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16 deg 57 min 28 sec
16.95776330 deg
or 3.5000 inches/foot
Is that exact enough?
JR
Did this change at some point? Every spec I can find says 16 deg 51 min.
I found a couple of references to Bridgeport R 8 spindles and they say 16 51', so maybe the R8 is a special Bridgeport created and not a 3.5 in 12 taper.
R8 specifications are 3.5"/foot. Almost all machine tool tapers are spec'd this way. Every time you see something else, it's a conversion done by somebody.
OK, I finally found the numbers that MH is using for the conversion 2 AcrTan (3.5/24) = 16.59428994 or
16 degrees ~ 35 minutes ~ 39.44 seconds.
The formula for the angle of a RA cone is 2*ARCTAN*(r/h). Don't ask me where they came up with 24 (other than is 2 * 12). Don't know, but that's what their using.
That's a lot of thinking for a FOG. Probably hurt myself.
JR
R8 specifications are 3.5"/foot. Almost all machine tool tapers are spec'd this way. Every time you see something else, it's a conversion done by somebody.
OK, I finally found the numbers that MH is using for the conversion 2 AcrTan (3.5/24) = 16.59428994 or
16 degrees ~ 35 minutes ~ 39.44 seconds.
The formula for the angle of a RA cone is 2*ARCTAN*(r/h). Don't ask me where they came up with 24 (other than is 2 * 12). Don't know, but that's what their using.
That's a lot of thinking for a FOG. Probably hurt myself.
JR
Indeed, 3.5/12 = sin(16.95776330). But the underlying construction implied by this calculation is not a right triangle, so using the sine function seems inappropriate to me. A better mental construction for a taper is a pair of identical, mirrored right triangles.
If one is trying to figure out what angle from the centerline defines the R8 taper based on the 3.5/12 taper, I think the correct approximation is 2 * arctan(1.75/12) or 16.594289... degress.
I know this is an old thread, but here's what I found, when I make a drawing in Autodesk Fusion 360.
I make a line 12.000" long. Then a 3.500" line, perpendicular from the end point, I have an angle of 16.260205°.
If I make a line 12" long and then make a line at 16.594289°. The perpendicular line is 3.57605.
If the formula is 3.5" per Ft (12.0"), I'm going with 16.260205°
Mike
You are thinking about it wrong, just as I was Mike. The correct angle is 16.594°..., as shown in the bottom triangle. Photobucket blocked the link to the pictures in my earlier post.
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