The width of the tape as well as the length is a factor in the minimum tension required. My Father always said that is the minimum boy. You are not going to stretch it. I did not realize that many others are afflicted with numbers like 0.00000645 or 20,906,000.
Larry Scott, post: 369556, member: 8766 wrote: He describes one chain, not two. And different tensions at 10 lbs at 100 ft v 20 lbs at 200 ft. And was asking if that means 8 lbs at 80 ft. I have never seen that in any reputable doc. Please link a doc that describes length dependent tension fully supported.
And, I guess it's project requirement specific. If you only need 1:5000, or if you need to be 1:25000 in 500-600 ft. And will another company measure across your work looking for a couple of hundredths.
Layout a bridge abutment with chain and consider what 0.05' is worth.
I have a 1" robot for that work.
Take tape in a parking lot and hook the zero on a spike, pk or concrete nail. Stretch out the full 200 ft. to a second nail. Pull a gentle 10-12 lbs, read it. Ramp up the tension and see "when does a tape stop stretching?". And if you the temps, shoot it with an EDM. You'll see that you can stretch a tape to read too short (a couple, a few, several of 0.01') a lot easier than you think.
See Special Publication 307, Steel Tape Measurements;
http://docs.lib.noaa.gov/rescue/cgs_specpubs/QB275U35no3071954.pdf
Loyal
zac stanton, post: 369427, member: 11630 wrote: Hi,
I just got an old fashioned peerless lufkin engineers tape 200' long. I am new school, so I am not sure how to use it correctly. I looked up the specs for pulling tension on flat, fully supported surface. States correct tension on flat surface for 100' tape is 10lbs, 200' is 20lbs. Say if I was to pull an 80' measurement, would correct tension be 8lbs if I've got it not fully unreeled, or would it be the full 20lbs for my 200' tape? Thanks for your help in advance. I can't find documentation, and I don't want to be an idiot.
C'mon chicken, ask another question:)
NIST description is calibrated at 50 newtons tension for all intervals of the tape. They also calibrate at 100 newtons for all intervals of the tape to determine AE constants for catenary calculation.
So, if one is using the 50 N calibration lengths, those lengths are for all intervals at 50 N. Per the report.
If one is using the 100 N calibrated lengths, those lengths are for all intervals at 100 N. Per the report.
The original Q was, if there is a length called out at 20 lb at 200' length, I assume per a doc, and a length at 10 lb at 100', the Q was "should he use 8 lb at 80'". That is no.
And 10 lb (50 N) is a constant. Not dependent on length. With its associatec calibrated lengths
And 20 lb (100 N) is also a constant. Not dependent on length. With its associated calibrated lengths.
They don't progressively increase the tension for longer intervals because it's longer.
And 20 lb is a comfortable tension, and not invalid, when the 20 lb values are used. At 50, 100, 150, and 200 ft.
20 lbs insures the tape is straight, instead of the small waves from being coiled up on a reel, and small deformities of use.
I'm not sure anyone actually spelled it out, but, according to FM 6-2; Tactics, Techniques and Procedures for Field Artillery Survey it says full pull on partial tape lengths.
2-10. BREAKING TAPE
When the tape alignment is unobtainable within 0.5 meter of a horizontal plane because of the slope of the ground, the tapemen use a special procedure known as breaking tape. (See Figure 2-4.) The procedure for breaking tape is discussed below.
a. The front tapeman pulls the tape forward a full length. He then drops it about on line and then walks back along the tape until he reaches a point at which a partial tape length can be measured. When the tape is held level, it should be no higher than the armpits of the downslope tapeman. At that point, the front tapeman selects any convenient full meter graduation. The tapemen then measure the partial tape length, aligning the tape and applying the full 25-pound tension. Clamping handles are used at any holding point between ends of the tape.
The manual mentions this several times in discussing taping with a 30 meter tape.
Measurement Systems; Taping Corrections, by
Robert J. Mergel, July 2004
Columbus State Community College
I searched and i could not find the power point
anyone have the link
If you are going to go "old school " always carry a hand level on your belt. All measures should be level. Also, clean it EVERY TIME you use it and run an oily rag down the full length! It will rust faster than you think.
Kris Morgan, post: 369462, member: 29 wrote: All you need to know is 0.00000645. 🙂
And the base temperature of 68 degrees if I remember correctly.
Duane Frymire, post: 369525, member: 110 wrote: I think geometry is the same in all States. Delta is an included angle, not a deflection angle. Although I guess delta could represent anything you want it to. Screw it, I'll go with James, colonial states are most correct:)
Okay.....the deflection angle is the angle that the new line "deflects" from 180å¡. When you are running cord-lengths to set points on an arc, you use the "deflection" angle to get the cord (which is "1/2-delta"). However it was once common practice, to run deflection angles on a traverse instead of "interior angles". You would backside with zero, flop the gun, and turn your deflection angle to the foresight point. in your arc situation, the deflection of the tangent lines equals the "Delta" angle.
I was wrong in that, when your running the arc, the delta angle of the chord is 1/2-delta. However in road work a person might set the PI, and turn the deflection to the next tangent. I'll take the ribbing for misusing the term in the context that was meant, but there is another application to the term "deflection" which is what I was thinking of.
Dane Mince, post: 370913, member: 296 wrote: Measurement Systems; Taping Corrections, by
Robert J. Mergel, July 2004
Columbus State Community CollegeI searched and i could not find the power point
anyone have the link
I have the document and can email it to you (it's only 3.7 mb), if you send your email addy.
Thank you all for your input. I realize now that I should be pulling the same 20lb of tension no matter how much tape I have unreeled. I also understand that I can use an EDM to check my pulls, but that a calibrated tape is the best option. You all have been very helpful. Thanks again.
rfc, post: 372446, member: 8882 wrote: I have the document and can email it to you (it's only 3.7 mb), if you send your email addy.
[email protected] or the email address in a signature tage thanks for the help
Dane Mince, post: 373810, member: 296 wrote: [email protected] or the email address in a signature tage thanks for the help
Done.:-)