UBI Framebuilding Class - Day 5

5/15/2015 - Day 5

• Frame Tubing
• Choosing Frame Tubes
• 8/5/8 is OK to use
• Wall thickness
• Overall length of tube should reach to at least halfway across adjacent tubes
• Check seat tube with actual seat post to ensure fit and determine butted/non-butted ends
• Locate tube butting (look inside)
• Watch for short vs. long butts
• Bias long tube butts towards the headtube
• Mark tubes just past center of adjacent tube
• Label tubes and their orientation
• Machining Dimensions (see worksheet)
• TT/ST: 73°/17°
• TT Miter Length: inside corner to inside corner
• TT/HT: 73°/17°
• Notch ST for Lugged BB, Notch DT for Fillet-brazed BB
• Tube Mitering 
• On the Milling Machine
• Diameter of Cutting Tool/384 = approximate cutting RPM
• By Hand (specific to TT/HT Joint, others similar)
• Only rough-cut one end
• Scribe to inside of headlug
• Use Bevel Protractor/angle gauge set to HT/TT angle as filing guide
• Cut miter and file
• Clean out inside of tube (file/emery cloth)
• Scribe mark down length of HT for vent hole locations
• Drill 0.25-inch hole (#3 drill bit)
• Henry James Jig Set-up (specific to HT/TT)
• Level out the TT blocks against the jig's backplate with provided angle-iron
• Set centerlines for TT
• Adjust lower blocks first
• Adjust upper V-blocks next
• Set Head Angle -- watch for loose gauge block
• Head Tube Rod - put HT on
• Head Tube Height Adjustment
• Align HT vent hole with TT
• Check HT height from drawing
• Rock tubes in lug to ensure they're fully seated
• Make sure all clamp bolts are tight
• HT/TT Brazing
• Silver flux everything
• Rotate jig to expose obtuse angle of tubing/lug joint
• Tack obtuse angle
• Tack acute angle
• Follow brazing sequence to complete lug braze
• "Paint" with torch flame to move the silver where you want it to go
• Seat Tube
• Notched for lugged frames to locate tube in BB
• Locate ST in BB and lay on drawing to locate ST/TT vent hole
• Check BB port angle against drawing
• Brazing the Frame
• Mount tubes in Henry James jig
• Ask instructor for help
• Flux everything
• Brazing
• Remember: Obtuse angles first
• Tip jig to point joint downwards to leverage gravity
• Use soft reducing flame, barely roaring
• Start w/HT/DT lug, braze similar to HT/TT lug 
• Move to BB (rotate jig)
• Do obtuse/bottom/outside angle first
• Then do back/acute angle
• Don't cook CS ports
• FEed fillter at DT, look for it at ST
• Then do sides of ST
• Last do ST/TT lug, obtuse angle first (rotate jig)
• Feed filler at TT, look for it to come out at ST

On to Day 6