I've played with heat treatment for decades. Knives, military, and aviation. It blows my mind that you can use a torch to braze and not draw out the temper of a tube that thin.
@@ellisbriggsbikesi was just thinking: don't we have adhesives that can replace brazing .. at least as far as bicycle frames go? I'd guess we must have that technology. Then, we eliminate the loss of heat treatments, and cut expenses. There are some strong long lasting epoxies without brittleness similar to a firm silicone. Has anyone ever investigated this angle? There is also cold metal transfer welding (CMT) which eliminates 90% of the heat of traditional TIG welding. It would be nice to retain original heat treatment properties. It would eliminate the time+cost of secondary heat treatments after assembly. There is a lot of research being done in the area of joining metals.
Touring bikes usually need to be stiffer than unloaded bikes but the rider size and weight also needs to be taken into account. So for example if I get a small rider I may spec Reynolds 631 in standard sized tubing. A bigger rider may need oversize tubing and a thicker wall in order to achieve the same ride feel. This is the beauty of custom steel bikes. They can be truly personalised to the rider whereas a mass produced frame has to be designed to accommodate the biggest riders.
Enjoying the videos , what is your take on titanium, is it something you use / build with , is it any better than highest quality Reynolds, also what is your favourite tubing to work with ? I have a book called the custom bike builder which I read about 40 years ago, am sure it makes reference to Italian builder Pogliaghi preferring silver solder so lugs can be brazed at slightly lower temperatures, does that make sense to you. One last question which frame builders do you think are the most skilled , I've always thought and heard Roberts frames are very good as I'm sure are many others.
I think I should do a video answering these questions at some point. However - I think one of the main advantages with Titanium is that it has a more exotic appeal than steel which lends itself to boutique handmade frames. Also the work around 3d printing in titanium is really inspiring. But in terms of mechanical properties I don't think it has much advantage over steel as it is not as strong or stiff. And with stainless steels you get the corrosion resistance too.
Sorry pressed reply too soon! On tubing I like working with Reynolds 853 for its good all round properties without getting too expensive. Skilled builders that are still around, I would have to say people like Kevin Sayles, Doug Fattic, Richard Sachs to name a few. Those who are time served, because you can't learn experience it has to be earnt.
@@ellisbriggsbikes Interesting , I had wrongly assumed titanium was stronger than steel as the military tend to use it, maybe just its lighter quality they like . I'll look up the 3d printing side of it as my son is doing basic engineering apprenticeship . Am enjoying the video's , I think keeping them in bite size chunks is good too, between 3-12 minutes. Thanks for reply.
@@pinarellolimoncello it depends on the grades of steel but equivalent grade of steel compared to titanium is stronger but you can manipulate properties a bit with tube shapes and with titanium usually a larger diameter tube is used to get similar properties to a smaller diameter steel one. In the end the weight is comparable
Steel tubing is all prone to rust. In practice though it depends on how you look after your bike. If you keep your bike dry and warm it will not rust. If you put a wet, cold bike in a damp garage you'll have problems
@@ellisbriggsbikes thank you very much for the response. I have rubber cable guide that seats on each holes of my steel frame, is it enough? Also, from your experience, does columbus tubes considered very durable despite if it has rusts? I've seen raw looks on this.
631 has pretty much replaced 531. The only practical difference is you can Tig weld it. 853 is that same alloy but is heat treated, so it is stronger and you can make the walls thinner. 931 is slightly stronger than 853, so the walls can be slightly thinner again. It is also stainless steel so it won't rust.
Any steel tubing could be strong enough with the right wall thickness. If it was strong enough though, it would build a heavy frame. The advantage of bicycle specific tubing is the alloy used has a higher tensile strength, so you can have a very thin wall. Couple that with the butting process, which produces a thinner wall in the middle of the tube where less strength is needed. By the way this technology was perfected over a hundred years ago now!
Pace tried it for mountain bikes about 20 years ago. It wasn't a success. The frames were ridiculously stiff and weren't light either. They are ollectable now though
Still have a couple of road bycyle from the 80s one has Columbus SL, the has super vetus 938.
Be interested to know about lugs v braze v silver v anything else.
Plus frame angle effects
I have some videos coming up which will cover both of those. Watch this space
I've played with heat treatment for decades. Knives, military, and aviation. It blows my mind that you can use a torch to braze and not draw out the temper of a tube that thin.
