How to unstick center disk of round slide rule?
in [Design]
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From: Paul Hovnanian P.E. on 19 Feb 2010 21:05 Joerg wrote: > > Gents, > > My round slide rule is developing a sticky center wheel. I can still > move it but afraid my thumbs will rub off the lettering over time. It's > this model: > > http://sliderulemuseum.com/SIC/C35_SIC_SINCO_250_1962.jpg > > Obviously the old "rub with a bar of soap" trick like on the linear ones > doesn't work here. I also haven't tried any semi-destructive methods to > pull it off. Any safe tricks to unstick it? I can't tell from the photos. Does this have a single center wheel or does the disc with the C scale ride on top of the one with the D scale (the T scale wheel on the other side would be a separate smaller disc). If the single center wheel rides inside the outer wheel, can you tell how the two are kept flat w.r.t. each other? If this was a straight slide rule, it would be a tongue and groove, but I don't see how one could assemble (let alone take apart) such a circular device. Looking at the trig side, I see what appears to be the end of what could be a screw in the hub. There's a possibility that one could grab each hub and unscrew them, allowing you to remove the cursor. In fact, each side of the cursor is attached to its hub and by unscrewing the spacer at the end, the center axle may be loose enough to unscrew by manipulating the cusrsors (gently). But from there, it depends on how the center and outer wheels are configured. -- Paul Hovnanian mailto:Paul(a)Hovnanian.com ------------------------------------------------------------------ I have a very firm grasp on reality. I can reach out and strangle it any time!
From: Joerg on 19 Feb 2010 21:51 Paul Hovnanian P.E. wrote: > Joerg wrote: >> Gents, >> >> My round slide rule is developing a sticky center wheel. I can still >> move it but afraid my thumbs will rub off the lettering over time. It's >> this model: >> >> http://sliderulemuseum.com/SIC/C35_SIC_SINCO_250_1962.jpg >> >> Obviously the old "rub with a bar of soap" trick like on the linear ones >> doesn't work here. I also haven't tried any semi-destructive methods to >> pull it off. Any safe tricks to unstick it? > > I can't tell from the photos. Does this have a single center wheel or > does the disc with the C scale ride on top of the one with the D scale > (the T scale wheel on the other side would be a separate smaller disc). > > If the single center wheel rides inside the outer wheel, can you tell > how the two are kept flat w.r.t. each other? If this was a straight > slide rule, it would be a tongue and groove, but I don't see how one > could assemble (let alone take apart) such a circular device. > > Looking at the trig side, I see what appears to be the end of what could > be a screw in the hub. There's a possibility that one could grab each > hub and unscrew them, allowing you to remove the cursor. In fact, each > side of the cursor is attached to its hub and by unscrewing the spacer > at the end, the center axle may be loose enough to unscrew by > manipulating the cusrsors (gently). But from there, it depends on how > the center and outer wheels are configured. > The center wheel is like an inlay but after Jim's hint I was able to gently pry it out. However, the thing looks a bit damaged inside, circular grinding marks, maybe from too much use or because the center has bulged up from the summer heat out here. Possibly the HP11C will outlive it. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Paul Hovnanian P.E. on 19 Feb 2010 21:25 Joerg wrote: > > Dave M wrote: > > Joerg wrote: > >> Gents, > >> > >> My round slide rule is developing a sticky center wheel. I can still > >> move it but afraid my thumbs will rub off the lettering over time. > >> It's this model: > >> > >> http://sliderulemuseum.com/SIC/C35_SIC_SINCO_250_1962.jpg > >> > >> Obviously the old "rub with a bar of soap" trick like on the linear > >> ones doesn't work here. I also haven't tried any semi-destructive > >> methods to pull it off. Any safe tricks to unstick it? > >> > >> I usually use the linear one but on the road this slide rule is nice > >> because it fits into the shirt pocket. > > > > > > If your slide rule has plastic-on-plastic ot plastic-on-metal, talcum powder > > should work. Disassemble to the point where the center can be cleaned with > > water/detergent solution, then dry completely and lube with dry talcum > > powder. > > > > Done, but as Jim hinted, if it's buckled it's too late. And mine is :-( Don't try this until your only alternative is to throw it out. I have a 'Dead Reckoning Computer', a pilot's circular slide rule with a rectangular plastic panel that slides back and forth through the center. The slide had become so warped that its previous owner broke it in half trying to pull it through the body*. I extracted both pieces and expoxied them back together. Then, I placed the slide between a couple of hand towels and applied a warm iron to soften the plastic. one it softened (I gradually increased the iron's heat), I placed it between two heavy books (thanks Winfield for the AofE) until it cooled and remained flat. *I hope this didn't happen to the pilot during flight. There were some notes mentioning "Howland Island" that came with it, so I hope they made it OK. -- Paul Hovnanian mailto:Paul(a)Hovnanian.com ------------------------------------------------------------------ Dedicated to the unrestricted propagation of worthless information across the Internet.
From: Martin Riddle on 19 Feb 2010 22:34 "Joerg" <invalid(a)invalid.invalid> wrote in message news:7u90fsFrohU4(a)mid.individual.net... > Dave M wrote: >> Joerg wrote: >>> Gents, >>> >>> My round slide rule is developing a sticky center wheel. I can still >>> move it but afraid my thumbs will rub off the lettering over time. >>> It's this model: >>> >>> http://sliderulemuseum.com/SIC/C35_SIC_SINCO_250_1962.jpg >>> >>> Obviously the old "rub with a bar of soap" trick like on the linear >>> ones doesn't work here. I also haven't tried any semi-destructive >>> methods to pull it off. Any safe tricks to unstick it? >>> >>> I usually use the linear one but on the road this slide rule is nice >>> because it fits into the shirt pocket. >> >> >> If your slide rule has plastic-on-plastic ot plastic-on-metal, talcum >> powder should work. Disassemble to the point where the center can >> be cleaned with water/detergent solution, then dry completely and >> lube with dry talcum powder. >> > > Done, but as Jim hinted, if it's buckled it's too late. And mine is > :-( > > So, scrape marks in the aluminum and the plastic wheel. Maybe if I > could find really thin Teflon I can get some more life out of it. They > don't make'em no more. Maybe not the SIC but... Concise still does <http://www.concise.co.jp/eng0731/slide.html> Cheers
From: life imitates life on 20 Feb 2010 01:08
On Fri, 19 Feb 2010 20:21:09 -0600, "Dave M" <dgminala4444(a)mediacombb.net> wrote: >Joerg wrote: >> Gents, >> >> My round slide rule is developing a sticky center wheel. I can still >> move it but afraid my thumbs will rub off the lettering over time. >> It's this model: >> >> http://sliderulemuseum.com/SIC/C35_SIC_SINCO_250_1962.jpg >> >> Obviously the old "rub with a bar of soap" trick like on the linear >> ones doesn't work here. I also haven't tried any semi-destructive >> methods to pull it off. Any safe tricks to unstick it? >> >> I usually use the linear one but on the road this slide rule is nice >> because it fits into the shirt pocket. > > >If your slide rule has plastic-on-plastic ot plastic-on-metal, talcum powder >should work. Disassemble to the point where the center can be cleaned with >water/detergent solution, then dry completely and lube with dry talcum >powder. To keep the writing from coming off, cover it with a thin layer of fingernail polish (carefully), like cloisonne. |