Tool Review: Great Innovations Ultimate Engineering Screw Chart


Great Innovations Ultimate Engineering Screw Chart Front Detail

The slide rule may be a quaint anachronism in this age of ubiquitous computing, but there’s still a place for the slide chart, the volvelle, the nomogram, and other hand-held “paper computers.” These are still published by a few companies, and are a handy source of on-the-spot reference data, particularly in field or workshop environments that may be inhospitable to or inconvenient for electronic devices or books. Slide charts containing key screw, bolt, and nut data have been around for decades, and the folks at Great Innovations identify TAD’s Universal Reference Calculator, discontinued in the mid 1990s, as inspiration for their chart.

The thing itself is simple enough: a clear plastic outer sleeve printed with dimensional drawings and callout fields on both sides, and an opaque plastic inner card printed with the callout data. Sliding the card back and forth in the sleeve indexes all the callout data simultaneously, and of course can be used bidirectionally—you can get key dimensional data from a known fastener size, or figure out fastener size from some real measured dimension. Overall, the chart is about 1/16″ thick, flexible, and measures 8.75″ × 11″—about the same size as a standard sheet of printer paper.

Engineering Screw Chart - Front

The front includes sliding tap, drill and stress area callouts for SAE and metric screws, in both standard and coarse threads, as well as key dimensions—such as countersink depth, counterbore depth, socket cap size, etc.—for various types of screw heads, points and nuts. Detail boxes cover metric and SAE shoulder bolt dimensions. The areas not occupied by the sliding chart fields are filled up with static tabulated data—metric/SAE drill equivalent diameters, fractional/decimal drill diameters, common unit conversions, metric prefixes, and SAE bolt grade markings.

Engineering Screw Chart - Back

The back has sliding indices for sheet metal and wire gages, dimensioned thicknesses, densities, and minimum bend radii; critical dimensions for tapered pipe threads both NPT and BSPT; and a hardness converter for Shore durometers A-OO with typical reference materials (e.g. “Shopping Cart Wheel”) and conversion factors for Brinell and Rockwell A-C hardnesses, as well as approximate tensile strengths. Static tabulated references include the numbering system for carbon and alloy steels, a circular actual-to-nominal pipe size gauge, and a slew of handy equations from statics, dynamics, electrical engineering, and statistics. One of the long edges is printed with an English ruler, and the other with a metric rule. No space is wasted; pulling out the sliding inner card reveals three more handy tables printed in the “dead spaces” between the keyholes—densities of common metals, a key to common mechanical drafting symbols, and a key to AWS standard weld symbols.

I use the chart in my workshop quite often—mostly, so far, to look up tap drill sizes and gauge nominal pipe diameters. It’s compact and durable and water- and grease-proof, and has saved me a lot of time running back and forth between my web-connected smartphone, tablet, laptop, or whatever (all of which I like to keep clean) and my dirty workshop and tools. Mine is a review unit I got for free, and I would recommend it enthusiastically to others if not for the price of $24.99, which is about $10 more than I think I would pay for the thing. A functionally-equivalent app is available for both iOS and Android for $5 less, but in my mind that sort of defeats the purpose, which is that you can keep the chart on-hand in an environment that might not be hospitable for a handheld electronic device, and don’t have to worry about keeping it clean, charged, or safe from damage.

Engineering Slide Charts

8 thoughts on “Tool Review: Great Innovations Ultimate Engineering Screw Chart

  1. So glad to see this back in circulation. My dad had one of these back when I was working in his mechanical design practice. It wasn’t indispensable, you could always look things up in Machinery’s Handbook, but it was a very fast way to work.

  2. Every time I see this thing I click over, ready to buy it for $5-7. But it’s $25. You can buy a used copy of Machinery’s Handbook for that and get a LOT more information. If you bookmark the pages you use most, it doesn’t even take any more time to use.

  3. I have the Machinery’s Handbook, 26th Ed. in PDF, AND I have a sliding reference tool similar to this one. The sliding reference is — by a long shot — THE “go to” tool for a quick look at the sort of information that this product includes. I use mine OFTEN in my engineering work, but it has NOWHERE NEAR the variety of information on it that this one includes. I have the “Universal Reference Calculator” from TAD Products Corp, which is no longer available. But, TAD Products got bought out by these guys…

    Media Marketing Assoc.
    P.O Box 686
    Beverly, MA 01915

    …and they sell a similar type of sliding reference tool for about $19 each. Oh, but wait; you’ll have to buy TWO, because the sell inch and metric versions separately

    Of course, it is true that the info on this handy tool IS in the Machinery’s Handbook, and — yeah — you CAN get a used copy for about $25, BUT you’ll either have lots of dog-eared pages, or you’ll have PostIt notes poking out of it all over, or you’ll be flipping through a whole lot of pages every time you want to look something up. In practical application — even though my Machinery’s Handbook is in PDF format — getting the info from the all-in-one-place sliding reference tool next to my elbow is about 100 times faster.

    So. all in all I’d say quitcherbitchin about the $24.99; if anything, that price is LOWER than it oughta be.

  4. Bringing up metric is a good point. I *don’t* have to buy two, since I never use metric. (I love it, but I don’t have money or room for two complete shops.) So I’m a little hesitant to pay $25 for a single page I can use half of vs a an entire book I can use all of.

    1. If you’re worried about wasting space on metric info, you’ll have to throw out half the machinery’s handbook!

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I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I am a long-time contributor to MAKE magazine and My work has also appeared in ReadyMade, c't – Magazin für Computertechnik, and The Wall Street Journal.

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