Past Projects

Tool Lock

While I was inpatient at Sacred Heart Medical Center in Eugene Oregon, in February of 2019 suffering from a blood infection and eventually having my ring and pinky finger amputated from my left hand. I had my family bring up one of my 3d printers so that I could start prototyping prosthetic devices while I was living in the the hospital. at the same time I was also learning how to write with my right hand as I was left hand dominant. one of the first devices that I was investigating was a mount that let the user affix small hand tools to the palm of their residual hand and use the tools and with a twist of the locking ring change to a different tool.

A video of an early prototype can be viewed at

the design has gone through many revisions in the time that I’ve been working on prosthetics.

Impact Driver

This was a project that I Designed and built out of a need to use an impact driver. When you are missing fingers it becomes incredibly difficult to do simple things like drive screws with an impact driver. usually you hold the driver with one hand while the other places and guides the screw. well without a second hand you have nothing to hold the screw.

Game Controller

This was a build request from one of my You Tube subscribers that is part of the missing parts club. this mod presses the L1 and L2 buttons on the controller. by pressing the 12m tactile buttons on the side of the controller, the micro servos depress the factory controller buttons. the potentiometer on the front varies the button press cycle time if the rapid fire mode is turned on.


This project was also a You Tube subscriber request. it is a forearm mounted retractable electric chainsaw. I was using it as a filler project while I was struggling on reworking finger designs, every so often I revisit working on it. being that it has no viable real world application it is pretty low on my completion schedule. eventually, but not right now. Sorry all you Evil Dead fans.

Prosthetic Hands

In the time since my I lost my hand and started building prosthetic devices I’ve explored many different designs. In my experience I have come to the opinion that mechanically powered devices offer the the best user experience. both from the standpoint of durability and speed. After convincing my insurance that finger weren’t a luxury, they provided me with an Ossur I digits quantum. in my experience the motion of the fingers is incredibly slow, with 1 second to open and again to close. the device was frustrating to operate and use on the daily. another thing that I found frustrating was the battery life. the hand would lose functionality of course at the most inopportune time with little warning, leaving you with little more than a boat anchor strapped to your arm. after months of designing and prototyping I came up with my first mechanical prosthetic. the fingers were printed on a peoploy maoi sla printed using the tough resin. The design was powered by motion of the hand in relation to the wrist. curling the hand would close the fingers while adducting the hand would return the finger to their open position.

Laser fingers

The laser finger design was one of my first ventures into the finger design. the many layers were cut from 2mm acrylic sheet on my co2 laser stacked up and then bolted together to form the finished finger. this design had many good design aspects, but one huge deficiency, that being it is far from a compliant design, meaning if during general use it were to meet with an unexpected impact, rather than being able to flex out of the way, it would simply break because everything is rigidly affixed and driven.

152 Blue

this revision was my first successful design that i actually started to use on the daily as a prosthetic device. this design used a rotor core that translated the linear motion of the #15 chain to rotate the proximal and then with a second chain connected to the end of the proximal cause the medial and distal of the finger to curl. rubber bands were used to extend the fingers to the open positions.

153 Red

this was my second successful design, as with the previous version, the finger segments themselves are printed on a resin printer and then sanded and assembled. as with the other version, the proximal is rotated by the lineal motion of the chain, although with this version the center distance of the rotor core was increased in order to improve the grip strength and the rubber bands were replaced by springs due to early failure of the bands

154 Finray

This design was a short experiment trying to add some of the innovation found in pick and place robotic manipulators. the primary issue that I was running into with this design for this application was the 270 degrees of deformation that was needed in order to form the grip of the finger. in order to get the finray to flex enough that all of the input force wasn’t being used to deform the finger, the cross section of the profile ended up being too thin for repeated daily use. so this design was shelved.

155 Mechanical

the 155Mech was the first successful all metal hand that I have used for an extended period of time with very good success. in the near year that I have been using this device daily, I have had to only replace I piece of the linkage due to wear. All in all I have been very happy with this device. even though this device has been a success I am still looking to improve the design. improvements that i am looking to implement are silicone traction pads to increase the coefficient of friction, and of course a change to the linkage geometry to increase grip strength.

156 Compound 1

this design got as far as first article prototyping which consisted of printing a complete unit and one made of aluminum. while the design proved to be compliant and flexible, i found the design to have way too many pieces and it was too fiddly to take any further. so the design was evaluated for its positive attributes and killed.

156 Compound 2

this is where I currently am design wise. it is a much simplified version of the compound link. Part count was greatly reduced, but with that a couple elements of compliance were eliminated. Hopefully that does not become an issue further down the line during real world testing

Lend Me A Hand

As you can imagine, I am contacted many times a week to help people that have suffered a loss of a portion of their hand. this request can vary from “Hey, I have an amputation similar to yours” to “I’m just missing a couple of fingers, can you help me out?” those requests are usually met with a simple question and answer form that I have written asking about expectations of what a prosthetic device would be able to return to their lives, comorbidities, location, and activities. It also asks if they are willing to have their story placed on this website and my YouTube channel.

Designing and building a bespoke prosthetic device takes quite a bit of time and material. and with that, they can end up being quite expensive. for instance, my daily driver, the one that I currently use daily, took over 600 hours to fabricate and design. The shop rate of my machine shop is $80/hr that would make my aluminum prosthetic hand cost in the neighborhood of $48,000, while that may seem like a lot, it is actually quite a bargain in the world of prosthetic devices. my Ossur I-Digits quantum was invoiced to my insurance at $80,000 and it doesn’t have near the function that my mechanical device does.

So how do you get a device and I get paid for my service?

Ideally I would film and produce a series of YouTube videos centered around the design and fabrication of the prosthetic device. a portion of the adsense revenue from those videos would go to financing the prosthetic. I would also publish your story on the Lend Me A Hand section of my Patreon, where patrons could chose to donate directly to the building of your device.

So that should take care of the fingers, but what about the socket? well, in 2020 I produced a series of videos describing how to cast your residual limb and later make a mold of it so that you can layup and create a custom socket yourself, complete with silicone liner. If you chose to have me build you a device , you would need to fabricate a socket, and trim and fit it to your hand. I would want you to wear it for several hours daily for a couple of weeks to make sure that it fit you well and didn’t create and hot spots on your limb. from there you would box it up and send it to me where I would affix the custom fingers that i created for you, to the socket. from there If you couldn’t come to my shop to fine tune the completed device, I would box it up and send it to you for you to enjoy.



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