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View Full Version : dividing head/rotary table/superspacer....whats the difference?

lbhsbz
02-01-2011, 10:13 PM
I have a 8" superspacer....looks like the typical rutland/enco/grizzly unit where the chuck bolts straight to the table, and if you want T-slots, you have to bolt the T-slot plate to the table.

Then I see dividing heads/indexing heads...which I assume are the same thing...and look simply like they allow one to turn a workpiece X degrees without putting much thought into it once you've determined the correct holes to use.

I don't have any divider plates for mine....but I was wondering, with some math and if I pay attention, can I not get to the same result by simply turning the table to the appropriate degree/minute?

Aside from ease of use...what's the advantage of using a dividing head/indexing head over a rotary table or superspacer?

Also....what, about my superspacer, makes it super or a spacer. Seems like a rotary table to me....you turn the handle, the table turns..rotary table.

Seems like there's way to many names to describe the same thing....and I'm getting confused....again.

sch
02-01-2011, 10:23 PM
They vary in the granularity of the rotation. Spacer is settings that divide circles into small multiples of 2, 3 or 4, and come with
indexing plates that allow rapid shifts from one point to the next (eg 2, 3 ,6 or 12 parts)
Dividing heads can give you settings down to 5-10D apart, with
some verniering capability so you may be able to get to 1D separations (360degree circles). Rotary tables start at 360D divisions and with
added plates can give you circles with odd # of divisions not divisible
by 3, 5, 7 etc or circles divided into prime number divisions such as
37 or 53.

becksmachine
02-02-2011, 01:45 AM
I believe Superspacer is a brand/model name invented by Hartford, it doesn't necessarily have any intrinsic meaning other than it has seemingly been adopted to describe similar units made by other manufacturers. If your superspacer has a handle to "turn" it probably is one of the combination units that combines features of a spacer and a rotary table. A classic superspacer only has a shotpin/latch to allow rotation.

And ease of use is the key here. Or maybe I should say reliability of operation. It may not seem a big deal to index, say, 39 divisions one time on your rotary table, using numbered degree divisions and a vernier, which translates to 9° 13' 50" (somebody check my math). Now if you could do that reliably for 50 gears with no thick, thin or skipped teeth, you are a much better man than I am. ;)

Dave

form_change
02-02-2011, 03:30 AM
A rotary table as the name suggests is a table that can rotate. Therefore you can clamp a piece of material to it and by using the handle mill a curve into a part. A typical use is milling a curved slot or an arc segment. I've used one to shape a 60 degree gear sector and if you rotate the table 360 degrees you can mill a round part. Very handy if you need to bore something and don't have a boring head. A common ratio is 90:1 - that is, 90 turns of the handle is one full revolution.
A dividing head is a device set up for static cutting - that is, index to where you want the part to be, lock the head, cut and repeat. A common ratio is 40 turns of the handle is 1 full revolution.
Both devices are available with indexing plates so that they can index regular amounts. Two things a (universal) dividing head can do that a rotary table can't is a) differential indexing, where spindle motion is fed back into the indexing mechanism, allowing indexing of prime and other difficult numbers (such as 127), and b) use on a vertical mill allows the cutting of spiral gears.
I've never met a 'super spacer' so can't say what it is.
It depends on what you are planning to do of course, but of the two (R/T and dividing head) a horizontal/ vertical R/T can do most of the simple dividing tasks a dividing head might and so is probably the more useful accessory to get for a mill.

Michael

John Stevenson
02-02-2011, 04:20 AM
I think a lot of this is brand and name engineering where different makers are fudging descriptions which detracts from the known descriptions.

oldtiffie
02-02-2011, 06:19 AM
https://www.machineryhouse.com.au/Products?stockCode=R004

JCHannum
02-02-2011, 08:18 AM
Kind of what John said. What, as far as I know, was among the first spacers was the Hartford Super Spacer. This was a plain spacer with a master plate and masking plates for rapid spacing.

http://www.industrialsurplus.com/index%20hd/053a-149.htm

Since then, the term super spacer has morphed into defining the spacer that incorporates the master plate plus worm features that Tiffie's link describes.

