This is a centerline marking scribe, similar in general function to many other centerline scribes. However, it is custom designed to fit the Pentel GraphGear 1000 (PG1019) 9mm mechanical pencil (7mm & 5mm would probably fit as well; other brands of mech. pencils might also work if they have similar dimensions). It is also designed to make it easier to apply forward, downward and sideways force while simultaneously holding the pencil in place (in a traditional position that one would hold a pencil). The custom pencil shaft provides a nice, snug fit without damaging the pencil tip, but for best results, it is good to hold the pencil in place. There are contoured surfaces to allow one to use all 5 fingers to accomplish this while applying the necessary force to keep the tool aligned. There are channels cut into the studs to help reduce inaccuracies that can be caused by rough side corners and splinters. The studs are .4" long, to make it possible to scribe 1/2" tall material without the studs dragging on the support surface. There are three sizes with stud-to-stud clearances of 1.75", 2.75" & 3.75" (Sm., Med. & Lg.). Hanging holes are also provided for storing them on pegboard hooks, nails, etc.
Printer brand: Creality
Printer: Ender 5
Rafts: Doesn't Matter
It is strongly recommended to do all that it possible to increase build plate adherence. This design (long and somewhat skinny) tends to want to have the bottom ends of the studs curl up and printed model can be somewhat bowed or warped. A flat print is always best when making tools. I tried printing one tool laying on its back, but the end result was not good at all. Print it vertical for best results.
After printing, carefully clean out the pencil shaft. If necessary, use a small diameter (1/16" or smaller) drill bit or file to bore the smallest pencil tip shaft. This will help the pencil fit nicely into the shaft. If your printer is more accurate than mine, this may not be necessary. First clean out the hairs and printing goop, then gently determine how the pencil fits. The tip of the pencil when extended should reach nearly to the end of the shaft, so that lead can be seen extending out of the tool with just 1-2 clicks of the pencil. When inserting the pencil into the tool, it is best to have the pencil tip already extended, but with the lead (only) retracted. Then click the lead to extend to the desired depth. As with all 3D printed tools that interface with my hands & fingers, I suggest sanding and softening all surfaces and edges to a desired smoothness.
ORIGIN OF DESIGN:
A few months ago, I looked into center-line scribes on our favorite online mega shopping site. I saw many plastic versions, but I decided on a metal one with swiveling wings -- it's a tool, metal should be better. When it arrived, I tried it out. What a pain! It was difficult to hold a pencil in place while trying to use it. I felt like I needed three hands to use it. I like my GraphGear mech. pencil for projects and woodworking, so I decided to design a tool that I could use with just one hand, and which worked with the GraphGear. There you have it.