There is a company here called Uni-strut in Wayne, Michigan that sells tel-spar tubing, tubing sized so that it telescopes. Its about as accurate as it gets for tubing. They have it with holes and without. Steel from other sources is getting like lumber in that its best to go to the supply house and pick it out. The characteristics of tubing vary from mill to mill. Of course, standard procedure with a fabricated weldment such as the brackets and framing like those that are used in a homebuilt CNC would be fabbed and then machined. Making the accuracy of the steel irrelevant. With this in mind, I think mills have dropped their standards to save costs. I know alot of us dont have access to a 10' boring mill so we have to make do. In the past and in a pinch, I have pre-machined the components of very large weldments prior to welding. With good results. If one takes time to set everything up and clamp solidly then stitch weld to keep the warpage minute, the results are satisfacto ry. Ron
"Tyson S." <[EMAIL PROTECTED]> wrote: 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 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 --------------------------------- Do you Yahoo!? Yahoo! Mail Address AutoComplete - You start. We finish. [Non-text portions of this message have been removed] 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/
