Buy the second kind, but not that one. NO RUST. Also, I hate to say it, but you don't really need Starrett here, General is just fine. Just go to the hardware store and buy an inexpensive one. If you ever get to the point where you need to gage 84 tpi threads *then* buy a Starrett. Save the $$$ for taps and dies where you should *not* skimp.
I'd vote for the Starrett, I've had one, like the one you linked to, since G-d was a little boy, and it, a micrometer and Machinery's Handbook are all I've ever needed to identify a US fastener size and pitch.
Bear in mind that you'll likely need a comparable set of metric thread gauges to stay current though.
Whitworth is an now obsolete British thread standard not much encountered in the US unless you work on vintage Brit cars or firearms.
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The "necklace" thread gauge you linked to looks like it would be handy at a hardware or big box store, hanging near the fastener drawers to help non-techie types figure out WTF they needed. I've seen similar things in such places, metal plates with labeled threaded studs sticking out and corresponding nut sizes fastened onto them.
I have run into them quite a bit. Mostly on valves for navy ships. Whitworth was still considered one of several thread series as standard for the U.S. Not a common series, but one of many. At least 20 years ago when I worked in the ship yards. If it still is? I don't know. I know it was a pain when making a new valve stem that had a 4 pitch Acme thread on one end and a Whitworth on the other end. I still have a HS threading tool ground up for Whitworth in my box. Even though I can't remember the last time I used it.
I wouldn't hesitate to buy the Starrett on ebay. Unless the photo is very misleading there appears to be very light rust mostly on the thumb nuts. Even a bit of pitting on the blades themselves isn't going to hurt the function of the tool unless it's so bad the marking on the blades is unreadable. The starting price is about 10% of a new Starrett or 20% of a copy, the seller has good feedback, and the shipping is reasonable.
By themselves the first convenient. With a caliper or micrometer and a thread chart, the second is more useful. 8 to 48 pitch covers most inch thread ranges.
Hmm ... this would be convenient for *common* sizes, and gives you both the diameter and the pitch in a single device. And, it is more convenient to use on tapped holes.
I've got a plate thread checker set (three plates -- two size ranges of imperial threads, and one of metric. This covers more of the different sizes including some of the specials.
This precise one is one of the two screw pitch gauges which I consider the bare minimum for my needs. The other is also by Starrett, but is for metric threads.
It is better when you need to check a threaded part which does not happen to be a standard diameter (such as threads on lens assemblies or hydraulic cylinders, or something similar which won't match up to a thread checker. You need, in addition, a set of micrometers, or a good caliper to get the diameter to go with the thread pitch.
What is your general use? The first one would be far more convenient for something like automotive fasteners, but if you need to check a lathe spindle thread (one of mine was 2-1/4x8) -- think of the size that would be, and how much space a set which went up that large would take up -- not to mention the weight to lift them all threaded together.
I like the way that metric is differentiated from Imperial (inch) threads by the color.
All you can get, if "most threads" includes those made special on a lathe, so you can duplicate it with your own lathe. "All you can get" includes both the Starrett which you showed in that auction (a good choice, IMHO), but also a metric one (which needs fewer blades overall).
That particular Starrett is probably the best blade type for Imperial threads -- and it is what I use most of the time -- but I have some others which came with the other contents of used machinists' toolboxes which are sometimes easier to fit into awkward places than the three-cornered one.
If you are just needing this for automotive work, the first one should do fine (and is easier to use for checking smaller tapped holes). I keep samples of the most common screws screwed into the screw checker plates for checking tapped holes. If you are machining things, go for the blade type, and get a good way to measure the diameter of the screw separately from the thread pitch.
That Starrett one is dirt cheap, and if I did not already have one, I would probably bid on that one myself if you did not. I forget what I paid for mine back around 1975 or so, but I am sure that it was more than three times the current price. (And the shipping cost via USPS seems reasonable, too.)
Anyone here actually used that kind of gage to determing the size of a threaded hole in a immoveable object?
It looks like the individual gages don't come off the cable without cutting it, so it seems like it might be a bit of a pain to thread one gage into a stationary threaded hole while the cable and the rest of them are flopping around.
Yes, I noted that, but I was thinking it'd be a lot harder to try a gauge in a stationary threaded hole because you'd have to also twist and turn the whole length of the cable, which would probably be flopping around and fighting you. I'd expect it would be more frustrating doing that that just threading a screw into that same hole with your fingertips. (If you had one the right size that is.)
I do -- and the real test is to try it and find out whether they've put enough length of extra cable in there.
I'm not at all sure that I care to make the investment to find out, however. The other means discussed are better for my purposes.
You've identified the problem with using a screw -- just having the right size on hand -- and sometimes *knowing* that you have it, and where. A single "right screw" is too likely to get put into a project, leaving you with the problem of remembering to replace it. :-)
I have both the types of thread checkers that you show plus the plate type (General) with threaded holes. As with all tools each has its own advantages and disadvantages depending on your application. If you are just checking the occasional machine screw the blade type is probably the most versatile; however, I find it difficult to use on small diameter internal threads. It also takes some time to sort through the leaves and make an accurate comparison. Sometimes you need the help of a magnifying glass. Also you need a separate instrument to gage the diameter. That being said it covers a wider range of thread pitches. The plate type works for external threads only, but is quick to use. It also only measures up to about 5/16" diameter. I purchased the gauges on a cable because I had a large quantity of mixed English and metric sizes that I needed to sort, and it was great for that. It also measures larger sizes than the plate type gauges. Its ability to check internal threads on nuts is also very useful. Your choice depends on your application.
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