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Staff Compass "cross hair"

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(@howard-surveyor)
Posts: 163
Estimable Member Registered
Topic starter
 

My boss asked me?ÿ if I could fix the small sighting line on his old staff compass which is an older K&E. It appears to me, that is was something similar to monofilament line, possibly a white horsehair. Anybody had experience on replacing those?

 
Posted : 17/02/2021 1:37 pm
(@peter-ehlert)
Posts: 2951
 

I believe they were a single strand of a spider web darkened with soot.

David Ingram is the guy that would know. I have no idea if he visits here.

 
Posted : 17/02/2021 2:08 pm
(@peter-ehlert)
Posts: 2951
 

oops. I was thinking of the internal cross hairs.
my staff compass has a wire, non magnetic.

 
Posted : 17/02/2021 2:09 pm
(@sergeant-schultz)
Posts: 932
Noble Member Registered
 

looks to be a braided line on my K&E.?ÿ You could maybe use very small dia. braided fishing line?

?ÿ

 
Posted : 17/02/2021 2:24 pm
(@mike-marks)
Posts: 1125
Noble Member Registered
 

@peter-ehlert?ÿ Yup, a thin SS wire, spider webs were too delicate.?ÿ Monofilament fishing line didn't appear until the 1950s and wasn't in use in surveying instruments.

Long ago surveyed maybe 20 miles total of primitive roads with a staff compass on a Jacob's Staff using a steel tape with a 4 man crew. We were careful, slope chained tension clamps & temp corrections with Abney levels, plumb bobs for distance, and forward & back azimuth observations.?ÿ I was surprised we could close to better than 1 in 1500 on multileg traverses, that's less than five feet error per mile.?ÿ I hope you honor our monuments (which we only placed every ten legs, rebar & tag). Yes, inaccurately surveyed but accepted as the road location for the last 50 years.?ÿ And they are definitely the original monuments.

antique queen co philadelphia pa 1 c2ec09f0c5d9e7767835153302f3eebc
 
Posted : 17/02/2021 3:11 pm
(@nate-the-surveyor)
Posts: 10522
Illustrious Member Registered
 

@Mike Marks, at the very core, finding, and respecting old corners though NOT accurately set, they became the corners that built America. Now, letƒ??s go ƒ??fixƒ? em. Letƒ??s shift whole towns. Letƒ??s move the world over.?ÿ
I have been in the fix it mentality. And in the yield to it mentality. I am now so educated, learned, and experienced, that one ONE survey, I can yield to one that is 60ƒ?? out, reject one that is 8ƒ?? out, and set a new monument. And, not believe Iƒ??m violating myself, landowners, or my fidelity to God in heaven. Comes from surveying for 40 yrs.?ÿ

thank you,

N

 
Posted : 17/02/2021 4:36 pm
(@howard-surveyor)
Posts: 163
Estimable Member Registered
Topic starter
 

@mike-marks

That is what it looks like and I know it was build before monofilament line was around. Being a fiddler for a time, and a constant bagpiper, it closely resembles the hair on a fiddle bow, or horse hair sporran and is white, I think so it shows up better on the black post. Either way, I can use monofilament or a fine copper wire, but haven't determined how it was connected. It appears the small holes to anchor each end are plugged with something (leather) and there is a small adjusting screw by the post hinge so it can be adjusted 90?ø to the slit in the post. Can anybody see how the line is anchored in the post on one they own?

 
Posted : 18/02/2021 6:09 am
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