Dividing Head for Taig (and others) - Part 1 - Body and introduction

The dividing head was inspired by the work done by Tony Jeffree, and then heavily modified to suit my own circumstances and situation. (Note - Tony has a second design which uses a Taig spindle - see this link)
All photos in this series of articles were taken after construction had concluded since I did not have a camera during the build. This build occurred in Q2-3 of 2005 and was documented on Nick Carter's page back then.

Figure 1 - Dividing head in use on Taig Lathe

You can buy dividing heads - example shown here from Amazon, and there are books which touch on building your own (another example from Amazon) - in short, you need to decide what resources you have,and determine the best course... in my case I did not have a great amount of money, and I did have some time, and a willingness to learn - this meant I made my own. If I had the money... the start of many dreams. I don't have either of these products, but show them as examples of alternatives to scrap metal, wrecked sewing machines, etc.


















Building the dividing head body and base.
I started by making up a spindle. Tony's one used a drill chuck, but after reading many text books which talked about not disturbing work in chucks, I decided it would be better to make my dividing head use the lathe chuck if possible. This meant I had to make a spindle with a nose of 3/4"-16 tpi, with a 30 degree included angle for collets, and a through spindle bore of at least 3/8".
I had previously bored the spindle of my Taig lathe to 7/16" not long after purchasing it so I could pass 3/8" stock through the head - I used the same drill size to bore out the spindle of the dividing head.

Using a larger lathe (Thanks Dad!) I turned a 3/4-16 thread on a piece of 3/4 shafting, and drilled/bored the 7/16" through hole. I then made a collar which was shrunk on to form the register face for the lather spindle nose. This register face ensures the alignment of the lathe chuck. Whilst facing the register face, I also bored the tapered seat for the taig collets.
At the same time as all this lathework, I also threaded the other end of the spindle (3/4-16) to use for thrust nuts, and securing worms , etc.

By the time I'd finished the spindle, I was back home, and unable to access Dad's lathe - this meant all subsequent work was done on the Taig Lathe.

The body of the dividing head was made from a short length of 50x50 (2' x 2") aluminium I picked up at the scrap dealers.
The base plate of the dividing head was made from some 1/2" plate which was a reject from some CNC mob (I picked it up at the same scrap dealer as the 2"x2" piece)
I found if I stacked the 2" x2" on the plate, on the carriage, the centreline was in line with the spindle. Perfect for my immediate plans, and in line with my longer term goal.
The theory was I'd build the head on the plate base, and then should I every need to use the head on another lathe, it was simply a case of making a new base plate.. all other parts will transfer across.

The base plate was cut to square the end (The off-cut piece became the handle of my 3/16" allen key) and appropriately drilled and counterbored for the Taig slot pattern.


Figure 2 - original base plate shape - allen key handle made from off-cut.






The square body was then bolted to the plate, and line drilled and line bored on the Taig. Somehwer in all the line boring I used a shaft as an arbor, and turned the square body on the shafting to form a spigot at one end of the body.

The line boring provided a clearance fit for the 3/4" diameter spindle, and a light press fit for the bushes used at each end.

Figure 3 - Body on base plate

A brake was made and fitted to the front of the body which engages the collar shrunk onto the spindle.


Figure 4 - Front of body showing brake on collar

The spigot which was turned on the rear of the body is used to support the plate carrier. I saw somewhere that some dividing heads are used horizontally and vertically, and that some models allow the position of the plate to be changed to make things easier on the user... seemed like a good idea to incorporate into my build.

The worm and gear for my dividing head was salvaged from an old Singer sewing machine I found on the side of the road on curb dump day. It's a 24:1 ratio set which is OK for this design. I bored out the spur gear to suit the spindle, and cross drilled and threaded some grub screws in place. A normal 3/4-16 nut was cut down and faced to become a thrust adjustment nut. The other half of the thinned nut is often spun on to the spindle after the spur gear as a lock-nut. The grub screws on the spur gear engage in filed flats in the spindle thread.

Figure 5 - spigot, thrust-nut and worm on spindle.

The plate carrier will be discussed in another article, but here is a photo of it in it's place on the spigot.

Figure 6 - Plate carrier in place on spigot

The body really isn't much more than support for the spindle, and a means to hold everything else on the dividing head. I tried to design the body to make the head transferable from one machine to another - the base plate is the designed mechanism to permit that.

The plate is designed with holes in a grid to allow the plate to be mounted on Taig T-slots either parallel, or perpendicular to the slots.

Next articles: Plate carrier, plate generation, and sector arms and worm driving.


