How to unstick center disk of round slide rule?
in [Design]
|
From: YD on 21 Feb 2010 22:59 Late at night, by candle light, Joerg <invalid(a)invalid.invalid> penned this immortal opus: >Paul Hovnanian P.E. wrote: >> 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. > > >Thanks for the hint. I'll try, but first I'll ask a guy who seems to be >a slide rule enthusiast: > >http://public.beuth-hochschule.de/~hamann/ Place it between two glass plates, as heavy as available on top. Leave in the sun for a few hours, then take back in to cool off. Well, works for warped LPs. - YD. -- Remove HAT if replying by mail.
From: Phil Hobbs on 21 Feb 2010 22:57 On 2/21/2010 4:48 PM, Joerg wrote: > Phil Hobbs wrote: >> On 2/19/2010 9:31 PM, Joerg wrote: >>> Jim Thompson wrote: >>>> On Fri, 19 Feb 2010 17:46:11 -0800, Joerg <invalid(a)invalid.invalid> >>>> 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. >>>> >>>> Take it apart and carefully clean/de-grease. Then apply talc to the >>>> slides. Beware, it may be too late if it warped :-( >>>> >>> >>> Thanks, I didn't know you could just peel out the center wheel. Well, >>> it's buckled upwards in the very center and there are serious wear marks >>> underneath on the outer radius :-( >>> >>> Cleaned it real good, gave it a dose of talc but no dice. It does turn >>> ok with wet fingers but I guess spitting into one's hands wouldn't be >>> looked upon favorably in engineering. >>> >> >> Chalk dust tightens it--use graphite. >> > > My wife would read me the riot act if I came back from a biz trip and > there's faint black stains on all the shirts :-) > You don't need much, and besides, my fingernails are always that colour. (You think faint black stains cause annoyance--try faint lipstick stains.) ;) Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 email: hobbs at electrooptical dot net http://electrooptical.net
From: Michael A. Terrell on 21 Feb 2010 23:17 Phil Hobbs wrote: > > You don't need much, and besides, my fingernails are always that colour. > (You think faint black stains cause annoyance--try faint lipstick > stains.) ;) Yours, or someone else's? ;-) -- Greed is the root of all eBay.
From: JosephKK on 22 Feb 2010 02:38 On Fri, 19 Feb 2010 18:31:37 -0800, Joerg <invalid(a)invalid.invalid> wrote: >Jim Thompson wrote: >> On Fri, 19 Feb 2010 17:46:11 -0800, Joerg <invalid(a)invalid.invalid> >> 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. >> >> Take it apart and carefully clean/de-grease. Then apply talc to the >> slides. Beware, it may be too late if it warped :-( >> > >Thanks, I didn't know you could just peel out the center wheel. Well, >it's buckled upwards in the very center and there are serious wear marks >underneath on the outer radius :-( > >Cleaned it real good, gave it a dose of talc but no dice. It does turn >ok with wet fingers but I guess spitting into one's hands wouldn't be >looked upon favorably in engineering. You could try again with a BN lubricant, spendy but not black like graphite.
From: JosephKK on 22 Feb 2010 02:46
On Fri, 19 Feb 2010 18:51:53 -0800, Joerg <invalid(a)invalid.invalid> wrote: >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. Photos, Photos, Photos. Oh and some dimensional measurements might be nice. |