Given the same size screw, which is the lightest: Titanium, Aluminum, or Stainless Steel?

Lately I have been running black alloy screws but they seem to be quite heavy.

Thanks
EH

Aluminum is the lightest and the weakest...
Titanium is lighter then steel and is three times strongher then steel. (best used for T-plate and motor screws.)
Stainless Steel no way!!!

I've been using some stainless steel ones for a while with no problems whatsoever. I origionally got them to replace the junk that comes from OEM offroad cars.

Never had a problem with them

Stay away from alum. fasteners. They are way to weak. I use mostly stainless.

Titanium is heavier then steel. Titanium is stronger allowing the part to be machined smaller thus saving weight. Aluminum is fine for non-stress points.

I dis agree gezer2u I have felt the difference in my hands between the same size block of Steel, and Titanium, Trust me the Titanium was CONSIDERABLY lighter!!!

my cars always tend to need a lot of weight so i use the strong stainless screws for the chassis. it keeps the wieght at the lowest point.

joe ivo

i like the look of stainless, but i have found recently that they strip out very easily.. it seems the head where the allen fits, is not sunk in as far as standard steel ones.. so when you tork on them they round off very easy... if you need to lose weight, screws isnt the way to go... but if you choose aluminum, only use them in low stress locations... If you insist on using them every where, i recomend a dab of light oil on the threads if you put them into aluminum... aluminum and aluminum, seem to fuse together.. then they break off when you take them out...Ive never tried titanium..

Aluminum is lightest yet very soft as far as r/c grade goes. I have yet to see aircraft grade aluminum fasteners in R/C. Titanium is lighter than steel by far. Stainless is the heaviest. It is always smart to use oil on threads and rely on torque or a locknut to keep them from loosening.

Ok here are actual facts.

Aluminum 7075-T6 (Aircraft Grade)
This is the grade Fastener Express uses.

Density = 0.102 lb/in^3
Ultimate Tensile Strength = 83000 psi
Tensile Yield Strength = 73000 psi
Enlongation at Break = 11%

Stainless Steel 316 (seems to be a common grade for fasteners)

Density = 0.289 lb/in^3
Ultimate Tensile Strength = 84000 psi
Tensile Yield Strength = 42100 psi
Enlongation at Break = 50%

Titanium 6AL 4V (grade that Lunsford uses)

Density = 0.16 lb/in^3
Ultimate Tensile Strength = 131000 psi
Tensile Yield Strength = 120000 psi
Enlongation at Break = 10%

What this means.
Aluminum is the lightest followed by Titanium with Stainless being much heavier.

Titanium is by far the strongest with Aluminum and Stainless very similar, in ultimate strength. Aluminum has a much higher yield strength than Stainless though.

Stainless is by far the most ductile. Aluminum and Titanium are similar to each other and much more brittle.

So here is how this all stacks up. If you use Stainless you will have screws that will tend to bend in an accident. If you use Titanium or Aluminum your screws will be more likely to break instead of bend in an accident. Especially so with titanium because it has a poor shear strength. One very large advantage titanium will have is that it will be much harder to strip the head. Personally I would use titanium as i hate stripping heads, like the light weight and would rather have screws break in accidents as opposed to bending.

Also, as others have mentioned aluminum screws will want to seize when screwed into aluminum. That grade of titanium screw will want to seize when screwed into most types of metal.

Bar 26- You are correct! :thumbsup: My mistake. A block 1"x 1"x 1" weighs as follows:

Steel- .28 lb's,

Stainless- .29 lb's

Titanium- .16 lb's

Aluminum- .10 lb's

http://www.alloytech.com/IE/DLmetcalc.asp
I have used Fastners Express screws to hold the pod plates on my pan car and never bent one. And not for lack of trying. :) I have bent aluminum screws before that were not in a stressed area. So it can be done. :)

Anyone know a place online where you can buy the Titanium 4-40's in bulk like how fasteners express does with the alums and alloys??

I see Silva and Lundsford both carry them but its about $1.25 per screw.
There has to be a cheaper source somewhere ??

PM, The grade of alum you talked about is aircraft, is that the type of aluminum used by the screw manufacturers? (No I am not trying to nitpick still!!! Just curious what you know about it since you seem to have some good info) I have always thought most, not all, but most RC alum screws were fairly weak. Barsalow said he has never seen any aircraft ones. If I could find good alum screws I would run them most everywhere. I use stainless for most of my fasteners though. I also have some of the titanium screws. I believe Hardcore sells them, they used to anyway, and I was thinking they were cheaper than Lunsford, maybe not though. I have bent titanium screws in my offroad stuff, but then again any other typ of screw would have bent there also. I just checked out hardcore...tey are $10 for 8 screws...so back to the 1.25 a screw. Pretty popular price!!!

I know that APS sells bags of stainless steel screws (both metric and standard) in a ton of sizes and head configs. www.magmarc.com. I use them because they are stronger and a little lighter. Plus they look cool LOL!

PM, The grade of alum you talked about is aircraft, is that the type of aluminum used by the screw manufacturers?

VWAL,

Yes that aluminum is aircraft, as I mentioned. That is the grade used by Fastener Express. I know many people on here use them for their anodized aluminum screws.

Titanium, like anything else, can bend. It is just more likely to break than bend, if it is damaged at all.

Ok here are actual facts.

Aluminum 7075-T6 (Aircraft Grade)
This is the grade Fastener Express uses.

Density = 0.102 lb/in^3
Ultimate Tensile Strength = 83000 psi
Tensile Yield Strength = 73000 psi
Enlongation at Break = 11%

Stainless Steel 316 (seems to be a common grade for fasteners)

Density = 0.289 lb/in^3
Ultimate Tensile Strength = 84000 psi
Tensile Yield Strength = 42100 psi
Enlongation at Break = 50%

Titanium 6AL 4V (grade that Lunsford uses)

Density = 0.16 lb/in^3
Ultimate Tensile Strength = 131000 psi
Tensile Yield Strength = 120000 psi
Enlongation at Break = 10%

What this means.
Aluminum is the lightest followed by Titanium with Stainless being much heavier.

Titanium is by far the strongest with Aluminum and Stainless very similar, in ultimate strength. Aluminum has a much higher yield strength than Stainless though.

Stainless is by far the most ductile. Aluminum and Titanium are similar to each other and much more brittle.

Right!!

FYI Why Stainless steel is bad for racing applications ??

Stainless steel RETAINS HEAT!!! :freak:
Most of todays pot and pans are made stainless for this reason..
Not good for racing... Titanium is the best!! :thumbsup:

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I just stayed at a Holiday Inn Express last night!!
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Right!!

FYI Why Stainless steel is bad for racing applications ??

Stainless steel RETAINS HEAT!!!
Most of todays pot and pans are made stainless for this reason..
Not good for racing... Titanium is the best!!


RPM,

I'm glad you agree, but your reasoning is actually incorrect. Titanium has a much lower thermal conductivity than Stainless. That means it retains heat longer. Besides, I can't imagine why an electric oval racer would care about the thermal properties of his/her screws anyway.

Pat

i love stainless cause its strong and looks nice. i had no problems with strippin them. TI would be nice but its alot more expensive.

joe ivo