What "unusual" uses are there for a cylindrical square?

opscimc · Dec 26, 2012

I searched the archives without finding an answer to this. I have a Brown & Sharpe 558 cylindrical square, which is the perfect implement for "calibrating" the vertical travel on my Talyrond roundness tester. Thanks to the B&S 558 I know the ways on the vertical transport mechanism are perpendicular to the face of the rotating table to better than 0.0001" / 5". I've also used it to check how perpendicular my mill's spindle is to the table (and how square my two precision machinists' squares are). But, at that point I've pretty much run out of things to measure with it.

Although a cylindrical square is highly specialized, it seems a shame that such a beautiful piece of precision instrumentation is destined to live most of its life in its wooden box for lack of measuring tasks to apply it to. Which brings me to my question. What other, possibily unusual, tasks are there where a cylindrical square could be put to good use? Not necessarily tasks where only a cylindrical square would do, or tasks that might be done almost as precisely with something less expensive (e.g. machinist square), but any task where a cylindrical square could be put to use.

Your answers will determine whether my cylindrical square becomes a productive member of society, or lives out its life in darkness and solitude.

The real Leigh · Dec 26, 2012

One common use for cylinder squares configured for it (not at all unusual):

If one face is ground slightly out of square with the cylinder, the cylinder's surface can be calibrated with rings of equal error, allowing
precise measurement of very small deflections.

- Leigh

opscimc · Dec 26, 2012

The real Leigh said:
, allowing precise measurement of very small deflections.

Right. But, small deflections of what?

The B&S 558 has one end slightly out of square, and lines of deviation marked every 0.0002", so holding my machinists square against it on my surface plate, and seeing no light, says my square is, well, square. It is designed for measuring small deviations/deflections, so my question is tasks for which that is useful. What tasks, other than the ones I mentioned, does one need to measure the kinds of small deflections this cylindrical square is designed to measure?

The real Leigh · Dec 26, 2012

This is easy to do and hard to describe.

If you measure the vertical distance from the surface plate to the various error lines, you'll see that they proceed in an even progression.
For example, if .0002" is 2" above the surface plate, then .0004" will be 4" up, .0006" will be 6" up, etc.

In use, you place the square very close to the item being measured (NOT in contact with it*), and rotate until you have a uniform sliver
of light across the entire length. Then measure the vertical distance from the plate to any calibration line.

The error is the calibrated value per measured distance, e.g. .0004" in 3.5" (= .0008" in 7", etc).
It is extrapolated to a standard distance like 6" algebraically: .0004"/3.5" = x/6", so x = .0004"*6"/3.5" = .0006857" per 6".
As a check, we'll evaluate the alternate error .0008" per 7": .0008"/7" = x/6", so x = .0008" * 6" / 7" = .0006857" per 6"

You can also express the angular error directly as arctan(error/distance) = arctan(.0004"/3.5") = .00636° = 22.9 arcseconds.

- Leigh

*NB: Never rotate the cylinder while it's in contact with the work, as that can abrade the cylinder's surface.
Also, always wear gloves while handling the square.

opscimc · Dec 26, 2012

The real Leigh said:
This is easy to do and hard to describe.

You misunderstand my question. I know how the circular square works, and am now looking for other applications of it.

Think of this as a question about applications of a hammer. Your response tells me how to hold the hammer, but my question isn't about that. It's about what things, other than hitting nails, might a hammer be good for. Assume I know very well how to hold the hammer, and how to pound nails with it, but I haven't thought of the idea that I could use a hammer to punch holes in drywall, open walnuts, pound a screwdriver between the slats of a wooden crate to help open it, etc.

I know how a circular square works to detect and quantify deviations from perpendicularity, and now am hoping to learn of applications beyond checking the perpendicular ways on my Talyrond, spindle on my mill, and machinists square.

kustomizingkid · Dec 26, 2012

Throwing at your boss when he expects you to hit a very unreasonable tolerance with a clapped out Bridgeport.

opscimc · Dec 26, 2012

kustomizingkid said:
Throwing at your boss when he expects you to hit a very unreasonable tolerance with a clapped out Bridgeport.

It's too heavy to throw, so I'd have to shot-put it at him. Unfortunately, that would make it way too easy to dodge.

