All About Slide Rules Book (PDF)

[Derek W]

(04-16-2015 03:26 PM)MarkMason Wrote:  Derek,

Yes, I've found Sphere and have been considering the N500ES. Susan replied to my e-mail and she still has some of these left. How do you like yours? (and what rules have you compared it to?). How do you find the weight and size (height)?

I have my eye on their biggest, the N4ES, for the Log(Log(x)) implementation of the LL scales. Seems that all other Log Log rules are actually have Log Ln scales, i.e. Log(Ln(x)). But the N4ES is also quite tall and may not handle as well as a more typically sized rule. Dick Rose has these in stock at Rose Vintage Instruments, again the prices are a little more than flea market, but dealing with them is better than launching a campaign on TAS.

Thanks for the input.

Mark

Mark,

My apologies for a very delayed response - not enough quiet periods at work to have time to browse the Forum recently :-(

The N500ES is quite a compact size - 308mm long x 38mm wide (12 & 1/8" by 1 & 1/2") and not noticeably heavier than a similar size plastic rule. The slide and cursor move smoothly but somehow I find it a little harder to read than others - I'm not sure whether this is because the printed markings are less clear than engraved or whether it's just that the scales seem a little more crowded together, with 5 scales on the 14mm (9/16") wide slide. The scale layout seems a little unusual too, with LL1 and -LL1 on one side, and LL2/-2 and LL3/-3 at opposite edges of the other face. My others are all engraved plastic, from a variety of mostly European makers, mainly Thornton and Blundell Harling in the UK, and Aristo and Faber Castell in Germany.

I had never come across aluminium slide rules until recently, AFAIK they were unknown in the UK in the 1960s and 70s when I used them in earnest. So I am quite happy that I bought these for the variety they bring, even though one wouldn't be my first choice for ease of use.

During my first year of university (1971) I paid GBP5 for a top of the range Thornton P221 slide rule, compared with GBP30 a couple of years later for a CBM/Commodore 4-function calculator. Now slide rules are expensive collectors items while my local discount shop sells low quality (but functioning) scientific calculators for GBP1!

Derek