Aluminum or Magnesium Backspacers, Liners?

[Bolster]

What is the reason that aluminum or magnesium backspacers are not prevalent? Is the purpose of a solid steel backspacer to move the balance of the knife to the rear? To give the knife more overall heft? Would aluminum or magnesium be too flimsy to hold a lockback spring...but how could it, G-10 and FRCP backspacers exist.

While we're on the topic, has Spyderco ever made a knife with aluminum or magnesium liners?

[cjk]

The OG military had an aluminum backspacer.

[u.w.]

Magnesium is VERY prone to corrosion, so there's that...

Aluminum though, some 7075 T6 (very hard stuff, relatively speaking) might work well.

u.w.

[JRinFL]

There was a Police version that used aluminum for the handle and a few other models had aluminum versions as well. I don’t recall Spyderco using it for liners in any models, but I could be wrong.

Cold Steel has used aluminum liners in several models. I don’t know why Spyderco didn’t use aluminum liners or why they stopped making aluminum handled models for the most part. I know they made those exclusive PM2s not too long ago.

[yablanowitz]

Maybe because people insist on taking their knives apart. Aluminum and magnesium threads strip out much more readily than steel, especially when the users think torque specifications are a myth.

[Bolster]

Maybe because people insist on taking their knives apart. Aluminum and magnesium threads strip out much more readily than steel, especially when the users think torque specifications are a myth.

And the clip screws do screw into liners on many models, good point. But how do we explain G-10 and plastic backspacers.

[RustyIron]

I think there are two reasons for not using aluminum or magnesium:

1. They don't offer any benefits over the existing materials.

2. It's aesthetically distasteful to build something out of one material, and have one mismatched part. Gross.

[Fireman]

I want titanium liners. It’s party cost I think. Sometimes the metal back spacer can aid in balancing the knife

[StuntZombie]

The OG military had an aluminum backspacer.

Was it? I was under the impression that it was polymer or G10. Pretty sure that's what mine was at least.

Some folks have mentioned aluminum not doing well when threaded, but I also think that aluminum liners might not have the tensile strength of steel or titanium. Maybe that's why it can be used as scales, but not liners. Just a guess.

[Bolster]

...1. They don't offer any benefits over the existing materials.
2. It's aesthetically distasteful to build something out of one material, and have one mismatched part...

1. Light weight, if compared to steel. I'm looking at a Native Chief backspacer thinking "That's one big hunk of steel."
2. While it's not uncommon for a knife to be built of several different materials, I suppose there could be an aesthetic component if the aluminum or magnesium weren't anodized.

I wonder if an aluminum backspacer would wear a lot faster; but then again, wouldn't G-10 and plastic, and they are sometimes used for backspacer material also.

[Ramonade]

Most backspacers are just here to fill space.
When the backspacer is actually needed for structural integrity, we often see it made from steel or titanium.

However, G10 is a material that can resist a LOT. Certainly more than aluminium in many categories of impact, torsion or pressure.

[phaust]

The OG military had an aluminum backspacer.

Was it? I was under the impression that it was polymer or G10. Pretty sure that's what mine was at least.

Before switching to standoffs, the backspacer was delrin for a bit (that's probably what yours was) and aluminum after that.

[yablanowitz]

There is also a matter of galvanic corrosion to consider. If the spacer is also functioning as a spring holder, such as on a lockback, having the steel spring in direct contact with a dissimilar metal can cause unwanted reactions.

[vandelay]

I'd guess a reason for not using aluminum liners is because screws strip out of aluminum much more easily than steel. I'm not sure if that'd be a problem in a backspacer though.

I don’t know why Spyderco didn’t use aluminum liners or why they stopped making aluminum handled models for the most part.

Aluminum handles are slippery unless they're textured very aggressively and they aren't fun in cold weather. Anodized aluminum also looks pretty bad once you beat it up a bit. I'd imagine G10 just sells better because of that.