Ok, the shaft of a Hamilton Beach blender seized. No more margarita :-( Mfg said too bad, it's just out of warranty. Bought another one, of course from a different brand. Margaritas are back :-)
Took the old one apart and couldn't believe it: It looks like they chrome-plated the brass shaft, chrome flaked off in some areas and then it seized. Has anyone seen that? Is chrome-plating a shaft that becomes part of a fast-spinning bearing kosher? In the ME classes that I (clandestinely) attended back at the university that "technology" certainly was not taught.
Joerg wrote: > Ok, the shaft of a Hamilton Beach blender seized. No more margarita :-( > Mfg said too bad, it's just out of warranty. Bought another one, of > course from a different brand. Margaritas are back :-)
> Took the old one apart and couldn't believe it: It looks like they > chrome-plated the brass shaft, chrome flaked off in some areas and then > it seized. Has anyone seen that? Is chrome-plating a shaft that becomes > part of a fast-spinning bearing kosher? In the ME classes that I > (clandestinely) attended back at the university that "technology" > certainly was not taught.
Hard-chroming various parts to make bearings is not uncommon. Hard-chroming bearing journals on crank shafts is fairly common, either to bring the journal up to size to match the bearing, or on a new part for friction and wear control. Chrome has a very low surface energy (think of it as metallic Teflon), and hard chrome can be very durable.
But getting chrome plating right requires that you get _all_ your ducks in a row. Chances are they had a bad day in the plating shop, or they sought to trim some cost out of that process in the plating shop.
Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" gives you just what it says. See details at http://www.wescottdesign.com/actfes/actfes.html
On Sat, 19 Jul 2008 14:16:52 -0700, in sci.electronics.design Joerg
<notthisjoerg...@removethispacbell.net> wrote: >Ok, the shaft of a Hamilton Beach blender seized. No more margarita :-( >Mfg said too bad, it's just out of warranty. Bought another one, of >course from a different brand. Margaritas are back :-)
>Took the old one apart and couldn't believe it: It looks like they >chrome-plated the brass shaft, chrome flaked off in some areas and then >it seized. Has anyone seen that? Is chrome-plating a shaft that becomes >part of a fast-spinning bearing kosher? In the ME classes that I >(clandestinely) attended back at the university that "technology" >certainly was not taught.
Tim Wescott wrote: > Joerg wrote: >> Ok, the shaft of a Hamilton Beach blender seized. No more margarita >> :-( Mfg said too bad, it's just out of warranty. Bought another one, >> of course from a different brand. Margaritas are back :-)
>> Took the old one apart and couldn't believe it: It looks like they >> chrome-plated the brass shaft, chrome flaked off in some areas and >> then it seized. Has anyone seen that? Is chrome-plating a shaft that >> becomes part of a fast-spinning bearing kosher? In the ME classes that >> I (clandestinely) attended back at the university that "technology" >> certainly was not taught.
> Hard-chroming various parts to make bearings is not uncommon. > Hard-chroming bearing journals on crank shafts is fairly common, either > to bring the journal up to size to match the bearing, or on a new part > for friction and wear control. Chrome has a very low surface energy > (think of it as metallic Teflon), and hard chrome can be very durable.
> But getting chrome plating right requires that you get _all_ your ducks > in a row. Chances are they had a bad day in the plating shop, or they > sought to trim some cost out of that process in the plating shop.
Interesting, didn't know they used chroming. So I guess we'll just chuck the whole thing then.
Martin Griffith wrote: > On Sat, 19 Jul 2008 14:16:52 -0700, in sci.electronics.design Joerg > <notthisjoerg...@removethispacbell.net> wrote:
>> Ok, the shaft of a Hamilton Beach blender seized. No more margarita :-( >> Mfg said too bad, it's just out of warranty. Bought another one, of >> course from a different brand. Margaritas are back :-)
>> Took the old one apart and couldn't believe it: It looks like they >> chrome-plated the brass shaft, chrome flaked off in some areas and then >> it seized. Has anyone seen that? Is chrome-plating a shaft that becomes >> part of a fast-spinning bearing kosher? In the ME classes that I >> (clandestinely) attended back at the university that "technology" >> certainly was not taught.
Joerg wrote: > Martin Griffith wrote: >> On Sat, 19 Jul 2008 14:16:52 -0700, in sci.electronics.design Joerg >> <notthisjoerg...@removethispacbell.net> wrote:
>>> Ok, the shaft of a Hamilton Beach blender seized. No more margarita >>> :-( Mfg said too bad, it's just out of warranty. Bought another one, >>> of course from a different brand. Margaritas are back :-)
>>> Took the old one apart and couldn't believe it: It looks like they >>> chrome-plated the brass shaft, chrome flaked off in some areas and >>> then it seized. Has anyone seen that? Is chrome-plating a shaft that >>> becomes part of a fast-spinning bearing kosher? In the ME classes >>> that I (clandestinely) attended back at the university that >>> "technology" certainly was not taught.
Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" gives you just what it says. See details at http://www.wescottdesign.com/actfes/actfes.html
> > Hard-chroming various parts to make bearings is not uncommon.
> I though hard-chroming was a different process to the shiny chrome seen > on motor cars etc. Sounds like the latter was what Joerg had. > Alan
It is a different process but I think it's just in the details. I don't know how different the end product looks, although chromed car parts are shiny because they've been carefully polished -- unpolished chrome isn't much to write home about.
Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" gives you just what it says. See details at http://www.wescottdesign.com/actfes/actfes.html
<notthisjoerg...@removethispacbell.net> wrote: >Ok, the shaft of a Hamilton Beach blender seized. No more margarita :-( >Mfg said too bad, it's just out of warranty. Bought another one, of >course from a different brand. Margaritas are back :-)
>Took the old one apart and couldn't believe it: It looks like they >chrome-plated the brass shaft, chrome flaked off in some areas and then >it seized. Has anyone seen that? Is chrome-plating a shaft that becomes >part of a fast-spinning bearing kosher? In the ME classes that I >(clandestinely) attended back at the university that "technology" >certainly was not taught.
After 9.5 years designing marine radios, I learned a few things about corrosion and material science.
I'll assume that the brass base metal was visibly corroded. Thin chrome plating tends to be porous and full of cracks. Acids get into the cracks and corrodes the base metal. The usual fix is a thin nickel plating, and then a hard chrome layer over that. Another way is hard chrome with more than about 50 microns plating thickness, which is usually (no guarantee) thick enough to not have the cracks go all the way down to the base metal.
My guess(tm) is that you won't find any nickel plating and that the chrome is the comparatively thin "decorative chrome" or more accurately "thin dense chrome". The thin stuff runs about 5 microns plating and will rot out fairly quickly. However, it has the huge advantage of not requiring the secondary finishing of nickel plus hard chrome.
If you're seeing large flakes of chrome plating, then it was probably just a lousy plating job. You may also have an overheating problem, where the differences in coefficients of thermal expansion between the brass and chromium plating, is sufficiently different to cause the rather brittle chrome to break off. Digging.... <http://www.engineeringtoolbox.com/thermal-expansion-metals-d_859.html> brass = 11.2, chromium = 3.3 Yeah, it's possible.
You can aggravate the problem by mixing highly acidic foods in the blender. These will cause the cracks to enlarge which will eventually hit base metal. I suggest you abandon the kitchen chemistry experiments and use a proper chemistry mixer, vortex mixer, magnetic stirring suppository, or vibro shake rattle and roll table.
I'm rather surprised that Hamilton Beach chrome plated the brass shaft. Nickel plating would have been more acid resistant, generally better and more durable (but more expensive).
I dunno if chrome plating the shaft is a good idea. The stresses are substantial and the brittle chrome plating is almost guaranteed to flake off. I find it interesting that they apparently did not protect the bearings or bushings from external crud. If they had a proper bearing seal, it could have survived the chrome flake problem without seizing.
On Jul 19, 4:16 pm, Joerg <notthisjoerg...@removethispacbell.net> wrote:
Solution - "on the rocks". ...or straight from the bottle. :)
On an absolute impulse buy, I recently purchased one of these "Magic Bullet" things. See: www.buythebullet.com
When, as often occurs here, folks each want a different twist on their poison, something like this really comes in handy. I just hope it holds up in the long run, as it actually is a pretty cool product. IMO.
> Joerg wrote: > > Ok, the shaft of a Hamilton Beach blender seized. No more margarita :-( > > Mfg said too bad, it's just out of warranty. Bought another one, of > > course from a different brand. Margaritas are back :-)
> > Took the old one apart and couldn't believe it: It looks like they > > chrome-plated the brass shaft, chrome flaked off in some areas and then > > it seized. Has anyone seen that? Is chrome-plating a shaft that becomes > > part of a fast-spinning bearing kosher? In the ME classes that I > > (clandestinely) attended back at the university that "technology" > > certainly was not taught.
> Hard-chroming various parts to make bearings is not uncommon. > Hard-chroming bearing journals on crank shafts is fairly common, either > to bring the journal up to size to match the bearing, or on a new part > for friction and wear control. Chrome has a very low surface energy > (think of it as metallic Teflon), and hard chrome can be very durable.
> But getting chrome plating right requires that you get _all_ your ducks > in a row. Chances are they had a bad day in the plating shop, or they > sought to trim some cost out of that process in the plating shop.
It sounds to me like they got it exactly right. It lasted just a little longer than the warranty.
BTW: Just because you think you just bought a different brand doesn't mean you really did.
