Have you ever wondered about how bikes are made? Or have you ever thought about welding a bike frame? This may sound difficult, but with some help, materials, and guideline, the task can be made doable and simple.
There are many methods and materials to use in building a bike frame. But the actual joining and welding of the parts are almost the same regardless of the methods. So, if there are required parts and instructions, welding a bike frame becomes not that hard as it sounds.
In this article, we’ll try to make this task a bit easier by giving you a step by step guideline on how to weld a bike frame.
How To Weld A Bike Frame – 5 Simple Steps
Before we weld a bike frame, we divide the tasks into steps and choose a place where we can get all the materials under one roof. This way, the process will be time convenient and easier to understand. Also, the tasks will be organized and not make a mess. Let’s move on to the steps of welding a bike frame!
To weld a bike, the very first thing we’re going to need is a design, according to which we’ll weld the bike. Without the design, it’s quite difficult to make a bike with only the materials and instructions (but if you’re a pro, that is exceptional).
The design can be made through any CAD software or the old school drawing table. If we use the drawing table design, the tubing of the bike can be done over the actual 2-D model of the bike, and we’ll be able to see how things are shaping up.
No matter how the design is made, we have to be accurate about the drawing’s dimensions and angles, for the bike will take the exact shape of the design.
A bike frame has several parts- head tube, seat tube, top tube, down tube, bottom bracket, chain stay, and seat stay. We should focus on two major points while designing a bike frame- how well it fits and how well it feels. We need to focus on the frame’s fitting, size, and perform ability according to it.
The fit parameter depends on the Seat Tube length and the Top Tube length. Feel parameters depend on the Back bracket, Seat Tube angle, Head Tube angle, and Chain Stay length. The best way for a newbie in welding is to determine the feel and fit parameter by measuring another well-fitted and well-adjusted bike.
2. Cutting the Tube
After deciding on the parameters and the design according to preference, it is time to build the frame. For the build, we’ll need the tubing cut in the required shape and size.
The tubing should be selected according to the design dimensions, and there should be enough butt length for each joint. The standard measurements for a road/track frame are: Top Tube- 25.4mm, Down Tube- 28.6mm, Seat Tube- 28.6mm.
We can cut the tubes by hand using tin snips and hand files, or with a milling machine. The tubes should be cut in such a way that all the angles fit perfectly in every joint. After cutting the tubes, it’s time to forge the frame.
The easiest way to build a bike frame might be to start with the bottom bracket. This way, the Seat Tube and the bottom bracket in a proper configuration. The end of the seat tube should be cut in 90 degrees.
A notch will be created, and this should fit the Bottom Bracket perfectly. After that, fit the Head Tube with the Bottom Bracket and the Seat Tube. In the same way, we’ll cut the Top Tube and connect it through the hole in the Seat Tube.
The Down Tube should be prepared the same way as the Seat Tube and the Head Tube. The joint of ST, DT, and BB can be a bit complicated. The DT needs to be cut three times- once for the HT and twice on the other end.
After joining ST, DT, HT, and BB together, we’ll get a triangle, which is the front part of the bike.
3. Dropout installation
The first thing that should be taken care of is the installation of the dropouts. Dropouts are a type of fork end that allows the rear wheel to be removed without first dealing with the chain.
We’ll need two dropouts 6mm*6mm and slightly angled. The inner dropout faces need to be parallel and at a certain distance. The dropouts should fit inside the Chain Stays very tightly. The Chain Stays angle inward from the dropouts to the Bottom Bracket shell.
After the Chain Stays, the dropouts and the BB are placed together, it’s time to weld the pieces. To hold every piece accurate and in places, we can use a fixture. It is important to make sure the angles are correct.
4. The welding/ Brazing
With the help of a jig, we’ll need to line up the Seat Tube in the BB shell center and perpendicular to it. After pinning BB to the ST, pull out the jig, and join them.
Weld the entire joint and do the same with the rest of the tubing. Once all the joints are pinned, remove the front triangle from the jig and weld the joints.
5. The Rest
Set the seat stays on the dropouts firmly and mark where the stays are to be attached. After fixing them, make a space in the Seat Tube, place the seat stays, and weld them well.
Braze-on the overall frame based on its use. Add features to the base according to your desire. After that, clean all the joints of the frame by submerging it in hot soapy water and get it painted with your favorite color.
After following all the steps properly, we should have a high performing, strong, and well-fitted bike frame in our hands.
We hope this step by step instruction on how to weld a bike frame will come in handy for you. And lastly, we’d like to say, “Go nuts with the welding toys, Boys!”
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