This is not a "tack in lead". Nor is it a brass screw. This is a very distinctive monument of a certain City Surveyor by the name of Ramsey who worked in the early part of the 1900's. It is a brass pin set in aluminum, commonly known as "Ramsey Points". A common characteristic is that after 100+/- years the concrete sidewalk they are set in has eroded leaving them slightly proud of the surface. Ramsey's work was always very good, and these points, while not original, are sure to be the oldest monuments to be found. If you find one you should do the happy dance and hold it at the appropriate offset per Survey Y5/10. If your crew comes back from the field reporting that they have found a "tack in lead" show them this picture before you file an ROS perpetuating their ignorance.
I didn't work in the Portland area very long, so I didn't have the pleasure of finding a Ramsey Point. But coworkers did make me aware of them and I'd hoped I'd be one of the lucky surveyors to stumble upon one.
I'd also like to say that one of my favorite features of this forum is the sheer number of surveyors that seem to be paying attention to detail. It's so refreshing to know that we have such a high ratio of the "good ones" who visit and inform us every single day. So, thank you, Mark, for your diligence and enlightening the rest of us! I'm sure I speak for everyone here when I say it is much appreciated.
Sorry, that was a bit off-topic. I hope you'll forgive me. 😉
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Obviously not a tack. But the aluminum would have fooled me. Why aluminum? How did he install them?
Were they put in when the concrete was poured (in which case why not just use the pin alone), or did he drill a hole that was a slip fit for an aluminum cylinder and drive the pin which was tapered to expand the aluminum?
This is a brass screw. Also very characteristic of Portland. Very old ones like this have slotted heads and are often in very small diameter holes such that no lead is exposed at surface. At the bottom of this picture, left of center, is the stub of a second screw with it's top broken off (a pioneer pincushion). The quality of the positions of these screws is variable. But if you find one like this you can be certain that it is a veteran. Notice that the concrete sidewalk has eroded from around this one leaving it slightly proud of the surface. I have no record of it's setting but my guess is that it is from pre-1950. They can be hard to spot - I searched a small panel of sidewalk for a couple of minutes before spotting this one.
This phillips head brass screw is probably much newer than the slotted head one above. Note the surplus lead as well as the phillips head. Shooting from the hip guess is that this will date from c.1950-1990. Newer than that would have a 3/4" washer attached.
These three monuments were found within a block of each other.
Bill93, post: 433671, member: 87 wrote: Obviously not a tack. But the aluminum would have fooled me. Why aluminum? How did he install them?
Were they put in when the concrete was poured (in which case why not just use the pin alone), or did he drill a hole that was a slip fit for an aluminum cylinder and drive the pin which was tapered to expand the aluminum?
The exact manner of setting them is lost to antiquity. There was a lot of sidewalk construction hereabouts contemporaneous with the Ramsey work. Their shape varies enough to suggest that a hole was drilled for the aluminum. I'd guess that the aluminum may have been melted into place with a blowtorch? But that's just a guess.
The aluminum remains shiny. Lead is much greyer. The lead is easier to scratch with a car key than the aluminum.
Wendell, post: 433664, member: 1 wrote: I didn't work in the Portland area very long, so I didn't have the pleasure of finding a Ramsey Point.
Many have fallen victim to ADA wheelchair ramps, more still to redevelopment. They are getting a bit scarce. Which just makes it so much more important to properly identify them and perpetuate their positions.
If you are looking at an inner Portland survey record that claims to have found a "tack in lead" chances are good that you have a Ramsey point on your hands.
Mark Mayer, post: 433676, member: 424 wrote: I'd guess that the aluminum may have been melted into place with a blowtorch?
Not likely, as aluminum oxidizes readily when melted, especially with a torch. You tend to end up with more oxide than metal.
Some annealed aluminum alloys are quite soft, and can be hammered into a hole pretty much just like lead. I sometimes use aluminum wire for homemade rivets. (I picked up a few dozen feet of some that's about 3/16" diameter that I found lying around somewhere years ago.) I would imagine that a pilot hole would be needed for the brass pin.
Jim Frame, post: 433717, member: 10 wrote: I would imagine that a pilot hole would be needed for the brass pin.
I suppose that once the aluminum was pounded into the hole a pilot hole could have been drilled into the aluminum using an egg-beater style drill (keeping in mind that this was c.1910)
Have you ever asked Eric about it? If anyone knows how they were done, it would be him.
I always wanted him to give a talk at a chapter seminar or conference, but I never made it happen before I moved.
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Mark Mayer, post: 433674, member: 424 wrote: These three monuments were found within a block of each other.
Which means they'll be gone in a year or so. It always seems to work like that. New construction seems to find original monuments.
Paul, post: 433734, member: 624 wrote: Have you ever asked Eric about it?
Do you mean Erric? If so, he's not returning my calls.
Mark Mayer, post: 433748, member: 424 wrote: Do you mean Erric? If so, he's not returning my calls.
Yeah - Erric. He is THE GUY when it comes to downtown surveying, and has forgotten more about it than most of us will ever know. If you can get him talking at a conference or PLSO meeting, it is a pretty interesting time. His guy Brady used to go to all the PLSO meetings (maybe still does), and is pretty knowledgable too. As you probably know, they have all the Marshal brothers records and other stuff that NOBOBY else has. I wouldn't work downtown without reviewing their stuff first.
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