The 101 Association, Inc.
For the preservation and enjoyment of 1928 to 1931 Indian Scout Motocycles
"You can't wear out an Indian Scout"
 

Frame repair to 1928 101

  • 30 Jun 2017 9:34 PM
    Message # 4927251

    I just got 28 Scout 101 with various areas of the frame having been poorly welded in the past. Is it advisable to grind and re weld those repairs or replace the rail between joints. With repairs, I would need a frame jig. Does anyone know where I could get one or have plans for building one?


    Billy

  • 01 Jul 2017 2:11 AM
    Reply # 4927347 on 4927251

    A frame jig is such different device depending on what you aim to achieve with it. Basicly just for measuring you only need a flat table with a custom clamp where you can bolt the frame in exact position from time to time and a fixed rigid, true square around the frame, to use as a secure support to measure from.

    A frame jig is really different if you want to have it for straighten bent tubes or correct angles that is out of kilt, then the rig needs to be really strong, boxed, still versatile and adjustable to support chains and pushing/pulling hydraulic tubes. 

    And if you want it for welding tubes in position, then you may want an open jig, maybe just a flat table where you can add or take away and maybe weld supports and helping devices on.

    Can you combine all of that, measure, straighten and repair an assembled bike as well as a disassembled frame, and a jig that is light and possible to stow away in a flat pack on a shelf, then I am definitely interested of a drawing of that!

    It also has to be cheap :-)

    Last modified: 01 Jul 2017 2:37 AM | Carl-Erik Renquist
  • 01 Jul 2017 3:05 AM
    Reply # 4927382 on 4927251

    How the frame is repairable depends much on how and where it is previously repaired. All major joints are reinforced with an inner sleeve and the frame is brazed together with spelter. It is not ordinary filler but a copper-zinc alloy, hell of a material that is impossible to remelt, and when it is heated too much it admix with the cast iron in the joints. Then the joints are ruined.

    I am barred from Facebook because they want my driver's licence, bank account and birth certificate to play so fuck that, and my link sources are limited, but Tim and others in the club knows a lot about frame repairs. 

  • 02 Jul 2017 10:07 AM
    Reply # 4928611 on 4927251
    Tim Raindle (Administrator)

    Billy, don't dive in with a welder or start cutting tubes. 

    You should not steel weld near any original joints. As Carl-Erik says, all joints are brazed. If you steel weld on the bronze it will melt the bronze into the steel and form an alloy with all the strength of soggy cardboard.In addition, arc welding on the cast malleable lugs can also make them brittle. Any repairs near a joint need to be checked, and repaired with bronze.

    Cutting and retubing is not a good solution either, except in extreme circumstances.  Many of the joints have an internal spigot which is brazed in. You may well find bronze spatters several inches away from a joint, and cutting and welding on them will just create more problems. 

    Do a lot of frame repairs here, and the most difficult ones are fixing other peoples repairs.

  • 02 Jul 2017 11:43 AM
    Reply # 4928684 on 4927251

    - What kind of tubing was used ...combination of C1020 mild steel and chrome vanadium mix, which modern racing car frames, in some cases, are still using today.

    - Were the connection pieces forging or castings - some literature referred to them as forging, but since forging was expensive, they are most likely castings.

    - what type of welding may be used ...brazing keeping heat below 2000 degrees F.  Be careful of exceeding this heat range, as 'Admixture' will occur.  This is when steel tubing or joint connection is heated to close to its melting point, and absorbs the brazing material into itself.

    What's a good brazing rod and flux ? - since where unlikely to come up with a good joint as the original, we should choose a brazing rod with both 'build up' and 'thin flowing' characteristics.

    All these answers and much much more, are available in The 101 Association's Shop Manual.  It may be purchased, and is an absolute must.  Most of its articles were compiled by the highly esteemed ...late George Yarocki.

  • 03 Jul 2017 1:49 PM
    Reply # 4930165 on 4927251

    Vahan Dinihanian mentioned this in a facebook discussion a while ago, just for information..

    Vahan Dinihanian: I used to talk to George Yarocki in depth about metallurgy and we found that the strongest and our favorite brazing alloy for repairing frame joints was MG130FC Flux coated brazing rod. super high tensile strength brazing alloy. I think the last place i purchased it was through Castolin Eutectic.

  • 04 Jul 2017 7:52 AM
    Reply # 4932311 on 4927251
    Tim Raindle (Administrator)

    Carl-Erik, I have never seen George use a flux coated brazing rod. We use a standard low fuming bronze, and powder flux, will pass on specs when I pop into the shop later. George had been brazing for over sixty years when he passed, and I never saw any flux coated bronze rod in the shop in the ten years I worked with him. He didn't like using it. Dipping the rod in the tin of flux was like a reflex action for him. I have been out on emergency jobs with a welder in his mid seventies who asked George for a job when he was sixteen, and worked for Torrington Metal until he retired, and he is the same. 

  • 04 Jul 2017 8:12 AM
    Reply # 4932328 on 4927251
    Tim Raindle (Administrator)

    By the way, there is no particular reason not to use the rod Vahan is suggesting, its just that George did not use it. A brazed repair will work particularly well with it, but for bronze welding, ie the majority of repairs on a frame, you will have too much flux after the initial "tinning". On large repairs I tin using a 1/16" rod to tin, and move up to 3/32" or 1/8" rod for filler. 

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