Snapped titanium screws.

[Jonathan]

I replaced all the scews on my car a long time ago for titanium ones , no problems.

Racing on sunday after completing a qualifying round just fine I felt some lumps in my undertray ! The heads had sheared off about eight rather important screws !

The screws looked to have a weak point, like the heads were too deep ? Has anybody suffered with the same problem ? Im tempted to go for stainless steel now ?

[jimmy]

Yeah i think they were speed mind the ones I had - heads too deep leaving a tiny ammount of material keeping the head on - snap!

Better quality screws me thinks.

I don't like stainless screws - the ones I've had in the past were crap.

[Jonathan]

Ok, so not a unique occurance, cheers Jimmy. These were 3 racing, can anyone recommend a good source of titanium or stainless ?

[Mike Hudson]

northy (nortech racing) should be able to sort you out stainless screws ) can't recommend any ti screws to you as I've seen too many different brands snap on the threads, head, random places etc too many times, there too brittle,

[Alfonzo]

In terms of the best material for doing the job, you won't really beat steel. The advantage of Titanium is minimal at best, good for showing off but ain't gonna do much on the track, especially if they snap! Stainless steel is nice insomuch as it won't rust, but is a little weaker than regular steel.

[mark christopher]

TIR racing

they make screws for mclaren F1 team of the same material

[SlowOne]

I've had this problem with F-Max screws. It stems from the fact that some manufacturers put a larger hex in the head than the accepted standard - in the 4-40 F-Mac screws (usually 1/16th hex) they put a 2.5mm hex. That makes the screws easier to turn, and makes the hex last longer (Ti is relatively soft) but it means there is much less material where the hex, the taper and the screw thread meet - and they snap.

Ti is much more ductile than steel or ally, so it should take shock and constant bending loads more successfully. However, shear loads are another matter! It's not the material that's at fault, it's the design of the screw.

There's a saying I first heard from Keith Bontrager, mountain bike pioneer. It goes

Strong, light, cheap - pick two.

Which two were those screws, I wonder!!

[chb]

Originally Posted by SlowOne

I've had this problem with F-Max screws. It stems from the fact that some manufacturers put a larger hex in the head than the accepted standard - in the 4-40 F-Mac screws (usually 1/16th hex) they put a 2.5mm hex. That makes the screws easier to turn, and makes the hex last longer (Ti is relatively soft) but it means there is much less material where the hex, the taper and the screw thread meet - and they snap.

Ti is much more ductile than steel or ally, so it should take shock and constant bending loads more successfully. However, shear loads are another matter! It's not the material that's at fault, it's the design of the screw.

There's a saying I first heard from Keith Bontrager, mountain bike pioneer. It goes

Strong, light, cheap - pick two.

Which two were those screws, I wonder!!

Ti is great(it does NOT rost either), it's used in fighter jets, F1. Stainless steel is weak/soft. Between stainless steel & carbon steel, no hesitation, go for carbon steel (I prefer a little bit of rost on the rainy day than having hex round off). The only vertue of stainless steel is rost, in everything else

The problem is not Ti, it's the quality of those screws

I agree 101% with you: Every bit of your post SlowOne !

If anyone knows of Ti screws we can trust, let's list them (interested in getting some myself)

[chb]

Thinking about it again.... I find selling this quality unacceptable.

Jonathan, you should consider contacting 3 Racing

Being Far-East based, I am sure they would prefer take input from your experience and refund or send you corrected ones

[SlowOne]

Originally Posted by chb

If anyone knows of Ti screws we can trust, let's list them (interested in getting some myself)

The ones I've had most success with are made by Corally, but M3 only! HTH

[mark christopher]

Originally Posted by chb

Thinking about it again.... I find selling this quality unacceptable.

Jonathan, you should consider contacting 3 Racing

Being Far-East based, I am sure they would prefer take input from your experience and refund or send you corrected ones

there are different grades of ti material, 3 racing use a lower quality material

[SlowOne]

There are two we should usually expect to encounter. Ti6/4 is the grade used for forming and forging and would usually be seen by us in sheet applications. Ti3/2.5 is the grade used for machined items being of superior strength, and is the one we should expect to see in screws, turnbuckles, etc.

