# Smoother DNA Pencil Helix

Feb 11, 2018

### Thing Apps Enabled

Im new to this what are the dimensions?
or where can I find this info? thank you

Fully assembled: Height = 22.5 cm Base Width = ~10 cm

On Print Bed: Height = ~11.25 cm (112.5mm) Base Width = ~10 cm (100mm)

Is it difficult for you to make a longer helix for more pencils?
My pencil set has 48 pencils.

What's the diameter of the holes for the pencils? I'd like to scale this up slightly to accommodate small expo sharpies at exactly 11 mm diameter. Currently doing a base print to just measure myself, but figured getting the info out here would be helpful to others. Thanks for the design take care!

I cut 8.2mm holes in this design. So to get the thin expos or sharpies, I suggest cutting them at 11.2mm to give you a little room. So if my calculations are correct, you need to scale up the design 26.8 percent. However, the distance between the right and left spiral arms might be too far apart with this scale. Let me know how it works out, I may be able to make another version with bigger 11.2mm holes while keeping the arms close enough to hold the thin sharpies and expo pens.

This is a wonderful design. I am using this model as a teaching aid for very young students. However I want to make some essential modifications and would really appreciate if you could share your Solidworks part or even if you could explain how you made it. Thank You.
Here is my id - hasansam3@gmail.com

This was a tricky part (for me) to design in Solidworks and it was designed as I was learning Solidworks. So my solidworks file for this would not make a great learning aid. This is one of those designs I'll need to revisit and redo in the future to clean up the design.

Tell me a bit about the modifications that you want to make. Maybe I can help or create a foundational part file that I can share with you for your modification purposes. Do you just want the Helix and Nodes without that pencil cuts or base, that I can provide.

Okay so essentially want I want to achieve is to be able to slide in rectangular laser cut strips of acrylic (3mm thickness and 7mm height) into the cuts of the nodes which are currently circular in shape basically I need the cuts to be rectangular. I will engrave each strip with some text and each strip will be of a different color. Also I want the height to be decreased by 20% size but keeping the size of the nodes the same. These are all the modifications I need. I would really appreciate it, if you could help with these changes. Thank you again.

I'm new to 3D printing but love this design for a classroom pencil holder. Does anyone know if you need to set support material to build along with this model? The MakerBot at my school would place support in each of the holes where the pencil slides in, as well as under the sugar-phosphate backbone. I was wondering if I could turn that off and get away with it printing without it but I'm assuming it needs those in order to print correctly. Any suggestions?

Yes, this will print fine without supports - so yes, please click off the support options before printing. I've printed this about 5+ times on various printers with no supports and no rafts. So don't worry about that sugar phosphate backbone sagging. Welcome to the best hobby in the world and best of luck with all your printing projects!