I just aquired a k&e at goodwill for couple$,had no idea what it was just knew I needed it😀 planning on using it to take over world

I used my Castell rules, a 62/82 and a longer one with no number for the state school leaving exams back in 1968. Everybody was using log tables and nobody knew what I was doing. No hyperbolic scales, just trig on both and exponential scales on the shorter one. They still work smoothly after more than a half-century!

Excellent comparison. I own both the Deci-Lon and the Versalog II and agree that certain functions are simpler with each. However, I feel that the addition of the B scale on the Deci-Lon allows for more intuitive division (since the denominator on B appears below the numerator on A), since using the C and D scales for division requires inverting the ratio. This is of course a minor advantage, but I think it is significant. I agree that the radically different construction and styling is really "apples and oranges" here. The Versalog II is truly a handmade work of art; its engraved-celluloid-over-bamboo is stunning. However, the plastic molded Deci-Lon has a more rough-and-tumble aspect to its construction; it doesn't fear water (or soap) and it doesn't develop a static charge on the surface (sadly, the Versalog is a sort of magnet for dust, hair, and lint). The Deci-Lon also doesn't care about temperature extremes, although it should be said that the Versalog is much less sensitive to these changes than the other mahogany rules by K&E and others... but the Deci-Lon is my constant companion in winter cold as well as summer heat. Both rule and case are lighter, as well, so there is that. I don't worry about dropping the Deci-Lon as much, either-- I've already had to repair its cursor with superglue twice, and it was an easy fix. So I think they are comparable. I would say that the sliding movement on the Versalog is smoother due to the oils (still present in the wood after almost fifty years!) and that it seems built to a higher degree of accuracy due to its cursor construction (the Deci-Lon cursor line is more easily capable of lateral movement and therefore alignment can be an issue). So if I wanted a rule on my desk for indoor work, I would pick the Versalog-- it's everything a classic, wood-glass-and-metal traditional slide rule could hope to be. But the space-age ruggedness of the Deci-Lon edges it out for all-weather, anytime-anywhere calculation, and if I could only choose one, its unique asymmetry takes pride of place. Although the Deci-Lon represents the final production model of American slide rule design, there appears to have been a rule on the drawing board to upgrade/replace it in the K&E lineup. Dubbed the "KE-Lon", this proposed rule incorporated the "all eight log-log scales on one side" design prevalent in European rule designs like the Faber Castell 2/83N and the Aristo Hyperlog. Sadly, it was never produced by K&E due to the swift rise of the electronic calculator. I would also recommend checking out Zvi Doron's Ultralog design, which some slide rule aficionados hope to see one day realized, although it's admittedly unwieldy due to its over-the-top inclusiveness. kzread.info/dash/bejne/gH6O0NlrZ7mwZtY.html Thank you, Professor, for taking the time to compare and contrast these final giants of the North American slide rule market. It's really almost a "King Kong vs. Godzilla" debate.

The Versa log has clearer scales . They are darker and easier to distinguish.I prefer the Versalog .

This video brings up an interesting side topic. I'd be interested to see your discussion of hyperbolic functions on rules that don't have hyperbolic scales. The K&E 4083 and Pickett Model 4 have them, but these are the exceptions. You don't really see Sh or Th scales, but you never know when you're going to need to compute the curve of a suspended rope, or compute velocity change using special relativity...

@ProfessorHerning

6 жыл бұрын

Gary, I was just thinking of doing a video like this.

I managed to snag a Pocket DeciLon for about $80 with shipping a month or so ago. It was MARKED as a 68 1100 in the listing on eBay, though the pictures were all of a 68 1130. Also, it didn't have the original case, but a nice quilted fabric case the owner had clearly made for it. If I have the opportunity to get a proper case I will, but I managed to get it for $90-120 LESS than most go for. I took heavy advantage of the mismarking and snagged it with the "Buy It Now" option. I'd been looking for a pocket DeciLon for a long time, but they all were going for between $160-$220, and even those were rare. It's one of my favorite rules, along with my "Kip Russell" K&E 4081-5 20" Log-log Duplex Decitrig, straight out of Robt. Heinlein's "Have Spacesuit, Will Travel", and my Faber-Castell 2/83N Novo Duplex.

@ProfessorHerning

6 жыл бұрын

I'm still looking for a deal on a pocket Deci-Lon. I must admit I think they are a bit funny looking with their extreme width-to-length ratio.

@JennyEverywhere

6 жыл бұрын

I find the stubby shape oddly pleasing. It's not just useful, it's CUTE. I liked this video. I hadn't started collecting any of the Versalogs. I only have a couple of Hemmi-based rules, notably one of the "Made in Occupied Japan" models, a Sun Hemmi 1447 in exceptionally good condition.

I have both a Versalog and a Deci-Lon. My Versalog is from the early 70s and has a plastic case. The Deci-Lon has the leather case. My personal preference is for the K&E.

