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neonman
01-19-2009, 09:45 PM
I have the opportunity to get a Hardinge dividing head. I need a dividing head for some upcoming projects, need to divide from about 24 through 100.

I never used a dividing head, so I checked machinery's and got some scoop
on how they work. Every brand but Hardinge. The text centers around a gear ratio of 40:1, but the Hardinge is 4:1. There 6 plates (one missing) with the Hardinge, instead of 3 as with Brown & Sharp..., but the hole circles with this head have about the same number of holes as with other brands.

Does anyone out there have a Hardinge dividing head, or has anyone used one?
I would like to know if the hole plates with this head will give me the divisions I need, and also, Is compound indexing needed with this dividing head to get the range of divisions I need? If needed, does this head support compound indexing, and how does one do compound indexing with this head?

hole plates:
17, 18, 19
20, 21, 23
27, 29, 31
37, 39, 41
43, 47, 49
48, 66, 70


Thanks,
neonman

neonman
01-20-2009, 06:54 PM
All, I called Hardinge today, and asked for a parts list. The head is missing a few minor parts. Their web site still shows the tool, but it also shows it out of stock. They say they don't have a manual for it, so does anyone out there have one or know where one might be?

The link ot the Hardinge site:
http://www.shophardinge.com/product.aspx?catID=6547&partNo=PC%200000055

It's a nice looking dead, but I need to know how the 4:1 gear ratio vs. the 40:1 standard affects things. Any hints?

Thanks,
neonman

JCD
01-20-2009, 07:11 PM
I don't have an answer to your question, bit if you decide not to buy it, let me know, as I have interest in the purchase.

Thanks

JCD

Jim Caudill
01-20-2009, 08:33 PM
I have all the documentation for the Hardinge dividing head, but I don't think I can answer your questions. If the head has a 4:1 ratio, then one revolution of the handle is good for 90 degrees. If you then have a dividing plate with 30 holes, that means each hole is 3 degrees. I'll send you a PM.

TGTool
01-20-2009, 08:45 PM
Neon,

You can work out the factors you need for any number of desired divisions if you know the ratio of the dividing head (as you do). For instance, if you needed 8 divisions, you'd start with 4 / 8 (ratio divided by divisions-needed) which could be factored down to the ratio 1 / 2, meaning that to get 8 divisions you'd move 1 hole in a 2 hole plate for each division you need. Of course there isn't actually a 2 hole plate, but you can multiply both numerator and divisor by any number to find one with holes that work for you. If you multiplied by 9, for instance, you'd get a 9 / 18 ratio meaning use 9 holes in the 18 hole plate to get your 8 divisions.

Carrying on, you mention needing 24 divisions. That's 4 / 24, which multiplied by 2 gives 8 / 48, so set up for the 48 hole circle and move 8 holes for each division. I haven't worked out the rest, but you can take it from there.

Do you need every division between 24 and 100? Sit down, see what you need, see what you can produce with the plates you have, and if you need a hole circle you don't have you can make one. There have been discussions, including fairly recently, of different ways to do that. And don't forget that you can use one of Marvin Klotz's utilities (or a calculator or spreadsheet) to build a table of X-Y locations for the holes on any circle diameter you need. On a mill with dials if you can expect to reliably get all the holes within +-.002, the dividing head reduction means your final divisions would be within +-.0005, perhaps good enough?

neonman
01-20-2009, 09:44 PM
Jim, you say you have the docs for the Hardinge dividing head. Would it be possibel to get a copy of it, or at least part of it please? I would be interested in whether there is a table to get the turns/holes for different divisions, and also, there is a little backlash in the gear, and I was wondering if that can be adjusted out, if so, how? Could you email me off the board about the manual:
maury@ecpi.com

TGT, I believe I understand how to get at least some of the divisions that have even fractions, but what I don't know how to get is the large indivisible numbers, like say 97.

I will be making a set of change gears for a gear hobber I'm restoring, and will need most of the divisions between 24 and 100. Some can be made on the hobber, but you have to have some before you can make 'em. Those I'll have to make on the dividing head.

Additionally, reading about compound indexing in machinerys introduces an additional complexity I don't know how to calculate with this r4:1 ratio.

Thanks,
neonman

Jim Caudill
01-20-2009, 09:50 PM
I had made a posting here that became redundant, so I edited it to this remark.

dm1try
01-20-2009, 10:43 PM
here're all divisions you can get in the 24 to 100 range.
division: hole ring/stop in each Nth hole

24: 18/3 or 48/8 or 66/11
26: 39/6
27: 27/4
28: 21/3 or 49/7 or 70/10
29: 29/4
31: 31/4
32: 48/6
33: 66/8
34: 17/2
35: 70/8
36: 18/2 or 27/3
37: 37/4
38: 19/2
39: 39/4
40: 20/2 or 70/7
41: 41/4
42: 21/2
43: 43/4
44: 66/6
46: 23/2
47: 47/4
48: 48/4
49: 49/4
52: 39/3
54: 27/2
56: 70/5
58: 29/2
62: 31/2
64: 48/3
66: 66/4
68: 17/1
70: 70/4
72: 18/1
74: 37/2
76: 19/1
78: 39/2
80: 20/1
82: 41/2
84: 21/1
86: 43/2
88: 66/3
92: 23/1
94: 47/2
96: 48/2
98: 49/2

neonman
01-20-2009, 10:47 PM
Guys, thanks so much for the responses. I understand all I need to know about this thing now, so guess it's time to put it to work.

Thanks,
neonman

oldtiffie
01-20-2009, 11:21 PM
Deleted by author.

Jim Caudill
01-20-2009, 11:45 PM
That list price is just to disuade people from trying to order one. I have a couple of them (one with taper nose and one with a threaded nose). I have seen them sell for as little as $150 and as much as $500 on the used market. There are always some sage sellers that think they can get over $1,000 for them, but I've yet to see one bring that kind of money. Here's the one with threaded nose.
http://i72.photobucket.com/albums/i183/Ferrofab/MVC-006S-8.jpg

edited to remove my display of ignorance regarding the term "compound indexing" ;-)

tiptop
01-20-2009, 11:48 PM
neonman,

I think that to bring up the topic of "change gears for a gear hobber I'm restoring" requires pictures of the gear hobber before all the answers are given. Jay

oldtiffie
01-21-2009, 12:56 AM
Deleted by author.

Jim Caudill
01-21-2009, 01:33 AM
I defer to your superior knowledge. I know nothing about compound indexing. I was referring, of course, to using the sector arms to allow easy locating of the holes.