Believe it or not, it has been a YEAR since we launched the LTT Screwdriver. One. Whole. Year. And while we’ve been relatively quiet on new tool launches during that time, our team has been hard at work building our knowledge base around the plastics we use, and refining our process around production to make some extremely exciting new stuff possible - including our recently launched Stubby and Solid-color Screwdrivers.
Assembly, consistency, and waste reduction have all been massive points of conversation, and we’ll touch on a few of our biggest learnings in this newsletter!
The year is 2023. While planning for LTX, Linus came up with a cool idea - giving LTX attendees an option to pick & build a custom colored screwdriver themselves. To make this happen, we had to answer two big questions - can we adjust our assembly to include a cold-press fit rather than a hot-press fit, and can we use our molds to reliably produce a variety of colors?
Hot-press vs cold-press
If you’ve seen our original Why our Screwdriver took 3 YEARS video, you may recall our in-depth explanation of our assembly process which included hot-pressing the ratchet assembly into the handle of our screwdriver to ensure a tight pressfit. This was based on the existing assembly process established by our production partners, and worked well for our plans at the time.
Hot, freshly-formed plastic parts maintain a bit of flexibility, which allows for the plastic to “form around” the steel spline of our ratchet, forming the main assembly of our screwdriver. The theory behind this is that a hot-press maintains a significant strength advantage over a cold-press, where we would be deforming a cold plastic part rather than “permanently affixing” our hot plastic part to the steel spline.
Cutaway of a hot-press and cold-press assembled driver after assembly. As you can see, the impressions left by the ratchet spline are almost identical.
And while that theory is sound, it doesn’t appear to make a meaningful difference in day to day use. We can’t give a specific force rating on this as we don’t currently have access to tools which would allow us to reliably measure any difference in pull-force between separating a handle and ratchet which have been hot-pressed vs a set which has been cold-pressed, but after months of internal use and over a month of customer use through our LTX “build your own” screwdrivers, we’re confident that the cold-press will live on!
All the colors of the rainbow
We’ve produced over 150,000 screwdrivers at this point, and the vast majority of those are black or black and orange. With that type of volume, it should be simple to throw some other colors in the mold and make any other color we want, right?
Injection molding offers endless creativity to produce high quality parts, but is limited in some ways. Typically, different colors of plastic are achieved through dry pigment mixing - adding a small amount of a colored pigment to a “virgin” (colorless) material, which gives us a wide, wide range of colors on finished parts. The only challenge here is that every different color comes with slightly different properties - they may react slightly differently to heat, or cool differently leading to slightly different sized parts or ugly “shrink marks” on the outside of the part. While these slight differences may only be one or two thousandths of an inch (¼-½ the thickness of a sheet of A4 paper), they can make a press-fit product like our screwdriver feel sloppy and inconsistent.
And size is far from the only consideration for consistency… colored parts can vary significantly between production runs, and depend on a number of factors like the settings of the machines, the air temperature around & inside the machines, and the amount of reground plastics (cooled materials from previous injection shots which cannot be used & are ground down to pellets to minimize waste) in the mix. We’ve made some missteps along the way (like this unfortunate inconsistency that we found in some yellow drivers prior to LTX), but we’ve been able to make corrections along the way and minimize any waste that we do wind up producing thanks to the incredible work of our engineering team.
Color variance between production runs can be significant. We were able to catch this and fix it before our "build your own" driver setup was ready for LTX, but consistency is a never-ending battle.
Ingenuity & problem-solving
After the launch of our original Screwdriver last year, we reinvested heavily in our internal prototyping capabilities. We added a suite of SLS, SLA, and additional PLA 3D printers, and we picked up a small injection mold machine to improve our understanding and internal capabilities around this process - if you're on our paid video platform, Floatplane, you can check out our behind the scenes video going over this awesome machine!
And enabling our team in this way has had an incredibly positive impact on what we can do day to day. Our early prototypes have never looked better (holy CRAP SLS printing is awesome…), and we’ve produced a variety of tools which have allowed us to do things previously thought impossible, like replacing the press-fit plastic housing on our ratchet without any damage to the ratchet itself. If you’re interested, they’d love to do a deep dive on some of those tools in a future newsletter - let us know on Twitter (... X… lol) @LinusTech if you want to see something like that!
This bit clip on our precision screwdriver sample was printed in-house with our SLS printer. The fine control is extremely impressive, with elements of this part as small as 0.5mm
What does the future hold?
All of this means that you’re going to see a lot more from us in the coming months and years - from different colorways of our screwdriver like the Noctua, Transparent, and recently teased Retro drivers, to totally new endeavors like our upcoming Precision driver.
And of course, more awesome launches like the Stubby Screwdriver and Solid-color Screwdrivers that we dropped on September 1st. We’re extremely proud of both of those projects, and we’re so happy to see the positive response from our community. This is just the beginning, and we can’t wait to show you what else we have in store.
Nick Light & the Entire lttstore Team