Death of a Corsa (1.0 Twinport)

The sad remains of my Z10XEP engine.

The piston rod fractured just next to the big end bearing with “intersting” consequences. It didn’t sound as bad as it looks; it sounded like there was just something like a branch caught under the car. Initial diagnostic scan was P0335 – CKP Sensor A Circuit Performance – because pieces of swarf and broken piston ring were stuck to the sensor (it is magnetic).

The Big End (showing its fracture)
The Piston Rod
The Remains of the Piston

LED Caving Lamp – Adapting an “Oldham” Caplamp

Some incomplete notes from a recent conversion of 3 old cap lamps to run off white LEDs extracted from a cheap (yet astonishingly bright) headtorch and powered by Lithium-based cells salvaged from an old laptop battery. One of the 3 caplamps was from a 1991 Apex 2 and the others were ex-NCB pit-lamps of unknown age.

Raw Materials

  • some pieces of brass (see below)
  • a 5W, 270 lumen headtorch powered by 3xAAA cells. Cost less than £5 incl postage from Hong Kong via ebay. I bought a few cheap torches looking for suitable de-mountable modules (see the photos below). A simple on-off type was chosen rather than multi-mode (bright, dim, flashing…)
  • A pair of 18650 3.7V Lithium cells with solder tags or salvaged from a laptop battery
  • A cheap “travel charger” for these cells. I bought a pair of cells with a charger for about £5 via ebay and use the cells in a hand-held zoomable torch that serves as a caving backup and dark-corner-probe.
  • A potting box and potting resin (Maplin does suitable)
  • Heat-sink compound (see Maplin’s again)
  • a few solder tags, a couple of M3 machine screws
  • 4x #40-40 stainless steel cap-screws at least 3/4″ long (this is an American standard thread. Try radio control model suppliers)
  • An old caving lamp
  • A through-headset charging part. I had one of these “lying about” but they may be hard to find these days. If so, adapt the design with charging connectors on the battery some-how.

Headset- Components to Make and Fitting

Remove all the components from the headset except the  negative wire (fixed to the body) and the switch moving part and its spring-contact. I actually removed all parts to overhaul everything.

See the dimensioned drawings and photo of the finished result below (both are available in larger size by “clicking” the image). The dimensions on the plate are approximate; be prepared to make some adjustments and in particular note that the photo shows a small cutout to clear the on/off switch. I tapped the holes to secure the LED modules but you could just drill to clear an M3 screw and use a nut on the rear.

Cap Lamp Parts to Make
Cap Lamp Assembled

The smaller part on the drawings is a pillar that will be located at the top of the lamp where the pilot lap is. This needs rounded corners to fit. For the Apex 2 caplamp, this fits neatly without any work on the caplamp body. For my other two, there is a lump to machine away. I used a slot-drill in a pillar-drill but a router-cutter would probably work. Beware that this process exposes some brass. This brass is actually part of the (negative) circuit embedded in the body and it must not be allowed to contact the pillar. The pillar should, however, have a good contact with the body in order to conduct heat away from the LED. I simply milled a recess over it to avoid contact.

Heat-sink compound was applied between the LED module and the plate and both top and bottom of the “pillar”.

The #4-40 screws will have to be made the correct length: 2 at 3/4″ and 2 at slightly less than 5/8″ (both dimensions include the head of the cap-screw – sorry I failed to measure thread-length.) . These screws fasten the brass plate to the cap lamp body. “Clear” in the diagram means that the screw will easily pass through; these are plain drilled holes.

The wiring is mostly obvious from the photograph. The negative wire from the LED is attached to one of the switch contacts using a solder-tag. The other switch contact is not used and was not refitted. Don’t trust the pictures – work it out!

Small padding washers are used for the LED module hold-down. These could be old inner tube, although I used some gasket paper. The idea is just to reduce the risk of damage.

The reflector will need to be sawn off as in the photograph. A Dremel tool (etc) is quite handy for this. Find a way of marking off the cut height or mount the Dremel at a fixed height over a flat surface to get this cut neat, even and to avoid cutting off too much. The LED module I used had quite good combination of central beam and spill-out and the end result with the reflector as shown is quite satisfactory.

Battery Pack

This is just a pair of 18650 cells in parallel cast in potting compound. A piece of rubber was placed beneath the cells to avoid direct contact with the box anywhere. Make sure the hole for the cable is tight otherwise compound will leak out. I would have used a grommit but bought the wrong size. An outer protective layer of inner tube and gaffer tape finishes the job off. This will he helmet mounted and only be used for light caving so is not “bomb proof”; I do not expect to bash my head against many long awkward passages.


