LG-6001
LG-6001 External Lead Gage
LG-6002
LG-6002 Internal Lead Gage
ST-7001
RSC Pin Standoff Gage ST-7001
with standard
ST-7002
RSC Box Standoff Gage
ST-7002
Back to the Basics:
Does Thread Lead Affect Standoff?
LG-6001onPipe
The Relationship Between Lead & Standoff
In the last newsletter, we discussed the effect of pitch diameter on standoff for tapered threads. Now, we’re going to take it a step further and talk about the relationship between lead and standoff.
We’ve covered this before, but we can’t stress it enough, thread lead is one of the most important elements of a thread. We know that lead has an effect on thread flank engagement, functional size, and ultimately, make-up. In simple terms, lead affects the way threads fit.
Most people know that standoff is linked to functional size/pitch diameter and ovailty. What they often miss is that lead has a tremendous effect on pitch diameter, and consequently, on standoff as well. Remember from the last article that standoff is a function of taper and pitch diameter.
What is the Effect of Lead Error on Standoff?
ST-7000-on-Tool-Joint-
The effect of lead error on standoff is greater than most people realize. For instance, on a typical 8-Round Tubing and Casing thread with a 60° form and 0.75″ Taper Per Foot (TPF), every 0.001″ of lead error affects the pitch diameter by 0.0035″ and, consequently, standoff by 0.055″.
Let’s take a deeper look…
For a 2″ TPF rotary shouldered connection, a 0.001″ change in pitch diameter will alter standoff by 0.006″. On the other hand, 0.001″ of lead error correlates to a 0.0035″ change in pitch diameter and a 0.0208″ change in standoff. In other words for this thread, lead error affects standoff over three times as much as the same amount of pitch diameter error. Note that on rotary shouldered connections that just 0.001″ of lead error can cause you to exceed all of your standoff tolerance.
LG-6001
LG-6001 External Lead Gage
LG-6002
LG-6002 Internal Lead Gage
Lead is so critical that Gagemaker developed new lead gages, the LG-6001 and LG-6002, featuring…
Comfortable ergonomic design
Easy setup and operation
Contact point spacing for all API and Premium threads
Accuracies available: ±.0005″ or ±.0001″
Maximum travel of 1 revolution
Field repairable with easy change indicator
Available in both load flank and stab flank models
Smooth, repeatable movement
Uses Gagemaker Lead Standards
Look out for more on Gagemaker Back to the Basics!
It’s That Time Again!
Visit Us at OTC 2014OTC RGB 450×450
Are you ready? We are! We’re excited for another big year at the Offshore Technology Conference in Houston, TX.
Stop by Booth # 9745 in the Reliant Arena to check out some of our new products and packages. Learn more about our training programs. See some old friends, and even make some new ones.
Visit www.otcnet.org and register today.
What: OTC 2014
Where: Booth # 9745, Reliant Center, Houston, TX
When: May 5-8, 2014
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