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davidh
08-26-2009, 10:20 PM
i have a rotary table. . . it has a degree wheel on it so you can see where you are when using it. i want to divide that 360 degrees into 100 parts by numbers. 3.6 7.2 10.8 etc, on a sheet of paper that i can use when im in the shop actually cranking the handle ? ? ? ? ?

what is the formula i need to apply to A1 or A2 so it will show these numbers for me ? ? ? ? ? ? ? ? ?

thanks. im spending too much time in excel trying to figure it out.

mwechtal
08-26-2009, 10:31 PM
i have a rotary table. . . it has a degree wheel on it so you can see where you are when using it. i want to divide that 360 degrees into 100 parts by numbers. 3.6 7.2 10.8 etc, on a sheet of paper that i can use when im in the shop actually cranking the handle ? ? ? ? ?

what is the formula i need to apply to A1 or A2 so it will show these numbers for me ? ? ? ? ? ? ? ? ?

thanks. im spending too much time in excel trying to figure it out.
Quick and dirty:
In A1 put "=360/100"
In A2 put "=A1+\$A\$1"
Copy A2 down all cells to A100

Don't type the " symbols

If you want to divide a circle into some other increments, change cell A1, and change the number of cells A2 is copied down.

Don't feel too bad, I do this stuff every day, and I still have to refer to help a lot if I do something new.

ptjw7uk
08-27-2009, 03:42 AM
Just put 3.6 in cell A1
then 7.2 in cell A2
Highlight A1 & A2 then drag down Excell will automatically insert the increase by 3.6.

Peter

psomero
08-27-2009, 05:11 AM
by drag down, Peter meant click on the little black square on the bottom right of the highlighted cell, then drag down...

Barrington
08-27-2009, 05:47 AM
Don't want to complicate things too much, (but I usually do :) ....) - if your rotary table is calibrated in deg/min/sec then decimal degrees may not be very convenient - you may want to display the results in the same format you're setting the dial to:-

To convert decimal degrees in A1 to B1 deg, C1 mins, D1 secs

In B1 enter:
= INT(A1)

In C1 enter:
= INT(ROUND(60*(A1-B1);6))

In D1 enter:
= 3600*(A1-B1-(C1/60))

(Excel formula includes the "=" sign.)

Then fill down the columns.

The 'seconds' column is redundant for your divide by 100, (except perhaps as a useful check of the calcs - should all be zero) but it may come in useful sometime...

Cheers

edit: corrected rounding error...

Davek0974
08-27-2009, 06:25 AM
Hows about a formula for dividing plates:- turns / holes / which plate??????

hornluv
08-27-2009, 08:38 AM
Hows about a formula for dividing plates:- turns / holes / which plate??????

That should be pretty easy. You just need to know the gear ratio. If you've got 90:1 and you want 8 divisions then you divide 90 by 8 to get 11.25 and that's the number of turns you need. So eleven full turns and then find a hole circle that can be divided by four and use 1/4th of that circle for the quarter turn.

For and Excel chart, just have 1 to 100 or whatever in column A and in the adjacent column have "=90/A1" or A2, A3, etc. Replace 90 with whatever your gear ration is.

davidh
08-27-2009, 09:17 AM
thank you all for the input. its simple when you know how. and the conversion factor to degrees and minutes will make the little project that much more correct.

i have a degree wheel with all the holes, etc, and read the instructions about how to figure out what you want. . . . gad ! i couldn't absorb that to save my butt,, so excel was my friend as were you guys. . .

im use to the old parallel drafting machine, thats been around forever. . ..

thanks again. . . .
davidh

Davek0974
08-27-2009, 09:43 AM
Ok i just got these results, setting excel to show fractions to 3 places, do i read it correct that to cut 76 teeth, i index 1 full turn and 7 holes on a 38 hole plate? (My rotary is 90:1)

If so then thats really neat i think.

Teeth - Turns - Holes/Plate
76 1 7/38
66 1 4/11
55 1 7/11
26 3 6/13
20 4 1/2
15 6

Obviuosly the two hole plate is just a half turn on an even numbered plate.

oldtiffie
08-27-2009, 10:03 AM
i have a rotary table. . . it has a degree wheel on it so you can see where you are when using it. i want to divide that 360 degrees into 100 parts by numbers. 3.6 7.2 10.8 etc, on a sheet of paper that i can use when im in the shop actually cranking the handle ? ? ? ? ?

what is the formula i need to apply to A1 or A2 so it will show these numbers for me ? ? ? ? ? ? ? ? ?

thanks. im spending too much time in excel trying to figure it out.

David.

This is the start of the table for each dial setting on the rotary table - in decimal degree as well as deg:min:sec format/s for 100 divisions on your rotary table dial.

There are 100 lines and far too big to post.

I suggest that you print them out:

Number of divisions = 100

DIVISION degdec deg min sec
0 0.0000 0 0 0
1 3.6000 3 36 0
2 7.2000 7 12 0
3 10.8000 10 48 0
4 14.4000 14 24 0
5 18.0000 18 0 0
6 21.6000 21 36 0
7 25.2000 25 12 0
8 28.8000 28 48 0
9 32.4000 32 24 0
10 36.0000 36 0 0
11 39.6000 39 36 0
12 43.2000 43 12 0
13 46.8000 46 48 0
14 50.4000 50 24 0
15 54.0000 54 0 0
16 57.6000 57 36 0
17 61.2000 61 12 0
18 64.8000 64 48 0
19 68.4000 68 24 0
20 72.0000 72 0 0

mwechtal
08-27-2009, 12:28 PM
thank you all for the input. its simple when you know how. and the conversion factor to degrees and minutes will make the little project that much more correct.

i have a degree wheel with all the holes, etc, and read the instructions about how to figure out what you want. . . . gad ! i couldn't absorb that to save my butt,, so excel was my friend as were you guys. . .

im use to the old parallel drafting machine, thats been around forever. . ..

thanks again. . . .
davidh
I bet you thought you were asking a simple question!