.

In terms of the "lash" this isn't a precision tool, it's a marker holder. Because there's a piston mechanism there's a little play as it slides up and down, not a lot, but it enough so it can't bind. Also, since you're shoving a marker into an opening that's a bit larger than the marker itself it is entirely possible to mount it off center ever so slightly. This assembly is heavy enough that it doesn't rotate when you're drawing so it doesn't really matter.

This tool is great for a lot of things. I use it to put numbers on Wikihouse parts that I mill. It's also great for doing basic labeling of parts. It's best use case is a training tool. You can let someone draw over and over until they get a tool path right. It's quiet, save and doesn't waste material. Most of all it's damn fun!

@knight this has a bit more than .5" in travel for the spring. I've run off the edge of cardboard and been able to get it back on the cardboard because the spring acts as a suspension system. If you're careful about setting your zero you should be OK in most cases...

[Chuck Keysor]

Thanks Eric for your detailed reply. Chuck

[tlempicke]

I have one of the holders that a guy was selling some time ago that look quite a bit like what you have. It is the handiest gadget I have seen. For instance, Do a C3 and then move the pen to a set of coordinates. Like say x=6, y=6. Now use the pen to draw the x and y axis at the new location. You can reliably fasten stuff at those lines and cut with very little waste and excellent repeat ability. Need a quick sign, no problem.
The biggest drawback is the use of mini sharpies. They only come in a couple of colors and are hard to find. I have had to buy packs of four, each one a different color, just in order to get what I needed.

[knight_toolworks]

I have one of the holders that a guy was selling some time ago that look quite a bit like what you have. It is the handiest gadget I have seen. For instance, Do a C3 and then move the pen to a set of coordinates. Like say x=6, y=6. Now use the pen to draw the x and y axis at the new location. You can reliably fasten stuff at those lines and cut with very little waste and excellent repeat ability. Need a quick sign, no problem.
The biggest drawback is the use of mini sharpies. They only come in a couple of colors and are hard to find. I have had to buy packs of four, each one a different color, just in order to get what I needed.
you can't get the pens anymore I bought a lot of packs though color does not matter to me. but the tips are fragile and if they hit a little crack or go off the edge kiss it goodbye. I have ruined every pen that way. I use them when doing sign blanks for others it lets me see the placement and make sure the vcarving is in the right location.

[EricSchimel]

I've had no problem finding sharpies that fit around here.... In any case it should work with a wide variety of marking devices as there will be three set screws so you can put it whatever you'd like...