What Are Micro Screws?
How Small Is A Micro Screw?
Micro Screws, also colloquially known as ‘tiny screws’ or ‘nano screws’, are a type of specialist fastener that is significantly smaller and lighter than the average precision screw.
Just look at the size difference when they are placed beside a pencil!
Typically, for a fastener to be considered a Micro Screw, it will have an outer diameter (thread size) of M1.6 or below. However, it can be argued that screws with a thread size of up to M3 also fit the criteria for a Micro Screw, due to their comparatively small size.
Featuring such a tiny head size and drive, these screws are ideal for intricate assemblies where factors such as increased precision, size, space, or weight-saving considerations are necessary.
Accu’s Range Of Micro Screws
They may be small, but Micro Screws are becoming a fundamental part of engineering, making way for new possibilities and transforming our ability to work on a smaller scale.
Despite their impact and growing popularity, these tiny screws are still quite hard to come by, particularly in smaller quantities and on short lead times. As the size of a thread gets smaller, so does the component's availability for purchase, especially in a range of head and drive types.
At Accu, we want to make engineering as accessible as possible, getting these precision components to our customers when and where they need them. With small and micro sizes ranging from M0.5 to M3, the project possibilities are endless.
M0.5 to M1 Micro Screws
Accu’s smallest range of Micro Screws, with metric thread sizes of M0.5, M0.8, M0.9, and M1 are available in Slotted Countersunk and Cheese Head variants.
These fasteners are typically manufactured with a slotted drive due to their nano size. Not only is a slotted drive the easiest to install on this scale, but it is also the most rudimentary and therefore most cost-effective drive type to manufacture for these incredibly small screws.
These fasteners are available in A2 Stainless Steel for Cheese Head Micro Screws and A2 and A4 Stainless Steel for Slotted Countersunk Micro Screws.
M1 Micro Screws
Alternatively, for slightly larger metric thread sizes, Accu has a range of Micro Screws between M1 and M2. Where the options for these components are not quite as large as Accu’s standard ranges, they are available in a greater variety of head and drive options in comparison to the smaller M0.5 to M1 Micro Screws.
M2 and M3 Screw Sizes
All fasteners with a thread size of M2 to M3 are included in Accu’s standard component ranges in various materials and many head and drive types.
Although some may consider that screws above M2 are not Micro Screws at all, they can offer many of the same benefits as smaller-sized fasteners.
As they are much easier to get a hold of, whilst also being such a small screw, M2 and M3 fasteners can be used for a range of intricate assemblies such as those in electronics or the automotive industry. Nevertheless, the larger the screw the lower level of control and customizability you should expect.
Despite offering a slightly lower level of precision, their smaller size can be excellent for projects where this is useful but not quite as necessary, such as glasses repair or a range of hobbyist builds.
Where Are Micro Screws Used?
Providing an unmatched level of intricacy, Micro Screws are ideal for applications where precision is key. For example, these tiny screws are commonly used for watch manufacturing and repairs and are also a great component for many electronic assemblies, such as mobile phones.
Micro Screws Used In d.m.h Custom Built Watches | Case Study
As a small and complex piece of mechanical engineering, there is limited space inside of a watch, making it a challenge to fit all of the necessary components in. As a result, each element of a watch must be small-scale and lightweight whilst also being robust enough to support continuous, precise movement.
Micro Screws are the ideal fastener for watchmaking, fastening the assembly without compromising its functionality.
Fred Dingeman, a bespoke mechanical watchmaker in The Netherlands, relies on these tiny stainless steel screws for the build of his watches.
With a career history in fine mechanics and repairing machinery with smaller-sized components, Fred has always held a particular fondness for solving problems through engineering. This, combined with his love of mechanical watches, inspired Fred to build his own handmade timepieces, d.m.h Watches.
The name, d.m.h, stands for ‘Dingemans Mechanische Horloges’ and translates to ‘Dingemans Mechanical Watches’.
Fred began to make wristwatches from his garden shed in 2008, a few years prior to the bankruptcy of the company he worked for at the time.
He shared “In hindsight, losing that job is the best thing that has ever happened to me. It really made me step up my game and become my own boss.”
Starting small, Fred slowly began to build his watches using a self-restored lathe and drilling machinery.
The watches are fully designed by Fred, including the large crown which can be seen placed at 2 o’clock.
Addressing his concept, Fred shared that this specific positioning is ideal to achieve the large crown style and shape whilst ensuring that the watch is comfortable to wear and that the crown does not dig into the customer's wrist.
Taking a unique approach in comparison to many large-scale watch manufacturers, Fred uses ‘new old stock Tenor Dorley movements, a popular choice for jumping hour watches in the 70s.
