TI Bolt substitute. 1

[CompositeGeek]

Have need of replacement bolt. Bolt is titanium shoulder bolt, 0.5" diameter by 1" long, hex head. Aluminum pigmented coating.

Bolt meets 100KSI Tensile requirement and 90KSI shear.

Need a suitable replacement because it takes 2 years to get this by lead time.

Suggested alternates? Or someplace I can go to research them for myself?

Your support is GREATLY APPRECIATED!!!

Composites and Airplanes - what was I thinking?

There are gremlins in the autoclave!

 

[KENAT]

What thread form is your bolt, Unified of some form I assume but what pitch/is it UNR?

KENAT, probably the least qualified checker you'll ever meet...

 

[rb1957]

if it weren't for the composite angle, there are lots of steel fasteners. if you're feeling lukcy, your could go with a coated steel bolt, but it'll corrode pdq if if sees graphite.

why not buy a bunch of these long lead items, so you'll have some on hand ? maybe you could even source them for other customers (for a price of course !)

 

[israelkk]

rb1957

I will give you the management guys answer. We buy "just in time" we do not stock. Now ask them how to solve CompositeGeek problem.

This was at least what happened in the company I used to work for. The idiots in management in a company that has a production line of 2000 products during 20 years (100 per year) uses slogans such as "Just in time" which was invented for line of millions of products per year.

 

[wes616]

Compositegeek,

Clickbond sells a line of Glass/PEK bolts that may fit the bill for you, and be closer to the 12 Week lead time that most CB parts are. I looked on their website for some Sut values, but they are not listed, and I can't find the sheet that was given out by the rep on them. May be worth a call. Not cheap though, if I remember right.

Also, you may want to consider a sleeve which would protect a standard cres bolt from your carbon.

Wes C.
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[RPstress]

If this bolt is procured to a spec then it may be available in A-286 instead of Ti. Probably have almost as bad a lead time.

Usually A-286 cres is considered compatible with carbon. The Al coating is mostly to protect an aluminum part in the joint from the bolt material.

If it's a part manufactured to drawing then several possibilities exist. Use A-286 bolt grade material to AMS 5853. This might be ok for full life, or you can issue an instruction to replace with the standard part after a maximum number of hours.

An alternative material such as PH13-8Mo could (almost certainly - depends just a little bit on the Ti alloy used) be shown to be better than the Ti for all of strength, crack growth, KIc, fatigue. However, it will probably be a bit less corrosion resistant, so inspection or replacement would arguably be necessary. It depends a bit on the environment and what the bolt is doing.

 

[WKTaylor]

Composite Geek...

Ti Bolts, Hex Hd:
NAS6403--NAS6402 [short thread]
NAS6803--NAS6820 [long thread]

A286 Bolts, Hex Hd:
NAS6303--NAS6302 [short thread]
NAS6703--NAS6720 [long thread]

WARNING: aluminum coatings are NOT compatible with carbon-fiber structure...and unnecessary for most CRES, Titanium or Nickel alloy structural materials. Use BARE** Ti or CRES bolts where ever feasible.

Bare** = bare or anodized Ti and passivated CRES


Regards, Wil Taylor

 

[CompositeGeek]

Thank you very much for all the input!

We eventually found an alternate Ti-bolt design that will meet our needs for a limited effectivity.

FYI~It is a classic tail, tell the customer you will shut down his production line (for about a year) and it becomes AMAZING how much faster they open up their minds to alternate design ideas!

Composites and Airplanes - what was I thinking?

There are gremlins in the autoclave!