Dividing Plate Numbers

Susan_in_SF

Wood and Metal Goddess
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Jul 18, 2017
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Hi Guys,
I picked up a 6"rotary table that had a double sided dividing plate on it. As a newbie, I don't know what the two column of numbers on each side mean. When I tried looking up the answer via Google, all I found were the complex explanations on how to use dividing plates, but no simple answer as to what the numbers on the plates mean. Are the plate #'s the # that the row can be divided evenly into?
Thanks in advance for any useful info.
Susan
 
Number of holes per 360° usually. Pics would help.

Sent from my H3123 using Tapatalk
 
On my dividing head (my rotary table doesn't have the index plates) the number on each row is the number of holes in that row. You can look up which row to use and the total quantity of holes needed for each desired division on standard tables in a lot of books or on-line.

Check out YouTube. Here's a quick one I found on a dividing head and I would imagine most, if not all, could be applied to a rotary table as well. I didn't watch the video, just skipped around, but it looks like it explains it much better than I can in a message.


Ted
 
On my dividing head (my rotary table doesn't have the index plates) the number on each row is the number of holes in that row. You can look up which row to use and the total quantity of holes needed for each desired division on standard tables in a lot of books or on-line.

Check out YouTube. Here's a quick one I found on a dividing head and I would imagine most, if not all, could be applied to a rotary table as well. I didn't watch the video, just skipped around, but it looks like it explains it much better than I can in a message.


Ted
Thanks Ted. I will check out the video
 
Well, I feel silly. I assumed the numbers were 2 separate columns of #'s. It didn't occur to me that the #'s represented the # of holes. Duh!!
Thanks guys for the answers!
Susan
 
Btw, I did some calculatons, and determined that my vintage rotary table has a 18:1 ratio where with 1 full turn of the handle, the table rotates 5%, or 18 degrees. I got this rotary table from the guy who also sold me Original lathe legs for my baby 6" Craftsman metal lathe. He gets his stuff from auctions. With 1 turn only moving 18 degrees, is this considered a good feature, or a bad thing to have with one's 6" rotary table. Fyi, my female arthritic wrists nearly imploded when I tried carrying this sucker. Bigger isn't always better, lol ;-)
 
OK, let's check this... if turning the crank 1 time equal 18 degrees then the ratio is 20:1 not 18:1

Just to double check, count how many full crank turns it takes to make your table turn one complete turn (360 degrees). This number would be the ratio to one.

I don't know what the ratio of my Phase II 10" rotary table is, but my diving head is 40:1 which is pretty much standard. I don't really use my rotary table all that much.

Ted
 
What you will eventualy find, by moving the handle one and 1/3 revolutions, (20holes on a 60 hole plate) You'll get 24º, and other needed numbers. ie., more than one way to use an RT.
 
Google is your friend! Did a quick search for common gear ratios for a rotary table and came up with 40:1,72:1 or 90:1. So, the number of turns and number of holes you use on any indexing plate with vary with the ratio of your table. Make sure you know the correct ratio and use that to determine the correct plate/hole spacing to use.

Again, mark your table with a reference line or use some other means of establishing a base line. Count the number of turns it takes on the crank to make one full 360 degree rotation of your table. The number of cranks will be the ratio. So, if it takes 90 full crank revolutions for one full table revolution your ratio is 90:1. BTW, 90:1 must be pretty common because my little Black Book has one table in it and it is for 90:1 ratio rotary tables.

Ted
 
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