HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
<<  <  Page 2/2
Larry M
User Rank
Platinum
Re: A Litle Dab Will Do Ya
Larry M   10/10/2012 11:21:35 AM
NO RATINGS
> "A little dab'll do ya."

No it won't. Not unless you have a thorough understanding of the plastic involved. Nylon, for example, is formed of long, twisty molecules that intertwine with one another, resulting in a mostly-ridgid, somewhat flexible, self-lubricating solid. But if you use any lubricant, it allows the twisty molecules to disengage one another, resulting in a soft, mushy material unsuited for most uses.

Now, as I get it, this application doesn't use the commonly used shoulder bolt, a bolt with increased diameter for a region starting at the head and supporting the wheel, with a smaller diameter threaded region opposite the head. These bolts need only a nut as additional hardware, but obviously need the shoulder to be just a bit longer than the wheel's axle bore.

Instead, this application uses a bolt of constant diameter, with an added sleeve to perform the shoulder function. This situation gives an additional point of friction. Is the wheel rotating on a tightly-clamped sleeve (plastic on metal) or are the wheel and sleeve rotating on a tight bolt. This latter condition would result in a metal-on-metal contact which definitely should be lubricated.

My guess is that it's the former situation--the sleeve is tightly clamped when the bolt is sufficiently tight. There should be no noise from a plastic on metal contact. I wonder about end contact. No one has discussed the question of thrust. I'm wondering about either end of the wheel hub rubbing on the bolt head outboard or the mounting plate inboard. If there's a metal washer at either end, sticking to the wheel and rubbing against the underside of the bolt head or the mounting plates inboard, it certainly makes sense to lubricate these metat-to-metal contact surfaces.

 

 

 

sbkenn
User Rank
Gold
Re: Stainless
sbkenn   10/10/2012 10:26:50 AM
NO RATINGS
I bought a bunch of hydraulic type stainless fittings to go on a boat.  I asked if they were available in 316 grade.  The supplier said that they could get them marked as any grade, but reckoned that they were all the same.  Guess which country of origin !

Battar
User Rank
Platinum
Stainless
Battar   10/10/2012 9:19:01 AM
NO RATINGS
My guess - the designer specified stainless steel spacers, the manufacture didn't check the quality of the material  at incoming inspection.  The (won't mention country of origin) spacer manufacturer got paid for 18/8 stainless, supplied sub-standard parts, and kept the change. Our company has had a similar experience with a split-pin supplier.

Charles Murray
User Rank
Blogger
Re: A Litle Dab Will Do Ya
Charles Murray   10/9/2012 7:16:34 PM
NO RATINGS
I agree, Tekochip. At the very least, a note of explanation or direction would be appropriate. No one expects a brand new product to squeak.

Rob Spiegel
User Rank
Blogger
Re: A Litle Dab Will Do Ya
Rob Spiegel   10/9/2012 1:59:02 PM
NO RATINGS
Good point, Tekochip. However, if they decide not to include grease before shipping, it would make sense to be very clear to the buyers that this needs to be added before usage. Including a package with grease would help as well.

JimT@Future-Product-Innovations
User Rank
Blogger
Substitute Plastic discs-?
JimT@Future-Product-Innovations   10/9/2012 12:34:42 PM
NO RATINGS
From your description, the steel spacers sound like they were disc-like in appearance to provide a smooth plane for wheel rotation-? (to eliminate wheel wobble-?). If that's the case, I would have used polycarbonate (Lexan, or other PC) in the design. Much more water-friendly moving thru a wet lawn.

naperlou
User Rank
Blogger
Light rust often a problem
naperlou   10/9/2012 10:03:40 AM
NO RATINGS
Vern, while there should have been grease on the part, it may have just been left off of your unit.  Sometimes when you get into a new car the dealer will tell you that there may be coat of rust on the brakes, since they have not been used.  This is not a problem.  A few applications of the brakes and the rust is off.  Most uncoated metal parts will acquire some surface rust.  It would be interesting to know, from either the store or the manufacturer, if this was a problem others had reported. 

tekochip
User Rank
Platinum
A Litle Dab Will Do Ya
tekochip   10/9/2012 8:49:36 AM
NO RATINGS
It seems a shame that they couldn't include a little grease or at least a note to add some, since there may be hazardous shipment laws about including grease in the carton.

<<  <  Page 2/2


Partner Zone
Latest Analysis
Valentine’s Day seems like a good time to recognize those folks around us who have had a hand in our success.
Makers of industrial PCs are continuing to take advantage of Moore’s law expansion of processing power enabling creative automation and control schemes with multicore processors.
Researchers at Lawrence Livermore National Laboratory have published two physics-based models for the selective laser melting (SLM) metals additive manufacturing process, so engineers can understand how it works at the powder and scales, and develop better parts with less trial and error.
The designer can now analyze temperature distribution in a design, tracking input and output of heat loads, and also turn it into a thermal stress study.
The Internet happened.” Those three words spoken yesterday by Marc Ostertag, North America president of B&R Automation at Pacific Design & Manufacturing, now taking place in Anaheim through Feb. 11, continues to bring ever-lasting changes to our ways of life and will undoubtedly transform manufacturing.
More:Blogs|News
Design News Webinar Series
1/28/2016 11:00 a.m. California / 2:00 p.m. New York
12/8/2015 11:00 a.m. California / 2:00 p.m. New York
2/18/2016 11:00 AM PT | 2:00 PM ET
2/24/2016 11:00 AM PT | 2:00 PM ET
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Jan 11 - 15, Designing ARM Devices Using Segger Tools
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6 |  7 | 8 | 9


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2016 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service