Alternative method of solo taping (illustrated)

The solo method works fine, and you know what the guy on the other end is doing.

Below is data I got from a validation. I had to check the previously-certified cal course. It checked to within 0.02 feet. I was happy with the agreement.

I do tension by feel.




This shows the 9.6 cm offset of the zero mark from the nail center

I originally tried to use nails. It was 20 deg F out and I was having a helluva time trying to pound them in.

I was using concrete nails and even tried a hand (4 lb?)sledge hammer. They would bend, come flying back at me, go in crooked...

That's when I gave up and rigged up the skid.

My 330 foot tape has its zero mark offset from the end. That eliminates one more possible source of error.

In warm asphalt, it probably would have gone much better.

The fat PK Nail, as in the photos, always goes in without trouble unlike thin nails, except if the road is concrete. However, I do like the innovation in your idea a skid.

OK, I did a google search and found out what a P-K nail is. I figured McMaster-Carr would have every kind of hardware known to man, but aparently this is a surveyors' specialty item.

This should be explained in the Course Measurement Manual. I read it cover to cover and could make no sense of the nails aspect, so I just used concrete nails. Since you have to drive them in a couple of inches and they are skinnier, there is more potential for trouble.

Thanks for you kind words on my skid.

Pete:
Do I have the readings for the offset correct?
Nail center 6,098 mm
Tape zero 6,002 mm
Offset 96 mm
Your caption indicates 93 mm and your table 96 mm.

Neville,

96 mm is correct. Parallax in the photo makes this difficult to see. I have corrected this in my post above.

Mike:
You could have clarified your description of the method you show by giving the tape readings. I am assuming the first nail was at 5 mm, the second at 49,992 mm, and the distance between the nails was 49,987 mm

Neville read the tape correctly!

Any beginner wanting more details of laying out calibration courses will find a great deal of information elsewhere. The basics are well covered in the following two on-line references:

IAAF Booklet (.pdf)

USATF Course Measurement Manual

However these two don't deal with the solo method , which is the one I now teach all new measurers as the preferred method. The pictures, which I used to communicate the idea but not the detail in response to Stephen's posting of his photo-album, were actually taken from the on-line course measurement seminar. The seminar contains more details which may be of use to measurer undergoing training. You can read a bit more about the seminar in a posting I made here last year:

on-line measurement tutorial

I am afraid the only the introductory lesson can be readily accessed by all. You have to pass the introductory test and be given a password to again access to the full theory training seminar, which is supported by an on-line tutor. Although at present the seminar uses UK language, measurement forms, certification procedures, and assumes driving on the left(!), it could be internationalised if there is a demand.

P.S. ABOUT P-K Nails
It was Pete who first gave me a box of P-K Nails, years ago. I now give each new trainee a small bag of these, enough to layout his home calibration course. By the way the size, which I find generally useful, is 1 1/4 inch long and 3/16 inch diameter. However I do keep some slightly longer ones just in case I encounter very soft tarmac when the short ones might move under 10lbs side ways pull.