Butted or plaine gauge weight difference.

thefonz78

I plan on starting building frames for fun mainly. I will start by just using cheap mild steal from a scrap yard to practice. after this i will try using chromoly. Would it be a lot cheaper to by standard 4130 chromoly from a aircraft company than using reynolds steel until i'm more capable. What would be the weight difference be using plain gauge not butted? Are all the main triangle tubes butted? Are bmx and mountian bikes also butted?

schweiz

Steel? From an aircraft company?

Aircraft are primarily made from aluminum, titanium and composites. You'll be hard pressed to find much steel.

Anyway, why would you buy metal from an aircraft company? Go to where they buy it from which is a metal dealer.

Also, Reynolds, Columbus and the like sell their tubing pre formed for the different tubes needed for a bicycle frame so you're better off going to a company that maufactures cycle tubing.

Take a look here...

http://reynoldstechnology.biz/our_materials_953.php

and here

http://reynoldstechnology.biz/assets/pd ... s_list.pdf

Have a read of this too....
http://reynoldstechnology.biz/assets/pd ... xtract.pdf

and this.....

http://reynoldstechnology.biz/faqs_butted_tubing.php

thefonz78

Well when i google 4130 chromoly it comes up with 2 or 3 aircraft supply stores
http://www.winged-aviation.co.uk/4130_Steel_Tubing.htm and http://www.winged-aviation.co.uk/4130_Steel_Tubing.htm

schweiz

They are suppliers to the aircraft industry, they are not aircraft companies! They are a metal dealer which is where I suggest you looked!

When you actually go into that site it takes you here http://www.aeroautometals.com/. You see that they also supply to other sectors that required certified, graded metals (e.g. auto, military) not just aviation.

There is not much steel on an aircraft, believe me, I'm sat in an aircraft factory as I type this! If I could be bothered, I could nip downstairs and speak to one of the Mechanical Design Engineers to find out exactly what is made from steel.

Also for the quantities you'll be wanting, they'll probably not be interested. Even if you keep the top tube, down tube, seat tube and head tube the same diameter and the chain and seat stays and any bridging pieces the same diameter, you're only talking about a couiple of metres of each. Give them a call though. I've occasionally managed to scrounge off-cuts from similar companies. In fact my dad has a 1" aluminium tube TV aerial mast obtained that way!

huuregeil

Gruezi Schweiz!

Actually, steel is quite common in certain types of light aircraft structures (e.g. trusses, prop engine mounts - the ones that look like bike frames, cunningly :-) ) due to it's weldability. It may not be in use with Pilatus, but that's not to say you'll never find it in the aerospace industry! For example, the Piper Super Cub is a steel truss design, and is in widespread service still.

It's worth noting that the strenght to weight of steel is comparable to aluminium. The reason it's not used in stressed skin structures is because it's very dense, and the thinness of the sheet elements gets you. But, it's perfect for covered trusses!

huuregeil

PS Home built aircraft designs are typically steel framed for obvious reasons, hence the availability of steel tube from aircraft industry suppliers.

schweiz

Have a read of this....

http://suzyj.blogspot.com/2007/09/wow-dialogue-box.html

or give these people a call....

http://framebuilding.com/

apparently 30 quid will get you a columbus cro-mo tube set.

schweiz

Grüezi huuregeil,

Bisch zwäg?

I don't work at Pilatus anymore!

I work north of Luzern now!!

I didn't say steel wasn't used. I've seen quite a few home built microlight/sport aircraft kits with a welded steel space frame and like you say, the engine mounts on many aircraft are often a welded steel frame (even on Pilatus aircraft!). Stainless steel fasteners are also commonly used, especially since cadmium plating was banned but as a total percentage of the material used in an aircraft, it is very small.

I was just questioning the need to go to an aircraft company to source it. An aircraft company wouldn't have supplies to sell and are unlikely to have stock that they have overbought that they want to dispose of.

Also when you buy tube from a dealer it won't have been annealed for the purpose for which it will be used, so if you buy raw metal you would need to find someone to heat treat it. Making a bike out of constant OD tubing will look rubbish too, especially on the chain stays. Then you need specific sizes for the BB and head tube so that the bearings will fit.

I doubt that any supplier to the aircraft industry will be able to supply small quantities at a competitive price to a company that sells bicycle tubes made for the job the OP wants. I've been quoted over a £100 ex VAT, ex Delivery for 100 stainless 20mm M4 screws before now. These place aren't usually interested in small orders.

If the OP wants to practice, he'd be better off getting an old lugged steel frame and pulling it apart and re-brazing it back together. Also he'd be advised to do a course in welding/brazing. Too much heat can not only affect the strength of the joint but the characteristics of the tubing.

Anyway, I'll get back to my avionics and software...01101010101010100101010!

thefonz78

I've been on framebuilders.com ceeway before. They have no prices on the website. Is it only 30 quid for a tube set?!![/quote]

schweiz

From the Blog I linked to:

http://www.littlefishbicycles.com/frame/materials.html

thefonz78

Thats a great price. I

ynyswen24

thefonz78 wrote:

I've been on framebuilders.com ceeway before. They have no prices on the website. Is it only 30 quid for a tube set?!!

[/quote]

if you look at the Ceeway website there's a scrolling message along the top, click on this and it'll take you to details (with prices) of complete kits for novice builders lugs as well as tubesets. They're a good company and very helpful...

satanas

Dismantling and modifying cheap old frames is a good way to start off. Like anything else, practice is important, though less so if you're already an expert welder/brazer. May as well use high tensile for the first few experiments, then switch to something better once things are more under control. I've bought plain gauge CrMo from airfield-based suppliers here in Oz before today, handy as they would sell in small quantities, not only complete lengths. Scrap metal merchants and council clean ups can be useful too, and the other things is to hang onto any reasonable sized offcuts or bits of scrap!