Building things out of metal isn’t as difficult as you might think: V-slot and T-slot aluminum extrusions make frame construction easier. Join me as I tell you what it is and how you can get started creating something amazing.

What is aluminum extrusion?

Aluminum profile length

Aluminum extrusion is aluminum that has been pushed out through a hole in a funny shape called matrix . Much like how much plastic and food is produced, hot metal is squeezed out through a shaped hole that yields a useful product. This is a somewhat simplified representation, so if you want to know the ins and outs of the manufacturing process, take a look here.

This may seem like a lot of effort, but it has many benefits. Extruded aluminum is actually stronger, lighter, and uses less material (meaning it’s cheaper) than its durable counterparts. Extrusions come in a wide variety of shapes, so you can often find one that fits your particular use case. Finally, aluminum is very easy to work with, using only basic tools. It’s often not suitable for heavy-duty applications (such as combat combat robots), however you might be surprised at what can be done with it.

V-slot vs. T-slot

There are many different forms of extrusion. The cross-sectional shape is called a profile. You will need two main profiles: T-Slot and V-Slot.

T-slot has T- shaped groove on each side:

T-Slot Aluminum Profile
Image Credit: homydesign via Shutterstock

The V-Slot is similar but has a slightly bevelled edge:

Cross Section V-Slot

While this may seem like a minor difference, it has a big impact on how you use them. The V-slot allows the bearings and wheels to sit inside the profile, meaning it can also act as a linear rail, greatly reducing the cost of motion control parts.

They are somewhat interchangeable, but it’s usually best to stick to one type for each project. Basic parts like brackets and T-Nuts work great with either, however slightly more specialized parts like bearings or fancy connections can only work with one or the other. Also, if you mix and match parts, you may need to change or adapt your design and end up purchasing more lengths of one extruder or the other.

V-Slot was created by Mark Carew of OpenBuilds and is open source. While there are several other options available, this article will focus on the V-Slot. OpenBuilds explain their system in this video:


V-Slot 20 80

The V-slot comes in a variety of sizes and the range is expanding. It comes in various lengths and some distributors will even cut in length. Most popular sizes:

  • 20mm x 20mm
  • 20mm x 40mm
  • 20mm x 60mm
  • 20mm x 80mm

Even the smallest diameter parts (20mm x 20mm) are very strong and the largest parts are more than capable of working in tough conditions.

Cutting and working

You can cut the V-groove in a variety of ways. Manufacturers claim it can be cut exactly like lumber on a cutting saw, however I don’t recommend it — it’s a quick way to dull the blade, and if you don’t have a special blade for cutting metal, it may not work well. or.

The easiest way to cut it (even larger than 20 x 80) is to use a hacksaw (UK). Use the engineer’s square (UK) to mark the exact line, then cut it slowly (after pinning it to the appropriate desktop). Don’t worry about a junior hacksaw (even for small things) as they are often trash.

Any uneven areas or non-square cuts can be corrected with a file (UK). Be careful not to mark the edges of the aluminum.

final extrusion

You can purchase the V-slot in two finishes: raw and black. Raw is just aluminum as is, while black has been anodized, a chemical process that reacts with the surface of the metal.

The black ones look much cooler but are easier to tag or damage. Plain allows you to anodize in different colors at a later date. Paint is not suitable, nor is powder coating, as they both contain a layer of paint on the outside of the part, which reduces the effectiveness of the bearings.

Connecting parts

V-Slot T Nuts

Putting the pieces together is very easy. The most common method is through T Nuts . These slots into slots in the aluminum, and allow the bolt to press against them like this:

T nut in the groove

They are fairly cheap ($12.99/100), although they can sometimes be fiddly to align a few properly. Open Builds sell a variety of connecting braces for different uses.

If you want to save some money, you can 3D print your own connectors:

Aluminum extrusion 3D staples

In addition, metal braces from the hardware store can often be purchased very cheaply:

Aluminum extrusion brackets

Because they come in a variety of sizes, you may want to write down some measurements to help you buy the right size brackets. Using these brackets is very easy to insert two (or more) T-nuts into the extrusion channel:

Aluminum Insert T-Nuts Nuts

Then align your parenthesis:

Aluminum extrusion bracket located

Then fix it with the appropriate size bolts:

Bolted Aluminum Extrusion Bracket

Use the same method to connect another part of the extrusion:

Aluminum extrusion connected at right angle

The bearings are simply bolted on (assuming the correct spacing):

Aluminum extrusion bearings

Although you may want to drown the bolts:

Aluminum extrusion countersunk head bolts

Where could I buy

The easiest place to buy is the OpenBuilds store. It costs $10 for 1M from 20 x 20 to $20 for 20 x 80. Various connectors, plates and wheels can be purchased in different sizes and specifications as seen in this video: sells parts, as does Aliexpress. While parts may seem cheaper on Aliexpress, postage can often negate the price as well as any import duties.

What can you do?

Something! The most commonly used are 3D printers (what is 3D printing?), CNC machines and robotics. Anything that requires smooth linear movement is the ideal project to use an aluminum profile.

It is entirely possible to produce something using only off-the-shelf parts. If you want to save some money, you can easily make your own wood or plastic parts. Make sure to brush up on your tech skills» first turn.

I designed and 3D printed this camera slider over the weekend:

V-Slot Camera Slider

I designed these parts using Google Sketchup — it’s very easy to use. Be sure to read the basics . If you still need some inspiration, take a look at these computer workspace updates. Updates improve these IKEA office hacks or maybe you could build a smart home like Mr Robot.

Have you built anything using an aluminum profile? Let me know in the comments below, I’d love to see!

Image Credits: Petr Sobolev / Shutterstock

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