Seize the moment.

Stripped and ready for action.

Stripped and ready for action.

The decision to get cracking on the bike coincided with two pieces of good fortune. First, work called just before I started on it to ask if I’d mind staying at home that week as there wasn’t enough work going through the studio to keep me busy. Regret that I wouldn’t earn any money that week was countered by the prospect of getting a fair crack of the whip on my bike build, so a reasonable result. Then, to my utter surprise, the weather turned unseasonably warm and sunny for about a week, perfect for fettling bits of metal out in the shed and garden. Having wrestled the bike into the back garden, no easy task given a very narrow access alley out back and the need to fit some much reduced width handlebars, the strip down was quick. Originally I’d built it in a way that would enable me to take it apart if I ever needed to and so was grateful for having made that decision. The work plan was front mudguard first, then the clocks and headlight area and finally the rear mudguard. After a quick once over and a clean it was time to get started.

Not bad, considering.

Not bad, considering.

I’d sketched out several solutions for mounting the front guard but, in the end opted for the simplest one which used two straps or hoops connecting the mounting holes on the fork legs with the guard mounted on top. Ok, not that elegant, but essentially all you need and adhering nicely to one of my general philosophies when approaching making anything, which is the KISS principal (Keep It Simple, Stupid). Due to the front forks having a leading axle arrangement, the mounting holes are off-set to the wheel centre so the straps needed to be of different lengths, and so I slotted the holes on the rear one to enable some positional adjustment when finally mounting the guard. Trimming the guard from the longer piece of rolled section I had was relatively easy, the tricky bit is joining it all together. For this you need to find the centreline of the guard, awkward on a thing that curves in two planes. My simple solution was to lie the piece on its side and establish the centreline as a height rather than a width, using a pen taped to an adjustable square. That done, it’s much easier to define the hole positions for your fixing screws or rivets to attach the mounting straps. Nothing worse than drilling holes only to find they’re in the wrong place. With the holes drilled I screwed the whole thing together using some M4 button headed screws and thread lock compound. Doing it this way allowed me to tighten things up just so, and minimise the risk of pulling the surface down onto the straps too much and dishing the top surface. The rolled mudguard blanks came with a polished finish but this is a nightmare to maintain, so the final thing was “brushed” with Scotchbrite before a treatment of anti-corrosion spray. Ok so far. Next up, the clocks and front light area.

Creative imbalance and making the most of what you’ve got.

Small, but with lots of potential.

Small, but with lots of potential.

It is the only word I’ve managed to come up with in trying to describe what’s been going on of late, imbalance. I’ve got a fair idea about where it’s come from and it has taken me a while to get to grips with it.

Rather than castigate myself for allowing it to happen, it has been much easier to recognise it for what it is and deal with it through action and a little reasoning. This imbalance stems from a shift in my working life over the last few months, and hence my creative output, which I’d not accounted for. Although my role is only part time, it has involved a lot of idea generation and thus a massive amount of drawing and sketching. Big projects, which require a lot of this kind of thing in their early stages, need sustained creative input and masses of ideas. It’s exhausting, creatively and physically. Where I went wrong is not remembering this to be the case and failing to keep any creative energy in reserve for my own stuff once I returned home. So it’s been difficult to draw, but more to the point, it’s been hard to generate ideas.

Shed_2

I’m showing you a couple of pictures of my garden shed, here in my back yard, as it has proved to be the answer to coping with this imbalance. Rather than spend any more time staring at blank sheets of paper the solution lay in getting out there and making something, turning raw materials into something else, using some tools and getting my hands dirty.

 

There had been a plan in the back of my mind for a while to refresh the little 250cc motorcycle that I’d modified some years ago when I started this blog. Over the years, as the miles have racked up, it has suffered the usual knocks and scrapes that these things are victim to, and overall the finish was starting to look very tired. I wanted to give it a freshen up, and make some changes to the overall design that I’d not got right first time around. So what to do for a making project was all ready and waiting, I just had to start. Before now I have relied on using workshop space owned by other people, this time around I didn’t have that option so my little shed was going to need to be the work space that I could use. As you can see it’s a small building with very limited floor area, but it does have an electricity supply, a big light on the rafters  and a work bench across one end. It houses all of my various tools, materials and other useful stuff accumulated over years of working as a prototype builder and modelmaker. Being of a sturdy design and construction it allows all manner of things to be hung from the walls, freeing up floor area and permitting at least a modicum of organisation. I don’t own any large machine tools, I’d need a bigger shed if I did, so most of the work would be done with hand and power tools with my trusty old Black and Decker Workmate acting as a secondary work bench. The only thing I can’t, and likely won’t do in there is spray paint, that will have to happen elsewhere. The shed was here in the garden when we moved into the house and I’ve always wanted to use it as a making space. now was my chance to put that thought into practice.

It just about fits in.

It just about fits in.

