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Maching Gears: Dividing Head Or Rotary Table?

tfleming

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#1
Ok, so I know that using a dividing head is absolutely the easiest way to machine gears. However, they can be pricey, and not everyone has one. Rotary tables are a wee bit easier on the pocketbook. I happen to have both, but was considering using the rotary table just to "do it".

Pretty simple to my mind, divide the number of teeth into 360. That will tell you how many degrees to space each tooth. Should work, right? Higher chance of error that way? Yup. But, if you are careful, it should work out just fine......

Thoughts and comments welcome!
 

Bob Korves

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#2
With the RT, it will help if you write down all of the numbers for the degrees, minutes, and seconds for each cut before you start. Otherwise, you can get confused and forget what your last numbers were. The dividing head works a lot better for indexing because you do not need to keep doing the math as you index. It is not a good thing when you get to the end of the gear and have only half a space for the last cut... It depends on the number of teeth as well. If it is a 12 tooth gear, it is probably easier on the RT than using the dividing head. If it is an 11 tooth gear, the dividing head would be much easier. The setup for actually cutting the teeth also comes into play in your choices...

If your rotary table has dividing plates on it, that further confuses the issue...
 

Tony Wells

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#3
It works. I have done it. Just make up a chart showing DMS for each cut, and start in. That's one application where a guy could justify a rotary encoder and put a DRO on a rotab.
 

tfleming

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#4
Bob and Tony, thanks for the comments. I love the idea of a rotary DRO. That would solve a lot of things! My rotary table is pure DMS (no plates). However, it is one that can be mounted vertical or horizontal. Takes an MT2 center, and has T-slots that can be used with a dog. My Indexer is actually more of a duplicator, as it is an Atlas one for the their horizontal mills. It actually works pretty well, if you have a gear to copy. I just received the cutter to make the smaller gear I talk about in my Lodge and Shipley thread over on the Antique forum. I have been contemplating using the rotary table for the fun of it. It is a 48 tooth gear, so 7 degrees 30 seconds is the angular indexing number. that shouldn't be too difficult. I also have a 48 tooth gear for the Atlas duplicator. I just thought it would be a fun project to use the rotary table.
 

JR49

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#5
Sorry, was going to ask a question but while typing it the answer came to me. Happy New Year to all!!!
OK, so now reading tfleming's post above this, I've got another question. Shouldn't you're indexing number be 7 degrees 30 MINUTES, not 7 degrees 30 SECONDS ??
 
Last edited:

f350ca

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Active Member
#7
Have you removed the degree wheel on the rotary table to see if the dividing plates from your dividing head will fit. Mine are both Vertex and they can be swapped.

Greg
 

tfleming

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#9
JR, I didn't even take it that way. I goofed, and you caught it. I am good with that! LOL. f350CA, my rotary table does not have removable plates, but if it did, I totally understand what you are suggesting.