There's definitely some loss of tensile strength when the tubes are joined. Silver brazing just below critical temperature
@@ellisbriggsbikesi was just thinking: don't we have adhesives that can replace brazing .. at least as far as bicycle frames go? I'd guess we must have that technology. Then, we eliminate the loss of heat treatments, and cut expenses. There are some strong long lasting epoxies without brittleness similar to a firm silicone. Has anyone ever investigated this angle? There is also cold metal transfer welding (CMT) which eliminates 90% of the heat of traditional TIG welding. It would be nice to retain original heat treatment properties. It would eliminate the time+cost of secondary heat treatments after assembly. There is a lot of research being done in the area of joining metals.
According to your experience, which is the best chromoly type to build a touring bike? Thanks
Touring bikes usually need to be stiffer than unloaded bikes but the rider size and weight also needs to be taken into account. So for example if I get a small rider I may spec Reynolds 631 in standard sized tubing. A bigger rider may need oversize tubing and a thicker wall in order to achieve the same ride feel. This is the beauty of custom steel bikes. They can be truly personalised to the rider whereas a mass produced frame has to be designed to accommodate the biggest riders.
💯
Enjoying the videos , what is your take on titanium, is it something you use / build with , is it any better than highest quality Reynolds, also what is your favourite tubing to work with ? I have a book called the custom bike builder which I read about 40 years ago, am sure it makes reference to Italian builder Pogliaghi preferring silver solder so lugs can be brazed at slightly lower temperatures, does that make sense to you. One last question which frame builders do you think are the most skilled , I've always thought and heard Roberts frames are very good as I'm sure are many others.
I think I should do a video answering these questions at some point. However -
I think one of the main advantages with Titanium is that it has a more exotic appeal than steel which lends itself to boutique handmade frames. Also the work around 3d printing in titanium is really inspiring. But in terms of mechanical properties I don't think it has much advantage over steel as it is not as strong or stiff. And with stainless steels you get the corrosion resistance too.
Sorry pressed reply too soon! On tubing I like working with Reynolds 853 for its good all round properties without getting too expensive.
Skilled builders that are still around, I would have to say people like Kevin Sayles, Doug Fattic, Richard Sachs to name a few. Those who are time served, because you can't learn experience it has to be earnt.
@@ellisbriggsbikes Interesting , I had wrongly assumed titanium was stronger than steel as the military tend to use it, maybe just its lighter quality they like . I'll look up the 3d printing side of it as my son is doing basic engineering apprenticeship . Am enjoying the video's , I think keeping them in bite size chunks is good too, between 3-12 minutes. Thanks for reply.
@@pinarellolimoncello it depends on the grades of steel but equivalent grade of steel compared to titanium is stronger but you can manipulate properties a bit with tube shapes and with titanium usually a larger diameter tube is used to get similar properties to a smaller diameter steel one. In the end the weight is comparable
Thanks for watching!
Do chromoly tubings sensitive to rust? For example the inner tubes most especially when it has internal cable routing?
Steel tubing is all prone to rust. In practice though it depends on how you look after your bike. If you keep your bike dry and warm it will not rust. If you put a wet, cold bike in a damp garage you'll have problems
Internal cable routing can be completely sealed if done properly but bad examples on production bikes are usually just holes in the tube
@@ellisbriggsbikes thank you very much for the response. I have rubber cable guide that seats on each holes of my steel frame, is it enough?
Also, from your experience, does columbus tubes considered very durable despite if it has rusts? I've seen raw looks on this.
I have a Bob Jackson with Reynolds 531 bild in 1985. .What is the difference from 631 , 831 931?
631 has pretty much replaced 531. The only practical difference is you can Tig weld it. 853 is that same alloy but is heat treated, so it is stronger and you can make the walls thinner. 931 is slightly stronger than 853, so the walls can be slightly thinner again. It is also stainless steel so it won't rust.
Thanks . Btw , love your Chanel.
would EMT conduit be strong enough for a bike frame ?
Any steel tubing could be strong enough with the right wall thickness. If it was strong enough though, it would build a heavy frame. The advantage of bicycle specific tubing is the alloy used has a higher tensile strength, so you can have a very thin wall. Couple that with the butting process, which produces a thinner wall in the middle of the tube where less strength is needed. By the way this technology was perfected over a hundred years ago now!
Has anyone tried square tubing yet? It's supposed to be stronger than round
Pace tried it for mountain bikes about 20 years ago. It wasn't a success. The frames were ridiculously stiff and weren't light either. They are ollectable now though
Muddy Fox tried tubing that was round, but morphed to square at the ends. If I recall, it made little difference, except adding weight.