Factory Tour: LH Thomson’s Massive Stem, Seatpost & Aerospace Machine Shop
Factory Tours are some of our favorite things to do. Not only do we always learn something new, but witnessing how things are actually made generally bestows upon us a new appreciation for the parts, bikes and gear we all ride.
LH Thomson’s machine shop was no exception. In fact, the stem CNC machines are simply mind blowing. Alongside work for the aerospace industry, some of our favorite seatposts and stems are being designed, made, tested, packed and shipped. While some of the tippety-toppest secret stuff was hidden in advance of a foreign industry group’s visit on the same day (the NSA actually called them and told them to hide anything confidential!), we still managed a few sneak peeks at some killer bike stuff coming down the pipeline. Some of it we covered in the recap of their forthcoming dropper post, the rest is here, along with a close look at how blocks of aluminum are turned into some of the most durable parts on the market.
Here’s how they got started and how it’s all made…
The company was founded by Loronzo Herald “Ronnie” Thomson in 1981. His son and daughter were into cycling, and she brought her team home to GA for winter training one year. One teammate was neighbors with Gary Klein, who heard of LHT’s manufacturing capabilities and suggested they start making bike parts. Klein and others said a high quality seatpost would be a great start and would really put them on the map. After about two years of development, the first posts were made and sent to Gary Klein for testing. He liked them so much, he stuck them on bikes and sold them before LHT had officially signed off. Things moved quickly from there and the first LH Thomson posts started shipping in 1995. The Elite post hasn’t changed much since those first ones, mainly just alloy changes on the cradle and the addition of a setback option. More recently, they added a reinforcement ridge on the Elite post for the two larger diameters to improve fatigue life. Stems followed in 2000, and last year they introduced their bars and the dropper post.
About 70% of business is making parts for Boeing, Cessna, Gulfstream, etc. The bike department is pretty small. Eric Lassiter is the only dedicated engineer working on bike parts, and Dave Parrett oversees the testing, marketing, PR and project management.
“Because we’re so small, you get to wear all the hats and really take a project through from start to finish,” said Lassiter as a way of explaining that the smallness was a good thing.
The inside of the building is virtually all machine shop. The panorama above shows it all. Raw materials come in on the left, and things generally flow toward the other end of the building as they make their way through production. Here’s how it goes:
Big plates, rods and beams of metals (steel, titanium, alloy) come in. Most are pre-cut based on their intended use to sizes that’ll fit in their CNC routers and lathes. The largest sheets are carted to a small suction crane, which lifts them into the cutting machines. Not only are they very heavy, but the crane makes it much easier to position the large sheets inside the machining booth.
By the bay doors are the metal saws, which cut away bigger chunks of metal that would otherwise prematurely wear their router bits. At left, a cube is sawed into an “L” before going to the router. The end result is a 737’s Thrust Reverser Fitting shown on the right.
Those large sheets are used for larger pieces that are first machined for depth and shape, then cut out.
Now, on to bike parts…
Stem blanks come in precut by a mill in Indiana using Alcan material that’s extruded in Minnesota. When the plant is finished milling them, they go to Pennsylvania for anodization. Parrett admits there’s quite a bit of diesel fuel consumed during the transportation process, but it’s simply not feasible to put in giant vats of acids and ano chemicals inside their machine shop.
A Dual Turret Lathe cuts the base of the stem in about 40 seconds, turning a solid block of 7000-series aluminum into a bike stem. Stop reading right now, scroll to the bottom of the post and watch the video to see how fast this happens. It will blow your mind.
All metal shavings are collected and recycled, filling a tractor trailer with aluminum about every 2-3 months. They keep steel and ti scraps separate and also recycle those.
While they don’t use it to test bike parts yet, they have a Programmable CMM (Coordinate Measuring Machine), which takes a 3D model and compares the model to the actual part to make sure it’s in spec. A separate climate controlled QC lab has a larger CMM for bigger parts. Bike parts are still checked using physical calipers. The benefit of a CMM is that you don’t need a vast array of calipers and specialized measurement fittings and bits for each and every piece…it’s all digital and can be programmed to check any aspect.
After the stem’s main bodies are cut, they head over to another cutter. This stem machine is the original one purchased to make stems, and it’s made every stem they’ve ever sold. It’s capable of producing about 5,000 stems per month.
