MWF FEED
18th February 2020, 01:50 PM
SAM_0604.jpg (https://metalworkforums.com/attachment.php?attachmentid=384828&d=1581988991)SAM_0603.jpg (https://metalworkforums.com/attachment.php?attachmentid=384829&d=1581989036)This old goat made a mistake.
The first shot shows where the grinder finished up. Second shot is where it was first.
While reading thru a cutting tool handbook I realised that as built, the grinding wheel was working parallel to the cutting edge. The edge being ground was vertical and the grain descending on the wheel. This causes the striations to be parallel to the cutting edge and gives stress raisers just behind the edge. You guessed it the drill failed in use. No pic due to temper tantrum. A section 1.5mm X 10mm long peeled off. I would guess 15 thou deep.
With the drill holder re-positioned and now at the bottom of the wheel the striations are at 90 degrees to the edge. I hope it's fixed.
BC
Attached Images
https://metalworkforums.com/images/attach/jpg.gif SAM_0603.jpg (https://metalworkforums.com/attachment.php?attachmentid=384829&d=1581989036) (138.3 KB)
https://metalworkforums.com/images/attach/jpg.gif SAM_0604.jpg (https://metalworkforums.com/attachment.php?attachmentid=384828&d=1581988991) (195.6 KB)
Read the full thread at metalworkforums.com... (https://metalworkforums.com/showthread.php?t=204581&goto=newpost)
The first shot shows where the grinder finished up. Second shot is where it was first.
While reading thru a cutting tool handbook I realised that as built, the grinding wheel was working parallel to the cutting edge. The edge being ground was vertical and the grain descending on the wheel. This causes the striations to be parallel to the cutting edge and gives stress raisers just behind the edge. You guessed it the drill failed in use. No pic due to temper tantrum. A section 1.5mm X 10mm long peeled off. I would guess 15 thou deep.
With the drill holder re-positioned and now at the bottom of the wheel the striations are at 90 degrees to the edge. I hope it's fixed.
BC
Attached Images
https://metalworkforums.com/images/attach/jpg.gif SAM_0603.jpg (https://metalworkforums.com/attachment.php?attachmentid=384829&d=1581989036) (138.3 KB)
https://metalworkforums.com/images/attach/jpg.gif SAM_0604.jpg (https://metalworkforums.com/attachment.php?attachmentid=384828&d=1581988991) (195.6 KB)
Read the full thread at metalworkforums.com... (https://metalworkforums.com/showthread.php?t=204581&goto=newpost)