tuz

Not a build but a WIP. Carbon fibre lug in the style of Calfee for Lemond's 1990 frames. 3D-printed 3-piece moulds, wet layup, consolidation by mechanical clamping.

ponchotempest

Just finished my first complete frame. It's mostly Columbus Zona tubing with a 38mm downtube, 44mm headtube, 27.2 seatpost, non-boost spacing. It has plenty of clearance for 29x2.3 tires, and could probably fit a 2.5 if I slide the wheel back. Still needs to be finished and painted, but wanted to ride it first to make sure it needed no adjustments. The frame alone weighs 2045g. This was all done with a 115V flux core welder (not the prettiest but turned out better than expected)

guy153

Wow this has to be the most ambitious flux core project of all time! I think a bike frame is one of the hardest welding projects you can do (thin-walled, round, thin to thick, safety critical) and flux core is one of the harder processes to control finely. This is why TIG is usually used.

People may comment that this is a bit sketchy and it might be. Be careful and keep an eye out for failures. But big respect for trying it and making it happen.

I used to make a lot of welding projects with FC and played around trying to join round tubes dreaming of one day making a bike. But never did until I got a TIG.
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ponchotempest

Thanks, that's why I didn't paint it before the first ride. After one successful ride I just sprayed on a clear coat so it won't rust and I can keep an eye on it.

guy153

Latest build completed. As you can see some pretty rad yet traditional geometry on this one. The idea is high stack for commanding road position, no sore neck, hands or shoulders, plus a comfortable seat. Rotating the whole riding position back like this implies a slack frame angle, which also makes a seat with a wide back more comfortable.

Seat tube angle 70 degrees, HT 72. CS length 450. Stack 717mm, reach 334mm, 26" wheels, BB drop 65mm. Similar geometry bikes ("omafiets") traditionally use very long quill stems to achieve the high stack. I prefer the threadless system and because this is made-to-measure based on my fitting bike the HT goes all the way up. This does however compromise standover. It might have been better to join the TT to the HT lower down and leave a bit jutting out at the top, but I'm not a big fan of the aesthetics of that.

It's basically road tubing (0.8/0.6 1" TT, 9/8" DT) for the front triangle as the rider is light and does not use heavy front racks (although I am making a rando rack for it). Reynolds 631 main triangle, 525 rear, and the fork is Columbus. TIG welded but accessories and things (from ceeway) are TIG brazed. My first disk fork which came out well I thought. The steerer is the longest Reynolds supply (420mm) and uncut! The brake lines are longer than they need to be but idk exactly how rando bags are going to fit in with all that so will probably cut them shorter later.

The very slack ST, relatively low BB drop and small chainrings (it's an MTB groupset from ebay, low gears are good as the rider is a spinner) created an interesting problem I've not seen before. I couldn't get the front derailleur as low as it really should be because the back of the cage actually starts to hit the chainstay. It seems to be OK but I could modify the derailleur to shorten the cage a bit.

The paint is spray.bike primer, Montana Gold "frozen strawberry", one coat of 2K clear, then the flies who got stuck in the 2K clear, then more 2K clear.

I would have given it a bit more tyre clearance at the back but its owner wanted "shot-in" seatstays and I didn't have much luck bending them. They were long enough that I could have a go and if that failed (which it did) cut them at that end and go with straight. But these were the tyres I had already bought anyway and they fit absolutely fine.

The CS bridge is actually made of the two cut-off ends of the CS, butt-welded together at the thicker ends and then with a bottle boss brazed in for the fender mount.

It's very light as you would expect from the quality road tubing, is super-comfortable (but no long trips have been undertaken yet) and rides beautifully.

SilversSpeed

That is Awesome!!! I wonder how it handles. The pedals move with the forks?

Devin Rickey

guy153 I love it! Very cool!! I need to build something like that for my wife. She isn't comfortable unless she is in a very upright position.

guy153

That sounds like my wife whose bike this is I think it's a milestone in every framebuilder's career when his own wife trusts his welds enough to let him make her a bike

She's now done several long rides (like 4 or 5 hours) on this and has found it to be super-comfortable, much better than her previous more conventional bike, which gave her sore shoulders, neck and hands. One of the really nice things about a bike like this is you don't have to bend your neck up to see where you're going-- you just look straight ahead. Really the only compromise is aero.

The low standover is not ideal though, but she's getting used to it. I think if I were going to make it again I would make the ST a bit shorter-- as you can see there is very little seatpost sticking out-- and also join the TT to the HT a bit lower, so there was an inch or so of HT stiicking out above the junction. I've also made quite a cute rando rack for it, with a really tall tombstone to match the super long HT, which I should post a picture of soon.

Devin Rickey

Did you consider doing a step through? Might solve the standover issue...

guy153

It would solve that issue but is a bit of a nuclear option. Really a step-through is an engineering compromise to support people who either want to ride in a dress or are used to getting on a bike that way. Neither applies in this case. I also quite liked the idea of something "traditional yet modern".

A friend has a step-through Pashley with a curved TT and a long quill stem and the riding position is actually very similar. Her only complaint about her bike though is that it weighs so much! These are 100% retro bikes basically made the same way they were in the 1950s out of probably 16 gauge mild steel.

