hardinge 4 to 1 dividing head

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joshuaj97
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hardinge 4 to 1 dividing head

Post by joshuaj97 »

would anyone have info on a hardinge dividing head as far as getting charts etc. this dividing head has a 4-1 ratio instead of a 40-1 ratio which seems to be more common
the # ON THE HEAD IS 170 A i dont know if thats the s/n or a model #.
any help is appreciated, thanks josh
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GlennW
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Re: hardinge 4 to 1 dividing head

Post by GlennW »

Have you actually tried it to verify that four turns of the handle is one turn of the spindle? (4:1)
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spro
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Re: hardinge 4 to 1 dividing head

Post by spro »

Universal dividing heads are complicated if a person doesn't know excactly what's going on or parts are missing. There were different styles but what I'm getting to is the "screw" is internal and by various locks and unlocks the spindle is driven by miter gears and not by the shaft with divisions. The ratio is in the quadrant attached to the table and the spindle could follow that 4:1 in spiral milling. Then the actual dividing is accomplished by the plates. so yes a person needs an info sheet on this.
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Re: hardinge 4 to 1 dividing head

Post by Richard_W »

Generally an index head is 40 turns of the crank to 1 turn of the spindle or chuck. I have run into 20 to 1 index heads, but they are rare.

Most rotary tables are 90 to1, but it depends on what the manufacturer wanted to make.

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jim rozen
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Re: hardinge 4 to 1 dividing head

Post by jim rozen »

The standard hardinge universal dividing head is in fact four to one ratio.
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GlennW
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Re: hardinge 4 to 1 dividing head

Post by GlennW »

Interresting...

It must use large diameter indexing plates with a LOT of holes in them by comparison to others!
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astronrs35
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Re: hardinge 4 to 1 dividing head

Post by astronrs35 »

Help. I got what I thought was a great deal. Well I found out it is a Hardinge 4 to 1 ratio Dividing Head and spiral. The one plate it has is a home made plate. Instead of it being 15,16,17,18,19,20 it is 19,18,17,16,15 and 3. well 20 is a very important size. I have looked everywhere for the plates but so far no joy. It uses a 5+ inch plate 1/4" thick. I would love to rent/borrow/steal/and last result buy a correct plate. I am just learning so please keep your answers to a beginners levels. I have a Bridgeport and a DRO along with a Chinese 10x40 lathe. I saw some coordinates to drill for a 40 to 1 but almost nothing for a 4 to 1. I had hoped to find the correct plate and copy it. Turbocain or Mr. Pete222 does show how to use it so I have made using the 18 line and moving 13 spaces it makes a nice 6 sided part. And help would be greatly appreciated.
pete
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Re: hardinge 4 to 1 dividing head

Post by pete »

In theroy any common ratio dividing head is pretty simple. Real world and miscounting even one hole will ruin anyones day. Those 4-1 Hardinge heads aren't all that common today and they usually go for big bucks on Ebay. My guess any original plates would be real rare with a price to match. With 4 turns to a full spindle revolution you just have 90 degrees per turn. The more usual 40-1 heads have 9 degrees per turn. Any angular division will be a number of turns and / or fraction of a turn. That fraction is what the plate holes are for to state the obvious. If you've exhausted your Google searches for finding out what plates and number of holes the originals had then if it were me I'd try over on the Practical Machinist Hardinge / Bridgeport forum as well as the same on there antiques sub forum. For sure somebody there will know exactly what they had.

Building new plates isn't impossible of course, and a dro with a bolt hole funtion would likely be the fastest, most mistake free method today. Better check exactly what your dro is capable of before starting though. Some will only do a maximum of 99 holes. Hole location isn't super critical on 40-1 and 90-1 heads because the inaccuracy of the plate hole location is divided by the heads worm and wormwheel ratio. With a 4-1 head you have much tighter requirements since there's a much less ratio those location errors will get divided into. The general recommendation I've seen mentioned while home building a few different designs of dividing heads is to use a good high quality NEW and proper short shank spotting drill for hole locations and that's for the more usual 40-1 ratios. So it's not the place to start cutting corners and pinching pennies if you want something that can be depended on to be accurate. 40 and 90-1 heads can have one generation of plates built then the head itself can be used to build a second generation series of plates by using the first ones. Any inaccuracys in the first plates should be around 1/40th or 1/90th depending on the heads ratio on the second set of plates. With only having that 4-1 ratio going that way obviously doesn't work as well.

