You’re building a steel bike with cheap tubes, because it’s a first try (if it’s not the first, you can call it an “early prototype”). Here’s a list of resources.
Tubes:
Make your first frame from straight gauge tubes. Fancy bike tubes are butted, which means they have thinner walls in the middle for weight savings and thicker walls on the ends for weldability. Those tubes are nice, but you want basic tubes, that have the same wall thickness all along their length. What you want is 4130 seamless tubing.
4130 tubes are sold by outside diameter and wall thickness. Bike materials are typically specified in millimeters, but aircraft materials are specified in inches. Some units back and forth may be required. 1 inch = 25.4mm.
Here’s a chart with common outside Diameters and wall thicknesses.
| Tubing OD (mm) | Tubing OD (in) |
| 25.4 | 1.000 |
| 28.6 | 1.126 |
| 31.7 | 1.248 |
| 34.9 | 1.374 |
| 38.1 | 1.500 |
| 42 | 1.654 |
| 44.5 | 1.752 |
| Seat Stays OD | Seat Stay OD (in) |
| 14 | 0.551 |
| 16 | 0.630 |
| 17 | 0.669 |
| 19 | 0.748 |
| Chain Stay OD | Chain Stay OD (in) |
| 22.2 | 0.874 |
| 24 | 0.945 |
| 28 | 1.102 |
| Wall Thickness | Wall Thickness (In) |
| 0.5 | 0.020 |
| 0.6 | 0.024 |
| 0.7 | 0.028 |
| 0.8 | 0.031 |
| 0.9 | 0.035 |
Here are some online vendor options:
McMaster. I could go on all week about how great McMaster is. They have everything you want for making stuff out of metal. They have great customer service and will sell small quantities. They have a reputation for being expensive, that isn’t always true at those small quantities.
Aircraft Spruce – They sell stuff to build airplanes. Some of that stuff is 4130 tubes.
Wicks – They also sell stuff to build airplanes. Some of that stuff is 4130 tubes.
Online Metals – The name says it all. They have 4130 tubes too.
Everything Else:
These vendors have brazons, dropouts, and other small parts. If you must use butted tubes, they have those too.
Nova Cycles Supply – They have lots of good stuff and will sell framebuilding kits along with individual tubes. I’ve done a lot of business with them over the years and they’re good folks.
Henry James – They also have lots of good stuff and will sell kits along with individual tubes. Their braze ons, lugs, and other misc doodads are nicer than than the Nova ones.
Joe Bringheli – Bringheli is great, a super old school DIY framebuilding source. I’ve ordered from him a number of times and it’s always a good experience.
Richard Sachs – Richard Sachs is awesome, and his stuff is top quality. Probably not a great choice for a first frame, but worth mentioning.
Paragon – Paragon Machine Works sells all the dropouts, brazeons, and other doodads you want. They have all the parts you want except tubes.
Torch and File – They sell Reynolds tubes and have some super nice tools.
Paul Carson Designs 