ShaunJohnson

I shared my first frame in this thread back in 2010. I thought I would share my second that I completed this summer:

pcconsult

Look my album in my profile - album/22823399
My custom hardtail bike have BSA83 and rear hub 157mm. Chainring is 46T. Frame is build from my drawing.

guy153

Would like to see your build but can't find the album! Do you have an URL for it?

pcconsult

https://bikeforums.net/g/album/22823399

pcconsult

Devin Rickey

Finally posting some pics of my first frame. It is two weeks old and has about 50 miles on it. So far so good! The brazing isn't great, but seems to be holding up. Just left it natural until I know it is sound. Gearing is a bit short and tire clearance a bit close, so planning to drop 2 teeth off the back soon.

Boiled Linseed oil finish.


Paragon dropouts and Gates Belt drive.

guy153

Nice work! I don't know much about brazing but it looks good to me. I've been tempted to make a belt drive frame but with regular horizontal dropouts and the belt welded into the frame for life (or replace with a chain when it wears out). Just to troll anyone looking at the bike wondering how the belt goes on, a bit like a ship in a bottle.

duanedr 

Did you weld that? they look like nice welds. Are you a welder in another field?

dsaul

He said it was "build from my design", so it probably was built by Waltly Titanium.

pcconsult

Yes - drawing is mine and frame is made by Waltly Titanium. Look at https://custom-titanium-bikes.com/

guy153

Update to this previous build: remember how I said standover height was a bit of a problem? Well 6 months on and it still was. So I dropped the TT. It's a new tube (another Reynolds 631), and then I put a little gusset tube in because of the huge cantilever from the handlebar. Probably not necessary. Also considered cutting the HT much shorter and using lots of spacers. But that (a) looks goofy and (b) doesn't ultimately reduce the load on that TT/HT junction anyway.

The gusset tube is the end of a stay, probably a seatstay, that I had in my offcuts box. It'll be Reynolds 525 or some kind of cromoly. I just TIG brazed it on which I like to do for anything joining to something relatively thin-walled. All the main welds on a TIG frame are either onto the HT (which is thick), the BB (which is even thicker) or the top of an externally butted ST (also quite thick). I use braze for bridge tubes. This isn't necessary, lots of people weld them, it's just how I like to do it.

My new jig came in very handy here since it actually holds the frame properly solid. So I put the frame into the jig, got it all bolted down, and then cut out the old TT and fitted up the new one, without anything moving in between.

What's interesting is how now that the bike is built up again it actually looks more normal (at least to me). The main triangle is now a more familiar shape and you don't especially notice the gusset tube or very long HT.

I think this is quite a nice way to make this kind of high-stack frame (if you don't have the technology to curve the TT, and that would also entail using a plain-gauge cromoly tube rather than a double butted one as I have here).

sdodd

Hi all - I just finished building up my steel frame CX bike. This is my first bike frame that I built in the fall of 2020 at one of the UBI steel brazing classes. Having done mostly (non-bike) MIG welding for projects, the brazing was a little strange for me. I'm sure I pumped in way too much heat into some joints and had enough ****ery blobs that it took me a while to get motivated to file... hence the delayed build.
I'm short (5'6") with really short legs and a long torso. This frame has a 27.5" standover with 700x32 wheels/tires. That is just low enough for me that there is no touching. The top tube is ~58cm equivalent. Most of the tubes are 0.9/0.6/0.9 with a 44mm paragon HT and a 68mm wide bb. Syntace dropouts allow for a little bit of centering adjustment of my rear wheel without having to try and bend the snot out of the stays.
Color is homage to my hometown / undergrad University - Oregon State. I haven't actually taken it on trails yet because I don't want to get it dirty... but it will happen soon.
simon

Andrew R Stewart 

That's a vivid color combo! Like Celeste it would take some time for it to grow on me

As I look at your fillets and brazing the later joints (seat stays on drop outs as example) the work looks better. Very typical with beginners as the time with the torch is greater than when they do the first few joints. For this reason I have tried to come up with little projects that I can practice my brazing on before the next frame. Andy

sdodd

Is it strange that I like the classic Celeste/puke green too? At least nobody is going to confuse my bike with theirs.
I doubt I will ever braze another frame. My second frame is a TIG Ti that I'm just finishing the component build on. TIG is more natural for me and Ti with the thicker tubes and minimal 'clean up' makes it a much more forgiving build for me. While the materials are 3x a steel build, I will likely only ever build for me/friends/family so I'm not too worried.

sdodd

This is my second frame built - Also through UBI in Ashland, OR. It is a TIG Ti frame that I found easier than brazing. Not the prettiest of welds, but more frames will help that.
Straight gauge TI with Paragon HT, BB, dropouts. It is a 73mm bb with 110mm front and 148 rear. Clearance for 2.6" tires as this is really a XC frame for me.
Notice the special 'anti-mixte' horizontal tube between my 'top tube' and seat tube. I'm so short and the 120mm fork / 29" tires have so much height that my top tube is nearly parallel to my downtube. The anti-mixte tube helps me feel a little better, though I doubt it does much more than just bend my seat tube and top tube in weird ways.
Rides really nicely! Smooth on the descents - though that is probably due more to the front fork - my first new shock fork since the mid-90s.