THANKS-Re: [CAD_CAM_EDM_DRO] Re: Machining Ferrite Alumina Ceramic Sapphire Quartz Silicon Nitrid

Thanks Ron:
     Since the parts are so FRAGILE did you turn them a little at a time
and then push them farther out of the collet like a swiss lathe?  Or did
you use a support rest behind where the grinding wheel was applying
pressure as it ground the work?
     How old do you consider old?  I'm 78 now and I started in  Blueprint
Reading in the fall of 1948 (7 Th Grade) and Machine shop and Pattern
Making in fall of 1951 (10 Th Grade), Then Advanced Engineer's Machining
at GMI in 1954.  I finish out an Employee in Training program at Buick
Engineering Machine Shop of Buick Motor Div. GMC. in January 1962.
Some of the OLD Timers I worked with there had been machining since in
in the last part of the first World War.  The one told of his tool box being
in the ribbon of his hat where he carried a pair of inside and outside calipers
and scale. Along the way I started my own shop in 1957 and home business
in 1959.  I also worked the summer of 1961 at Lester Associates in NY. the
summer of 1961 while on layoff from Buick.  I built a training model for the
US Navy of the Talous Launch Missile while I was there.  I retired from Buick
with 34 years service in January 1988 and have enjoyed doing all kinds of
engineering and building since.
                                                      GOD'S BLESSINGS
                                                            Bill Thomas

On 22 Apr 2014 13:46:49 -0700, ronkline wrote

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> Hi Bill
>  No , we tried to centerless grind these

but they are Ferrite and TOO fragile and the grade of material didn't come in anything smaller than 1/4" . After many hair raising weeks we came up with a methiod that gave about a 20% yield that eventually was refined to about 95% yield.

>   You might understand this but I don't know how

many others on this list will , we used a "Spin Jig" to rotate the part like a lathe but more precision bearings then attached a DC motor and a Variac powersupply to dial in the desired RPM then this was mounted on a surface grinder with adjustable spindle RPM for the diamond wheel and we built a CNC controller with Geckodrives and a laptop computer for precision feed rate.

>   All in all it is a bit like turning a part on a lathe , the

basics of this was an idea given to me by an OLD machinist at NASA in 1970 when I was a student there.

>
>

Ron

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