Taig Lathe cabinet - base frame

The frame of the lathe stand

The frame was built based a size calculated to permit the Taig lathe to be mounted with enough room to allow the mounting of a motor, space for changewheels, backgearing, control space for the leadscrew control, and any accessories I planned including a taper turning attachment and profile copier.
 

Figure 1- Base frame with headstock reinforcing

The overall baseplate dimensions became 500 x 850mm (20 x 33.5"). The baseplate became the core of the design with a sheetmetal tray built to sit under it with a lip coming up from the front and sides, and an extended lip coming up at the back making a swarf tray capable of containing swarf or coolant.



Figure 2 - Base frame with drip tray and top sheet

The frame was welded up from 20x20mm (3/4 x 3/4") angle iron, or tubing from the scrap pile.



Figure 3 - Base frame with backboard frame attached

The Taig lathe is a cantilever bed lathe with a foot under the headstock. To provide a strong stable mount for the lathe I welded a piece of 4mm (5/32") into the base. (shown in Figure 4) This means the lathe is mounted to 8mm (4+4mm) of steel, whereas the rest of base will have a thickness of only 4mm. I deemed 4mm as thick enough for magnetic bases, or drilling and tapping into, whereas I felt it prudent to have it thicker under the lathe foot, and for mounting the motor assembly.



Figure 4 -Base frame from rear, showing angle iron brackets for back board, and reinforcing sheet at headstock

The backboard for the lathe stand adds 560mm (22") to the height of the stand and runs the full width of 910mm (36"). The backboard is attached to the baseframe by some bolts mating the board to some angle iron brackets.(refer Figure 4)

The frame contains room underneath the baseplate assembly for drawers - the height of which is 100mm (4"). The drawer widths are governed by the spacing of the stiffeners added to support the plate under the lathe foot, and a small offset at the tailstock end to support the E-stop. The space behind the E-stop is used to house a "swarf drawer".


Figure 5 - Bare frame with drip tray and top sheet removed, backboard frame attached.


The frame has 2 fold-away handles attached for moving the lathe - these are located at each end of the base.


Figure 6 - The fold away handle at the tailstock end of the base frame

The backboard was clad with a sheet of polycarbonate approximately 6mm (1/4") thick (a salvaged shop display shelf when the local postoffice was renovated), and a piece of colourbond "signwhite" from a salvaged shop sign. The sheet of polycarbonate served 2 purposes:
a - the additional thickness stood the sheet of colourbond away from the frame at the bottom edge permitting the lip of the base drip tray to slide behind it - preserving the sealing of the tray assembly, and
b - the additional thickness added stiffness and "meat" to the backboard providing substance for screws to engage with, and to dampen any movement in the colourbond sheet.



Figure 7 - clad backboard - rear view.

A few other features are in the frame, but those will be elaborated upon during the articles describing what they support.
Overall dimensions - 710 (H) x 550 (D) x 910 (W)  = 28" x 22" x 36"

Hose suspenders - Part 2

I tried using a similar method of bending the tighter curves for the "square hook", but it was too tight a turn, and the forces tore the slipper apart. I was back to either forging, or some other method. (Trust me, I want to forge, but I also want to reduce the number of outstanding projects first.. once I reduce my workload, then I'll fill it back up again)
In the absence of forging, I decided to cut the rod and using the cuts as weaknesses, bend and then reweld (sort of like scoring cardboard to bend it)


The above photo shows a piece of rod with the cuts made, and another piece already being bent using the cuts as a weakness.



This photo shows how the pieces come together to make the finished hook. They are welded together as part of the construction, and the cut rod will have the exposed areas built up by welding.

Nine hooks welded up, all cut areas built up, both hooks joined at the top, bottom, and back, and the ring added.

A note about the rings. They started life as an offcut of scrap I fished from the scrap bin. I cut them into 1" (25mm) long pieces on the cutoff machine (aka drop saw) and then took them home. I chucked them in my lathe, and deburred them inside and out. I then turned a deep 30 degree chamfer on the inside at each end of the pipe section.

Once everything was welded, I hit then all over with a flapwheel in the grinder (these things are amazing!!! never used one until Bender - Now I'm buying them online whenever possible)


The results of flapwheeling the hooks was pretty good, I found a few welds to redo, then got the hooks ready for painting - the primed hooks shown below.



After two coats of primer, I painted two coats of epoxy paint over the hooks. It's "handrail yellow" supplied from the fitters at work. I reason the paint stands up to a lot of knocks and scrapes pretty well, and the bright colour will help the equipment stand out, and not be missed on the fireground. From memory the paint brand is "Galmet" - I can't be sure since I returned the tin once I was finished with it. The primer was the same primer I used for Bender - local "White Knight" steel primer.



