This is how I do it. There's no secret, no tricks, no unrevealed machinist helper... just some good old fashioned MacGy-Fu and elbow grease. This isn't an all-inclusive, end all/be all, difinitive guide, just a "this is how I do it" to get the ball rolling.
Essentials:
- A good shop vac - hacking, cutting, grinding, sanding is a messy business. Good means reliable, strong, but versatile.
- Bench Vice
- Hacksaw
- Pipe/tube-cutters - I have 2: one for larger diameters (1.5"+), one for smaller diameters (3/4"-1.25")
- Files
- at least one very coarse for grinding
- a few for shaping (Rounds, angles, radius, etc)
- a few still for clean up
- mini set for detailing.
- Sand paper, I use 40g - 1500g, for shaping, sizing, and finishing
- Electric drill + bits
- Center punch (or manual punch + hammer)
- Never drill a hole with out punching first.
*punching refers to locating the spot where you want to the hole, placing the punch's point at the exact location, and compressing it until it clicks or giving it a solid thump with the hammer. This creates a small guide-divot precisely where you want the bit to start cutting - Taps (with correct size bits) - inch and metric. I like metric for tapping thinner walled or single layers of tube; there are more threads per inch/mm
- Expander bit (a.k.a. Uni-bit)
- Flap wheels
- Rubber Compression plugs (in various diameters)
- Dremel - I mostly use sanding drums and cutting wheels, so quick-changes for those are good
- Digital calipers... or a reeeelly good eye.
The materials that I get for telescoping tubes. *telescoping just means "stepped sizes" tube A fits neatly in the ID of tube B, tube C fits neatly inside tube B, etc.
Online metals, for serial - great source for tubes.
Telescoping (0.058" wall, separated by 0.009"):
1.5" OD x 1.384" ID
1.375" OD x 1.259" ID
1.25" ODx 1.134" ID
1.125" OD x 1.009" ID
1" OD x 0.884" OD
0.875" ID x 0.759" ID
etc. etc...
Also dxengineering is a great source for telescoping tubes, they're in the antenna section.
Using pipe/tube cutters will leave a raised edge and inward flare on the edge of the cut, which messes with the fit. It has to be removed before you fit it to another tube, or at least, reduced for a tighter fit.
I use the coarse grinding file and file it down to the edge of the raised section. It's important to watch the part as you're filing it down, and periodically rotate it in the vice, because you're always going to attack it from a different angle. Use the raised edge as your guide... just as if you had marked it yourself. This eliminates both the OD and ID bumps.
Use a finer file to get rid of the deeper file marks, and then finish it up with some hand-sanding with sand paper (350g). If you did it right, you should have a perfectly square edge that fits perfectly with the appropriate next step up and next step down.
A cut with the hacksaw, pipe cutters, or dremel is never a finished edge. always use files and sand-paper for clean up, squaring edges, fine-tuning a fit, etc. etc..
A lot of my process is just finding a way to achieve a certain look with either available parts, or modifying the parts I have. Here's some examples:Example 1
For a ribbed section, similar to the MHS part, I can't lathe grooves, so my solution would be to cut rings out of one tube and slip them over the other. Does it look as pretty? No, but it looks close, AND, I can, 1) move the parts around, and 2) I'm not restricted to MHS size - it can be any size.
Steps:
- Cut the tube with the pipe cutter into equal sections
- use either a sanding drum or flap wheel to reduce the inner edge
- use files to smooth outer edges
- use sand paper/fine files to clean up edges
- repeat for all rings
The take-away with this example is that you can get clean lines (from raw parts, 2 tubes = $12) with a practiced process and patience. Use this (or similar process) for cleaning up edges, it's pretty much the foundation for everything else.