In the meanwhile I got the carcass of the field desk made yesterday, and hope to have the woodwork completed over the next week or so, then make up the catches, hinges, and handle over the next week, then inletting, finishing and it's complete. Everything takes time since I only have one day per week to do work - I try to keep the Sabbath holy, and work does a good job taking the other 5+ days... My wife is a darling since she encourages me to spend at least half of every Saturday in the shed - for that I'm most grateful.

Taig Lathe Stand/Cabinet - introduction

The current project...
My Taig lathe has been residing on a sheet of 18mm MDF for the past 10 years. The sheet has a wooden drawer built in underneath it, and a clutch/ jackshaft system for speed control. I will put a photo up in this series of articles, but not yet, this post is more a "preview".

Basically the old base (lathe stand) works, but it has limitations and problems. Some of the problems are the result of a certain removalist, some the result of bad design on my part, and most are simply the result of cutting corners due to cost constraints. - whatever the reason, it's time to make things better.

I'll do up a series of articles covering the design and build (mechanical and electrical) later, but for now here's some progress photos and a brief note of some features...
Lathe stand/ cabinet features:
full length/width drip tray
2 lockable equipment drawers under the drip tray with full extension
removable swarf tray
swarf gate in drip tray for dumping swarf
removable back board
4 switched GPO's (power points) with MCB
adjustable motor mount with belt unloader (clutch)
fold in carry handles
magnetic base with enough thickness for tapping holes if needed.
enough room to permit/ support my planned projects (backgear, change-wheels, taper turning attachment, indicator bases)

Motor controls:
24VDC 500W PWM VSD with reversing switch
16-20A over current protection
NVR (No Volts Release) circuit with additional e-stop at tail stock end




Just  waiting on the postman to deliver a few parts and this job is finished. The VSD cabinet (LHS rectangular section) contains:
500W 24VDC PSU (courtesy surplus parts online)
6800uF capacitor from a Seimens VVVF (for smoothing)
125mm fan (with some trickery in the ducting) for forced cooling
PWM circuit (with heatsinking)
control switches (Start, Stop, Speed control, reversing switch)
IEC socket with filter

DIN mount rail containing -
16-20A SFKOL overload protection device
NHP Terasaki MCB for isolating all 240VAC circuits
Industry standard relay mount and relay for NVR circuit
The DIN mounted components are accessible through the front panel (for resetting, or fault finding)




Both drawers are accessed from the front, on ball bearing slides with full extension - no excuse to have things lost in the back of the drawer again.




The removable back board supports the electrical circuits, and a tray for storing things during work - a work light will be attached to this backboard as well.




The range of travel in the "unloader" mechanism is shown here (the distance between the shaft and the vertical steel ruler - about 35mm (1.5")). The adjustable motor mount is shown midway through it's 100mm (4") of travel.




A photo from the tailstock end of the cabinet showing the tray mounted on the backboard - the rectangular holes visible in the slanting face are for the GPOs. The tray has a false floor and is sealed so the GPOs and cabling are protected. The GPOs were mounted in this manner (downwards sloping face) to provide easy access, but also make it impossible for swarf or coolant to fall into the outlet holes.

The materials used is basically salvaged sheet metal - some 4mm gal sheet for the load bearing areas, and sign-white (colourbond) for the rest.
The frame is a hotch potch of 25x25x3 angle, and some 25x25x1.6 square tubing.
All sheet metal bending (that worked - see future postings) was done using metal clamping with judicious use of hammers, wood blocks, and muttered cussin'
Most of the electrical parts are salvaged, however the power supply, and PWM section are purchased/ built  - all other parts removed from salvaged equipment (even recycled some bus mounts from a switch board to make the drawer handles)

The techniques, design, and details will be covered once I get the main computer fixed (power outage cooked one of the bridges in the mobo - lost the O/S drive and a few other peripherals), and few other demands on me at this time

Next update will most likely be in two weeks time - the pictures are already taken, it's just time to type, format and upload.

Bender's antenna - part 2

Before I get too far into the ball and how the antenna holds together, I found this slightly blurry photo of the washer pressed into the bottom of a deodorant lid to stop the lid collapsing in the lathe chuck. The washer was nothing special, not even properly round, just an old thrust washer from the junk box.
So, I've mentioned the three components which make up Bender's antenna.. the ball at the top, the tapered shaft in the middle, and the dome at the bottom.
The ball in this model was an old deodorant ball (Lynx if it matters, but they all seem to be the same size). I considered gluing it to the model, but didn't trust the join. I decided the best approach would be to affix the ball to a shaft which ran through the tapered shaft, and was retained in the dome, or valve. I drilled a 1/4" hole in each of the balls, and then prepared some 1/4" shaft. The shaft was threaded at the end which would be away from the ball, and the "ball end" was hacksawed for a length of around 20mm (3/4") along the middle. I then made 2 small wedges of scrap steel which had a narrow point, but then a steep taper followed by parallel sides of 1/4". The point was to allow a friction fit in the hacksawed slot, the steep taper to force a wide split in the slot once driven in, and the parallel section just for length.
The idea was to use the wedge to lock the ball onto the shaft by making it wider than the 1/4" hole. I mixed up some 30min epoxy resin, and filled the inside of the ball with a 50-50 mix (by volume) of resin, and brass swarf (from under the lathe).
I put the wedges in place (held with a single turn of sticky tape) and carefully inserted the shaft into the ball via the hole, then tapped the shaft down against the wedge so the shaft would expand inside the resin filled ball. The photo below shows the two balls with their shafts waiting for the resin to cure.

