Subject: Need help on grinding trig problem

From: [email-masked] (Vince Miller)
Date: Thu, 22 Dec 1994 15:59:48 GMT

This is a follow up question to my previous post about having a woodworking 
plane ground.  Thanks to everyone who responded.  

The machinist at a school shop said he'd do it for me on a tool and die 
grinder.  The advantage being ease of setup, the plane is placed on its side 
which makes it easier to avoid distortions during clamp down.

The t&d grinder uses cup stones.  To lessen stress on the stone, he said he 
will have to tilt it 1 degree.  This will result in a a cup accross the 
width of the sole of the plane.  Here's my attempt at the math:

6" wheel, deflected 1 deg around .048 deflection from center to 2.75 [tan 1 
deg * 2.75"] radius.  The plane sole is 3" so it will intersect the wheel at 
+ and - 45deg from the x axis, so cosine 45 time total deflection equals 
.0339", which subtracted from the total deflection, to get the deflection in 
the feild of the 3" sole yeilds: .014" cup accross the width.

It's been years since I left engineering and took up the humanities and I'm 
very rusty (why did I give all my books away?!).  Please correct my math.  
I'm thinking of asking him to make several passes along the length of the 
sole, each ofset by 1" or so, to further the cup, resulting in several 
shallower ridges.  Will this be a pain for him to do?  Would better results 
be obtained with a smaller wheel?  Yep I think, but any advice would be 
welcommed.

tia

Vince