Camera Phone Lathe Crocodile

Camera phone what?

It's an articulated filming and photography aid for the metal lathe (or I suppose it would work nicely for a wood lathe, or in-fact most workshop machines). The basic structure of it can also work well as a pull-out wall mounted work light. Anyway back to this one for the lathe.

I'll admit it, I'm practised but not well trained on the metal lathe. I've read books and had a bit of experience, but nothing formal. Make a video or two, though I, put them on the tube or even here on Instructables, and see what critical feedback some of the old hands have. I also thought it would be nice to play back macro footage, to see exactly whats going on when you have more time to digest it - when your primary concern isn't dodging chips and ensuring the carriage doesn't explosively crash into the chuck.

The problem was getting footage or photos proved challenging. The lathe has a lamp bolted to the carriage, which I in turn, attached (bodged) my phone to. This sort-of worked, but it wobbled about a lot with any small vibrations in the lathe and was difficult to setup and adjust.

This called for a quick(ish) solution, that wouldn't take up much room or get in the way when I didn't need it, wasn't attached to the lathe itself (didn't vibrate), and was easy to adjust and focus in on the metal turning action.

Look out, here comes the "Camera Phone Lathe Crocodile!" A SNAPPY tittle huh? (sorry)

If you watched the video, you know I had a bit of a false start here. Simply put, you are going to want some wood to make the frame of this crocodile. I like using reclaimed stuff, so I ended up using some chopped up beech chair, and some teak off-cuts from a big skip haul that has slowly been used up.

I really like contrasting colour woods - the teak looks snazzy with the light beech. Obviously this is a workshop fixture, helping hand thing, so we don't need to be too precious about the look, but strong hardwoods are still nice here for the same reason they make good furniture: hardwoods will hold up much better over time, and are less likely to deform under the leverage force of the boom arm. My sizes were approximately:

Beech bits - 3 of there - 3/4" (19.5mm) x 3.5" (87mm) x 9" (225mm)

Teak bits - 4 of these - 3/4" (19.5mm) x 1" (25mm) x 9" (225mm)

But all these dimensions are flexible, use what you have. If I was doing it again I'd be tempted to use aluminium square tubing (if I could find any) for extra rigidity and light-weighted-ness. If you have read any of my other instructables you will know I am a great fan of what I call 'material based design'. Which is just another way of asking, "how can we look afresh at our junk pile, transform it in our minds, and design around that?"

Apart from the frame, I used some bits and bobs for the camera head swivel mounts, a bit of old steel pipe, some titanium, you know, the usual stuff ;)

And some lengths of threaded rod for the pivot points.

Plane and cut the wood to size. I used a bandsaw, tablesaw and jointer, because it's what I have. You could use one of ten thousand other combination of tools (handsaw, hand plane, for example, would probably be the minimum, unless you are masterful with a knife)... I'll talk about my process in order:

1) Bandsaw: I usually use this first as it is a comparatively safe way to begin to square up uneven timber. Attacking uneven surfaces with any kind of circular power saw can be quite the danger game. But on the bandsaw, as long as one or more faces are roughly flat the rest can be cut straight, either with a rip fence, or in cases where there isn't a another straight edge, by following a scribe line freehand. As an aside, for some good bandsaw setup tips check out this article I wrote.

2) Planer: or jointer, depending of your favoured terminology. This is great for getting the faces absolutely flat, cleaning off saw marks and correcting bandsaw mistakes. Having done two faces on the jointer, one feels safe taking the piece to the table saw.

3) Table Saw: In this instance I use the table saw to rip the crocodile segments to a consistent thickness. The flattened edges rest, one on the table and one on the rip-fence. After doing both sides I then crosscut them to length, also on the table saw.

There are so many different materials and methods that would work for this that I am somewhat bemused with what I came up with. It works well enough.

I used a scrap left over from these Bandsaw box draws. I squared it up on the bandsaw, and cut into it so that the first beech arm would nestle in there like a hinge (see pics). With the majority of that relief cut made on the bandsaw, I took it to the table saw and sled to clean it up to finished size - a technique I often use when making 'channels' in things.

Because all the wood grain ran in the same direction, we needed to add some strength to this bracket.

By cutting partial depth groves on the table saw and adding in some splines, with the grain running perpendicular to the existing direction, we can strengthen it up significantly.

It's easiest to make the splines oversized (not in thickness, but length and width) and trim them down after the glue has dried.

