Catnap 

I haven't been on this site as much as I have in years' past, in part because my interest in vintage bikes has shifted from collecting and restoring them to building my own frames. I started building last year, and have been using vintage lugs from the 1950's and 70's, and classic tube sets. I've made three frames so far, two lugged road bikes and one track frame. I'm purely a hobbyist builder, my goals being to build vintage style bikes and to develop my craft further.

Yesterday I began my latest project, which is to build a track frame using a set of vintage 3Rensho / San Rensho lugs. I decided to photograph and journalize every work session as I build the frame. I'll be publishing the photos and updates in this thread and also on my blog, djcatnap.com. Yes, I know there's a framebuilding forum here as well, but frankly no-one reads it. This is a vintage reproduction of an iconic Japanese brand, so I think it's appropriate for this forum.

So let's start out with all the parts laid out:



Columbus SP tubes make up the main triangle with Columbus tandem indented chain stays. The seatstays are Columbus as well, from Nova Cycles, as is the rear "wishbone" kit, fork blades, and steerer tube. The head lugs and seat lugs are the "Moduelo" type as designed by Yoshi Konno of 3Rensho fame. I'm not sure about the bottom bracket, but it matches the look of the lugs well. The fork crown is from a 3Rensho mold as well, available from Nova Cycles. The rear drop outs came from Russia; I decided to take a chance on a cheap supplier I saw on eBay and the product turned out to be good quality. Why are there two sets? Because I haven't decided which set to use...



This one should give you sense of how they all fit together. I was very pleased to see that the tubes fit into the lugs smoothly but snugly; all of the past vintage lugs I've worked with required a lot of shaping and carving before they would fit over the tubes. That's in part because they were pressed from sheet steel, while this set was cast - a more expensive process that generally yields much nicer results.



Here's the headlugs. Knowing that this will be a 53cm bike, I'm going to have to cut down the "fins" on the inside of the head lugs. It will be a challenge to do it in a way that preserves the flowing line of the head lugs.



And the seat lug.

Catnap 

Time to get started! The first step is to prep all of the lugs. That means filing and polishing them to remove any flaws and personalizing them by carving away some bits. The biggest challenge in this step is the bottom bracket - it was made for a road bike, and has a Cinelli-style fin cast into the underside that acts as a cable guide for the shift cables. It also has divots in the shell for the cables, and a large guide for the rear derailleur cable, below the drive side chainstay socket:





I used a grinding wheel and belt sander to remove the bulk of the fin and cable guide. Then I put the BB shell in a lug vise I have and worked it over with a set of hand files until it was smooth. However, I still had to deal with the divots that were cast into the shell. Time to get out my torch! I fluxed the bottom bracket, heated it up, and flowed brass into both divots. Here's what it looked like after it cooled down, but before I removed all the flux.





Next step was to file the brass down until it was smooth with the rest of the bottom bracket. I spent another hour or so with the files, working first with large ones, and gradually moving down to small jeweler's files and emery cloth. Here's the bottom bracket all done:





Now it's a track bottom bracket! That's it for the first work session. Next time I will work over the head lugs and the seat lugs, including cutting down the fins on the headlugs to match the correct height of the head tube. After that I will shape the track drop outs and mitre the tubing.

inkandsilver

Very, very, very cool. Thank you for documenting & sharing this.

gaucho777 

Wow, what an incredible project! Looking forward to following this thread closely, as well as your blog. Gorgeous set of lugs, too. Are you pinning the joints? What have you learned from your first few frames that you'll apply to this project?

Color? Chrome? What type of tubing?

daf1009

+1 Yes, THANK YOU...this will be cool to watch...

himespau 

That BB shell looks great.

romperrr 

and....subscribed. Interested in keeping track of this.

obrentharris 

Nice work Catnap! Good to have you back. I'm looking forward to following progress.

icepick_trotsky 

Following this one with interest. Where did you learn framebuilding @Catnap?

iab

I'll be watching too. I like threads where I can learn something.