Part 3 will cover the other part of the hose suspender.

Foundry "Robot" - part 2

Following on from "part 1".. the tilting joint (located under the main sleeve joint) is comprised a small pipe/bar joint atop the spigot joint.
The photo below shows the pipe welded to the top of the spigot joint, and the two cheek pieces holding the bar...

Photos of tilt joint in action - from one extreme...

To the other extreme...
The dust cover was also shown is those photos protecting the sleeve joint, and it's bearing shells. There is also a carry handle visible - I put it there since when I first moved the robot, I'd let the spigot joint open, and carry the base as a separate piece form the top... now they are always together with a hook, which is disengaged after movement.

The gripper...
Basically I designed this to be fully adjustable. By changing the "fingers" I can change what it picks up.
The fingers have a full range of movement between two extremes, shown below...

Above was "fully open", now this is "mostly closed"...


I say "mostly" closed since the finger design prevents further movement, but the mechanism permits more movement.

The gripper consists of some major parts - all of which are visible in the photo above.

a - The actuator and bell cranks -square pipe at low left and flat bar bolted to it, up to and including the small plates which tilt between the pincers

b - bolt on "fingers" - held to the bell cranks via 2 of 1/4" bolts - the angle iron "pincer" shapes with the small length of flat bar at the end near the bell cranks

c - nose piece - it's the small piece of round pipe visible protruding from the end of the square pipe... the nose piece actually includes the last inch of square pipe (removable)

These components allow the gripper to work, and be modified to suit the crucibles in use. My pipe crucibles have a "tang" which I use to locate them, and the nose piece mates with that. If I use a ceramic crucible, the nose-piece is swapped for one resembling an up-side-down letter "L" which locates the top rim of the crucible, and the fingers are broader, and more curved.

The next part will show the controls, and a test drive of the robot

Bender's Head - eye shroud

The fiddliest bit of the project - the shroud which goes around Bender's eyes.
I first planned on building this part using slices of extinguisher and simply flattening the round section onto a mold/pattern/former, and then cutting and welding it on - sounded good in theory, but nearly impossible to do in practice without resorting to heavy equipment, or forging temperatures. - sorry no photos of that attempt - all evidence was taken to the tip months ago.

The second (and successful) attempt was to use a "built up" approach. I split some of the pipe I used for the arms and legs longitudinally, and inserted pieces of sheet in between the pipe halves to form up the shroud. In the photo below the two halves of a shroud are seen on the left, and a completed shroud on the right.

I didn't bother making the sheet the same length as the pipe halves since I knew the pipe had to go back to the centre line of Bender's head, where as the sheet did not. In the next photo the marking for the intersection with the head has been marked with a cheap whiteboard marker. (I grab the cheap ones whenever the discount store is in town - I use them for marking metal if I need to have contrast, or the ability to erase the lines (if on smooth metal) - I basically use whiteboard markers like chalk on rusty metal, or prussian blue on smooth. - I do use chalk as well, just whatever suits, or is within reach at the time)

The waste material is cut away, and the shrouds are ready for fitting to the heads.

A sharp observer will notice I have not cut the corners at the back of the shroud too accurately, and have instead commenced thinning the metal from the inside. Knowing the pipe has wall thickness of around 4mm (just under 3/16"), it knew a smooth transition would require the metal to be thinned considerably.

Fitting the shroud to the heads was fairly straightforward. I attached an eye-plate to the head, and then labeled one head "A", and the other "B". I then marked each shroud with a corresponding letter, and marked the top surface of the shroud so the shroud would always be placed on the same head, the same way up. I then worked around the seam touching up grinding, thinning, and contouring until the fit was less than 1mm (~1/16"). I also marked the head so the indestructible red paint could be ground away for the welding.

A note about the red paint... I don't know what NuSwift used, but that paint is amazing. It prevented rust for over 20 years, is hard to remove, and doesn't burn very well. In the welding photos a margin of only 1/2" can be seen between the weld, and the unburnt paint. I weld salvaged material a lot, and the epoxy paints favoured by local industry burns to a margin of at least 1" when I weld comparable thickness metals. The interior of the extinguishers had another paint inside which was pretty good at well... a thin grey paint which was found failed in only 3 of the 40 extinguishers I cut open.

