Measuring Threads..?

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negatronix

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Hi Everyone!

I have a small project I want to do which requires me to measure some existing threads.

I'm hoping that someone might chime in and explain how to measure. I am looking to purchase a few thread guages, but am not certain how/where to measure the diameter.

Thanks for any help!
-Kory

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negatronix said:
Hi Everyone!

I have a small project I want to do which requires me to measure some existing threads.

I'm hoping that someone might chime in and explain how to measure. I am looking to purchase a few thread guages, but am not certain how/where to measure the diameter.

Thanks for any help!
-Kory

Sent from my SGH-T599N using Tapatalk
Click to expand...

Here is a link that explains how to measure threads using thread wires. They are relatively inexpensive and give you a method to accurately measure the thread. https://littlemachineshop.com/instructions/ThreeWireMethod.pdf


Tom S.
 
Measure od threads over the thread (thanks, smart alec, right?) Male threads will be a tad under nominal numbers. If you are trying to make and match male threads, you can just use calipers, just measure down in the thread and make new ones to match. Good for one off, or a few. If a lot, thread wires are a good way to go.
 
Threads have 5 or more important dimensions.

Lead, or as commonly expressed in the US "threads per inch" . Example a 14 TPI thread has a lead of .0714". If you do not have a pitch gauge measure by eye from crest to crest with a caliper, this may be wildly inaccurate however. A 2 start thread will have twice the lead.

Major Diameter, the nominal fastener size.
Minor Diameter, the bottom of the thread.
Included Angle, a majority of US machine screws are of the 60° included angle unified screw thread form.
Pitch Diameter is the most important, this helps assure that the external threads made by Company "A" work nicely with the internal threaded products made by Company "B", this is far more cumbersome to measure.
 
Well, do you mean how to measure threads per inch, or what is the major diameter of the thread, or do you mean how to tell if you are done cutting a new thread? You can always take you nut or bolt down to Ace hardware or Home Depot to use their thread checker, at least for the most common ones, gives you the first two above.
 
When I'm just trying to identify a standard bolt I use a drill gauge and a thread gauge. I have drill gauges in fractional, number and letter sizes and both inch and metric thread gauges. If you don't have drill gauges get some! I have some older USA made Craftsman and General that serve the purpose. Grizzly sells a set of all 3 for $7.50 H2985. If you have deep pockets I'm sure the Starrett drill gauges are nice but a bit pricey for my budget! I'm not a fan of the plastic ones but I do keep one on my boat. I have a older worn USA made General inch thread gauge and some newer ones both inch and metric from China. I'm keeping my eyes out for some better ones.
 
Thanks everyone for helping me out! Really appreciate it.

I guess I should have mentioned that this is basically a large threaded rod.. My cheapo thread guage lines up with 16TPI, and the diameter of the largest outermost portion of the threads reads 1 3/8.. It's a tierod end off of a 1 ton dodge ram. I really wasn't sure where to measure.. pretty new to all of this still. I am looking to make replacements that use heims.

I took the part to a bolt store and they couldn't help me.

-Kory


Sent from my SGH-T599N using Tapatalk
 
That's probably a Metric thread, and extra fine for adjustment. Tie Rod Ends are a highly stressed part of the steering system. That is also likely a forging, another way to ensure high strength in a part. I doubt you could find a standard Heim joint anywhere near the ratings of a TRE.
 
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