indexing head vs rotary table free sample

Dividing heads allow you to divide a circle into equal fractions conveniently. Anything that involves regular action around a circle is a candidate for a dividing head.

A rotary table has no stops so it is not convenient to do large numbers of things at equal intervals because you would have to painstakingly determine the interval. Also, the rotary table does not divide the circle. For example, if you were making 13 equally spaced operations using a rotary table you would have to calculate some wierd angle for each operation and dial it in--a tedious process. For example, here are the 13 angles for a circle division:

Do you want to manually set each of these values? Have fun doing that. Now, imagine doing it for 53 divisions. You will be there all night. Not only that, the error will be a lot more than a dividing head.

indexing head vs rotary table free sample

Rotary tables are mounted horizontally, and most can also be mounted vertically. In both cases only at 90° to the mill table. A Dividing Head is always vertical, but can be tilted through 90°.

Dividing heads are always fitted with "indexing plates" (holed wheels and clock hands), allowing a wide range of angles to be turned. The indexing mechanism can do intermediate angles. Rotary tables can be fitted with indexing plates as an accessory, but usually the number of angles supported is limited compared to a dividing head. (A generalisation. And, because rotary tables do all common angles, the limitation may not matter.)

Rotary tables are more convenient for general work because most jobs are mounted at 90° or 180° relative to the milling table. Possibly more robust than a dividing head for rough work. When close accuracy isn"t needed, jobs can be spun rapidly by the rotary table without cranking the handle - a time saver. When accuracy is needed the handle and worm are engaged. Usually there"s a vernier scale sufficiently accurate for most work. The handle is also relatively fast because most simple angles can be produced with it. For example, easy to crank from 0, 60, 120, 180, 240, 300, 0 to cut a hexagon head. Unfortunately not all angles are "simple"!

Indexing plates are useful for awkward angles. Cutting a 19 toothed gear requires 19 steps of 18.9474°, which is the hard to remember sequence 37.89, 56.84, 75.78, 94.74, 113.68, 132.63° etc. The Index plate and clock hand mechanism remove the need for the operator to track the sequence but they are still a pain to use in my opinion!

Indexing plates are so awkward that driving a Rotary Table with a stepper motor and microcontroller is popular. You simply tell the controller how many divisions are needed, press "Go", and the computer does the rest. Apart from reducing brain strain and automating a tedious task, the computer eliminates most mistakes. Computers don"t get sums wrong, have excellent memories, and are hard to distract! Also, a computer and stepper motor will do a good job of angles too complicated for the Indexing plates.

Generalising again, I suggest most people, most of the time, only need a rotary table. I see Dividing Heads as specialist tools and have never felt the need for one. For the same reason I drive an ordinary small car rather than a Land Rover. The closest I get to off-road driving is a supermarket car park! You might live on a farm...

Unless there"s a specific reason for needing a Dividing Head, I wouldn"t spend money on one. My rotary table is used a lot, in contrast a Dividing Head is only "nice to have".

indexing head vs rotary table free sample

I have used it in the vertical position to cut a 107 tooth gear which isn"t covered by any of the dividing head wheels I"ve got. I set up an excel spreadsheet with the angle required for each tooth which isn"t as easy as it sounds as the rotary table is calibrated in degrees/minutes/seconds rather than decimal degrees so it took a bit of figuring out how to do it.

indexing head vs rotary table free sample

These days it"s pretty trivial to create a spreadsheet to figure out the required degrees/minutes/seconds for some arbitrary number of divisions n, so it"s not all that big a deal to use a rotary table for dividing. A dividing head is, as others say, probably a bit more convenient both in ease of dividing oddball numbers of divisions and in less mass to get in the way of what you"re machining...but a rotary table will be more flexible. If you want to substitute for a dividing head, be sure to get a horizontal/vertical rotary table, as you"ll want "vertical" mode for dividing (and making gears).

If the rotary table has a Morse #3 center hole (or whatever), in vertical mode you could probably use Morse taper collets for workholding, which might be pretty handy. The only thing is, as hinted above, in vertical mode there may be a lot of rotary table in the way of what you"re trying to machine, if you need to get in close. It"s do-able, but you may to need to be a bit creative in workholding to arrange necessary clearance to get the tool where you need it.

indexing head vs rotary table free sample

A rotary table is a precision work positioning device used in metalworking. It enables the operator to drill or cut work at exact intervals around a fixed (usually horizontal or vertical) axis. Some rotary tables allow the use of index plates for indexing operations, and some can also be fitted with dividing plates that enable regular work positioning at divisions for which indexing plates are not available. A rotary fixture used in this fashion is more appropriately called a dividing head (indexing head).

The table shown is a manually operated type. Powered tables under the control of CNC machines are now available, and provide a fourth axis to CNC milling machines. Rotary tables are made with a solid base, which has provision for clamping onto another table or fixture. The actual table is a precision-machined disc to which the work piece is clamped (T slots are generally provided for this purpose). This disc can rotate freely, for indexing, or under the control of a worm (handwheel), with the worm wheel portion being made part of the actual table. High precision tables are driven by backlash compensating duplex worms.

The ratio between worm and table is generally 40:1, 72:1 or 90:1 but may be any ratio that can be easily divided exactly into 360°. This is for ease of use when indexing plates are available. A graduated dial and, often, a vernier scale enable the operator to position the table, and thus the work affixed to it with great accuracy.

