Need help attaching a shifter boss to bicycle

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Hi guys.  I know nothing about welding.  I need to figure out to attach this boss.........to an aluminum tube so that is looks like this.....The boss is steel but the bike tube is alumimum.The bond needs to be very strong because I will attach a shift lever to it.It does not matter to me whether or not some bicycle paint needs to be removed.Last edited by mike932; 08-17-2012 at 10:22 AM.
Reply:Hey, Mike, welcome.Steel boss to an aluminum tube ain't gonna happen via welding- but may I suggest a cruise through this site:http://www.thethirdhand.com/They will likely have a setup that mounts a shifter boss to the downtube using a worm-drive hose clamp, or a screw-on clamp. I bought a similar downtube shifter from them years ago- glad to see they're still around.What kind of bike are you working on? Sounds like a custom setup, or revitalizing an older bike.Last edited by asdf; 08-17-2012 at 10:29 AM.
Reply:Hi asdf.  Here is my bike....  http://www.bikesdirect.com/products/...ington2_IX.htm
Reply:I just checked: looks like Third Hand only has braze-on shifter bosses. But if you google "clamp-on shifter boss" there's a ton of hits.
Reply:asdf, the hard part is finding clamp on bosses that fit large diameter tubing.
Reply:Thanks for the link- my wife is looking for a bike, so we'll start at that website for sure. Looks like a good deal at $350, and free shipping.But I still don't get it: are you building a bike with that frame? Moving from shifters integrated with the brakes to downtube shifters seems like a step backwards (imho).If you go the clamp-on route, bear in mind you need the clamp to work with an oval tube instead of round.
Reply:The bike is excellent for the price.  I have 2 bikes from that website and have no complaints.I'm a dinosaur.  I have been using downtube shifters since 1986 and I actually prefer them over integrated shifters because they are simple, cheap, and shift crisper.
Reply:What about welding the steel boss to a stainless steel hose clamp?Last edited by mike932; 08-17-2012 at 10:53 AM.
Reply:Well, good on ya- that's not dinosaur, that's preference.You might check on the bicycle discussion forum at Craig's List, and ask if anyone knows a source for clamp-on bosses for an oval tube.In the mean time... how closely does the curve on that boss match the profile of your downtube? You might find a radiator hose clamp that wide enough and long enough, and drill two holes at the appropriate spots, then tighten down...? It would be a bit of a lash-up but would get you riding again.
Reply:Dang it, we're crossing posts again.Steel boss to a stainless hose clamp can be done: consult a TIG welder near you. But are hose clamps stainless? I thought they were steel with a shiny galvanizing coating.
Reply:Stainless steel hose clamps..... https://www.google.com/webhp?rlz=1C1...&bih=548&ion=1The curve on that boss matches the profile of my downtube perfectly because although the downtube is thick, it has shaped irregularly so that a boss will fit flush.How much would a welder charge to weld this boss to a hose clamp?
Reply:Welding charge will vary from shop to shop, and I couldn't even venture a ballpark guess.McMaster Carr offers hose clamps in a variety of widths (9/16", 1/2", and 5/8"). Is there any resonance to the idea of drilling holes in the band to accomodate the bosses, then clamping? The thickness of the clamp may take up too much of the available height of the boss, is a possible down side.
Reply:I think drilling holes and placing the hose clamp over the boss would interfere with placement of the shifter.  See directions....  http://techdocs.shimano.com/media/te...9830612533.pdf
Reply:Yup, been a while since I've installed one of those. Boss inside the clamp is not going to work.
Reply:Look into brazing. Most shifter bosses are brazed on. Aluminum to steel is uncommon, but not impossible.Look here: http://www.hobartwelders.com/weldtal...ainless-Steel&Last edited by fortyonethirty; 08-17-2012 at 01:40 PM.Ian TannerKawasaki KX450 and many other fine tools
Reply:4130, how much would a welder charge me to do this?
Reply:Reverse engineer the boss and machine it out of aluminum and TIG weld it on.www.tjsperformance.comDynasty 300 DXHTP 240HTP Microcut 380Hyperthem 85JD2 Hyd Bender and HF Hyd Ring Roller all in one =(Frankenbender)Bpt. Mill/DRO4' x 8' CNC Plasma TableInstagram: tjsperformanceYT: TJS Welding and Fabrication
Reply:Originally Posted by mike9324130, how much would a welder charge me to do this?
Reply:Can you extend the sides and bolt it on?Is there a central tapped hole in that piece?  Would love to see another angle of it. You can probably find a stainless clamp at a marine supply to weld that to.TA Arcmaster 300CM3XMT 304S22P12 suitcase feederX-Treme 12VSOptima pulserTA161SMaxstar 150STLHypertherm PM45OP setupStihl 020AVP, 039, 066 Magnum
Reply:There is a threaded hole in the piece.  Here are more photos....http://cgi.ebay.com/ws/eBayISAPI.dll...#ht_1118wt_952
Reply:Look up "silver solder aluminum to steel" in Google.  I got 1,570,000 hits.  It seems to be a possible and popular activity, but I would be careful choosing an expert and wouldn't attempt it with my low level of experience.
Reply:Weld or braze a steel saddle to the boss and rivet it to the frame. The frame is straight gauge 6061 and should take it fine. If in the event that the 6061 has been heat treated after welding, which I believe is wishfull thinking, welding or brazing the boss will kill the heat treat in that area.Otherwise I am with the others. Stay with what you have or get a stem shifter mount like the masses of Schwinns had. Any reputable bike shop should have tons of used stock in thier bins.Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:Even if the frame was not HT after welding, the areas outside of the HAZ would still be in whatever condition they were before welding. Considering where the shifter would be mounted on the downtube, and the compressive stress on that part, that is the last area I would want to soften with brazing or welding.
Reply:Clamps would be the least damaging option.  Something like this combined with the right mix of screw and bolts....Or these....Thread adapters would allow me to fit a shifter screw into the threads of the above clamps.....Last edited by mike932; 08-18-2012 at 02:53 PM.
Reply:This looks like a problem that can easily be solved by a maker or repairer of bicycle frames.  I suggest you visit a bicycle shop catering to racers and serious riders.I offer three choices: Good, Fast, & Cheap. You may pick two.Hobart AC/DC StikMate LXHarbor Freight AD HoodHarbor Freight Industrial Chop SawDeVilbis 20 Gallon, 5 HP Compressor