Back to fitting the shrouds on...
Once fitted, the shrouds were welded in place (see photo below), and I then ground and rewelded to try and build a neat consistent fillet.
The fillet is just visible in the photo below. I placed the eyes on the plate, and bolted it in for testing the fit and look - perfect!!


The next thing to do was the liberal application of bog (automotive body putty - "bondo"), and a lot of sanding and general clean up of welds, fits, and general appearance.
I didn't take photos since the amount of dust generated from the process coated everything with a lovely dust, and I didn't want the camera filled with it.
My approach to the preparation for painting was to sand back all rust, and paint, and then apply a skim coat of bog, and then sand back so the surface was smooth. I predominantly used a flap wheel on my grinder for the aggressive work, and used files, knives, and sandpaper for the finer work.

Looking back, I know I missed a few spots here and there - I'll be the first to admit I simply wanted to get this project finished, and weighed the effort for perfection, versus the return on my time. As I said a few times to people, "it's a lawn ornament, not a show piece. I can always go back and strip him back to metal and refinish him if I change my mind."

Next article... painting. I'll discuss the colours I used, and masking the "fiddly bits"

Bender's Head - head & neck

To build Bender's head....
As mentioned previously, the head was made from the top of a NuSwift 9Kg (20lb) DCP fire extinguisher. In the photo below, you can see Bender's head (incomplete) and one of the stripped extinguishers immediately behind him, and several more sitting on the low shed.

To make the head I simply stripped the extinguisher of it's valve, pressure gauge, and cut away the carry handle. I marked the head at the desired height (370mm = 14 1/2") and cut around the extinguisher. I marked up and cut out the opening for Bender's mouth, and marked on the upper and lower limits of the eye shroud. I also cut out the boss from the pressure gauge, and welded a patch in place cut from another extinguisher top (similar to what was done with the foot cups)
A closer view of the above photo shows the marks above the eye plate where the handle was cut away, and how the original valve boss was retained and used to secure Bender's antenna to his head.

With the upper and lower limits of the eye shroud marked on Bender's head, the eye-plate securing holes (bolt and prong) were spotted through, drilled and tested. For the progress photo I dropped a scrap of Colourbond inside his head to simulate his teeth, and start ironing out the details of how that would work.

I'll cover the eye shroud as a separate page (next I promise) and now discuss how his neck joint was built.


The neck joint needed to permit rotation of the head, and provide positive retention of the head. These objectives were both met with the design I used. I started with some scrap pipe which was 165mm (6 1/2") across the outside diameter. The interior diameter of the extinguisher was just under 180mm so there was a gap of approx 6-7mm (around 1/4") all around the smaller pipe. This gap was used to house the retaining ring.
The retaining ring was a 1/4" ring cut from the same pipe as the neck joint. I then cut the ring and added a piece of steel, and re-welded it in so the ring was a larger diameter, and an loose fit over the neck joint, and a slip fit inside the head.
The retaining ring was plug welded at several locations around the head through 1/4" diameter holes.
The retaining ring rides on a number of support bolts which have been tapped through the neck ring, and the head is retained by a number of retaining bolts which are held in nuts welded on top of the neck ring. A sketch of the joint is shown below...


And the photo below shows how it looks in real life, plug welds, retaining bolts, neck ring and gap containing the retaining ring all clearly visible. The neck ring is only 25mm (1") high, and the gap under the head edge, compared to the bottom of the neck ring is 1/4".

The bottom of the neck ring is welded to the top of Bender's body to attache his head. Since I made two heads, I made two neck joints, the spare neck joint being used to keep the spare head from scratching up the book shelf.

The hole in the top of the 44Kg (100 lb) propane cylinder where the valve boss used to be was oxy cut out by one of my friends from work. (Thanks Vince!!) I was originally going to chain drill it out, but oxy cutting was quicker, and easier. The same workshop where Vince works also has the bandsaw I used to cut the neck rings, and retaining rings. The guys at the workshop are always happy to see what nutty things I'm building at home, and got quite a giggle out of the arbor press I built using an old door closer. I don't know if they see value in what I make, but they're always willing to offer advice on techniques, and when I get some spare time, I'll be learning how to oxy cut from them. All I need is some spare time...

Next installment - building the shroud for the eyes.

Bender's failed eyes

I won't go into too much detail on this aspect of Bender's construction, but it was something worth trying, and it may be of use to someone.
I had this one gas cylinder, it was from inside a pressurised water extinguisher. The bottom of it was a perfect hemispherical shape, and the diameter was perfect for Bender's eyes... the problem was I only had one of them.