To attain his designs, Fred sources his own components and materials online. He uses steel to manufacture the timepiece case and case back and found Accu when on the hunt for quality stainless steel components that were small enough to work within his watch assemblies, using Accu’s M1 Cheese Head Micro Screws to hold the strap lugs.
Made to order for individual customers, the process for each watch starts with a customer design meeting, where the customer can discuss their choice of color for the hands and dial with Fred directly.
For Fred, one of the most important aspects of his manufacturing process, alongside the care and precision of the build, is the communication he keeps with his customers. Throughout the building process, each customer receives photographs of their watch being assembled as well as regular updates about how their watch is coming along.
Fred shared, “Having direct contact with the customer is the most important thing to me. I like to be honest and straightforward about the timescale.”
For this reason, Fred currently makes around 20 watches a year and limits production to 24 watches a year.
Saving Orphans Of Time: Micro Screws Used In Watch Repair | Case Study
Many times, assemblies that require specialist components and tools are neglected rather than repaired when they no longer function the same as they used to.
In the case of watches, Micro Screws are just as essential in repair as they are in the initial manufacturing process.
Having these small components readily available invites the opportunity for engineers to find innovative solutions to restore these assemblies.
John Hinkey of Geminus Technology Development, does just that, using a range of Accu’s micro components and 3D resin printing to repair vintage pocket and wristwatches.
We had the pleasure of talking to John about his restoration projects which he calls ‘Saving Orphans of Time’. He kindly shared,
“With the recent spike in the price of gold and silver, many vintage pocket and wristwatches have had their cases removed and melted down to be sold for precious metal scrap. This has left a large number of extremely high quality and/or ornate perfectly working watch movements without a case – essentially they have become orphaned watch movements.”
These movements from the mid-1800s to early 1900s are excellent timepieces capable of keeping accurate time to a few minutes per week and will never need a battery to keep going with daily winding. With proper servicing and care these timepieces can last another couple hundred years once inside a case.”
Being both time-consuming and a potential risk to the internal components, it is the sad truth that these discarded watches will not be repaired with their traditional gold or silver cases. As a result, other methods, enabled by modern technology, must be used to restore these vintage pieces.
“Thanks to recent advances in high-resolution 3D resin printer technology, development of affordable high-quality engineering-grade (high strength) resins, and the availability of micro components & fasteners from Accu, it is now possible to design and create replacement pocket or wristwatch cases that will protect these wonders of 19th-century engineering and manufacturing. This will allow them once again to be used as a timepiece as they were intended as well as be admired for their beauty and workmanship."
The images show both the design example and finished project for one of John’s restoration projects, an 1870s vintage Longines Pocket Watch movement with a 38mm diameter fitted with a three-part 3D printed open-faced case.
"The replacement cases for these watch movements require very small fastener components that Accu has in stock. Without Accu’s stock of these fasteners, it would not be possible to practically design and produce high-quality replacement cases – specifically machine screws, washers, pins, etc., that are in the 1mm to 1.6mm thread range. These fasteners from Accu usually come in a variety of material types and finishes which allows for some artistic design flexibility, not possible with stainless-only fasteners.”
“The three parts of the case are securely held together by 316 stainless M1.4 socket head screws and washers available from Accu.”
John was also thrilled to share some information about other, forthcoming projects from Geminus Technology Development. He shared, “Due to the availability of Accu’s AccuBlack finish screw fasteners, a white case with black fasteners is possible and is awaiting assembly.
We are also currently designing a fully-wearable wristwatch case for a 34mm 1870s vintage Longines movement using a similar construction also using fasteners and small parts from Accu.
We have a number of rescued case-less high-quality Swiss-made movements that will have replacement cases designed and 3D printed over the next year. This will allow these 100+ year old engineering works of art to continue life as fully working timepieces and we will continue to utilize Accu’s excellent selection of micro fasteners to make this possible.”
Micro Screws Used In Electronics
Another industry benefiting from the intricacy and precision of these tiny screws is electronics. Often found in mobile phones, cameras and laptops, Micro Screws can tightly fasten the integral workings of these devices without taking up too much room within the assembly.
This means that electronics can become more compact, efficient and slimmer, complementing the ever-evolving technology industry.
In stainless steel, Micro Screws also offer a clean visual appearance and corrosion resistance, this makes them ideal for everyday electronics that need to look good whilst also standing the test of time.
Installing Micro Screws
As you would expect, these micro-sized components can not be installed with any old screwdriver.
Accu offers a range of slotted screwdrivers that can be used to install Micro Screws with a thread diameter of less than M1.6, such as this Wera Kraftform Slotted Screwdriver.
Fasteners that are above M1.6 are within Accu’s standard range and therefore screwdriver options for these components are available in multiple sizes with additional drive options.