If I was doing this in a less cavalier manner, I would be tempted to use some kind of round bar stock and cut a small amount of thread on either end, maybe get the lathe involved and even add some bushings...

As it was I used 6mm (M6) threaded rod. This worked out just fine. I cut it with the hacksaw, but whatever method you use, it normally leaves a big burr that wants removing before you start using it. The Big Disc Sander is super excellent for this. A few light twirls holding holding it at a 45 degree angle against the disc and it's done. You could also use a file, that works just fine.

So we have something of a skeleton, now in order to join it up with our hinge pins we want to drill some holes.

Mark the centre of one stave and make a divet there with a centre punch or similar. Then get to drilling!

I used one stave arm thing as a 'master arm'. After drilling I used the 'master arm' to align all further holes, by lining it up and drilling through it. A drill press helps a lot, but is not essential.

I am drilling 5.5mm holes so that the 6mm threaded rod can be screwed in and will be somewhat tight.

The disk sander is great for this, but going cave man (plane, chisel or rasp) could work too.

Hopefully the pics are self explanatory here.

Lets make a swivel to go at the crocodiles mouth. The swing arms themselves adjust the yaw, so the swivel at the end wants to adjust pitch and roll.

If you watched the video in step one, you know things get a bit heavy about now. I start talking about titanium, do some metal lathing, then mill a pipe saddle joint, and weld it together.

All this could have been done in wood, with dowels and set screws and the like. But its nice to mix it up right?

This isn't the place for anything approaching a proper explanation of all these different processes - so if you're not into metal work just plough onto the next step. If you are, watch the video and see the picture notes/descriptions.

To mount the swivel on the crocodile head, I first drilled the hole to accept the titanium shaft (which the steel swivel bit moves on), and another smaller hole further in as strain relief. Then I used the handsaw to cut the 'mouth'. And another hole is drilled on top and for a tightening bolt.

If that sounds confusing, you should try writing this stuff - my brain's in knots. Essentially this is a wooden clamp. The picture notes should make it clear...

So there would have been loads of ways to do this, and the design I used is by no means the best - it does seem to work quite well though. The basic principle is that the phone is clamped across its width by two pieces of wood and the tension of a spring. The clamp is kept in line with a sliding dovetail. That wordiness will make sense if you look at the pics.

Here we are making the dovetail on the tablesaw, with the blade angled at 45 degrees. First cut the two edges, before squaring the blade back up and clearing the majority of the waste.

In my case the dovetail stopped (was not continuous) - because I was wanting some material below it to attach the 'phone cradle' piece to. If I was doing it again I would have cut straight through to save time and done the joint a bit different and not epicly over engineered it!

So I did a finger joint to fix the phone cradle piece to the dovetail piece. It was stupid. I just saw my rudimentary DIY finger jointing jig on the side, and well, things have a way of subtly directing your actions... Just gluing a piece onto the front would have more than sufficed. Ah well - it was good practice with the finger joint method, and the jig's been a bit neglected since I made it.

The design of the swivel clamp bit was somewhat more sane, being just a hole that clamps down with two wood screws.

The top clamp is simply the mating dovetail slider, with two bits of wood glued and screwed perpendicular to it.

It was cut out on the tablesaw, using bits from the odds and ends firewood bin.

The pics make it clear.

So far this has worked pretty good. I could go and sand all the edges nice and varnish it - that would probably be a good idea. I might get round to that in the next 5 to 7 years. For now, for a shop tool, the finish is ok.

If I was making it again I might be tempted to add to the metal swivel, so it had yaw as well as the pitch and roll. But a more important change would be to make it a bit shorter. As it is, it's a bit longer than I need and that extra length equates to more leverage, and therefore flex. I would like it a bit stiffer. After you move it the crocodile, it has a bit of a bounce that settles to still after a second or two, so not a big problem - but it grates on me. A lot of this flex actually comes from the wall it is screwed to, I can see the mdf panels distorting as the crocodile arm moves. Short of pulling the panel away and adding another stud right where the mount goes, I don't see obvious and easy fix for that?

For now I am happy with how it takes footage of lathe operations involving smallish things. The only thing left to work out is a good way to link it to the lathe carriage so that the camera can track the cutting action when turning long things, without introducing any vibrations... Ideas?

Thanks for coming along for the ride, I hope you got something out of all that. If so you would probably like my FloweringElbow facebook page (latest inventions and madness), and if video's your thing give me some youtube love and subscribe to my channel.