eMachineShop is a leading online machine shop that enables any company, or individual to design, price, and instantly order custom parts via the web. You can use your favorite CAD program or ask for the support of eMachineShop’s own CAD software system. The company offers Laser cutting, CNC milling, CNC Plasma Cutting, Waterjet Cutting, Metal Fabrication, 3D Printing and much more.
For those rebuilding old bikes and can’t find the right original parts and for those creating one-off parts for full blown custom projects the following feature tells the story of Christian Newman modifying his 1940 Harley Davidson Knucklehead. He knew, right off the bat, that he would soon be facing some interesting engineering challenges. After all, the final product he was imagining would only retain the motor and transmission from the original motorcycle, with the frame and almost everything else being completely custom. Among other challenges, he needed help for building custom wheels hubs…
As a skilled machinist and being proficient in CAD, Christian is quite capable of designing and making most of the needed custom parts himself. But due to equipment limitations, he wasn’t willing or able to machine some. The question of how to get them manufactured was lingering. Could they be made using an additive process like 3D printing? Or did their physical requirements require that they be machined from a solid piece of metal?
For most people, taking on just one big shop project like this in their lifetime would be enough, but not for Christian. And that’s because Christian is one of those people who really likes to make head turning, road worthy engineering marvels. Whether he’s building a Nissan Skyline powered BMW 3 Series, or a turbocharged Harley Davidson Shovelhead, Christian always seems to have his hands in something amazingly cool. And as a trained and seasoned mechanical engineer currently working at a sizable petroleum company, and just a generally creative person, he’s very well suited to come up with good, creative solutions to just about any problem.
One such problem was due to the unique drive mechanism whose details cannot be disclosed at this point in time. Let’s just say that it is different enough that the original Knucklehead rear wheel hub could not be used. When this was realized, the decision to custom design and fabricate matching front and rear wheel hubs was made. And if the front wheel hub was going to be made custom, why not go all out and make it extra special by designing it to be laced up with two different spoke patterns.
Generally speaking, when Christian needs a custom part, he just designs it in CAD and makes it himself on his manual Bridgeport machine. But this time things were a bit more involved, and he had lots of other custom work to do. So he set out to find a person or place that could make them for him. When first setting out to have the hubs made Christian reached out to a friend of his at a local machine shop, and although he was told they could make the hubs, the shop had quite a backlog and wouldn’t even be able to start the job for some time.
Seeking more immediate gratification, one of the major online custom parts manufacturers was approached in the hope that they would have a fast turnaround time. Unfortunately, although at first it seemed like they would be able to machine the part, it then became apparent that they would only be able to machine most of the features of the part, which didn’t sit well with Christian.
In what for a moment seemed like a great solution, he was then offered to have the part made using the additive manufacturing process of direct metal laser sintering. If you don’t already know, this is a 3D printing technology that uses a high-powered laser to selectively melt together little metal particles in what looks like a sandbox to build parts layer by layer from materials such as aluminum, steel, and titanium.
Although at first laser sintering seemed like a good idea, there were two issues with this manufacturing method. The first was that the strength and exact physical properties of a part created with laser sintering was a bit of an unknown. Even though generally speaking direct metal laser sintering made parts are quite strong, for an application such as a motorcycle wheel hub that would be load bearing and rotating at high speeds, betting one’s life on a generality is risky business. And even if this risk was willing to be taken, the price that was eventually quoted was just shy of $10,000! Clearly, this option was not selected.
A bit discouraged, but with a few more tricks up his sleeve, Christian kept looking around for a parts manufacturer that would take the job at a reasonable price and produce the part as designed. Finally, after a bit of research, he found a custom parts and prototype manufacturing company in New Jersey called eMachineShop. From what he could tell, eMachineShop had a good online reputation and quite a few years under their belt machining different types of parts, so he decided to submit his CAD drawing for a quote.
In less than two days he received his quotes for the front and back hubs, and considering that they came in at around half of what the company that couldn’t even completely machine the part quoted, and only a bit more than reproduction hubs based on the stock design, using eMachineShop to make the part was no brainer. Just stay tuned for a build update on Christian Newman 1940 custom Knucklehead.