Dividing Head & Cutting Direction

[omni_dilletante]

I am setting up my Dividing Head to cut some gears and something does not make sense.

1. The arbors for the Hardinge mill do not have a key way cut into them. So I believe they did not intend for me to secure the cutter with a key.
2. There is a left hand nut on the arbor. This tells me that it is designed to run clockwise, so that when the cutter encounters the work it will tighten the arbor nut and not loosen it.
3. As I am cutting the entire depth of the tooth in a single pass, the cut is too deep to recommend a climbing cut. So the cutter will travel from the right side of the work to the left side as it is making the cut.
4. The dividing head is designed to be on the right side of the table. I could rotate the head 180 degrees, but then the oil reservoir would be on the top and the oilers on the bottom. I do not think this is how it is supposed to work.

This means the cutter will start between the dividing head and the work piece. And the force of the cut will pull the piece away from the dividing head and toward the tail stock.

This does not make sense to me. I would think that I would want the work being pushed into the dividing head. Particularly when I am making cuts that cannot be supported by a tail stock.

What also does not make sense is that because the cutter must fit between the dividing head and the work piece the arbor holding the work must be longer. And a longer arbor, in my mind, is not as rigid as a short arbor.

So something does not add up.

Do I need to reverse the direction of my cutter?

Do I need to turn my dividing head upside down?

Or is it actually better to have a longer arbor and have the cutting force pull the work out of the dividing head?

 

[kd4gij]

I would reverse the cutter and run the mill in reverse.

 

[Mark_f]

What he said ..... reverse the cutter.

 

[4GSR]

If that was a Brown & Sharpe dividing head, it would be mounted on the left hand end of the table. Doing that, the cutter would be going the right direction.

 

[Chipper5783]

I cut my gear teeth in a single pass. See attached link to HM post (scroll down): http://www.hobby-machinist.com/thre...g-and-boring-machine-mh600.30766/#post-286313

I had the cutter on the other way, and cut towards the dividing head. The machine may have been in reverse (I don't recall). I did key the cutter to the arbor shaft (actually just made up a small dowel pin). Some of the responses I had was that the key was not necessary (some folks don't bother with a key and it is not a problem).

 

[chips&more]

Do not reverse the cutter. Install the cutter so as it engages force it tightens more onto its arbor. If installed in the other direction it will just unscrew itself and spin and then not cut and then the cutter will just smash into the blanks and bend and break stuff…Dave.

 

[Billh50]

Do you have a larger photo ? Something does not make sense to me. If your table is flat then you should be able to just turn the setup around so that you are cutting toward the indexer.

 

[omni_dilletante]

If that was a Brown & Sharpe dividing head, it would be mounted on the left hand end of the table. Doing that, the cutter would be going the right direction.

I was thinking the problem was that I am using an Ellis Dividing Head instead of the original Hardinge.

But the Hardinge Universal Dividing head mounts on the right side of the table. That is what makes this more confusing for me, the problem is not that I am using the wrong type of Dividing Head.



This mill is not mine...

 

[4GSR]

Boy! What a nice mill!!!

Pleas no offense here. Some dividing heads mount to the left of the table and some to the right. Yours is obviously correct.

Traditionally, you normally feed toward the dividing head, with the cutting forces toward the DH, too. As long as you have a good rigidity setup, it should not really matter. Just don't run the cutter rotation backwards!

 

[Billh50]

I am not familiar with that type of indexer. I had assumed it was like many that have a head that can be rotated vertically to the other side. Then it could be mounted on either end of the table. But if it can not be then you will be better off with a keyed cutter.