Does anyone make a right angle prism that attaches to a staff? Would be real handy when the rodman is giving an offset shot.
Thanks
WING DING
Just stand on line; close your eyes; hold both arms straight out, pointed up and down line; clap your hands together; open your eyes and your hands will be pointed at 90 degrees.
Close enough to set a dimple....;-)
This is the one I use:
From Foresrty Supply
Very accurate, when used with a plumb bob.....
> Does anyone make a right angle prism that attaches to a staff? Would be real handy when the rodman is giving an offset shot.
>
> Thanks
Sounds like a great DIY project. It would have to be rotational for left and right offsets. Maybe even hack a cheapo electronic distance measure tape inside for offsets(short range probably). Possibly design a bracket in 3D and then have one of those 3D printer services do a working model of it. Might cost a little though.
I know of no such product on the market.
Hayes Instruments has what you're looking for:
Sorry for the cut/paste.
I have the one RADAR posted, works good but it is usually in the truck when I need it most. Another option is the hand level. Roll it on its side and it is a right angle prism.
That does sound like a great DIY. I would start with one from eBay (china) for under $30 before spending $60 on the good ones.
Now, there's something you could make!
🙂
N
Most right angle prisms have two prisms in them, have seen a few with only one, installed a little ways apart so you can see between them. When on line with something to see on line each way, you line the visible objects up both left and right with the object you are wanting the right angle for. Get kind of good at focusing on three things at once, not really, but you do get good at getting on line. They have provisions for a plumb bob which can be used to get on a marked line or to mark the spot where line and the right angle are all in alignment, takes a steady hand. Have used them for data collection along a route using a chain for stationing and the right angle prism to find where to measure from for the left and right offsets, also have used them for the first try when wiggling in on line. Handy tool when used as intended with knowledge of its limits. Mine no longer rides on my belt but is in the rig and occasionally gets used. Throwing a Wammy is often done, but unreliable sometimes just holding the chain on the offset point and swinging an arc to find the shortest distance, works slower but with better results. Have used a 3-4-5 triangle as a layout tool.
jud
@ ontarget: Yep got that one. I think Otter6412 is looking for one that is attached to the prism or GPS pole. Will need a clamp with an offset mirror to see around the rod but still be on-line. Maybe a little off line can be be corrected for by mirror calibration. Could be mocked up in wood first, for a proof of concept, using a simple Dremel to shape. Use 123D to create a basic 3D model.
@ Scott McLain: Absolutely. Any development should use 'disposable' components.
"clapping a 90 ..."
That's what I teach my students.
"clapping a 90 ..."
> clapping a 90 .
> That's what I teach my students.
Well, it sound like it's very easy to get an "A" in your classes. Do they get a hundred if they get their name right? 😉
"clapping a 90 ..."
That's what I teach my students.
Set centerline control, clap 90, pull 19 feet and set hub. Curb layout is done!
/s
We haven't heard from Professor Mugnier in quite some time. More's the pity.?ÿ
We clapped a 90 to do profiles for various route surveys and used a hand level when it went thru dense woods and step leveling with a transit for more accurate locations.
I have an old Lietz right angle prism to get better accuracies than clapping a 90.
It it attached to a lanyard with a pocket rod on the other end to serve as a counter weight so the right angle prism will be plumb and when I need more accuracy I put a plumb bob on there and use a pole to brace it in place to reach out there and make an offset tie.
The Lietz has a smooth hollow barrel of a handle that could be slipped over 1/2?ñinch dowel and is in a satchel that I always carry.
Its also been known as "Arkansas a 90".
It seems to me that all you need is a slight variation of the mount that we have for one of our MiFi antennas.?ÿ Adjust it closer to the rod and make it for a smaller diameter prism shaft.
