Aluminum or steel straight edge better

[lcm1947]

I was looking at straight edges and remembered that I had seen several people mention that steel was better then aluminum but they never mentioned why. Can anybody tell me why?

[dlminehart]

I'd assume it's because steel is harder. Less likely to get dings or scratches on the edges. You'd want stainless steel, though, or you'd have rust problems. Don't know which expands and contracts more with temperature.

[wardprobst]

I have this Lee Valley aluminum straight edge that I like very much. http://www.leevalley.com/wood/page.a...at=1,240,45313

DP

[eezlock]

alunimum or steel straight edge?

Mac, what are you planning to use the straight edge for ? I assume you are talking about a guide for a circular saw when making long rip cuts or big
cross cuts on sheet goods ? Alunimum is a lot easier to handle and will do the same job as a guide with about 1/3 the weight of steel guide, so unless it is free, either one of them should work fine.

[lcm1947]

Hey eezlock. Actually I'm not needing it for those type things. I use several different length shooting boards for that. I'm just wanting something to insure how straight boards or plywood is after cutting it or to pick out precut boards at Lowes or HD. I also would like it to use for hand routing ( Niki's method ) to joint boards. I have given up trying to joint on the router table but was able to do a very good job with the hand router. I was just wondering if maybe the aluminum straight edges would warp or something over time or if maybe heaven forbid dropped. Yeah DP I was looking at those myself. Pretty nice. Those are good points dlminehart I suppose over time the aluminum ones would get dinged and or scratched. I wonder what other reasons though if any. Maybe not?

[Handy Al]

I found this week that an aluminum won't hold up to a carbide saw blade. I was cutting a sheet of 3/4" MDF. 47" is lttle beyond my easy reach. Lifting the saw, the blade made contact with straight edge before the guard closed. Straight edge is no longer straight. Of course if it was steel, I would probably be out a new 40 tooth saw blade also.

[ironhat]

I wouldn't worry about the dings and scratches, Mack. Those little imperfections won't affect your intended purpose and besides, aluminum is easy to repair - such as smooting out a curled edge where it struck something hard.

[lcm1947]

Hey Ironhat. That's an odd name for a woodworker isn't it. Well you are probably right there on being able to repair small scratches and stuff. I wonder if any good reasons to go steel instead of aluminum then. They sure are a bunch more expensive.

[ironhat]

I get a lot of questions about my 'handle'. It's the translation of my German surname which is, Eisenhuth. Incidentally, I have an aluminum straight edge - super cheap so I don't rely on it for a true edge - and I've had it for 15 years. It's still in great condition because it gets hung up in an out-of-the-way place.

Still havin' fn,
Chiz

[lcm1947]

Thanks ironhat for the answer to my question. Doesn't clear much up but maybe it's over my head. Well the aluminum ones sure are cheaper. I may try one if nothing else due to the price. I do take care of my stuff so it should last me.

[LarryG]

Mac, I have the same Lee Valley aluminum straight edge as DP (mine is the 38" version). I've had it a couple years, I guess. Still dead straight, still looks like new. I mostly use it to check the setup of tools.

I don't know why people would say that steel is considered superior to aluminum. (I'm not saying it is or isn't, only that I don't know why.) Aluminum does have a higher linear expansion coefficient than steel (about twice, IIRC) but I've not found that to be a problem for the tolerances involved with woodworking machinery.

[LCHIEN]

Mac, you talkin' stainless steel or just steel? Big differences.

lets assum stinless -=stainless steel, Alum = anodized aluminum, steel= plain old steel.

Order of raw materials price: Steel, aluminum, stainless
order of hardness: stainless, steel, alum
order of corrosion resistance: Stainless, Alum, steel (rusts) ( I put aluminum second because if scratched, the underlying aluminum will oxidize, whereas the stainless goes all the way thru)
strength per volume: stainless, steel, alum
Strength per weight: aluminum, stainless, steel
Density (weight per volume): Alum, stainless/steel (tie)

what makes a better straight edge?
depends on what your criteria is, strength, durability, weight, cost, etc.

[lcm1947]

Thanks LarryG & Loring for your replies. Well it looks like aluminum would be sufficent then for my needs and since cheaper makes even more sense. I appreciate all the replies and help. Like I said I had heard more favorable comments pertaining to steel over aluminum so thought I's ask before buying one. It appears aluminum is fine then.