The photo above also shows the dome and shaft assembled. This was done by half filling the dome with some expanding foam, then forcing the turned valve and shaft into it and letting the expanding foam lock in under the lip I turned. Once the foam was set, a simple trim with the knife cleaned away any spillage, or leakage.
I tried using a smear of the foam to fill the small gap in the ball seam, but it didn't really take too well.

The threads cut on the end of the shaft (with a die - I'm still working on building a driven leadscrew for my Taig) were matched with a brass sleeve nut I made up on the Taig. The brass was bored, then tapped for the thread, and then finish turned for the stepped bore in the valve. Once the lengths were finalised, I bored out some of the threads for easier assembly, and cut a tool slot in the sleeve nut. A similar tool slot was cut in the underside of the valve threads to make assembly easier. With the ball on one end of the shaft, and the nut at the other, the tapered shaft, and dome were locked together on the cut down valve, and the whole assembly was then placed on a spare extinguisher top for the last photo.

This extinguisher top is how the NuSwift DCP looked before I started cutting them apart - a large bronze boss in the top for the valve assembly, a smaller boss in the middle of the curve for the pressure gauge, a carry handle on the back.
A total of five extinguisher tops are used to make bender, one for the head, two for the feet cups, and two more which are cut up for patches on the others where the gauge bosses are cut out.

Why do I seem to have so many old fire extinguishers? I grabbed them when I was building and using my furnace/foundry. I was using the bottom halves to make cheap low use crucibles for my aluminium, brass and bronze furnace. I never threw the tops away since they had those big bronze valves, and bosses - the intent was to melt them down for stock. When I got the NuSwift DCP extinguishers, there were other extinguishers in the pile I could have had, but there was considerably more NuSwifts than any other type. Once I started bender, I would regularly collect other extinguishers to cut up for the arm and leg segments, but that didn't work out as well.

I will do up a page (or several) about the furnace and it's tools (including the "robot"), but that will be after I complete the documentation of Bender.

Bender's antenna - part 1

The antenna at the top of Bender's head is essentially made of three main components; the ball at the top, the tapered shaft, and the dome at the bottom. The raw material for each of these components is shown in the photo below.

The components in the photo are (left to right); original gutted valve, cut down valve, lid from deodorant, tapered sleeve, and deodorant ball.

The valve was cut down with a hacksaw into a rough shape, before being placed in the Taig lathe and turned down to make the valve fit inside the cut down lid of a roll-on deodorant. I basically turned down the valve to make it round with a lip at the top for glue to key to. I then bored out a stepped bore for the shaft to seat on, and a sleeve nut to be engaged from the bottom. I flipped the valve in the lathe and turned away half of the threads from the original length so it did not take as many turns to install.

A old chair very similar to this one was being tossed out when I noticed the tapered legs. I quickly grabbed it and cut the legs off. Once the curved sections were cut out, the resulting pieces gave me 2 short narrow tapers, 2 short wider tapers, and 2 long tapers. These pieces are shown below...

Once the pieces were measured up, I was able to make the shaft for Bender's antenna from the 2 short narrow pieces once the curve was cut away. The rest has been chucked in the "useful junk" box/container/shed/yard (Maybe I have too much "useful junk"...)

To turn the lid from a roll-on deodorant into the dome for Bender's antenna was pretty simple. I determined that the dome was to be a proper hemisphere, so I measured the diameter of the lid, and then marked the radius as my cutting point. I placed a washer inside the edge of the lid (force fit) to stop the lid collapsing in the lathe chuck, and then drilled/ bored out a clearance hole for the tapered shaft. In the photo below you can see a drill being left in place to capture the lid top as I part it off the rest of the lid.

Yes, my lathe needs a clean - Parting off the top of the lid was fairly easy and did not require any further operations other than deburring with a pocket knife.

In the next part I'll discuss how the ball was secured, and how that then ties the entire assembly together.