Re: [CAD_CAM_EDM_DRO] not stiff enough!

.132 deflection? What material is that shaft made from, what is the shaft
geometry? I can suspend a four foot bar on 2 "knife" edges, place 25 # in
the middle and wouldn't get that much deflection.

Smoke

-----Original Message-----
From: Les Watts <leswatts@...>
To: CAD_CAM_EDM_DRO@egroups.com <CAD_CAM_EDM_DRO@egroups.com>
Date: Saturday, January 20, 2001 7:41 AM
Subject: Re: [CAD_CAM_EDM_DRO] not stiff enough!

>It was mentioned before that you need some better end support on your
>machine. I ran some quick numbers on my
>beam deflection software for you to see what that would do.
>The dimensions are not exactly the same ( I forgot them)
>but are close enough to put things in perspective.
>
>For a .75" diameter shaft 4 feet long simply supported at the ends with a

25

>lb force at the midpoint I got .132" deflection.
>Over an eighth of an inch!
>
>Simple support is like a see saw fulcrum or a single small clamp on the end
>of the shaft.
>
>
>For the same conditions with FIXED supports on the end I got
>.03" deflection- four times less!
>
>Fixed support would be something like an end clamp making
>contact over at least a couple inches with the shaft rigidly fixed
>to a stronger support. It resists bending moments.
>
>Hope this helps.
>
>Leslie Watts
>L M Watts Furniture
>Tiger, Georgia USA
>http://www.rabun.net/~leswatts/wattsfurniturewp.html
>
>
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