Posted to rec.crafts.metalworking
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Holding rods in V-slots--mildly inneresting trig...
Believe it or not, I actually wouldn't mind seeing the derivations.
Thanks,
Adam Smith
Midland, ON, Canada
"Proctologically Violated©®" wrote in message
...
Awl--
Proly more inneresting to cadcamless muhfugguhs such as m'self, but mebbe
otherwise useful.
The Q is:
For a given 90 deg. V slot (eg, one V-slot in the back vise jaw), what is
the smallest rod that can be held in a V-slot (ie, too small a rod will
rattle), AND, what is largest rod that can be held by that same V slot
(ie, where the V slot walls will indeed hold the rod tangently and
therefore stable-ly, and not on the cusp of the V)?
Answer: ( d=depth of V slot; D=diam of rod )
D(small) = .829 d; D(large) = 2.828 d;
w/ the ratio of the large diameter to the small diameter being about 3.4.
Example:
Spose you want to hold a 1/8 rod horizontally in a vise jaw. You will
need to mill a V-slot no deeper than .151 deep.
Now, using the formula for D(large), the largest rod that can be stablely
held by this same V slot is max .427 diam. Or, just multiply the 1/8 rod
by the above 3.4 factor.
Probably, for 1/8 rod, you'd mill a V .135 deep, which would then limit
your large rod to about .375--still not a bad range.
Or so I think.
Now, what about iffin your V is not 90 deg? This is more of a pita, but
still do-able.
The formula becomes:
D(small) = 2d/(cos a + (sin a * tan a) + 1),
where the angle a is 90 - (included angle/2) of the V .
Or so I think.
Haven't gotten around to the D(large) for non-90 deg V's, cuz, well, my
vision is blurring and I got a bad sugar munchie attack.
Related to this is is *how high* a ball (radius = r) sits in a V-slot.
For a 90 deg V, a ball is raised by the amount .414 r .
For what it's all worth.
Iffin inyone is dyin to see the derivations, email me. Proly good SAT
practice'n'**** fer yer urchins.
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Mr. P.V.'d
formerly Droll Troll
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