[TheForge] Bandsaw blade joint (Was: Odd Vise)

[Mike Spencer]

me> Just failed to close a 1-1/2" (wood-cutting) bandsaw blade with
me> Silfos, failed again with US silver coin metal (1964 I think).
me> Both snapped when bent a little.  Succeeded with my ordinary
me> everyday green-coated brazing rod.

PF> I grind long opposing tapers on the blade as joint prep..seems
PF> to help a lot.

I would think so.  So how do you do that?  By eye?  With an angle
grinder?  Bench grinder?  Fixture of some kind?  I found it very hard
to get a good match on a long taper.  Finally ground and filed the
ends square, then made a very short bevel about (eyeball) 30-45 deg,
giving a very slight overlap.

PF> Also clamping the sides firmly in place so it doesn't shift as the 
PF> solder reaches solidus and cools is  important

Did that.  Made a jig from angle iron and other bits, Vise Grips.  Got
it nice and straight.

You say "solder".  What, exactly, do you use?  

I had some left-over ends of "silver solder" given to me by an old
geezer 40 years ago that eventually got used up.  Never knew exactly
what they were but they worked great on hard-to-join little jobs.  Now
they're all used up and my supplier offers "Silfos" (sp?  Silfloss?)
which is super strong but brittle. Also seems to have a pretty high MP
compared to ordinary brazing rod.  Apparently HVAC guys like it for
joining refrigerant tubing and the like.  Melted coin silver is also
brittle.  Jewelry friends have "silver solder" meant to match the
color of sterling plate and wire.  Would it be too high in silver, too
weak for saw blades and the like?

[Begin YAK]

There was a retired engineer, now deceased, who summered here who told
of making multi-part objects, the pieces of which were serially joined
with solders of increasing MPs.  By gradually and uniformly raising
the temp in an oven, the things could be disassembled one stage at a
time.  Nice shop trick but he couldn't help me much with a hacking
approach because he'd worked in an industrial environment where they
just asked for what they wanted in the way of materials and getting
it was Somebody Else's Problem.

I only worked in that kind of environment for a single year.  If I (as
lowly techie at Famous Institution) called up BigCorp and asked for 40
cents worth of Product normally sold by the carload, it arrived the
next day with a ribbon on it.  Famous Inst. might, after all, buy 70
of BigCorp machines at $100K each that would each use 40 cents worth of
product every minute, 24/7, forever.  Alas, here in rural NS, getting
small bits and pieces of many industrial materials leads to yarns too
tedious and boring to tell while sober.

[End YAK]

- Mike

-- 
Michael Spencer                  Nova Scotia, Canada       .~. 
                                                           /V\ 
mspencer at tallships.ca                                     /( )\
http://home.tallships.ca/mspencer/                        ^^-^^

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