This basically involves mounting the “travel charger” on the side of a box, having soldered mains supply to its circuit board and soldered some take-off wires for the head-set contacts. It is probably best to avoid charging via headset at the same time as separate cells.

Finished Product

NB: the Apex 2 headset was bodged to allow for through-headset charging.

Making Dice in Brass (or other metal)

Here are some notes on making dice (or just one die) in brass (etc) in the metalwork shop, suitable for a total beginner. I did it with my 10-year old. I used some half-inch square brass stock.

  1. Set the stock in the lathe using a 4 jaw chuck. Get it close to centred by sighting the edges against the cutting tool. I tend to face off with a TCMT (carbide tipped) tool where the tip points away from the tool post (i.e. a 60 degree angle to the work). I used my top speed of 1800RPM but you could go faster.
  2. Face it off.
  3. Mark out and cut off slightly over 1/2″ from the stock, file it down a bit to remove the unevenness.
  4. Fly-cut (1″ or slightly larger fly cutter) the sawn face to get to a cube.  Use a speed of about 1100 RPM and work in stages of measure-then-cut. This is quite easy even in a small mill/drill. Lock the table in position and the head in place while cutting. A digital scale on the vertical axis is really useful for this (the vertical fine-feed on my machine is hopeless) . An alternative is just to face-off this end in the lathe but I find it easier to finish off at the correct length flycutting and it demonstrated the technique.
  5. Gently remove rough or sharp edges with a fine file or emery paper.
  6. Set up an arrangement like the photo. The tool clamp provides a positive location so that the die can be turned over and around and returned to the same position.
  7. Turn the cube over so that the previously-turned face is upper-most. Fit a centre-drill into the chuck with a point of the size you want the die dots to be. Traverse the milling table so that the centre of the face is lined up. The marks from the facing-off operation should be sufficient and give a nice appearance. (this is why you need to get it “close to centred” in step 1). Make sure  you remember to take account of backlash in the leadscrews. I made sure I approached the centre by turning the handwheels in a clockwise direction. Zero the collars or mark off the handwheel positions carefully.
  8. Drill to depth. Set the depth-stop and drill again to meet the stop.
  9. Remove the die, rotate to another face, snug-it up against the tool clamp and secure the die. Drill another centre hole (say for the “3” side) then a final hole (say for the “5” side). Remember opposite sides of dice add up to seven.
  10. Decide where the corner dots will be and traverse both axes of the milling table to position the cube appropriately. Traverse the same distance for each axis. I opted for a whole number of revolutions of the handwheels for simplicity. Remember to turn them the same way as in step 7 to mitigate for backlash.
  11. Reclamp the table and drill a dot. Loosen the milling vice and rotate the die by quarter of a turn. Repeat until you’ve made the “5”. Use the same process to make the “3”.
  12. It should now be obvious how to make the “2” and “4”. The “6” is made by making a “4” then return one of the milling tables to its “zero” position (step 7). Reverse back past “zero” by about half a turn of the handwheel them advance back to “zero”. Clamp the table and drill. Rotate half a turn and complete the last hole.
  13. Polish it up, slightly round off the edges and corners and you are done.

My daughter was well pleased with the result and rather impressed by the simple little tricks that make it quite easy to get a neat and regular result with minimal fuss and fiddle: the trick with the tool clamp, rotating the die, the depth stop. If I were to make another, I think I would place the “spots” slightly further from the edges.

Wallace & Gromit Inspired Arms in Brass/Steel

Here is the product of a fancy, something less demanding than making something that really works. It was made relatively quickly from a page of sketches I made over a cup of coffee so it isn’t perfect. I’d probably change some details if I made another.

I’ve written some construction notes and transcribed my pencil sketches to a CAD drawing in case anyone finds that useful. I’d be pleased to hear of any improvements anyone makes.

Download: Zip of plans, construction notes and larger pictures (770kB total).The CAD plans were made using Draft-IT (by CADLogic) but a lower res GIF is included in the zip)


Easy Chili Sauce Recipe

There are lots of chili sauce recipes on the web but here is my variation. I grew some relatively mild chilies from nursery plants named “chenzo”, “cayenne” and “cheyenne” and this recipe worked for me, creating sauces that can be smeared thinly on bread with cheese or dolloped onto a plateful of food. The balsamic vinegar and “vecon” help to give a rounded taste.