There's no such thing as a lower quality Ti, just the wrong grade used. I doubt that 3 Racing used inferior material, but they may have used the wrong material. I still think that the problem is poor design of the screw, or fatigue - look at the failure on the photo, that doesn't look like a good piece of design to me! HTH

[mark christopher]

Originally Posted by SlowOne

There are two we should usually expect to encounter. Ti6/4 is the grade used for forming and forging and would usually be seen by us in sheet applications. Ti3/2.5 is the grade used for machined items being of superior strength, and is the one we should expect to see in screws, turnbuckles, etc.

There's no such thing as a lower quality Ti, just the wrong grade used. I doubt that 3 Racing used inferior material, but they may have used the wrong material. I still think that the problem is poor design of the screw, or fatigue - look at the failure on the photo, that doesn't look like a good piece of design to me! HTH

there are many forms of ti material,
http://www.mrtitanium.com/tigrades.html
http://www.cnmetals.uk.com/titanium-grades.htm
http://www.engineershandbook.com/Tab...niumgrades.htm

titanium in its raw form is softer than alloy, by mixing other materials then its strength is achived.
tir use grade 5, for mclarens and rc applications.

im told 3racing use a low quality titanium (as i said), which is brittle but cheap! and not suitable for our needs.

[Lee]

Years ago i bought a full lunsford set of hingepins for a tc3 (please spare the abuse) i fitted them on saturday and raced sunday and bent every single one, they were gash. the std steel ones were better.

Just thought i'd let you know, give me hardened steel any day.

[mark christopher]

Originally Posted by Lee

Years ago i bought a full lunsford set of hingepins for a tc3 (please spare the abuse) i fitted them on saturday and raced sunday and bent every single one, they were gash. the std steel ones were better.

Just thought i'd let you know, give me hardened steel any day.

sums up a tc driver skills, crash bang wallop moan.....................

[SlowOne]

Originally Posted by mark christopher

im told 3racing use a low quality titanium (as i said), which is brittle but cheap! and not suitable for our needs.

As usual, Mark, you must be right and I must be wrong. Of course, everyone sells crap titanium that does not conform to the certificates they issue with it, and so it must be the material's fault. Absolutely no chance that they simply chose the wrong grade? What could I be thinking...

Anyway, since they also chose the wrong hex size, and then made it too deep, that's why they fail. And why would they do that (and they all do that?)? Because, whatever grade they choose, the correct size hex would be too small to take the drive from the allen key, as the material is too soft - it would easily deform. All Ti nuts and bolts used in aerospace have a 12-point star hex on them so it can take the drive to tighten them without deforming. The Corally screws seem to have quite a shallow hex by comparison, so I'm guessing that's why they work OK.

In 12th, Ti and aluminium screws work fine on low-load applications, but we don't use them to attach high-load-bearing parts, like T-bars and pods. HTH

[JJ The Boat Wizzard]

Originally Posted by mark christopher

sums up a tc driver skills, crash bang wallop moan.....................

LMAO!

I Was Thinking Of Getting Tit Screws But From What Uve All Just Said I Dont Think I Will

John

[SlowOne]

Don't write off Ti screws. They work well in the right application. That would be holding one part to another where there is very little load - servos to posts, decks to posts, shock towers to chassis, gears to hubs, etc. They don't corrode and weigh about 2/3 of steel with about twice the elasticity.

However, alunminium screws will work just as well in these places, weigh half of steel, but can corrode if not anodised. It all depends on what you want the screw to do.

Bearing in mind that most Off-Road cars seems to add lead to some parts of the car, and so do most Tourers (especially the Super-Stock LiPo class) I am wondering why you need screws that are any lighter than steel? In 12th we use ally screws wherever possible to save weight.

Don't avoid something just because someone has a failure, just know the limitations of the product and don't stress it beyond that. Remember Keith Bontrager...

Strong, light, cheap - pick two!