Rotary tables are most commonly mounted "flat", with the table rotating around a vertical axis, in the same plane as the cutter of a vertical milling machine. An alternate setup is to mount the rotary table on its end (or mount it "flat" on a 90° angle plate), so that it rotates about a horizontal axis. In this configuration a tailstock can also be used, thus holding the workpiece "between centers."

With the table mounted on a secondary table, the workpiece is accurately centered on the rotary table"s axis, which in turn is centered on the cutting tool"s axis. All three axes are thus coaxial. From this point, the secondary table can be offset in either the X or Y direction to set the cutter the desired distance from the workpiece"s center. This allows concentric machining operations on the workpiece. Placing the workpiece eccentrically a set distance from the center permits more complex curves to be cut. As with other setups on a vertical mill, the milling operation can be either drilling a series of concentric, and possibly equidistant holes, or face or end milling either circular or semicircular shapes and contours.

with the addition of a compound table on top of the rotary table, the user can move the center of rotation to anywhere on the part being cut. This enables an arc to be cut at any place on the part.

Additionally, if converted to stepper motor operation, with a CNC milling machine and a tailstock, a rotary table allows many parts to be made on a mill that otherwise would require a lathe.

Rotary tables have many applications, including being used in the manufacture and inspection process of important elements in aerospace, automation and scientific industries. The use of rotary tables stretches as far as the film and animation industry, being used to obtain accuracy and precision in filming and photography.

indexing head vs rotary table free sample

The mill rotary table is one of the main accessories of milling machine. As a precision work positioning device, it is widely used for indexing drilling, milling, circumferential cutting, boring, etc. The rotary turn table for milling machine is made from casting with high quality, can work with a set of dividing plate.

Both vertical and horizontal with two functions. Circle cutting, indexing drilling, milling and more complicated work are possible when the vertical position of the table is used together with the tail part.

indexing head vs rotary table free sample

I used a scrap riser to mill a custom knob with 17 flutes as an example, because most traditional manual rotary tables and dividing heads struggle with dividing prime numbers.

I needed two large holes in plates, 46mm and 40mm. I mounted the plates on the rotary table, set the indexer to continuous run and slowly lowered the cutting bit. This saved me from having to buy 2 different size hole saws that I might never use again.

indexing head vs rotary table free sample

6.1. North America Automated Rotary and Indexing Table Market Size (US$ Mn) and Volume (Million Units) Analysis & Forecast, by Configuration, 2017‒2031

indexing head vs rotary table free sample

While a spin indexer might give us more flexibility, for creating simple divisions, a 3D printer can be extremely useful to make an object we can use as the reference for indexing. In Figure 3, we have used a 3D-printed octagonal part to create a collar for some 12 mm brass bar stock. We quickly designed and printed the octagonal collar with the inner diameter being a press fit onto the brass bar stock. Using the faces of the printed octagon, we can rotate the circular bar eight times and perform an operation on each face. In this instance, we have used a precision vice to clamp the workpiece. We set the position with the 3D-printed collar using a small riser block between the milling table and the collar, and then milled the small keyways into the bar stock, repeatedly indexing the part by resetting the piece to the next face of the octagonal collar.

Another workshop item that is a midpoint tool (and not as costly as a dividing head) is a rotary table. A rotary table is a milling accessory that is primarily designed for machining arc paths on the manual milling machine. However, as it can rotate a workpiece through a known number of degrees, it can also be   used for dividing purposes. It consists of a circular worktable which is rotated by a gear and worm-gear arrangement attached to a winding handle. It’s a common project for machinists to convert rotary tables into forms of dividing head by adding dividing plates but, even in its standard form, the rotary table can be useful for dividing. In Figure 4, we can see that we have used the rotary table and a vice to create a circle of 15 equidistantly placed holes around a pitch diameter. Simply dialling the table around 24 degrees per index using the graduated dial moves the workpiece to the next position, and a grub-screw on the table acts as a lock to clamp the table while performing the drilling operations.

With imagination, hackspace-type tools like laser cutters, 3D printers, and CNC machines can be used to create all kinds of tools that can help with dividing tasks. Printing or cutting dividing plates that can be attached to spindles can enable us to create dividing heads, and we have seen many examples of 3D-printed gears being used to index workpieces.

Any number of marks that’s a factor of 60 can be made by starting with the gear set to zero at the reference gear lock, and marking the first point and then indexing the assembly around to the desired division. So, for the example of a rocket tube with 4 fins, indexing and marking through the numbers 0, 15, 30, and 45 gives the correct points. Having marked the tube, we can remove it and extend the marks using a piece of aluminium angle to ensure the lines remain straight in relation to the centre point of the tube. While this application is a pretty unusual use case, we hope that it perhaps inspires ideas into how laser-cut or 3D-printed tools can be made that assist dividing tasks in projects. All the files for this particular tool are available here: hsmag.cc/UXcwxP.

indexing head vs rotary table free sample

The Motion Index Drives RT Series Fixed Rotary Index Tables encompass a large range of sizes, ranging from our model RT100 up to our RT1250. In addition, special cam-driven devices can be custom made to order for your automation needs. RT Series Fixed Station Rotary Table are offered in a fixed number of stations or as a flexible turntable with a servo motor or standard AC brake motor with encoder. With the addition of Motion’s patented NANO Indexer Technology, the RT Series Fixed Station Rotary Table becomes the world’s most accurate barrel cam indexers.RT Series indexing tables are constructed with strength and reliability in mind. Robust design and components ensure this device will maintain precision in intense factory settings.