Concise Ruler Circular Calculator Machine Tool 100867

I bought this slide rule as a backup to the Picket and Keuffel and Esser slide rules I bought on eBay (both like new condition). I thought this slide rule would be cheaply made but its not, its made of thick durable plastic. What surprised me is that the Picket slide rule was impossible to read even with my glasses on and the Keuffel and Esser is very hard to read as it has very find lines. So this Concise slide rule turned out to be very readable and so much easier to use. It would be nice if Concise could make a regular slide rule rather than just a circular one as it would be much better than the old kind which were made of metal and wood. Some other reviewers of this slide rule said that the numbers dont line up and showed pics to prove it. I didnt not have that problem with the slide rule I got. So hopefully that was a temporary defect that they found and corrected.

The 28N is handy because it fits in a shirt pocket. The C and D scales are great for conversions and great for travel calculations (it is basically e6b flight computer pilots are trained on) this does come with English instructions. I also use this in the kitchen for doing unit conversions and scaling servings in a recipe. For example the recipe is for two servings and I want nine. I dial it in and can look up how much of each ingredient to use as I’m cooking (instead of stopping to pound out each conversion manually on a calculator).The 270 is a great slide rule. Unlike the 28N this has a great quality tactile feel. The english manual can be downloaded from the Slide Rule Museum website are really good. They go over some nifty tricks including ways to solve various trig problems.The 300 is of the same quality as the 270 but also has LL2 and LL3 scales. Everything is aligned properly. This is now my favorite. The trig scales are read differently on the 300 than the 270 so that may be why some people think it’s off. I just saw a video on youtube show how to use the log log scales to calculate interest. It’s neat because you can just lookup when it will double or triples. You can put the number of times it compounds per year as well. It’s much easier than typing in the compounding formula on a scientific calculator and gives a ton of results with one setting. Of course you can use them for other power and exponent calculations as well.

The Concise 300 is a seriously capable 4" circular duplex slide rule. Scales on the front are K, A, D, C, CI, B, and L. On the reverse are LL1, LL2, LL3,D, C, S, T1, T2, and ST scales. Scales are engraved, clear and well aligned. The central slide rings on both sides move smoothly, as does the cursor.I have tested its most basic scales and found them quite accurate, well aligned and easy to read. I'm not yet familiar with all the scales on this model but have no reason to doubt they are equally well executed.The construction is sturdy and should be durable.My one complaint is the instructions are only in Japanese. I was able to download a set of instructions in English from a third party site. Failure to include them with the rule as shipped is a deficiency because the Concise circular rule operates differently from others like the older Picketts, and has different scales arrangements that require some significant changes in how the rule is manipulatedThe size of the 300 makes it too large for most shirt pockets. But, it will fit in most larger jacket or suit pockets.Aside from the issue with the instructions, the Concise 300 isa very satisfactory tool, easy to set and read with good precision, well made and darned convenient.

I was concerned that a slide rule on Amazon might be junk, but I was pleasantly surprised. Finding a new slide rule anywhere is difficult, and this seems worth the $35 I paid.The markings are crisp, and engraved into the plastic, not printed on top. The base is 1/8th inch thick, and doesn't flex under ordinary use. There are two separate sliding dials, one on each side, in the center section, held in place with spring washers. The cursor is substantial and accurate from side to side.The slide rule fits easily in a men's shirt pocket. In the case, barely.It comes in a vinyl case that feels like it will last. The case is about 4.75 in wide. The instructions provided are only in Japanese. From order to delivery in California took 7 days in May 2022.

Brings back my high school and early college days when I used slide rules a lot. Still have 5" and 10" log-log duplex decitrig and this has the same functions. I also have regular and small size circular slide rules, so this brings back fond memories.If you are a slide rule fan, this appears to be the only full featured one available.As I wrote in the title, there is no English manual but, because the slide rule itself is quite complete, I am not taking off any points.

It is a lot smaller than I anticipated. Good quality product but you're not going to get the accuracy you'd have with a standard linear slide rule.

The first two photos are my credentials as a Nerd. I won't explain anything about slide rules except they are analog computers dating back to the late 1700's. I have collected and restored over 120 slide rules, but this is only the 2nd circular rule I've bought.That's because they are expensive. I used slide rules until they went the way of the Dodo in 1975, with the birth of the hand held calculator. Those persons who used circular rules were 2nd tier nerds, laughed and ridiculed by us 'cool' nerds. That made circular rules rare by comparison.You can find dozens of slide rules in antique stores for under $30, but you seldom see a circular rule going for less than $75, and it's normally a piece of worn-out junk.This Concise circular rule has scales on both sides, has perfect alignment, and comes with a nice instruction manual (if you can read Japanese.) I believe it to be NOS since the market for these would be restricted to old nerds, and hardly worth the cost to manufacture.It's definitely worth the price I paid for it.

Exactly as described. Very well made. Thank you Concise for making a small sized circular rule, perfect!

Me gusta que no requiere baterías y los usos en cálculos solo muy amplios

Un rappel de mes années universitaires en génie.

Disappointed - it's a lot smaller than the screen image - less than 2/3 the size. I should have paid more attention to the size stated in the description.

Para los coleccionistas y amantes de reglas de calculo mas que recomendable, es un excelente articulo, entendible y facil de usar, aunque no se iguale a una calculadora sea cual sea, ayuda a enterder y analisar un poco mas las matematicas.