Thread: dividing plates, dividing head

It is my understanding they are all basically the same thing, just a different way of doing it. Most dividing heads can be set to different angles, whereas most rotary tables can only be used at 2 angles.

Indexing head - Wikipedia, the free encyclopedia

Originally Posted by Big Shed

It is my understanding they are all basically the same thing, just a different way of doing it. Most dividing heads can be set to different angles, whereas most rotary tables can only be used at 2 angles.

Indexing head - Wikipedia, the free encyclopedia

extract from wiki link
The tool is similar to a rotary table except that it is designed to be tilted as well as rotated. Most adjustable designs allow the head to be tilted from 10° below horizontal to 90° vertical, at which point the head is parallel with the machine table.

thanks big shed...i'm a little more wiser..i think

The other thing about indexers is that they are intended (or were originally intended) to go to set positions - in the Hare and Forbes photo there are some toothed discs that are used to make this easier. It looks like those ones are venturing into dividing as well.
As Fred said, the dividing head and rotary table with indexing plates will do the same thing. The key differences are that a rotary table will allow you to machine arcs which a dividing head probably won't (different gear ratios involved), but a dividing head will allow you to tilt and if you have a universal dividing head, allow you to index to some really odd numbers.
For cutting a 6 or 8 tooth spline, any of them would probably do the job.

Michael

Its all a little blurry between dividing heads and rotary tables. Most rotary tables have a tee slot plate, most SEMI Universal* heads had a chuck(spindle nose).
The indexing head is a rotary table that has indexing plates which are much faster than dividing plates and worn wheel, though aren't likely to be as accurate. (I think some semi universal heads can also do that). Though the one you linked to can only go up to 24 divisions with its indexing plates.


*A Universal head has an extra set of gears between the dividing plates and the worm.

D003 | BS-2 Dividing Head - Universal | machineryhouse.com.au

Stuart

p.s. Slow hands Stu lol. Michael why do you say you cant machine arcs with a dividing head? the 40:1 ratio? I'd think dividing heads would be a lot less rigid though.

(Bound to be shot down for this one...)
Two reasons that I'd give-
Firstly, the gearing ratio. A typical dividing head is 40:1, a rotary table is 90:1. I can certainly feel the cutter pulling on the job when using a R/T. I suspect that at 40:1 you would lose control for all but the lightest cuts.
The other is the way they index. Continuous cranking on a R/T is what they are made for. A dividing head is not going to crank around easily - the sectors will get in the way etc.

Michael

What are the sectors you refer to?

The brass fingers that help get the right number of divisions. I guess you could remove them and fill the space with a spacer.
You'd probably want to change the spring loaded handle too.

Michael

You would have the same result when using the rotary table if dividing plates were used.

Hello Eskimo,
I am sure that others will have much more knowledge of these machines than me but in my case, I have what H&F call a Super Indexing Head (although it is not a Vertex) . It has a notched plate for every 15 deg. and a vernier dial which supposedly gives 10 second increments. I would say it is a compromise of the three systems. eg.
When it is in the horizontal position,it takes up more vertical space than a rotary table. Even with the chuck removed and a faceplate fitted (I have a 10Kg.weight from a body builder set to make one), it is not as compact.
I don't think the rotary tables have the notched plate, but they have the 10 second vernier dial and a chuck can be fitted.
For serious gear cutting including helical gears, I think the dividing head would be the best. I assume they can allow gears with any number of teeth to be cut, with the correct dividing plates.
Dividing plates can be fitted to the rotary table and the indexing head which may be a better option than using the vernier dials.

Just buy one of each- Problem solved.

Hi,
The other downside with a rotary table for dividing (with the 6" vertex i have anyway) Is that the plates only allow you to do 2-100 division x1, then only even numbers above 100. So you cannot index a 127 tooth gear for a lathe gear train.

Not many manufacturers do a plate that allows 127.
You would also have the same result with the dividing head unless you use a universal.
You could allways try to get your 127 with the rotary with the use of the vernier scale.

With a 40 -1 head if the dividing plate has a 17 hole ring then advancing every 4 holes on the 17 ring will divide a circle by 127 .

Originally Posted by Retromilling

With a 40 -1 head if the dividing plate has a 17 hole ring then advancing every 4 holes on the 17 ring will divide a circle by 127 .

Would you like to show you workings for that?
I cant make it work. I get 170 divs

Stuart

I am not sure about divisions but I think 4 holes on a 17 plate will move 2.11 degrees,when you want to be spacing 2.83 degrees abouts.