Titanium Bolts, Nuts, and Studs: Sizes Wishlist

[Rootski]

Hey RVers,

I'm working a deal sourcing titanium bolts, nuts, studs, and other hardware for the GA/home build community.

Never built an RV before (but I've always wanted to) so I don't know what sizes would be most useful to RV builders.

What's your wish list? What sizes and styles would you like best?

[Mike S]

Travis, welcome to the good ship VAF

[fixnflyguy]

I substituted Titanium bolts for almost everything on my RV-4. Only the engine mount bolts and gear bolts are steel on my aircraft. Virtually all the internal wing bolts are Titanium Hi-loks with aluminum collars, which requires transition fit holes, and would not be a good option for those who do not fully understand the installation process. Every fairing attachment, cowling and wingtip screw is a reduced head countersunk Titanium machine screw, as well as all the interior panels,ect. My goal was to save weight, and eliminate corrosion. All my Titanium fasteners are aluminum coated and use stainless washers. Since I am in the business of heavy aircraft repair and overhaul, I have better access to vendors, ect. than most And the fact that virtually all Boeing and Airbus are built and repaired with those fasteners, it seems only "normal" to me. From an engineering standpoint ,the strength factor is much the same, although Titanium bolts should never be subjected to bending stresses, or be over torqued,as they will break rather than bend or stretch.

[Sid Lambert]

How much does your -4 weigh Bill?

[dhammer]

When Gulfstream built the GIV they were on a weight saving campaign. All the screws in the pylons were titanium. What we found out in service was although they saved a couple of pounds the effort wasn't worth it. The screws would seize in the nutplates and even though it is strong stuff it is also soft and after one use the phillips recess was rounded out and we had to throw them away. At that time they were $8 per screw. Gulfstream promptly issued an SB allowing them to be replaced with steel which everyone did.

Maybe newer screws are better treated against corrosion and cheaper, but my guess is if you replaced every screw in an RV you'd save at the most a couple of pounds. Leave your iPad home and you would save about the same.

[fixnflyguy]

My -4 weighed in around 955 lbs. (if I remember correct) but dont have my logs in front of me. I may have saved 5 lbs. or so overall with the Titanium, but I got mine cheap, and it wasn't a difficult thing for me to do..along with the usuall lightening holes and tapered spar strips I probably built as light as possible, but Im sure there are some others lighter. I primed everything inside..I hate corrosion! I just like Titanium...when you have a handfull of the steel bolts, and one full of titanium bolts , its an easy choice to make.

[RV7Guy]

I spent considerable time researching this. What I found was very few places to buy and very limited in supply choices. Many of the sources were custom bicycle shops. Most of their supplies are Metric.

It would be great if there was a source for standard AN replacements. Sure haven't found it.

Bill E. can you share some of the sources you have?

[fixnflyguy]

I have used the Boeing fastener codes/sources for all my Titanium hardware. Again, being in the industry helps, and for the most part, an RV uses 2 basic types, one being the hex head bolt, and the flush machine screw. I simplified the flush screw variations throughout the entire plane, and utilize all #8 screws/nutplates for fuel tank attach flanges,fairings,wheel pants,floor panels,ect.. But I used what is known as a "reduced head" 100 degree fastener. These screws have a smaller head that is equivelent to a #6 screw, but have a 5/32" shank diameter. The hex head bolts are a direct replacement for the AN3&4 diameters. The basic numbers are:
Hex head bolt : BACB30NR (diameter in 16ths)K(length in 16ths), so a BACB30NR3K3is a 3/16 diameter, 3/16 grip length Titanium bolt with aluminum coating (the K designation).
Flush head: BACB30VF2K3 is a reduced head,100 degree CSK #8 machine screw, 3/16 grip. The (2) diameter is for a 5/32" diameter, however a (3) would be 3/16", so dont let it throw you off. I know this is all a little confusing, but Google the numbers and you will probably find vendors/data..but I would start with the originator of this thread.

[krwalsh]

How about all of the 1/4-20 button or pan heads that hold the valve covers and most of the baffles in place?

[gtmule]

Someone weigh all the screws and bolts that are shipped in a kit (except wing attach hardware and whatever else you won't change) and multiply that by .5, and that'll be your weight savings (assuming you'll use Ti nuts). Now take the cost of the hardware and multiply by 5 or 10....

edit: The exception being where you take something from an AN bolt to a Titanium Hi-lok, you'll save maybe 2/3 there, but at 20X-50X cost.