I decided to use this one cylinder as a positive pattern, and make molds so I could replicate the hemispherical end. I cut up a scrap piece of 4" pipe for flasks, and using common packing tape to close off the bottom, half filled the pipe segments with sieved clay mixed sand. I tamped the sand down as I put it in the flask, and tamped the sand around the pattern as I sprinkled more sand in. Effectively I was creating an "open face mold" for each eye. I created six molds as shown in the photo below. The long 1/2" bolt was used for tamping the sand.

Now I had the hemispherical shape of Bender's eyes sorted, I needed a way to attach them to the rest of his head. I'd designed the use of an "eye-plate" which would bolt to the rest of his head, and essentially be a carrier for the eyes. This design made fabrication easier, and allowed for other features such as "clip on eyelids". To attach the eyes to the eye-plate, I made up some fixtures which were basically a 1/4" bolt, with some heavy wire welded to it. One leg of the wire was bent parallel to the bolt, and presented 15mm (~5/8") away from the bolt centre. This leg was to stop the eye rotating around the bolthole when fixed to the eye-plate. The rest of the wire was simply bent in a loose loop to be encased in the eye casting. The photo below shows a row of bolts, having their heads welded to the wire loops, holes drilled in the aluminium extrusion maintains the spacing of the bolt and the wire prong.

The molds were then filled with "post mix" cement, and the bolt/wires fixtures were inserted. The cement was left over from another job, and used pretty much straight from the bag, but I'd sieved out the larger aggregate so it'd flow better in the molds, and not have any inclusions.

Once the cement had cured, I removed them from the sand molds, and cleaned them up, and sealed them with sealer undercoat paint. I had a hiccup when two of the eye rolled whilst the paint was drying, and stuck to the benchtop, when I pulled them off, the paint pulled out of the cement - this was a warning of what was to come.

Maybe the cement was old, maybe removal of the aggregate did something, maybe the phase of the moon was wrong, maybe the mix was too wet, maybe, maybe, maybe - whatever the reason, the eyes were too fragile. I found I could "cut" them with my thumb nail, and I accidently dropped one of the eye-plates when it was loaded with the eyes, and the eyes flew apart. (see photo below)
Based on that, I decided cement eyes were not going to work. I retained the eye fixtures, plates, and started looking for a better method. What worked was only a minor deviation from this plan, but it worked well.

Grabby & Squeezy - Hands part 2

This page covers the shrouds of the hands, and fixing the hands to Bender's arms.

The shrouds are simple conical transitions. From my interests in model rocketry, I had a tool called VCP (Visual Centre of Pressure) which contains a simple little utility for generating the development of a conical transition on paper. I used the package to develop the template for the hand shroud using the arm diameter at one end, the flared diameter at the other end, and the length of the transition being set to the height I choose (83mm to match the arm diameter, but then padded the number out to 95 so I had room to adjust things during construction).
The resulting VCP printout was then cutout, and traced onto the colourbond offcut shown above.
I added some extra depth at the narrow end of the conical section for retaining tabs, and proceeded to cut out the shape.

The first shroud has been cut out, and rolled, the second one hasn't been cut yet. Rolling the colourbond would have been easy if I had some sliprolls, but I don't. I simply clamped some pipe to the benchtop, and pulled the colourbond piece through and manually forced the curve into the metal. I repeated the bending a few times to tighten the curve, then clamped, drilled, and pop-riveted the shroud together.

This picture shows the tabs I cut for retaining the shroud. Knowing the shroud can't move towards Bender's fingers due to the conical shape, I wanted to retain the rear of the shroud by pinching it in the wrist joint. I know if I'd measured and marked everything to the highest degree of accuracy, it wouldn't be necessary, but knowing my welding, the slightest warp would have betrayed the joint, it was easier to make the shroud retained against the joint for a seamless fit.

The photo above shows one shroud fitted to one hand, the second (right) as the two pieces. A small slot was ground into the wrist plate to provide clearance for the pop rivet. All rivets were beaten down flush with the sheetmetal to reduce the protrusion, then later tidied up with bog.


The hand is attached to the arm via the captive retaining bolt in the wrist plate. Prior to welding the spacer pipe into the plates, the bolt head was modified so a screwdriver could be used through the access hole to turn the bolt. The one bolt holds the hand in place, and positioning of the hand is accomplished by loosening the bolt, rotating the hand to a suitable angle, then re-tightening the bolt.

When the bolt is tight, the shroud to wrist seam disappears. There is a small step in the diameters at the seam, but that will be disguised when the painting occurs.


