Re: [GrizHFMinimill] Scraping update



Hi David,

Here's the site items in store on eBay!
Note that as they come they are not suited for scraping metal -- they have the wrong rake angle.  If you have a fine-enough diamond grinding wheel this will not pose a problem.  As they come, they also have no radius on the business end.  Also no problemo with the right grinding equipment.

FYI, all the various scraping resources I've seen indicate that a final pass with a 3,000 grit diamond wheel is sufficient.  I just went a little overboard with my 14,000 grit final pass.  Probably because I always examine things I've polished with a high power microscope (it's work-related, not OCD) so I know what a 3,000 grit "polish" looks like up close.  It really isn't all that nice.  By comparison, 14,000 grit starts to look pretty good.  I really doubt that going to 50,000 grit would be of any benefit in this application.

To get a 14K finish you will need a lapping disk or wheel you can charge with 14,000 grit diamond.  You can buy a "recharge roller" from a lapidary supply company or make one with a ball bearing mounted on a handle.  I took the latter course because I had a bearing that was about the right size, and a steel bar that had the right dimensions to make a handle.
 
Mark

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Posted by: mark.kimball2@frontier.com



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