JoeFin
02-02-2011, 09:16 AM
Perhaps I'll get schooled on this - but I'll give it a try

A Rotary Table can be set vertically or horizontally, typically has a 90:1 turning ration and can be equipped with dividing plates to mimic the capabilities of a Dividing Head

A Dividing Head sets vertically, has a 40:1 turning ratio, is equipped with dividing plates that include prime numbers, a quick indexing mechanism that allows easy indexing of common gear ratios - and can be rotated 0 - 90 degs to facilitate Beveled Gears. Additionally in some cases, they are also equipped with a "Table Feed" mechanism that allows the cutting of "Helical Gears"

A Super Spacer sets vertically, has a 40:1 turning ratio, is equipped with dividing plates that include prime numbers, a quick indexing mechanism that allows easy indexing of common gear ratios - and can be rotated 0 - 90 degs to facilitate Beveled Gears, and has a vernier scale

gvasale
02-02-2011, 09:27 AM
not all rotary tables use dual (h-v) mounting.

Hartford Chucks (super spacers) do allow (h-v) mounting

Dividing heads allow the chuck to swing up or down.

Someone may make super spacers with features simlar to a dividing head.

Universal dividing heads can be power driven to mate with gear drives on some milling machine (usually horizontal) for helical milling.

Not a complete description, but supplemental to what has been provided.

JoeFin
02-02-2011, 09:42 AM
Some thing we all left out -

Dividing Heads and Super-Spacers have a MT-4 bore to facilitate Collet Chucks too

Timleech
02-02-2011, 12:48 PM
Some thing we all left out -

Dividing Heads and Super-Spacers have a MT-4 bore to facilitate Collet Chucks too

Can be any bore or mount the maker fancies, 50 taper is quite common.
I've seen indexers (with no gearing) sold as 'super spacers', it seems to me there's a sort of gradual scale between the simple indexer and the all-singing, all-dancing Universal Dividing Head, with a multitude a variants and names along the way.

Tim

outlawspeeder
11-26-2012, 10:18 AM
I just picked up a used Hartford without a 3 jaw. It has a 8” by 8” round mounted on it. (yes it is very heavy) I pulled this off as it is cut with a crossed “V” and a couple of bolt holes.

I have a 9 “ round that is about an inch tall. It is not tool steel but it is close to it. It is an end piece that one side looks as if it was cut with a friction saw?? The other is painted yellow and blue and is being faced.

So now for the questions:

Will I be able to cut “T” slots into it?

Should I just put a spiral set of Tapped holes?

I started the facing with a 4” cutter took an hour to get across it. I was cutting it dry.

rohart
11-26-2012, 10:38 AM
Well,n ot much of the above tallies with my understanding. This is my take, for what it's worth.

A rotary table gives you a worm and a handle and no dividing plates in general. You bolt stuff to a table, usually using t-slots.

A dividing heads gives you a worm, a handle, dividing plates and you generally hold stuff in a chuck.

A universal dividing head gives you geared access to the worm gear, and possibly direct to the chuck spindle, so you can synchronise the rotation of your work with the movement of the table the whole thing is mounted on. Typically, mounted on the mill, you take a feed from the x-axis leadscrew to the head, to cut large tpi helices.

outlawspeeder
11-26-2012, 12:21 PM
I never thought about that way. This has dividing plates but NO handle to rotate it. This is a manual rotation until it locks in place.

I just don't know if it is worth trying to cut "T" slots in hard steel of if I should just drill and tap. I have to get the front and back parallel to each other.

So what should I use to cut “T” slots if I go that way?

rohart
11-26-2012, 05:34 PM
To cut T-slots you usually use a T-slot cutter. Hmm...

You mill the main channels nomally, and then you use a T-slotter that is like a few washers on a rod - the washers toothed like a circular saw blade but with only 5 to 12 teeth. I've never done it, and it looks like it would cause havoc with a small mill, but if you haven't got a shaper there's no other way to undercut the slot.

ulav8r
11-26-2012, 09:35 PM
I never thought about that way. This has dividing plates but NO handle to rotate it. This is a manual rotation until it locks in place. What you have is a spacer, the plates allow quick indexing for a limited number of divisions (limited by the plates you have and the size of the stop that fits into the slots in the plate).

lbhsbz
11-26-2012, 09:39 PM