Since I was out of "Ole Fortran" beer, I had to make do with one of the drinks favoured in this area. The Lemon-Lime SOLO is a nice drink, and I can see why the guys in the workshop prefer it on hot days (Isn't that everyday around here?) I know I got addicted to them after one shutdown, so now I try and limit myself to only one can per day.

So what haven't I covered yet? Still to come; antenna, head, eyes, and then painting.

Grabby & Squeezy - Hands part 1

Grabby and Squeezy - these are the names of Bender's hands.

Knowing how important Bender's hands are to him, I spent a lot of time trying to figure out the best way to build them.

I'd been collecting his fingers for ages - the fingers are discharged CO2 cylinders from life jackets. I tripped over some at work one day and recognised the shape. The guys on shift, and maintenance saved them for me and I ended up with enough to make 4 hands. I'm retaining the spare fingers in the hope of redesigning the hands in the future.

As with everything else in Bender, I started with scrap 4mm galv sheet. I marked out a number of disks, 2 to match the diameter of the arm pipe, 2 to match the inside diameter of the hand, and 2 to match the diameter of the flared hand. The largest plate (flared diameter) was then marked out with 3 radially spaced holes to match the diameter of the Co2 cylinders. (finger plate)
A central hole was also drilled in all plates for the retaining bolt.


The above photo shows the components which make up the hand. From left to right across the edge of the welding table the parts are; Arm plate with captive nut, wrist plate, captive retaining bolt, pipe spacer, finger plate, 3 fingers.
The retaining bolt has had the threads nearest the head undercut so the bolt can spin in the wrist plate and not fall out, or bind. The spacer pipe seperates the wrist and finger plates.
The pieces above the components on the table include the made up shroud, but that will be discussed more in the next page (part 2).


The components assembled. The arm plate has been welded to the end of the arm, the wrist and finger plates welded to the spacer pipe with the retaining bolt already captive in the wrist plate prior to welding. The fingers were set through the holes, with a moderate degree of flaring, and then welded in place. Another view of the the assembled hand structure is shown below...

Part 2 of "Grabby and Squeezy" will cover the construction and fitting of the shroud, and placing the hands on the arms.

Bender's Arms

The arms were made from the same size pipe as the legs, but needed a significantly more aggressive curve coming out from the shoulder. I marked up the 12,2,and 10 o'clock line as I did with the legs, but placed the cut lines closer in the are with the tightest curve. When I cut the 300 degree segments, I cut them wider by using the 2.5mm wheel, and making distinct V cuts, instead of simple straight cuts. The cut, but not bent, arms are shown on the welding table.


The welding table will be the subject of a page in the future, I'm rather pleased with how it turned out.


A closeup of the cuts showing the V cuts in the 300 degree segment. As I bent the pipe I had to tweak these cuts here and there to get the tighter curve for the upper arm.

As with the legs, I omitted to photograph the welding process, but it basically was grind out the cuts to remove the surface rust, then weld the cuts closed, and fill the open cut on the 60 degree segment cuts. The welded arms are seen laying on the ground in the last photo in the legs pages.

Now to make the shoulder/arm joints...

These shapes were made in the 4mm sheet I'd used everywhere else. The one on the left is the ellipse shape to match the arm pipe when cut at 45 degrees, the one on the right was welded into the shoulder joint (see the body page for this). The central bolt will be used for retaining the arm, and the smaller bolt will engage with one of the eight radial holes to lock the arm in one of eight positions. The photo shows the nuts I used to hold the bolt heads in place until they were welded in place from the back.

The above photo shows the ellipse plate welded to the arm pipe. I cut the arm at 45 degrees and then tack-welded the ellipse plate in place before grinding the closer fit, and then finishing the weld.
How did I mark the 45 degree cut on a the curved pipe? - A trick I read about used by blacksmiths was employed. I filled one of the quench buckets near the door with water to the brim, then carefully laid the pipe into the surface of the water so the waterline would mark the 45 degree line. Then I removed the pipe and highlighted the line with engineer's chalk. - The original blacksmith trick used coal dust floating on the water's surface to mark the line, but the rust on the pipe showed the line for me.

The "nut" on the central bolt was whipped up by welding a short length of 3/4" pipe to the nut, and then slotting the end for a scrap of sheet. A few tack welds and I have a long-reach wing-nut.
The photo below shows the wing-nut being used from inside the body to hold the arm in place at the shoulder joint.


A progress photo of the arms and legs attached. The arms were later shortened since I had deliberately made them longer than needed until I finalised the design for Bender's hands.



Next... Grabby and Squeezy - a.k.a Bender's hands