Elbow Tap

Around March last year, the COVID-19 pandemic was becoming of increasing concern in the UK. I was living in my student house at university and trying to avoid unnecessarily catching anything. Students’ houses and especially bathrooms aren’t exactly known for being the cleanest of places, and so I decided that what our bathroom needed was an elbow tap!

Okay, an elbow tap probably wasn’t necessary but I had recently purchased a 3D printer (to help me finish my final year project) and I had not yet learnt that I didn’t need to be printing attachments and modifications for everything in my life… Frankly, I still need to learn that lesson.

So I took to Fusion 360 and started building! I looked at pictures of proper elbow taps on Google images and decided I didn’t need to be making mine that big, just big enough that I could use it easily.

I eyeballed the measurements for the most part, to surprising success. I chose to split it into three parts (the arm and two halves of the clamp).

The parts were held together with M3 nuts and bolts, and fitted perfectly on the tap. Unfortunately, I’d failed to consider the fact that the existing tap handle was a perfectly smooth elliptic cylinder and so my attachment would be prone to slipping off. My solution to this was two elastic bands, one holding the attachment to the back of the tap and the other wrapped around the existing handle. This wasn’t exactly an elegant solution, but it worked and so it worked. Below is a picture of the elbow tap in use (along with 3 different bottles of soap for some reason).

Bioprinter… The beginning

A few months ago I decided I wanted to make a low-cost bioprinter, to give myself experience printing hydrogels.

Originally I was trying to decide between a cantilever design and a CoreXY design. The benefit of the former would’ve been its cost-effectiveness and the benefit of the latter would’ve been the speed and accuracy over the standard cartesian printers I am used to.

It is worth noting that, in part due to the pandemic, I have no income at the moment and so I was leaning in favour of building a cantilever printer. When writing up the bill of materials I quickly found that this was going to be rapidly approaching the £150 mark just for the base printer (that I would then be adapting with a Large Volume Extruder), with the mainboard, steppers, and power supply making up the bulk of the cost.

My original Ender 3X cost me £200, and so I assumed that adapting one of those was going to be cost-prohibitive. To my surprise, Creality was now selling the Ender 3 for just £116, and so I decided to order one and change my design.

In this project I am building off of the work laid out in two papers:

M. Kahl et al., “Ultra-Low-Cost 3D Bioprinting: Modification and Application of an Off-the-Shelf Desktop 3D-Printer for Biofabrication,” Front. Bioeng. Biotechnol., vol. 7, no. 184, 2019. doi: 10.3389/fbioe.2019.00184

K. Pusch et al., “Large volume syringe pump extruder for desktop 3D printers,” HardwareX, vol. 3, pp. 49-61, 2018. doi: 10.1016/j.ohx.2018.02.001

I would highly recommend giving them both a read if you are interested in this topic.