which type of metal do I want for...

[curmudgeon]

How do folks know, or figure out, which type of metal to use for a project? I don't have much of a scrap pile so I'll be having to break open the piggy bank...

Specifically, what type of metal would I use for a new guide post for my King WA-1403C bandsaw? The current post is 21mm hex bar with the bottom inch or so turned to 21mm round to accept the upper guide support bracket. A previous owner installed a DIY, 6" riser block. I'd like a a longer guide post to better support the blade when cutting thinner material.

Being new at metal shopping, I started at the frequently maligned Metal Supermarkets web site. First surprise, no hex bar in metric sizes. But that's OK, I don't see why I can't go with 7/8" (22.23 mm) and turn one end down to 21mm. The guide post clamp will accept the larger sized bar, and I can buy the bar a bit long to turn the other end to 7/8" in case I want to upgrade the guides later with a standard 7/8" kit.

So, Metal Supermarkets website lists 7/8" hex bar in:
- Mild Steel Hexagon Bar Cold Rolled 1018
- Mild Steel Hexagon Bar Cold Rolled 12L14
- Alloy Steel Hexagon Bar 4140
as well as stainless, aluminium and brass.

Is 1018 the right (as in least expensive that is fit for purpose) metal for this project? And, for the South Island folks, is there another local supplier I should look at?

Thanks,
-Steve

 

[whydontu]

12L14 is easiest to machine. 1018 would be more than strong enough for your application.

 

[Susquatch]

In my case, it's usually mystery metal. In other words whatever I have on hand or can find.

If I have to buy metal, it's only because I need something special required by the job. (stronger than normal, hardenable, stainless, aluminium, big, thick, etc) in this case I usually let price guide my final decision within the parameters of whatever I was looking for in the first place.

Usually, you can just make something bigger or thicker to meet your needs without buying stronger metal.

I'm not usually fussy about finish. But when I am, it helps to get good metal that is easy to get a good finish on.

 

[Dabbler]

In your application anything will be plenty stiff enough. Strength is far less an issue than stiffness. Cold rolled hex bar in 1018 or 1075 will be ideal... but anything will do!

Too bad you are so far away; Some of us in Calgary have a mini-MSM in their shop/yards.