DIY Frame Build

[Steven Knoetze (sk27)]

Check out the Caminade website for some steel goodness:

 

Website

 

A few photos of the one4all model, you can run this frame as a 160mm 26" or a 135mm 650b:

 

 

 

 

 

 

 

 

 

Those billet sections are really sweet!!!

[Jay_B]

Was looking at the Caminade website a few days ago... some really pretty bikes.

 

Yea it seems from all the suppliers i have contacted its going to be difficult getting the right size chromoly tubes locally.

 

One of my alloy supplies is putting together some pricing and information for me on titanium tubing. They did say it might be possible to get the tubes cut to length which makes it alot cheaper and cost effective.

 

My next contacts will be bike tube specific suppliers to see what they can help with and suggest...

[Brian Fantana]

I found numerous articles that stated that when TIG welding CrMo, it is advisable to pre heat or to weld on a heated jig. The less heat input to produce the weld pool the better. Sometimes the internal stresses in the weld are so severe that it will actually crack itself. Thus heat treatment/stress relieving afterwards is recommended.

 

I dont have any experience with this though, just some wise words from random dudes on the net......

 

You will find that people on the net generalise a lot when it comes to materials and their properties. There are different requirements for welding within the same material depending on the material shape, thickness as well as the welding method applied.

 

If you are TIG welding AISI4130 with a wall thickness of less than 3mm and follow the rule of thumb of 40A per mm of wall thickness, you don't require any heat treatment before or after the weld. No stress relief of the HAZ is required either. You only need to ensure that the temperature of the material is above 15ºC before you start welding.

 

For most bicycle frame, roll cage and other frames, you will not easily go over 3mm wall thickness, since a larger OD with less wall thickness can provide better stiffness to weight ratio, while keeping relatively good weldability.

 

However the correct weld settings and electrode length and shape also plays a big role. The welder also needs to control the tip to material distance accurately as some TIG machines automatically increases the voltage (and thus the heat input) as the arc length increases.

 

However when you go thicker than 3mm the HAZ microstructure will show that pre weld heat treatment is necessary.

 

 

You can read more about it here: http://www.millerwelds.com/resources/articles/Best-Practices-for-GTA-Welding-of-4130-Chrome-Moly-Tubing

[Josh0]

You will find that people on the net generalise a lot when it comes to materials and their properties. There are different requirements for welding within the same material depending on the material shape, thickness as well as the welding method applied.

 

If you are TIG welding AISI4130 with a wall thickness of less than 3mm and follow the rule of thumb of 40A per mm of wall thickness, you don't require any heat treatment before or after the weld. No stress relief of the HAZ is required either. You only need to ensure that the temperature of the material is above 15ºC before you start welding.

 

For most bicycle frame, roll cage and other frames, you will not easily go over 3mm wall thickness, since a larger OD with less wall thickness can provide better stiffness to weight ratio, while keeping relatively good weldability.

 

However the correct weld settings and electrode length and shape also plays a big role. The welder also needs to control the tip to material distance accurately as some TIG machines automatically increases the voltage (and thus the heat input) as the arc length increases.

 

However when you go thicker than 3mm the HAZ microstructure will show that pre weld heat treatment is necessary.

 

 

You can read more about it here: http://www.millerwel...ome-Moly-Tubing

 

Thanx Brian

 

That is very interesting reading there! If CrMo is anything like a Stainless to weld, then it should be very enjoyable. These types of steels tend to flow easily.

 

I would like to see what the OP gets himself into, could be very interesting.

[Jay_B]

Seems i may have found some good news that keeps alot of options open with regrds to material...

 

[Jay_B]

Quick update on the frame design... put together a full assembly to get an idea of what a complete bike would look like...

 

 

As for material i am still waiting on Titanium pricing so it seems like it may be a bit of a stretch.

I got pricing from Ceeway for steel tubing and its works out quite expensive for what i was looking for.

 

I chatted to a guy called Matthew at Saffron frame works and he suggested staying away from steel for a dual suspension but rather going the aluminium or titanium route.

I should have prices for aluminium by the end of the week hopefully.

 

We have dont a few test welds on some small aluminium pieces we have here in the workshop and it will come out quite nicely if we get the settings spot on.

 

The next stop is finding out about having the rear triangle made from carbon...

[HaydenWilson]

what were his reasons for staying away from steel for a dual suss? the DMR bolt is a steel dual suss frame....