I hit a water meter cover with one once. Not only broke the blade, it did some damage to the spindle and bearings as well.
The cover survived with minimal damage... Dan Sent from my iPhone On Sep 6, 2011, at 10:04 PM, G Mann <[email protected]> wrote: > Most mower blades is a pretty low grade of steel so I doubt you are doing > any damage with the grinder. The blades are intentionally half soft to bend > or dent rather than break when you strike the curb or a rock.... > > If you ever break a lawn mower blade tip off while mowing [and live] you > will remember it .... > BTDT.. don't want to do it again. I now look for cracks while sharpening. > > On Tue, Sep 6, 2011 at 1:39 PM, Mike Esh <[email protected]> wrote: > >> When I grind/sharpen my lawn mower blade with my electric grinder am I >> ruining it. >> >> Michael E. Esh >> >> >> On Sep 6, 2011, at 4:25 PM, G Mann <[email protected]> wrote: >> >>> Color change in heated metal is strongly influenced by metal composition. >>> More of one component or another in the makeup of steel [a compound >>> substance] gives different "color points" at different temperatures, thus >>> without controlled conditions with known materials most of what's being >>> offered in this thread is pretty baseless. >>> >>> Temper, hardness and other strength factors are also influenced by quench >>> time, coolant temperature, and other factors. All which need be tightly >>> controlled. >>> >>> Sorry to rain on your individual parade. No disrespect intended. >>> >>> >>> On Tue, Sep 6, 2011 at 12:58 PM, Fmiser <[email protected]> wrote: >>> >>>>> Max Dillon wrote: >>>> >>>>> My friend the machinist tells me that to affect the temper, >>>>> the metal needs to be heated until the color is correct >>>>> (glowing red or hotter/lighter), then quickly cooled. I think >>>>> 400 degrees is not hot enough. >>>> >>>> By the time it just begins to glow is is _way_ past tempering. >>>> >>>> Temper is a decreasing of the hardening. >>>> >>>> 400 deg F can effect a hard-tempered steel. Often 350 >>>> deg F is considered the maximum safe temperature to avoid >>>> affecting temper. >>>> >>>> To fully harden, heat the metal to glowing red, then quench >>>> (cool very quickly . This is often too hard and so must be >>>> tempered. >>>> >>>> To temper, remove the scale and oxide so there is shiny metal. >>>> Then heat and watch for surface color - NOT glowing color. When >>>> the color is reached, quench. >>>> >>>> The first color is often called "straw" - a pale tan or yellow. >>>> This is the least tempered, or the most hard. >>>> >>>> The last color is blue. This is the most tempered, or the least >>>> hard. At this point the hardness is nearly entirely gone. >>>> >>>> Here's a website with colors and temperatures. Keeping in mind >>>> that the actual temperature can vary depending on the steel >>>> alloy. >>>> http://www.engineeringtoolbox.com/tempering-colors-steel-d_1530.html >>>> >>>> -- Philip >>>> >>>> _______________________________________ >>>> http://www.okiebenz.com >>>> For new and used parts go to www.okiebenz.com >>>> To search list archives http://www.okiebenz.com/archive/ >>>> >>>> To Unsubscribe or change delivery options go to: >>>> http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com >>>> >>> _______________________________________ >>> http://www.okiebenz.com >>> For new and used parts go to www.okiebenz.com >>> To search list archives http://www.okiebenz.com/archive/ >>> >>> To Unsubscribe or change delivery options go to: >>> http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com >> >> _______________________________________ >> http://www.okiebenz.com >> For new and used parts go to www.okiebenz.com >> To search list archives http://www.okiebenz.com/archive/ >> >> To Unsubscribe or change delivery options go to: >> http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com >> > _______________________________________ > http://www.okiebenz.com > For new and used parts go to www.okiebenz.com > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
