In this third installment I describe some of the manufacturing processes we employ, and how they differ from Seven Cycles’ standard production methods. As I’ve mentioned in previous posts, this information isn’t meant to be a “how to” series of posts; it’s not the way to build ecologically low impact bikes. I’m simply sharing how we went about it—as more and more people have asked for details. I’ve also learned that we have a lot of room for improvement for future Viridianesque projects.
Within the framework of this low ecoimpact bike project, we had a number of internal and external goals; here I’ll explain another of our primary internal goals:
Goal: Cut frame building electricity usage by 25%
In short, we exceeded this target. At first, I didn’t think we were going to be able to do it; we already run fairly lean electrically. Here’s how we approached our electricity reduction goal. I’ve parsed our electricity use, on this project, into five categories:
- Elimination of electricity
- Reduction of electricity
- Tradeoff or Optional electricity
- Primary or Required electricity
- Offset electricity
- Bottom bracket threading, facing, and alignment. This was the single biggest electrical reduction. On this project we are doing this fully manual—like we did way back when we started the company. Nowadays we use a CNC machine for threading and finishing the bottom brackets. However, the CNC machine draws the most electricity—along with our welding machines—in the building.
- Head tube facing. Typically we do this on a lathe. Again, we went back to our old school and are doing it manually for this project.
- Paint. This one is simple—we aren’t offering it on the Earth Day bike.
Bottom bracket note: we briefly looked at employing a BB30 as an alternative to our standard threaded CNC bottom bracket shell. We decided against this because the BB30 still requires some CNC work, even though it requires less electricity, it’s still more than our old school manual method.
Some places where we reduced electricity use
- Elements of machining. We reduced our mill and lathe work by 25%—switching to more time consuming and labor intensive handwork. We only did this in areas that would not impact frame accuracy, durability, tolerances, or alignment. Of course, there aren’t many tasks in frame building that don’t affect one of those critical areas.
- Work within our core hours. This means no work on these frames during weekends, or before or after hours. This goal is to share light, heat, and other power sources within the structure of our standard work flow. In other words, no light, heat, or electrical power sources that are exclusive to this project.
- Employing natural light and heat. This may sound redundant to the Core Hours parameter. However, in March it’s still dark during some of our common work hours. And, New England can still get pretty chilly at this time of year.
- Decals. We traded decal-making electricity for “sand blasting” logotype and designs onto the frame. Over the life of a bike we probably see 4+ sets of decals get used. We estimate that the blasting electricity is offset by decal making. And there are some other compelling reasons for blasting.
The optional electricity we ended up using—the tradeoffs
Most of these had something to do with safety; we could have gone without, but for safety reasons, we opted to electrify.
- Light and heat. Again, for health and safety reasons. We actually could have done it all with daylight use but that’s not particularly healthy—for eyesight.
- Head tube reaming. It’s way too much material removal to do it manually. We could have done some pre-machining on a lathe to enable the final step to be manual, but the net electrical consumption would have been nearly the same in either method.
- Computers. Used to track the frame’s process. We felt it better to track each bike within our standard system, otherwise issues might occur. Seven’s production and kan ban system is fairly complex—from initial bike design concepts all the way through frame building process flow—so we thought the tradeoff made sense. And, computers are lower electrical use than the other frame building equipment we used on this project.
- Basic frame building. This is a bit difficult to describe in simple terms. But, we’re using 12 machines—mills, lathes, and drill presses—in the frame building process. Our average frame requires 17 machines. So, we’ve reduced equipment use by 30%. Granted, one machine is not the same as 1/17th of the electricity, but it is directionally accurate.
We could have done all the frame building with a hacksaw and file—like we did when we started—and avoided electrified machines all together. Some other time I’ll explain why building frames that way is a bad tradeoff.
The primary electricity we are using
- Welding. This was the most difficult area in which to reduce electrical use. You can either weld faster or not weld on some of the parts—cable stops or brake mounts, for example; that’s about it. Of course, neither of these ideas are appropriate for Seven. We were, however, able to minimize weld time by designing the bike with a non-butted tubeset. This type of tubeset welds a bit faster than a butted set. We also did minimize welded parts. In fact, the weld time on this model is about 25% less than on an average Axiom frame.
Places of electricity offset or “credits”
- Bicycle commuting covers more than the electrical use for each of the Viridian bikes. I described this in detail in the previous post: Part II.
- We also looked at generating power to build the frames through the use of bike trainers hooked up to generators. Ultimately, we decided that we simply could not generate enough power to make a reasonable difference. So we decided to focus on bicycle commuting—fuel consumption reduction rather than electricity production.
This post is getting long, again. We had some other areas we explored for this project, including consumables reduction and reuse, toxin ellimination, some materials tricks, and a few other LOHAS concepts. Another time, perhaps. Right now, I’ve got to shut down my computer to reduce electricity use…