[TheForge] TheForge Digest, Vol 106, Issue 24
Peter Fels & Phoebe Palmer
artgawk at thegrid.net
Fri Nov 16 17:04:22 EST 2012
Yeah! That's what i needed to know! Thank you Jerry! ( once again).
Guess resharpening an already sharp bit to a more aggressive angle, didn't work for a reason.
Nor did taking dinky little finishing passes, ever so timidly.
Glad you chimed in!
On Nov 16, 2012, at 1:13 PM, Jerry Frost wrote:
Ah Pete, there's a special need for sharpening bits used on copper, bronze,
brass, etc. Dad would put a typical very shapr edge on a bit then blunt it
slightly with a light brush across the oil stone he kept in his dedicated
tool bit box. A "SHARP" bit snags and tears copper alloys while slightly
blunted cuts well with the proper technique.
Then there's the technique for cutting copper alloys, they work harden very
quickly so you can NOT take light cuts without sticking your tools, making
really ragged cuts and just generally making a mess. You need to hog the cut
either depth, feed speed, or both, this prevents heat from being soaked into
the parent stock, it goes with the chips.
You get ONE finish cut if you want clean, smooth and nice results. Hog it
within a couple thousandths then use the finishing bit but at speed, turn it
fast and hog the feed.
Same for drilling, pilot within about 30% of the finish size and go directly
to the finish dia. Tryin to take it a few thou at a time or chasing a hole
close and it'll eat your bits, they'll gall and break, spin in the chuck,
the stock will spin in the vise or some similar failure mode.
Same goes for spinning, you'd only get so many passes with the tool before
you entered the "oh CRAP" that hurts zone. I found Dad knew exactly what he
was talking about when he said you got 3 passes so push it as far as you can
first pass, second pass will go almost as far and you have to feel your way
through the third, If you try more passes you'd better be on your toes or
it'll end up wadded around the die or flying in bits and pieces around the
shop.
Copper alloys are more temperamental than steel, I LOVED spinning steel. Get
the speed right and it'd just flow over the die politely. MAN this is
bringing back memmories I just HAVE to get a spinning lathe set up. <sigh>
Jer
----- Original Message -----
From: "Peter Fels & Phoebe Palmer" <artgawk at thegrid.net>
To: <mspencer at tallships.ca>; "Blacksmithing List Sponsored by ABANA"
<theforge at mailman.qth.net>
Sent: Wednesday, November 14, 2012 10:28 AM
Subject: Re: [TheForge] TheForge Digest, Vol 106, Issue 24
> OK...point made ( again).
> Metal content.
>
> There seems to be more than 1 kind of silicon bronze.
> Anyone want to offer a brief run down on the forging characteristics of
> each<
> and recommended sources for modest quantities?
> And.
> I'm a terrible hand at my old lathe..pig-ignorant. I was ineptly cutting a
> tapered hole in the length of a chunk of what i presume to be naval bronze
> shafting i'd drilled out, with an improvised boring bar... (it's about
> done now) , but it was slow and there were horrible squealing and
> crunching-gravel like sounds . The shavings were masses of tiny sharp
> pins..ugly! I tried changing all the parameters i thought might help ( bit
> level, cutting face angle, feed rate), to little avail. Perhaps the
> cutting bit had too wide a face? The boring bar wasn't as rigid as i would
> have liked.
> Any pointers would be appreciated.
>
> On Nov 14, 2012, at 11:00 AM, Mike Spencer wrote:
>
>
> Dave Mudge wrote:
>
>> Is this conversation getting a little too heavy for this forum?
>> Let's stick to metal and art and such and take politics somewhere
>> else, ok?
>
> Yessir, Dave, Sir. Anybody who doubts the wisdom of Dave's advice
> should have a quick look at the Usenet newsgroup
> rec.crafts.metalworking. [1] We don't want to go that way here, I'm
> pretty sure.
>
> Andy wrote:
>
>> But.. but... global warming...
>>
>> corporations...
>
> I can tell you what I think about corporate oligarchy in private
> email, Andy, or I can even point you to a lightly trafficed mailing
> list where an exchange of comment and opinion that is *very* much more
> level-headed and civil that rec.crafts.metalworking.
>
> Just to bridge us back onto topic: There is an Iranian [2] blacksmith
> here in Nova Scotia. Very deft at the anvil and a charming guy as
> well. He recently acquired Canadian citizenship, has been driving a
> cab for the last few years to get a stake. AFAICT, he's spent all his
> money on smithing gear and a site for his shop which should be under
> construction next spring.
>
> ObSmithing:
>
> Despite doing furious geometry gymnastics in my head, I welded my
> cellar door latch handle on wrong way to. Hadda slice the weld off
> with a zizz wheel and redo. Works just lovely now, looks better than it
> has in 100 years if you overlook the fact that, due to movement of the
> drystone foundation (now arrested) nothing is square, plumb or
> level. :-) I'm always entertained when I find myself patching up a
> pine or hemlock board that was a sapling when George III was still in
> short pants.
>
>
> - Mike
>
> [1] rec.crafts.metalworking should be available on Google Groups if
> you don't have proper news reader software, are disinclined to get
> such software or don't have access to a news server.
>
> [2] Iranian: He refers to himself as "Persian". I infer, without his
> having said so explicitly, that this is to associate himself with
> the long history of Persian culture while distancing himself from
> the politics and government of the contemporary sovereign nation.
>
> --
> Michael Spencer Nova Scotia, Canada .~.
> /V\
> mspencer at tallships.ca /( )\
> http://home.tallships.ca/mspencer/ ^^-^^
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