Eight stems are loaded on a “tombstone” while another stocked tombstone is inside the machine.
This is where the steerer clamp hole and shape is made, and they get polished up.
Two workers manually de-bur each piece to make sure there are no sharp edges that could cut you or damage your handlebar or steerer.
Seatposts are made at the other end of the building.
They start life as pre-extruded blanks (left) and end up with round exteriors and ovalized interiors.
For the both the Elite and Masterpiece seatposts, they can turn out about 40-50 posts per minute! After machining, the tops get drilled for the bolts.
After machining, Masterpiece posts are subjected to a cutting broach to remove material from the inside to make it lighter. This method allows far greater accuracy compared to a lathe, which is extremely important considering how long a seatpost is compared to boring out the center of a stem. If they’re off center even the slightest bit, by the time a drill bit got to the end of a seatpost, especially the longer ones, the wall thickness could be too thin on one side. Basically, this rod’s cutting edges are gradually larger in diameter, and it’s shoved under high pressure through the post, taking incrementally more material with it the deeper it goes.
The cradles are machined then dumped into a vibrating bath of shaped stones to smooth all edges. Notice the freshly cut edge on the top one compared to the roughened, smoothed edge on the bottom. Once they’re done, they’re shipped with the stems to PA for anodization, then come back for laser engraving (smoothing and laser engraving process are both also shown in the video below), then they’re ready to be packed.
With so much else automated and computer controlled, arguably one of the toughest jobs is assembling the parts and packing the boxes. After staring at posts for a while, they start looking the same. But each one has to get the right label, have the bolts greased, be packed with instructions and stickers, bagged and boxed. Parrett proudly says the error rate for mislabeled boxes is less than one per month.
Spare parts bins are kept close by. Boxes are stacked and ready to be moved back to the left side of the building to be loaded on trucks. Jerseys from sponsored athletes adorn the racks here and there.
That’s largely what’s done in house. With the introduction of their handlebars, Thomson made it clear they plan to eventually bring the carbon fiber bar manufacturing in house, too. Oddly, there was no mention of bringing the aluminum and titanium bar production here, but there’s a good reason why:
Parrett says the alloy bars are also made overseas because they need to be heat treated within a short period of time after the butting and schwaging, which is also a very different process from the machining and lathing they do. Basically, a handlebar’s tube starts out longer than necessary, then it’s compressed from the ends with mandrels inside the bar. Their bars are made using a high end 3D CNC bender, which requires no finishing work or sanding to create a smooth finish – it comes out of the machine essentially ready to go to ano. This means the material isn’t getting thinned out for cosmetic purposes, so it’s strong and pretty. Note the varying thickness of the Downhill bar cutaway shown above.
“There’s a lot of stuff people want us to do, but there’s a huge upfront cost. For each of our handlebars, there’s about $5,000 in materials just to get started. Each of the carbon handlebar molds is about $8,500. The heat treating furnace is about $400,000, and it would require a separate building. The titanium bars have 34 total hours of heat treating.”
So, it’s likely they’ll keep the alloy and titanium bar production overseas because the volume just doesn’t warrant the capital investment. Parrett says not only is it less expensive to set up a carbon manufacturing plant, but the potential market size and volume is much higher. Plus, they’ll need to start developing carbon parts for Boeing, so there’s added incentive. They have 26 acres of land, so eventually you’ll see a new building popping up and employing new people.
Does that mean they’ll ever offshore their post and stem production? No, because those parts are machined and lathed, and they can do it for less in house.
They also do a lot of testing in house. The carbon bars above were casualties of load and stress testing, and Parrett says theirs test very, very well compared to competitor’s bars.
For real world testing, they maintain mountain bike trails that are right outside their backdoor – which see a lot of local traffic. Parrett says it’s the second most used trail in the county. Makes for some great proving grounds (AKA getting paid to shred) and lunch rides.
Video shows three different procedures:
- Dual Turret Lathe machine’s monitor following the router process as it turns a blank into a stem body
- Seatpost cradle getting smoothed (briefly) to show how the machine works
- Laser engraver putting specs and logos on seatposts
Big thanks to Dave and Eric for showing us around!