[SEL] Introducing........

[Rob Skinner]

Very cool, Jimbo.

Not only does this provide a simple method of figuring out  
trigonometric problems, but it shows a neat way of using the indicator  
to measure the setup.

Thanks.

	
Rob Skinner
Antique Stationary Engines
La Habra, California

rob at rustyiron.com
www.rustyiron.com





On Oct 8, 2009, at 7:44 AM, Jim Kirkes wrote:

> OK here is how it is done, machine accurate angles, amaze
> your friends and earn big bucks.
>
> If you have a protractor scribe the angle you want about
> where the top of the vise jaws will be when you machine the
> part.  Put the part in the vise and
> pinch it on the scribe line.  Tighten the vise so that you
> can still move the part with a soft hammer.  If you have
> done this fairly accurately it helps to set one end (doesn't
> matter which) slightly high so you know which why it will
> need to move to be on the nut.
>
> Now get out your trig tables and look up the tangent of the
> angle you want to machine.  In Eldon's case  .1989 for 11
> deg 15 minutes.  Now put your indicator on the head of the
> mill.  I prefer a drill chuck but any way it is solid will
> work.  Use an indicator that read in  .001 increments.  Now
> contact the indicator to the work and adjust it till reads
> zero.  Drop the knee an amount equal to the tangent or .199
> (rounded off here) without touching the indicator
> move 1 inch.  If the indicator reads zero you have the
> angle, if it doesn't tap it slightly to correct the position
> and repeat the process until it reads zero for
> both ends.  The accuracy can be enhanced by working the
> baseline over a longer distance.  For instance if you use 3
> inches the tangent will have to multiplied by 3.
>
> If this is done with care you can easily machine an angle to
> several minutes of arc provided there is an accurate surface
> to reference to.
>
> Jim and Diane Kirkes
> Hemet, California U.S.A.
> jd.kirkes at verizon.net>
>
>
> _______________________________________________
> SEL mailing list
> SEL at lists.stationary-engine.com
> http://www.stationary-engine.com/mailman/listinfo/sel