Step 3: Install Lugs & Dropouts

Step 2: Assemble Jig | Step 4: Prep & Install


2 steps, ~45 minutes

Goal: Mount the bearing surfaces tightly on your jig.

Materials: • Metal Head Tube • Head Lug • Bottom Lug • JB Kwik (black and orange tubes) • 2 Mixing Sticks • Vaseline • 2 Adjustable Wrenches • Rounded File • Gloves

3.1 Install Lugs and Dropouts | Prep Head Tube & Install Dropouts

Why do we use metal in the bike frame?
Why don’t we use aluminum for bearing surfaces?


3.2 Install Head Tube & Bottom Lugs

Why do we make composite lugged bikes?
Why do we use lug cores instead of mitering?
Why do we use balsa wood for lug cores?

****NOTE: The video says to use the blue JB Kwik tube. JB has switched the colors they use so please use the JB Black we provided instead****

• Put on rubber gloves.
• Using a 1:1 ratio of JB Kwik Epoxy to Hardener, squeeze two quarters’ worth from the orange tube and two quarters’ worth from the black tube onto a piece of cardboard. JB Kwik is ostensibly non-toxic, but it is very difficult to remove from fingers once it dries.
• Mix with the mixing stick until uniform color. Once mixed, you have 4 minutes to work with JB Kwik before it hardens.

• Apply a thick smear of the mixed JB Kwik to the inside of the Head Lug.
• Position the Head Lug so that the flat face points towards the back of the bike.
• Press the Head Lug around the Head Tube and wait 10-15 minutes while the epoxy hardens.

• Apply a thick smear of the mixed JB Kwik to the inside of the Bottom Lug.
• Position the Bottom Lug so that the skinny end of the Lug is facing towards the back of the bike. The two wide flat faces of the Lug will face up towards the Seat Tube Dowel, as well as the Head Lug.
• Press the Bottom Lug around the Bottom Bracket shell and wait 10-15 minutes while the epoxy hardens.


Bike Making FAQ
Step 2: Assemble Jig | Step 4: Prep & Install