If what you said is correct and you have the far less common Hardinge head that's the universal one capable of spiral or helical milling then a full set of gears, banjo, and a method of adapting that gear train between your mills X axis feed screw and the input spindle on the head is needed. But that's only needed while doing that helical milling. I'm unsure if the Hardinge heads could do compound indexing or not. If they can the gears are used for that as well but there then not used with the mills feed screw.It's a fairly rare and valuable head with all the original parts. Extremely tough to find those today for any that are missing, and almost anyone that has those parts knows what there worth. It would be a great deal of work and again not impossible to build replacements. I'd look for an online PDF of the B&S universal heads which are 40-1 but would give you an understanding of how the helical milling and compound indexing is set up and used. Then finding the instructions Hardinge would have included with your head is going to be needed for sure. That gear train can get real complex to figure out even with one. If you've got a Machinery's Handbook it should also have the basics of setting up and using one of the B&S universal heads as well. I'm afraid I know very little to almost nothing about the Hardinge heads so can't be of much help.
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mklotz
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Re: hardinge 4 to 1 dividing head

Post by mklotz »

astronrs35 wrote:Help. I got what I thought was a great deal. Well I found out it is a Hardinge 4 to 1 ratio Dividing Head and spiral. The one plate it has is a home made plate. Instead of it being 15,16,17,18,19,20 it is 19,18,17,16,15 and 3. well 20 is a very important size. I have looked everywhere for the plates but so far no joy. It uses a 5+ inch plate 1/4" thick. I would love to rent/borrow/steal/and last result buy a correct plate. I am just learning so please keep your answers to a beginners levels. I have a Bridgeport and a DRO along with a Chinese 10x40 lathe. I saw some coordinates to drill for a 40 to 1 but almost nothing for a 4 to 1. I had hoped to find the correct plate and copy it. Turbocain or Mr. Pete222 does show how to use it so I have made using the 18 line and moving 13 spaces it makes a nice 6 sided part. And help would be greatly appreciated.
First a question...

With a typical DH you divide the gear ratio by the number of divisions desired to find the number of turns of the crank. For a typical 90:1 gear ratio and six divisions, this would look like:

90/6 = 15

so you would turn the handle 15 complete turns between each operation on the workpiece.

Applying this procedure to your 4:1 ratio and six divisions, this yields

4/6 = 2/3

which can be accomplished by moving 12 spaces on the 18 hole circle (or 10 spaces on the 15 hole circle). Is your "13 spaces" a typo or an incorrect count of the actual 12 spaces you moved?

There are several programs on my website that can help you. DIVHEAD will calculate turns and holes for any gear ratio and set of hole plates and its companion, DIVHEADT will generate tables of the same information. DPLATES will tell you which hole circles you need to make all the divisions up to some input maximum.
Last edited by mklotz on Wed May 24, 2017 8:35 am, edited 1 time in total.
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astronrs35
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Re: hardinge 4 to 1 dividing head

Post by astronrs35 »

It sounds like I would be better off selling the Hardinge unit and getting a cheaper unit that is complete. I realize I am a novice just learning and I am not ready for such precision. I will however check the forums you suggested. Maybe someone would consider trading me an entry level unit. I do not expect to be doing any real precision work. Just some general maintenance type work. I have the manual and parts list for the unit I got from " Ozarktoolsmanuals.com" Unfortunately it talks more about cutting spirals than setup and use. It does contain the tables and gears needed to accomplish this. To me, this is way over my head. Thank you for your wisdom and advice in this. I was at a loss but now I feel better knowing there is still Master out there to help. hank you so much, David B North Carolina
pete
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Re: hardinge 4 to 1 dividing head

Post by pete »

Yes you could do that. I wouldn't rush into doing so though. As I said those heads are pretty rare. And it really depends on your exact needs. If all you need is dividing the fairly cheap Vertex 40-1 dividing heads will do that. But one of the 6" or 8" horizontal and vertical Vertex rotary tables with the tailstock they sell for them and the dividing plates they also sell would likely be the better move since you can then do rotary milling plus dividing. There's cheaper units around. But my minimum would be a Vertex or better. If the dividing can't be done accurately then it's pretty much a waste of money.

If anyones got the math down 100% it's Marv. He's the real guy to listen to.
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Re: hardinge 4 to 1 dividing head

Post by Wolfgang »

astronrs35 wrote:It sounds like I would be better off selling the Hardinge unit and getting a cheaper unit that is complete. I realize I am a novice just learning and I am not ready for such precision. I will however check the forums you suggested. Maybe someone would consider trading me an entry level unit. I do not expect to be doing any real precision work. Just some general maintenance type work. I have the manual and parts list for the unit I got from " Ozarktoolsmanuals.com" Unfortunately it talks more about cutting spirals than setup and use. It does contain the tables and gears needed to accomplish this. To me, this is way over my head. Thank you for your wisdom and advice in this. I was at a loss but now I feel better knowing there is still Master out there to help. hank you so much, David B North Carolina
Instead of selling a beautiful and excellent tool, why not learn to use it? Yes, simple tools are easier to grasp and use but, a complex tool will also perform the simple tasks; vise versa not so much.

So, please don't rush out to sell your gem but learn to use it.

Wolfgang
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