I have made or purchased a number of pen holders for my various CNC machines. I want to show you how to build your own.
The key to a good CNC pen/marker, is that it must be weight or spring loaded so that it can provide even consistent pressure.
I have made some pretty elaborate pen contraptions, but by far my favorite is designs .014 thick brass tubes.
These tubes are designed so that the 15/32 tube will just fit inside the 1/2" tube.
CNC Pen Types
I break the brass tube style pens down into two types. These are the short pens and the long pens. The work much the same way, but each has its advantages.
Short CNC Pen
The short pen is designed to be inserted into a 1/2" collet of the router or spindle. It uses a mini marker or pen cartrige.
On the short pen, the main pen tube is bent or flared to keep the pen holder from slipping through. A weight in the pen holder applies the tension.
- Fits into router or spindle collet without modifications.
- There is no way to quick change this pen. You must remove it much like you do with a bit.
- The mini ultra fine tip sharpie markers are no longer available.
- Collet can damage the soft brass tubes.
- Using pen cap is troublesome.
I do have a very easy design for a short pen, but since I move to the long pens, I just have not used it.
Long CNC Pens
The long pen works just like the short pen except, the main tube is not flared. The weight assembly at the top of the pen holder is designed to keep the pen from falling through the main tube.
- The pen holder can be slipped into the top of the main tube. This allows for quick pen changes.
- Uses standard size Sharpie ultra fine markers. Normal pens and pencils can also be used.
- IF you remove the clip from the pen cap, you can slip the pen and cap as a whole through the main tube.
- You can use in a router collet, so you must make a mount to hold the main pen tube.
Since I have moved to the Long CNC pens I have not looked back. As you might expect it is this type that I will be concentrating on.
There are two pen designs that I have been using:
- Thin Pen
- Thick Pen
They work identical, its just that some of the tube diameters are different. Also the thin pen can be inserted into the thick pen main tube by using the thin main tube as an adapter.
To be contrinued .....