Henry III

Very cool as I'm kind of on the same level of building vintage style frames. Standard size tubing and those lugs are awesome. Where'd you learn or were you self taught? I just finished my second frame this past weekend and posted the thread a few days ago. Next build will be a mixture for my wife. Any pics of the other frames?

Catnap 

I won't be pinning the joints - I pinned my first frame (you can read about here My First Hand-Made Frame! « djcatnap.com) and it was a huge pain in the butt as it added a lot of extra steps and clean-up. Now I tack the lugs with the frame in a jig, and then check the alignment before fully brazing them. The biggest lesson I've learned so far is to go SLOW and check the alignment repeatedly. Most mistakes can be fixed, but if the frame is out of alignment after you braze it, it's ruined. "Measure 10 times, braze once" would be my motto.

I may chrome this frame if it comes out nice. This lug set is certainly worthy! I have no idea on the paint scheme at this point. Tubing is Columbus SP.

I read the Paterek manual, as well as Marc Chimonas's books on backyard building. Then I built my first frame under the guidance of Lance Mercado of Squarebuilt Cycles here in Brooklyn. Lance is now teaching classes, you can see his work and contact him via SQUAREBUILT. Since then I've just been muddling along on my own and learning whatever I can from local frame builders like Jamie Swan and Tom Callahan when I get the opportunity. Also, for NYC folks, Lance will be doing a free class on brazing lugged bikes at Nomad Cycle this Thursday evening - nomadcycle.com. Nomad is also where my studio is located (I rent space from the owner) and anyone who is local to NYC and interested in framebuilding should come check it out.

AZORCH

Subscribing now!

gomango

No interest in building my own, but I sure like to watch others in the process.

This looks like an excellent thread to follow.

Thanks for adding some pizzaz around here.

Kactus

This will be fun to watch. Subscribed.

unworthy1

the BB shell is an IC unit from Li Chen, I think. it's no Yoshi Konno job but since you're modding it I'd grind off the extra "horns" on the stay sockets and re-do the radius-es and it might begin to harmonize with the Konno lugs. Looks like a challenge and a great start so have FUN and we'll all be watching your progress!

jimmuller 

Very cool. Watching with interest...

Frame building is one of those skills I wish I had but ain't gonna' happen unless I start 40 years ago.

easyupbug 

What a joy to watch!

thinktubes 

Neet!!!

Catnap 

I went back into the shop yesterday evening for another round of work. First thing I worked on was finishing the rest of the lugs. This entailed putting each one in a lug vise and working it over with fine grit files and sandpaper. I wanted to remove casting marks, bevel the lug edges, and give them a smooth finish. Here is the lug vise I'm using, from Helm Cycles - Lug Vise Set - Helm Cycles.



Here's the tools I'm using: jeweler's files, emory paper, and an electric drill with brass & steel brush heads. Steel heads scour the surface, brass polishes.



Here are "before and after" shots of the seat lug that illustrate what I was doing:



Here's the finished lug set. Although... I may follow Unworthy1's suggestion about modding the bottom bracket. Hmmm...

Catnap 

Next up - I cut down the head lugs a little so that they match the head tube length in my blueprint (which comes from BikeCAD):



Then I moved on to the chain stays. I cut them to size and decided on the drop out that I wanted to use:



I was tired out at that point (about four hours of work or so) and called it a night. Next time I go in, I will spend a while cleaning up the drop outs. Then I will slot the chain stays to fit the drop outs into them, and prep them for brazing. At that point, I may braze the drop outs into the chain stays. Or, maybe I will mitre all the tubes first and assemble the bike in a jig. I'm not sure yet.

daf1009

The lugs look fantastic! Enjoying watching this one develop...

busdriver1959

It's never too late.

Cyclist3098765

Great thread, keep it up! +1 on BB mod, btw

Sir_Name 

Excellent content - thanks for sharing here. Fun to watch a project come along. Good luck and enjoy.