Regarding 17:00 Deci-Lon slide rule angular end pieces design aesthetic. The Keuffel & Esser Deci-Lon slide rule was introduced in 1962 which was during the era of the Jet Age. At that time trendy car designs included tail fins whose shapes were reminiscent of Deci-Lon angular end pieces. However ten years later by 1972 car tail fins had become passé which happened to coincide with the decline of slide rules.

I own both a Deci-Lon and a Versalog I. I definitely prefer the Deci-Lon because of the A B scales. It just make things easier to be able to do square roots on the fly. My 2¢.

@ProfessorHerning

6 жыл бұрын

I'm not a big user of DI, so I agree this is probably the main advantage of the Deci-Lon.

I gotta say that before I ever picked up my first slide rule, I read a million reviews and articles singing the praises of the Faber-Castell 2/83N as the best slide rule ever made, so that was the first one I bought. But now that I have these two and have worked with all of them for quite a while, there just isn't any comparison as far as I'm concerned. The plastic 2/83N feels so cheap and tawdry compared to these wooden ones. The colors are cool and all but meh, not THAT cool. Also, although mine looks great now, you can tell from ebay pics that the ink used for the Faber-Castell scales bleeds and leeches into the surrounding areas on them after a while, so who knows how long mine will stay looking like this. Meh. As long as I have a versalog and a k+e, I'm happy.

Marvelous video! Brought back some memories from the 50's & 60's. Thanks! There are several gauge marks on the K&E's C & D scales you didn't touch on. There are marks for converting between º, ', and " on the one hand, and radians on the other. (5.73, 2.91, 4.85). And 2π is also there, as I think you did point out. But what's that mark at 7.85? Fred PS: Also worth a mention: K&E stands for Keuffel and Esser (German immigrants to US)

@ProfessorHerning

6 жыл бұрын

I think that's pi/4.

@ffggddss

6 жыл бұрын

Yes, that's got to be right: 0.7854... Thanks! That clears it up. Fred

i have a question i do machine shop work as a hobby and i use vintage machines from the early 1900 . so i would be doing a lot of sine calculations to set up a sine bar but one think i would like to do is use the slide rule to figure out pulley sizes if my main line shaft is running at X i can use several different combinations of pulleys to get to y and iv herd this is a good problem on the slide becauls the ration would be the same and you can see the other possible pulley sizes on the rule with no adjustment . in not sure how to perform this and what scales would i need to do this?

@ProfessorHerning

6 жыл бұрын

I don't know much about machine shop work, but using vintage machines sounds like a cool hobby! I would guess that whether or not a slide rule makes sense depends on the accuracy and precision you need in your calculations. Most slide rules can be read to around 1 part in 100 or 200 on the main scales. With estimation, you can do a little better (many people claim 1 in 1000, but it depends on how well made your rule is, the condition, and your estimation skill). For the pulleys, you may just need the main logarithmic scales (C and D). When you move the slide, the ratio you see between any two numbers aligned on the two scales is constant. If you use CI and D then the product is constant. This might be all you need for that, but I don't know your exact calculation. The folded scales (CF, CIF, DF) are often added because of the off-scale problem when doing a calculation like this. You might set a ratio then want to move your cursor to something on C, but it is on the part of the rule that is sticking out. If you have CF/DF you can simply find the number on CF instead. I'm going to take a guess at your calculation: Let's say you have two pulleys connected by a chain/band. You want to triple the rotational speed of the input, so you want the ratio of the input to output pulley radius to be 3 (diameter or circumference could also be used). You would pull the slide so that the 3 on C is over the 1 at the left end of D. Now any number on C is three times the aligned number on D. By moving the cursor you can see different combinations of sizes that have ratio 3 (e.g. 3/1, 40/13.3, 75/25). If your rule has folded scales, then all possibilities are now showing either on C/D or CF/DF. Without folded scales you can see the other possibilities, but you either have to move the slide (so the 3 on C is over the 1 on the *right* end of D) or sacrifice some precision and use A/B instead.

@ProfessorHerning

6 жыл бұрын

To see if the slide rule might work for your sine calculations, have a look at one of my trigonometry videos like this one: kzread.info/dash/bejne/fodqqZZyccy-gto.html. There is a lot of variety in trigonometric scales, especially on beginner slide rules. For example, on many similar looking ubiquitous models, the S scale is used with A instead of D. This has less precision but has the advantage that the scale covers a larger range of angles (down to about 0.57 degrees). On many rules, the trigonometric scales divide degrees into minutes and seconds. The rule I'm using in the link has what's usually referred-to as "decimal trig." In any case, with some practice it's very easy to solve right triangles with a slide rule. I think for your application it would be a question of necessary accuracy.

@ProfessorHerning

6 жыл бұрын

I read a little about sine bars, and I guess the calculations would be pretty easy on a slide rule. If you had an S scale that was used with D (as in the video), you'd set the end of the S scale over the bar length on D by moving the slide, then if you move the cursor to an angle on S, you'd see the height you need on the gauge bar side on D. Conversely, if you moved the cursor to the gauge bar height on D, you'd see the angle on S.

