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HP Forum Archive 14

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HeavyCalc Upgrade (not HP)
Message #1 Posted by Norris on 23 Aug 2004, 5:33 p.m.

This posting does not relate to HP calculators, but I know that some people here also use Calculated Industries products, and they may find this of interest.

For some time I have been meaning to get a Calculated Industries "HeavyCalc", model 4315. This is a specialized construction calc designed for excavation problems. I finally ordered one online from the CI website last week, along with an "Armadillo" hard case.

Then I had a call from a CI rep. She told me that model 4315 had been discontinued, and that they would be sending a new upgraded "HeavyCalc", model 4320, instead. She also indicated that the new model had an integrated hard case, and that I didn't need the "Armadillo" case.

The 4320 came today. It seems to have the same functions as the old 4315, but the case is completely redesigned.

The 4320 has a hinged front cover that locks over the keyboard, but which can also swing completely behind the back of the calculator when it is open. The front cover has a "Quick Reference Guide" attached to a label on the inside.

There is also a locking cover on the back side of the calculator. The back cover conceals a small compartment which holds the manual and battery. The manual is 50 pages long and seems reasonably comprehensive; two editions are included, in English and Spanish. When both front and back covers are closed, the calculator fits comfortably in a shirt pocket.

Model 4320 must be brand new, because the CI website (as well as the catalog that came in the shipment) still show old model 4315. I don't know if other CI construction calculators will be getting this new case as well, but it wouldn't surprise me. Possibly the old-style CI construction calcs are about to become collector's items.

My overall impression is that CI put some real thought into the redesign of the "HeavyCalc", and that the new design is an unqualified improvement over its predecessor. I wish that I could say the same about my HP-33S.

Edited: 23 Aug 2004, 5:36 p.m.

Re: HeavyCalc Upgrade (not HP)
Message #2 Posted by Veli-Pekka Nousiainen on 24 Aug 2004, 2:30 a.m.,
in response to message #1 by Norris


Re: HeavyCalc Upgrade (not HP)
Message #3 Posted by John Cadick on 24 Aug 2004, 4:12 p.m.,
in response to message #1 by Norris


Calculated industries is at


Re: HeavyCalc Upgrade (not HP)
Message #4 Posted by GE (France) on 30 Aug 2004, 8:03 p.m.,
in response to message #3 by John Cadick

These calculators may be very helpful for professionals, but mathematically they are a sad joke. Apart from + - x / or their relatives (like inches conversions or F>C) you don't get much. I recall also that date calculations use 12 uniform 30-days months in the year, useless for financial decisions. Not to mention 'fraction' mode which just rounds with a fiwed denominator... you get the picture. Keyboard and case on the older generation was not brilliant either. Maybe others had another experience. On the other hand, I like the idea of locally produced, creative, original calculators. Thay should just buy some math library somewhere !

Re: HeavyCalc Upgrade (not HP)
Message #5 Posted by Vassilis Prevelakis on 31 Aug 2004, 2:05 a.m.,
in response to message #4 by GE (France)

GE (France) wrote:
> These calculators may be very helpful for professionals, but mathematically they are a sad joke. 

They are tools, not mathematical instruments. Nowadays these tools are the only things that keep new buildings in the US from falling down.

The Imperial system was the last act of sabotage against the US done by the British before they went home

This is what you get if you standardize on version 1.0 of any system. :-)


Re: HeavyCalc Upgrade (not HP)
Message #6 Posted by Norris on 31 Aug 2004, 1:52 p.m.,
in response to message #4 by GE (France)

I don't agree that the Calculated Industries models are "a sad joke". To take the specific examples you mentioned:

(1) The CI financial calculators apparently do use a 360-day year. But why is that "useless for financial decisions" ? It's a common approach in the US. In fact, the HP-12C by default calculates interest on a 360-day basis (you can get the 365-day result as well, but it takes extra keystrokes).

(2) The CI construction calculators do round fractions to a fixed denominator -- but you can select the desired level of accuracy. The default is 1/16 inch, but you can switch this to 1/2, 1/4, 1/8, 1/32, or 1/64 inch. Accuracy of 1/64 inch seems reasonable for practical construction purposes.

In fact, CI calcs offer some relatively advanced features, including:

(A) Feet-Inch-Fraction Mode. Suppose you have to divide 7 ft 3-1/4 in by 4. This is trivial on a CI (the answer, by the way, is 1 ft 9-13/16 in) but a hassle on a traditional calc. The optimal solution, of course, may be to abandon traditional English units for metric units, but that's not always a practical option in the US.

(B) Units Mode. Many calcs offer unit conversions, but these typically just multiply the displayed number by some constant. CI calcs actually attach units to numbers, which is a feature otherwise found only on advanced graphing calculators, like the HP48/49 series. The "HeavyCalc", for example, works with units of length, area, volume, and weight; e.g. "5 FEET" x "2 FEET" = "10 SQ FEET". Other CI models work with other types of units; e.g. the "ElectriCalc" works with volts, amps, ohms, etc.

Re: HeavyCalc Upgrade (not HP)
Message #7 Posted by GE (France) on 10 Sept 2004, 6:57 p.m.,
in response to message #6 by Norris

It is true that these machines are useful. What I meant is that they have no "advanced" function in the sense of anything beyond + - x /. So for any scientific use the function set is blatantly lacking. I have much respect for people who actually 'DO' things like building houses or curing other's diseases, as I am working in a very virtual world myself. But still, CI machines are not advanced *mathematically*.

Why does an imprecise count of days have an impact on financial decisions ? Let's take an example : $100 million borrowed at 3% between August, 26th and September, 4th. With the CI this is 8 days. In reality, it is 9 days. The difference in interest is about $8000. Is THAT negligible ?

Regarding the fixed denominator, I understand that in the real world this is no concern at all. However, for very small values he space between possible values (at least 1/64) can be not so negligible. Example : 0,1 is approximated with 6/64, which is 0,09375. This is 6% in error, no real world process should allow this.

It is a pity that they don't do something a little bit more scientific, it's so easy nowadays. Maybe in the future ?

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