PeteM · Dec 26, 2012

One use is to place it on top of various contracts, business plans, and the like -- let it sit for 24 hours, reflect, and then carefully observe. This way you'll know if you're getting a square deal or not.

opscimc · Dec 26, 2012

PeteM said:
One use is to place it on top of various contracts, business plans, and the like

Although it does address the question I asked, I'll file this with the "shot put" suggestion while awaiting other answers...

dandrummerman21 · Dec 27, 2012

I once was setting up a job on a Makino A88 horizontal, and needed to verify that the machine's X0 was indeed the center of rotation (as opposed to possibly being off after installation). We hadn't checked it when it was installed, because there was no reason to (never a need to work off of center of rotation).

Anyway, There was a job setup on the pallets in the machine. I couldn't take the pallets off of the table, as the machine still had plenty of work to do. One of the pallets had a top that was flat, so I threw the cylinder square on top of it, indicated it in so it didn't have any runout when rotating the pallet, and then probed it (the probe has always proven accurate to less than a thou in X). So I guess you could add that to your list. (The same basic thing could have been accomplished by some other object besides the cylinder square, though)

opscimc · Dec 27, 2012

dandrummerman21 said:
One of the pallets had a top that was flat, so I threw the cylinder square on top of it, indicated it ...

That's just the sort of example I was hoping for. Thanks.

daredo222 · Dec 27, 2012

opsimic,
For years I craved a cylindrical square, eventually made my own from a cylinder liner from a Volvo truck engine. Made dummy centres, ground it parallel to less than a tenth over it's approximate ten inch length, kissed the ends with the grinding wheel to be sure it was all square, checked it out all the ways I could, guess I used it twice in twenty years & let it go when I sold up.
Ray

easymike299 · Dec 27, 2012

Cylindrical squares come in different flavors. One has a large diameter base and a smaller diameter indicating surface. The base contains a magnet and can be used in the horizontal position to measure squareness of a vertical surface. It's used like this....

Gene

Mr Bridgeport · Dec 29, 2012

I use them to check tram on surface grinder spindles. Set it on the mag chuck and clamp a tenth test indicator to the spindle. Swing the indicator straight up and contact the side of the square. Rock table side to side to find the high point. Set indicator to zero. Now check at the bottom by carefully rotating the spindle. Tells you if the spindle is pointing up or down. With out disturbing anything, turn the indicator to the left side (turn spindle 90 degrees) and run table to the left to touch. Do the same on the right side. Tells you if the spindle is square to the travel to the table. Very important to have the spindle aligned for side and slot grinding. Harigs have set screws and other machines have there own adjustments, sometimes scraping is the only way to fix the alignment.
Bill

neanderthal mach · Dec 30, 2012

I've used one to check the knee movement on a vertical mill to see if it varied in both X and Y over it's travel. Depending on the exact condition and quality of your mill? You may want to wait and perform that test when your already in a crappy mood.

I bought a really nice condition late model B & S 558 last year the same as yours. They are very nicely designed and built.

Pete

The real Leigh · Dec 30, 2012

neanderthal mach said:
I've used one to check the knee movement on a vertical mill to see if it varied in both X and Y over it's travel.

That works fine as long as you lock the knee in each position before making the measurement.

- Leigh

neanderthal mach · Dec 30, 2012

Leigh,
Yeah I should have mentioned that detail I guess. But that "fine" term isn't a word I'd use along with what I found for results. :ack2:

Pete

The real Leigh · Dec 30, 2012

Yeah. Fine can apply to accuracy more often than to an assessment of the results.

- Leigh

RC99 · Jan 1, 2013

Depends on how much you value your cylindrical square I guess...

Ideally the good once are an inspection only tool...

But in the workshop for the cheapo or home made ones they can find other uses...

Here we have checking the squareness of a magnetic square level

I have also used this home made square (it is not perfect but pretty good) on the surface grinder clamping parts to it to grind them square...

The great thing about them is I find squareness is very very hard to create in the workshop without a good reference.... You can make a cylindrical square and ascertain it's squareness with basic equipment...

Glenn Wegman · Jan 1, 2013

You are comparing the V on one surface to the flat on the perpendicular surface. That doesn't indicate if the flat surfaces are perpendicular, or if the V surfaces are perpendicular.

Just an observation from the pic, which I may not be getting the whole story from.

It would also depend on the level of accuracy that you were trying to achieve.

What "unusual" uses are there for a cylindrical square?

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