Hi Tyson Tubing, square or otherwise, has much higher torsional stiffness for a given weight than I bar or channel.
Cold rolled or drawn materials are usually very accurate and clean, but have large residual hoop stresses due to the forming process. Hot formed structural shapes have much lower stresses due to the high forming temperatures, but usually have a heavy mill scale from oxidation. This can be easily removed with hydrochloric acid. I use hot formed ASTM A 513 welded flash in low carbon tubing and ASTM A36 hot rolled solids for minimum deflection during machining or welding. The 513 has some residual hoop stress but the effects are minimal with 2 force menbers. Les Leslie M.Watts L M Watts Furniture Tiger Georgia Main page: http://www.lmwatts.com Engineering: http://www.lmwatts.com/shop.html Cnc surplus for sale: http://www.lmwatts.com/forsale.html Carved signs: http://www.lmwatts.com/signwp.html -----Original Message----- From: Tyson S. [mailto:[EMAIL PROTECTED] Sent: Monday, October 25, 2004 8:42 PM To: [EMAIL PROTECTED] Subject: RE: [CAD_CAM_EDM_DRO] Re: sourcing motion control parts - steel vs aluminum So does anyone know of a type of steel that can be purchased that is straight and clean. I know cold roll flat bar is really good stuff, but what about square tube? --- Leslie Watts <[EMAIL PROTECTED]> wrote: > > Hi Hal > > I won't quarrel with your figures...they seem about right. > > The issue is the definition of specific stiffness... > > Steel has about three times the modulus of aluminum, but it is also > three > times the density! > > Specific stiffness is the ratio of those two parameters, so they are > about > the same. > > This is true for most alloys, hardened or unhardened. > > One way to think of it is an identically dimensioned bar of different > materials. > > The material with the highest specific stiffness will ring with the > highest > note when struck. > > FYI the highest specific stiffness of the common metals is beryllium. > > OK? :) > > Les ===== Check out my APRS digipeater: http://map.findu.com/FIELDR __________________________________ Do you Yahoo!? Yahoo! Mail Address AutoComplete - You start. We finish. http://promotions.yahoo.com/new_mail Addresses: FAQ: http://www.ktmarketing.com/faq.html FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/ Post Messages: [EMAIL PROTECTED] Subscribe: [EMAIL PROTECTED] Unsubscribe: [EMAIL PROTECTED] List owner: [EMAIL PROTECTED], [EMAIL PROTECTED], [EMAIL PROTECTED] Moderator: [EMAIL PROTECTED] [EMAIL PROTECTED] [EMAIL PROTECTED] [Moderators] URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO OFF Topic POSTS: General Machining If you wish to post on unlimited OT subjects goto: aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if you have trouble. http://www.metalworking.com/news_servers.html http://groups.yahoo.com/group/jobshophomeshop I consider this to be a sister site to the CCED group, as many of the same members are there, for OT subjects, that are not allowed on the CCED list. NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........ bill List Mom List Owner Yahoo! Groups Links Addresses: FAQ: http://www.ktmarketing.com/faq.html FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/ Post Messages: [EMAIL PROTECTED] Subscribe: [EMAIL PROTECTED] Unsubscribe: [EMAIL PROTECTED] List owner: [EMAIL PROTECTED], [EMAIL PROTECTED], [EMAIL PROTECTED] Moderator: [EMAIL PROTECTED] [EMAIL PROTECTED] [EMAIL PROTECTED] [Moderators] URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO OFF Topic POSTS: General Machining If you wish to post on unlimited OT subjects goto: aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if you have trouble. http://www.metalworking.com/news_servers.html http://groups.yahoo.com/group/jobshophomeshop I consider this to be a sister site to the CCED group, as many of the same members are there, for OT subjects, that are not allowed on the CCED list. NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........ bill List Mom List Owner Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
