UBI Framebuilding Class - Day 1

5/11/2015 - Day 1

• General info
• Instructors: Joseph Ahearne & Dan Harrison
• No eating/drinking at workbenches
• Daily class checklist
• QPB & Chris King orders
• Cost + 15%
• Orders needed by lunchtime on Friday
• Can only buy things here while attending a UBI class
• Check the online catalog
• Kasai tubing catalog
• Henry James catalog
• No disk brakes on forks built in class
• For fillet builders, you start on the main triangle first
• For lugged builders, you start on the fork first
• Jigs used in class
• Henry James is used for lugged construction
• Arctos is used for fillet construction
• Torch Setup
• Acetylene set to 5psi
• O2 set to 10-12psi
• Connections at regulator and valves are brass, so don't overtighten these!
• Turn off Acet first, then O2
• Bleed Acet from hoses first, then O2 -- this way the O2 pushes out any Acet left in the lines
• Torch Flames
• Reducing flame is used for Silver brazing ~ 1-2" secondary cone
• Neutral flame is used for Brass brazing
• Just a slight roaring sound
• primary and secondary cones are equal length (they converge)
• Oxidizing flame -- never want this
• Flux
• Blue flux for brass, thick consistency
• White flux for silver, thin consistency & use a lot more than you think you need
• Watch when the bubbles stop, which means you're near the working temp for the flux & filler
• First demo & practice - Brazing water-bottle bosses
• Drilling holes (#3/0.25" drill bit)
• Use tubing block
• Deburring
• Deburring tool, move in clockwise direction only
• Use half-round file inside the tube
• Emory Cloth
• Rubbing Alcohol to clean anything oily
• Clean the silver filler wire with Scotchbrite pad
• Heat the tube, not the H2O boss
• "Paint" with the torch flame
• Second practice - Lugs
• Headtube/downtube lug: 60°
• Headtube/toptube lug: 70° (start with this lug)
• Seattube/toptube lug
• Lug Prep
• Never fit the tube to the lug, always fit the lug to the tube (e.g. never remove material from the tube, only the lug)
• Remove burr from cut edge of tube with 2nd cut file
• Lug should slide on tube under its own weight (loose fit)
• Lug sockets are often oval due to casting process -- especially at thicker sections of casting since the cooling metal contracts more here
• Choose a file that matches the lug socket radius
• File in a criss-cross motion
• Be careful not to over-file the lug's points
• NOTE: Don't make the lugs loose on the tubes until after the tube is mitered!
• Tube Mitering Demo
• Push tube to meet the deepest points of the lug socket
• Scribe lines on tube
• Use metal snips or hacksaw to roughly trim the miter
• Red snips - CCW / right-hand cut
• Green snips - CW / left-hand cut
• Position tube in block, aligning miter with block seam, clamp in bench vise
• Try to file parallel to the floor, tilt the file slightly to bias material removal
• Ensure the mating tube sits squarely and completely in the cut miter
• If there are gaps at the sides of the valley, remove material from the bottom of the valley, possibly with a narrower file
• If there are gaps at the bottom of the valley, remove material from the sides of the valley
• Look for full contact around the perimeter of the miter
• Use the lug to check the tube angle
• Lug Brazing Demo
• Applying Flux
• 1/4" up inside of tube
• All around the outside
• Inside of lug completely
• Make sure tube is seated at miter
• 5mm excess headtube protruding from lug - gives a place for excess silver to flow onto
• Flux outside of lug completely
• Dry off flux with torch
• Sequence
• Wherever you add filler, the angle of the joint will pull tighter
• NOTE: Always tack in plane to the frame
• NOTE: Tack inside/obtuse angles on center first
• Then tack on acute center line (other side of lug joint)
• Finally go around right and then left side of lug to fill in with silver
• The sequence is important because it keeps things centered and ensures the order of completeness -- silver penetration all around and through the lug
• Flux should be evenly hot and clear on all joined surfaces -- watch for bubbles to stop coming out from the lug's edge
• Don't heat any points on the lug directly, else they'll overheat
• Tack just to the side of any lug points
• Preheat where you want silver to flow

On to Day 2