Pencil holder in progress

[Sharpsburg_Woodworke]

This is a pencil holder that can be placed in the router base. The pencil holder is used to draw anything with the maslow cnc. A pencil is placed in the center hole. A rubber band is strapped around the top piece. The next piece has a notch to allow for clearance. The rubber band is secured somehow to the pencil (your choice).
This is not a completed file. It needs to be tested for clearances. It is also set up for 3/4 in plywood and should be edited for the wood that you are using. Please try to edit the file and test the print. I can not test for it right now. Let me know what you think!
Without further ado… Here is the onshape file: https://cad.onshape.com/documents/347c7067ec01e99f961accc5/w/0460ee0f68e75e233b732160/e/2f4a71d3220ba3bbfa6c69ae

and pictures…

[jwolter]

Nice. What is the purpose of the piece with the flat on it (bottom right of your lower figure)?

[marm]

I am assuming the flat spot is for the router orange clip to fit into.

[Sharpsburg_Woodworke]

It is for the router lift to clip into so that it can be controlled with the z axis.

[dlang]

note that this will have a different weight than the router, so the chain sag
value that was found during calibration will be wrong.

We need a way to have a couple sets of calibration and switch between them
easily

[Sharpsburg_Woodworke]

We can either add weights into it out just out a hook on the sled and hang a weight for the difference.

[dlang]

you want the center of gravity along the Z axis to be the same as the router,
not just the total weight. This make it a little harder

[Sharpsburg_Woodworke]

Any ideas to fix that problem?

[dlang]

sure, do a calibration with the router, and another calibration with the pencil. The only thing that should change is the chain sag value, manually change that as you change equipment (ideally have GC and the firmware remember multiple sets of calibration and let you switch between them with a $ or B command)

[blurfl]

If you hook the weight to the dummy router instead of the sled, you can match the COG of the router. I’m not convinced that the z-axis COG is that important on an 18" sled, though. Match the weight of the router/sled combo and you’re close enough in my experience.

[gwheeler]

This is pretty nifty, but what about just using a pencil stub as a router bit? Then you don’t have to swap out the router and change calibration, etc.

[Sharpsburg_Woodworke]

They are expensive. I don’t believe it will need to be recalibrated either. We just need testing.

[Sharpsburg_Woodworke]

I have completed a prototype. I don’t see any problems with accuracy. Calibration is probably not needed. My cnc isn’t accurate yet so my measurements are off. I managed to get close and then chuck the pencil holder in the drill. I sanded off a bit until it fit. I will make the changes in the onshape file. Here are some rough measurements that you may need. You can use these to set your pen holder to hold different pens. I also recommend editing the side notch to be added higher up. I used a pin head brad nail as the guide. Overall, I need help with more testing and tweaking (@bar are you busy). Enjoy!!!

Measurements:

Sample of what this prototype can do. Sorry for bad picture.

[Sharpsburg_Woodworke]

I have abandoned this build. I just realized that @krkeegan had already designed something that is a lot better than my creation. I converted his files from fusion to onshape and exported each part into a dxf file. I made an svg with all of the parts on one page. I also made a svg with all the parts laid out on maker cam. I have included a cut file along with this. I plan to test the cut file out soon. Here is all the conversion files that I have so far. Pen Holder krkeegan.zip (48.9 KB)

[jwolter]

For anyone curious about @krkeegan’s design, here’s a thread: Maslow Pen Holder

[Sharpsburg_Woodworke]

Thanks @jwolter. I should have linked that thread also.