• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.
  • Untitled 1

    As promised, a formal announcement has been made regarding recent changes in the administrative staff here at H-M.

    Please take a few moments to go to our home page and review that announcement.

[4]

Dividing Head & Cutting Direction

[10] Like what you see?
Click here to donate to this forum and upgrade your account!

omni_dilletante

somewhat active
H-M Supporter-Premium Member
Joined
Jan 29, 2014
Messages
160
Likes
369
#1
I am setting up my Dividing Head to cut some gears and something does not make sense.

20160723_163924-001_zps62k86pyw.jpg
  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?
 

mark_f

Global Moderator
Staff member
H-M Supporter-Premium Member
Joined
May 2, 2014
Messages
2,006
Likes
2,277
#3
What he said ..... reverse the cutter.
 

4gsr

HM Shop Superintendent
Staff member
H-M Supporter-Premium Member
Joined
Aug 8, 2011
Messages
4,482
Likes
2,785
#4
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.:foot in mouth:
 

Chipper5783

Active User
H-M Supporter-Premium Member
Joined
Sep 25, 2014
Messages
578
Likes
412
#5
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

Active User
Active Member
Joined
Mar 19, 2014
Messages
2,071
Likes
1,396
#6
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

Active User
H-M Supporter-Premium Member
Joined
Jan 26, 2015
Messages
1,811
Likes
1,232
#7
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

somewhat active
H-M Supporter-Premium Member
Joined
Jan 29, 2014
Messages
160
Likes
369
#8
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.:foot in mouth:
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.

9361126238_8069b3d0fa_b_zps5wpjvwhn.jpg

This mill is not mine...
 

4gsr

HM Shop Superintendent
Staff member
H-M Supporter-Premium Member
Joined
Aug 8, 2011
Messages
4,482
Likes
2,785
#9
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

Active User
H-M Supporter-Premium Member
Joined
Jan 26, 2015
Messages
1,811
Likes
1,232
#10
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.
 

Reeltor

Active User
Active Member
Joined
Nov 18, 2014
Messages
739
Likes
316
#11
I have a similar situation with my Van Norman. In order to cut from footstock towards the dividing head the mill motor has to run in reverse to avoid climb milling.
Just tighten everything real good and check between passes to see if anything is unscrewing.

If I may sidetrack this thread for a moment. On-line gear making always show cutting the tooth in one pass. Is this also true when making large teeth? I need to cut some 4-dp gears .539 deep. This seems like a BIG cut to do in one pass.
What do you think?

Mike
 

4gsr

HM Shop Superintendent
Staff member
H-M Supporter-Premium Member
Joined
Aug 8, 2011
Messages
4,482
Likes
2,785
#12
I certainly would not cut the tooth in one pass. Yeah, take out as much as you feel comfortable with or the machine will handle in one pass. Always leave extra material for the finish cut. That way if for some reason the blank was to shift slightly from heavy cutting, the finish pass will fix that. Also, you generally get the PD on size using measurement over pins and taking finishing cuts to get the PD correct. If you hog out too much metal, you scrap a gear or you use a gear that the PD is undersize. This is ok on adjustable centers, but on fixed centers, it don't work too good. Ken
 
[6]
[5] [7]