uprights, hammer boring

[gordon stelter]

Small machinist's rule? Feeler guage? Draw line at
center pin, then measure distance once removed?
     T
>         This brings up a question for me that
> perhaps someone can
> answer. Although I don't replace many sets of
> hammers on uprights I
> presently have occasion to replace a set on an old
> Gulbransen upright. I
> tried to measure from the butt center pin to the
> string and I just
> couldn't get a measuring device in there to take the
> measurement. Anyone
> have a tip on what I could use to get a good
> reading? Might be too late
> for this set but I'd sure like to know for the next
> one.
> 
> Greg
> 
> 
> At 05:28 PM 3/12/2003, you wrote:
> 
> 
> 
> 
> I gave the technical on hammer boring at the chapter
> meeting, (with the
> back-up of the RPTs at the meeting), and nobody
> could explain what the
> criteria would be for determining hammer bore
> distance and rake for
> optimum performance on an upright. Sure, go by the
> original is an easy
> answer but what if it looks as if somebody who
> "hadn't a clue" put those
> hammers on. I have 3 old uprights here, a 1909 Smith
> and Barnes, a 1911
> A.B. Cameron, and a 1906 Kohler and Chase. The first
> two, the hammers
> shanks are close to parallel with the string plane,
> and the rake is
> minimal. Or, worded differently, the bore distance
> is the distance from
> the hammer flange center pin to the string plane.
> Rake is 1 or 2
> degrees. 
> The Kohler has much more rake, 5+ degrees and the
> shank is at the
> similar angle to the string plane so the hammer is
> square to the string
> plane when it hits.
> Why?
> Should I be looking at the angle of the jack to the
> whippen at the start
> of lift? The hammer butt/jack angle at let off?
> Or maybe it was something simple, like the little
> bit more clearance
> that could be had by moving the action closer to the
> strings.
> Anybody?
> Keith Roberts
> 
> ---
> 
> Checked by AVG anti-virus system
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> 
> Greg Newell
> mailto:gnewell@ameritech.net
> 
> 


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