The third shot shows the bike pretty much in the shed. I didn’t need it completely inside, just enough to get some soldering done on the electrical loom, but it meant that I could work on it in there if the weather took a turn for the worse. By being methodical and tidying up as I went it was utterly surprising what I managed to do in this small space. Most of us work in some kind of organised chaos. Some cope well the more chaotic things are, others less, and over the years my natural inclination has veered toward the organised rather than the chaotic and this is a boon when working in a confined space. Having everything to hand helps too but, the order one maintains around oneself really is reflected in how one deals mentally with the making process.

The fruits of my labours are in the next post.

 

The 3D Pantograph Club, Part 2: Jon’s Machine.

3D Pantograph built by Jon Tremlett.

The Pantograph, finished and installed.

In the previous post you will have read my story about a 3D scaling pantograph built by my sculptor friend Ed. As I also mentioned, my and Ed’s friendship started after we realising we shared a passion for motorcycles and an interest in these rather esoteric sounding pantograph things. So in this post I’ll shed some light on how it all came about.

The 3D pantograph, pictured above and covered in this post is a machine I built for a young artist a few years ago after being recommended for the work by another modelmaker. It is in some ways quite different to the one built by Ed, though in others it shares many similarities. There are no given set formats for these machines and so each is a direct response to a brief from the person who’s going to employ it. In my case the machine was to be wall mounted and capable of achieving quite a high level of accuracy, with variable scaling ability anywhere from 2:1 to 4:1. The artist sculpted in clay so no cutting actions needed, purely surface finding. As a consequence, this variability and need for precision dictated many of the design and fabrication decisions taken during construction, not forgetting the ever present need to work within a tight budget.

Cheverton Pantograph at soulcraftcandy.

The Cheverton pantograph used for reproducing scaled sculptures in alabaster.

To be honest I had never heard of a 3D pantograph when the job first landed in front of me, but all became clear as I took to the internet and arranged to go and visit one, currently residing in the archival warehouse of the Science Museum here in London. This particular machine was known as the Cheverton pantograph, named after the victorian industrialist who designed it for the manufacture of carved alabaster busts from scale models. It is a beautiful machine, quite a bit smaller than I imagined and a great example of a style of engineering design, lots of architectural references, so loved by the victorians. I freely admit that this machine heavily influenced my design, though it must be said that aside from some mentions of odd machines in America and Italy there is very little out there for the budding pantograph builder to study in order to construct their own. The Cheverton machine showed very clearly the pivoting arm for scaling pointer mounting, the different length pointers for achieving correct scaling and most important of all, a compact system for creating the two rotating turntables that enable the sculptor to access all points around a form.

3D pantograph by Jon Tremlett

The first iteration in the studio showing basic scaling function.

The image above shows the very first iteration of the machine temporarily installed in the artists studio. You can gather roughly how it works from the position of the two pointers relative to the positions of the two eagle sculptures positioned on the boxes. This was very much a prove out exercise, to make sure we were on the right track and to confirm some aspects of the geometry whilst I was building the rotating table structures. Because there was little or no documentation covering the detailed design of these things, it was quite a challenge to work out the exact geometry which governs how the machine works, and thus achieve the level of accuracy demanded by the artist. We encountered many problems to start with but overcame them once we’d realised what was going on. The essential premise is this: Firstly, the exact centre of the ball joint at the root of the moving boom needs to be on exacly the same line as the centres of the two scaling pivot joints. These three positions must be aligned by a straight line in space. Secondly, another straight line must pass through this ball joint and the two tips of the pivoting pointers. And finally, this latter line must also pass through two points at the centres of the tops of both of the rotating turntables. Simple enough you’d think, but a devil to work out without prior knowledge.

3D pantograph components by Jon Tremlett

The main pivoting components made using machined scaffolding parts and a lot of aluminium.

The scaling function of the machine is achieved through the relative positions of the pointer pivots along the main boom. For example, if the scale required is 3:1, then the second pivot would be three times further from the ball joint than the first. So if the first is say 500mm from the ball, then the second would be 1500mm from the ball joint. The pointers are also of different lengths in accordance with the selected ratio and correspondingly, the relative positions of the turntable centres needs to adhere to these spacings too. This means that for a machine like this, where an infinite degree of variability was requested (anything between 2:1 and 5:1), everything needed to be adjustable and lockable. Hence the pivots slide along the boom, the pointers slide through the pivot blocks, the turntables slide along their guide rails and finally, the chain drive that connects the turntables, which must turn in unison, expands or contracts in order to maintain chain tension across varying distances.

Rather than plough on endlessly, I’ll leave you today with some captioned photographs of the build which I hope will serve to fill in some of the background. Sadly I don’t have any more recent pictures, the machine was moved when the artist changed the location of his studio and I haven’t managed to gain access yet. I will keep trying though.

3D pantograph detail by Jon Tremlett.

Detail shot of the short first pointer locating small turntable centre.

 

3D pantograph detail by Jon Tremlett at soulcraftcandy.

Turntables, rails and chain drive under construction.

3D pantograph details by Jon Tremlett at soulcraftcandy.
Detail of the chain drive using proprietary bicycle components.

3D pantograph details by Jon Tremlett at soulcraftcandy.
The complete turntable and chain drive assembly ready to be installed.