@OldIronShops

6 жыл бұрын

that does sound simple a visual demo would help greatly

@OldIronShops

6 жыл бұрын

that level of accuracy is probably fine 1/2 a degree would be working to a very fine measurement and the sine bar starts to lose accuracy after 45 degrees i have a channel if your interested in checking it out. i do all sorts of things related to metal shop i also do a fair amount of foundry pattern making.

My initial reaction was that this was an unfair comparison, as the Decilon had more scales. Instead, it should be compared to a slide rule in its own class, such as some from Aristo or Pickett. Of course, the Versalog has the advantage of being made with bamboo.

I have a Deci-lon with the colored ends on the slide, serial number 171138. Any idea what year?

@ProfessorHerning

5 жыл бұрын

Looks like about 1970, judging by this: www.oughtred.org/jos/KE_Dating_ByHughesAndMcCoy-JOSPlusOnlyVersion_RevA.pdf

@michaelnicholas9086

5 жыл бұрын

Thanks. Somewhere in this video I thought you mentioned the year they stopped doing those colored ends on the slide and I thought that was before 1970, non?

@ProfessorHerning

5 жыл бұрын

If you look through McCoy's K&E Catalogs, I think it stops showing the colored ends around 1972. I forget if I mentioned it in the video, but I've heard it was because the mold was damaged -- the easiest solution was just to fill it in.

@ProfessorHerning

5 жыл бұрын

Just checking again. He doesn't seem to have a catalog between 67 and 72, so it's somewhere in there that the change happens.

@ProfessorHerning

5 жыл бұрын

They are fairly rare to see for sale, so that to me points to only very late production.

How about comparing to the larger Picketts, say N-3-es? Seems like they, and the Deci-lon are more of "smorgasbord" versions (e.g. KAB + sqrt & cube rt, yikes) while the classic Post is a better match to the older K+E models. Easy to like the bamboo & mahogany ones, but on some of the "big" rules there are hyperbolics & common logs: why? Does that represent a personal choice, a real evolutionary advantage, or just a frantic (dare I say hyperbolic?) overabundance of features?

@ProfessorHerning

6 жыл бұрын

Decilon vs Versalog was one of my most requested videos -- I think for a lot of people, the decision came down to one of these two which represent the top of the line general purpose rules from these two manufactures. I recently found an N4 and plan a video on that soon. Really, the comparable Pickett rule for this comparison is probably the N803. I think of the large rules with both eight log-log scales and hyperbolic scales as sort-of a separate class ("kitchen sink" rules). For my taste, those rules are a little much.

@ProfessorHerning

6 жыл бұрын

My theory with the large rules is that there was a little bit of a scale arms-race near the end of the era. None of the scales are really new or innovative, but manufacturers just kept squeezing them on to attract buyers who wanted "everything" on one rule.

@ProfessorHerning

6 жыл бұрын

Since you mention the N3, it's an cool rule although I don't have one. I'm curious as to why Pickett switched to base-e log log scales from the base-10 ones on the Model 3. My guess is that it was to lure buyers from the Decilon/Versalog, but as a consequence it makes the N4 a more interesting rule.

@MarkKrebs

6 жыл бұрын

Professor Herning Comparing n3 and others such as Versalog to the N4, I do end up liking it (n4) because of common logs (useful for dB and easy to calculate with) while ln is still available on CF/m. Also it's kinda cool the way Pickett shares the LL scales with their reciprocals. I can't love sinh though it's fun to say "shine" because I've never used it for real. My imaginary superrule would start with an n4, but remove hyperbolics in favor of M/CF (cool, eh?!) and K (the cube scale is too much effort in an era where I will cheat back to my phone if I really need a cube root. The slide rule meanwhile is for "wetwork" so fluidity matters. :) I look forward to your next talk & wonder especially how you value log vs ln on the LL scales?

@ProfessorHerning

6 жыл бұрын

Mark, I just posted a video on the N4. I'd have to say I prefer normal LL scales because of the reason mentioned in the video: you can fall off the end onto D. It's easy enough to use L for base 10 logs and the mantissa resolution is constant unlike when you use LL. If you want a quick base 10 log on normal LLs just set the index of C over the 10 on LL, move the cursor to the input on LL and read the log on C. Pickett's solution is definitely a tad faster, but you end up having to add DF/M. I guess I prefer the elegance of the normal solution.

I've been trying to by an excellent condition 20 inch slide rule for several years, and it's proveing nearly impossible! Almost none offered for sale. Those offered are in nasty to useless condition! And folks want way too much cash for an unusable instrument!

@ProfessorHerning

5 жыл бұрын

These were produced in such small numbers that they're very hard to find in good condition. I'd assume it's also extra difficult to keep the long wood or bamboo straight over the years. I don't have any 20" rule, and the only longer rule I have is the K+E 4110 Power Trig I made a video about a while back.

I still have my Post Versalog, in its leather holster. I like it better than the K+E; it's just more satisfying to use.