So not only do I get the chance to visit some great frame builders in the US, but I actually get to STAY at SquareBuilt.  I am a lucky boy.

Finished frames on the wall.

Squarebuilt's basement shop

Lance brazing with brass

Lance Mercado started building bikes back in 2003 after studying at UBI in Oregon.  He now has a very well-equipped workshop in the basement of his apartment on Myrtle Avenue in Brooklyn, and specializes in urban-style custom frames, whether they be single speed, track, road frames or polo bikes.  As I write this, Lance is designing a bike for a very small person, with a 650 front wheel and curved top tube.  Lance really enjoys making any bike that’s a challenge, for instance freestyle bikes, or where the customer gives Lance the task of designing the right frame for a very specific job.

Take a look at this amazing video of Lance and his co-builder Alex making (and powder coating, then building up) a frame in just 9 hours (opens in new tab):


Waterjet-cut SquareBuilt headbadge.

Made by hand in Brooklyn

Made to measure..

BikeCAD software comes in handy.

BikeCAD can make things easier to visualise.

..rules of the workshop

I watched Lance working on a frame. He decided to use lugs.  Sometimes, when Lance uses lugs, he’ll cut the lug in half with a small cutting wheel, put the two halves on the respective tube, and then brass braze in the middle.   The advantages with this method are that the lug doesn’t have to be manipulated to fit exactly to the angle required, and the points of the lugs can be made to lie against the tubes more easily. It is also easier to see the close fit of the mitre between the two tubes, and to make sure that they are pushed right against each other.

Cutting a lug into 2 parts.

Lug cut in two.

This time, Lance has decided to only use one half of the lug, and have it transitioning smoothly from a lug on one tube to a fillet braze on the other.

Two half-lugs brazed to the head tube .

Taking the temperature of the head tube with an infra-red thermometer. No more burnt hands!

..Then matching it to the water temperature so the flux can soak off without quenching the steel.

Head tube in water

Next, Lance fillet brazes the adjoining tubes to the head tube,

Fillet brazing to the front triangle (it's tacked in a frame jig first).

Then any excess brass is filed back to smooth out the transition.

Filing the fillets with a round file.

The fillets can be cleaned up further with an air-powered Dynafile.

Here are some more shots from around SquareBuilt’s workshop:

Checking alignment with a flat surface and a surface gauge (the heat can cause distortion of the tubing alignment).

Lance built his sandblasting booth himself. A whole frame can fit through the door on the end.

Plug-in track ends in position on the jig to test fit.

The bike starts to take shape.

More pictures from around the workshop:

Alignment surface with bottom bracket clamp and fork steerer clamp.

Fork blade bender

Powder coating booth

Lance prints out mitre templates for the seat stays.

The templates are then wrapped around the stays and ground/filed back to the line.

Stays are then put in the frame on the jig to test the fit.

A big compressor powers the sandblaster and air tools.

Lance is in turn powered by coffee..

Lance showed me this saddle rail clamp that's designed for brazing directly onto the seat tube, so a seat post is not needed. Just make sure you get the height right.

Powder pots in various colours

Tubing storage

A nice silver-brazed fork.


  1. […] When searching on the web, i found this method of cutting the lug and rebraze at the right angle : SQUAREBUILT BICYCLES, BROOKLYN, NY | ninelittletubes I haven't tried it yet. Hope this […]

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