[PatRyan]

Ger 21 above wasn't accurate when it comes to 80/20 extrusion - they are always straight. That is what you are paying for - tight tolerance and consistent clear anodizing color. Misumi is not the same as 80/20. They are a smaller manufacturer with less compatible parts, and less inventory in the US. 80/20 is made in the USA, and has the highest quality.
While 80/20 is not the cheapest extrusion you can buy - it will serve you well for years to come. The idea that the top brand is not straight is just nonsense.

[wizard]

I really have to disagree here.

Ger 21 above wasn't accurate when it comes to 80/20 extrusion - they are always straight.

Straight compare to what. 8020's specs are very clear here and not hidden. Beyond that if raw extrusions where that straight Mitsumi and other would not offer machining services to flatten surfaces for rail mounting.

That is what you are paying for - tight tolerance and consistent clear anodizing color.

Actually what you are paying for is a rapid assembly method, an adult erector set if you will. The tolerances are not machine tool quality!

Misumi is not the same as 80/20. They are a smaller manufacturer with less compatible parts, and less inventory in the US. 80/20 is made in the USA, and has the highest quality.

I don't know about the highest quality, we use a lot of 8020 at work and other manufactures as well and the quality is comparable across vendors. Aluminum T slotted extrusions have their place but it is a huge mistake in my mind to not consider alternatives to major parts of a machines structure.

While 80/20 is not the cheapest extrusion you can buy - it will serve you well for years to come. The idea that the top brand is not straight is just nonsense.

The comment is accurate, in the context of machine tool building extrusions are not straight, especially if you are considering them for axis linear rail mountings. There is nothing outlandish as 8020 documents their specs publicly. Now given that extrusions have tigher specs than you will see for most steel tubing suppliers. The fact remains that in either case you will require machining of the rail mounting surfaces or other approaches to flatten said surfaces. That being the case steel often makes good sense as it can be cost effective especially for a home build.

[PatRyan]

Although the specs may need not seem that exact, our experience is that 80/20 has an excellent QA process and so that spec would be a worse case scenario. As you know, company/product specs are easy to print in a brochure. But the good companies spend the money and time to check their manufacturing process to ensure they meet or exceed the published spec. or they re-melt it. That is part of the product cost that people forget about when comparing "foreign" extruded bars with lower prices that may not do this QA step. With many successful CNC frames in the field, I think you would see a lot of people jump in on this topic if their 80/20 t-slot extrusions did not work well. Yes you can probably find something less expensive that looks the same, or has the same spec - but you may or may not get what you want. Just saying specs aren't everything.


Straight compare to what. 8020's specs are very clear here and not hidden. Beyond that if raw extrusions where that straight Mitsumi and other would not offer machining services to flatten surfaces for rail mounting.

Actually what you are paying for is a rapid assembly method, an adult erector set if you will. The tolerances are not machine tool quality!

I don't know about the highest quality, we use a lot of 8020 at work and other manufactures as well and the quality is comparable across vendors. Aluminum T slotted extrusions have their place but it is a huge mistake in my mind to not consider alternatives to major parts of a machines structure.



The comment is accurate, in the context of machine tool building extrusions are not straight, especially if you are considering them for axis linear rail mountings. There is nothing outlandish as 8020 documents their specs publicly. Now given that extrusions have tigher specs than you will see for most steel tubing suppliers. The fact remains that in either case you will require machining of the rail mounting surfaces or other approaches to flatten said surfaces. That being the case steel often makes good sense as it can be cost effective especially for a home build.[/QUOTE]