  • 65g chilies
  • 2 cloves garlic
  • 20ml balsamic + 100ml white wine vinegar
  • 1/2 teaspoon sugar
  • 3/4 teaspoon salt
  • 1/4 teaspoon “vecon” vegetable stock


  1. remove stalk from chilies but do not remove seeds etc and chop or mince finely
  2. chop the garlic
  3. boil up chopped ingredients with the vinegar until tender and to reduce the volume slightly and a thicker consistency is achieved. Use a non-metallic pan. I kept the lid on initially until the chilies were part-cooked and then removed it reduce the mix.
  4. puree the chili+vinegar mix in a blender along with the remainder of the ingredients. a small hand-held blender is perfect
  5. Decant into bottles (preferably sterlised with e.g. boiling water), allow to cool and refrigerate

For the “cheyenne” chilies, which were sweeter but milder, I used 90g rather than 65g.


A Template for “Top Trumps” using MS Powerpoint

I had a fancy to create a template for my kids to make their own Top Trumps cards and thought I could do better – from the point of view of usability – than what I could (relatively easily) find on the web.

Here is my first attempt Top Trumps Template, NB only uploaded for MS Powerpoint 2007 as there are a couple of niggles to resolve for backwards compatibility. Let me know what you think. The same “Creative Commons” licence applies to reuse just as for everything else on this site. Please feel free to comment…

Some notes on using and adapting the template:

There are 3 layouts set for the “slide master”, one for the card (with lots of placeholder boxes for text and a picture), one for a title card and one for a rear side.

I’ve used a combination of placeholder boxes (i.e. the boxes you normally add your content to) and some boxes that are only editable in the slide master (for content that will be the same for all cards). I’ve also set the background colour in the slide master.

The table at the bottom of the card is achieved by a bit of a dodge. There is an empty table with an alternating row style which I have “sent to back”. In front on the left side is a text box with the category names that can only be changed in the slide master. In front (of the table) on the right side is a placeholder for per-slide text. Font size and line-spacing has been chosen carefully to match the table. Basically: if you want to change the number of categories you need to know what you are doing

Model Watt Governor – CAD Plans and Construction Notes

Having had a hankering to make a Watt-style governor but having failed to find any plans to my taste, I decided to design my own. Here it is, with 2D CAD plans produced with Draft-IT (and GIF images of the same) and my construction notes for download. The design is hand-cranked and lacking a valve lever because it was made as a retirement/60th birthday gift and I ran out of time to complete the valve lever (I wanted to assemble the governor before dimensioning the lever).

Inspiration for the design, and especially the proportions, came from Muncaster’s book and photographs I took of real governors.

All of the downloads are covered by the same Creative Commons licence as everything else on this blog. Feel free to adapt but I’d like to hear about modifications, ideas etc…


GPS/GPX Waypoints for PDMHS Newsletters 122-133

The download below is a GPX file suitable for GPS and digitak mapping software. The locations are of sites mentioned in the Peak District Mines and Historical Society newsletter editions 122-133. These are not sites I have GPS-located but have been transcribed from grid references in the newsletter. These are sometimes 6 figure OS Grid refs and sometimes 10 figure. They may be wrong! The comments are generally very brief and the intent is that reference is made to the appropriate newsletter, using these “waypoints” as a spatial index. The waypoint names are of the form “PD-N122-03” which means the reference is in Newsletter 122 and is the third one (generally in the “Observations and Discoveries” section).

(At present Newsletters are not on the PDMHS website but many of the old journals are. Join PDMHS!)

GPX download: pdmhs-newsletters-122-133-for-web

Using the British Geological Survey WMS Service with Mapyx Quo

Major kudos to BGS for making their 1:50,000 geological maps available online including via a WMS Service.

I’ve been struggling with scanning BGS maps and importing them into Mapyx Quo for a while. Its an arduous process and the scanned maps contain the roads, placenames etc as well as the OS topographic map I have in Quo so its not as pleasing to use as it could be.

I was thus motivated to write a little Windows .Net programme to access the BGS WMS and automate the import into Quo. The process is not completely automated (partially because Quo uses a non-XML file for storing the user-loaded maps) but is still quite simple.

The programme is not as polished as it could be – its good enough for me – and has only been written with the BGS service in mind (although it could well work with other services).

I am making the Windows installer (I use XP still) available (no warranty blah blah) but please do not distribute it (refer people to this web address instead): download installer (about 350k)

Usage is simple:

  • In Quo set the coordinates to WGS 84 decimal degrees
  • Right-click and copy the location of interest to the clipboard
  • Paste it into WMS2Quo (my programme)
  • Choose which layers you want. e.g Bedrock and Superficial (bedrock is the default)
  • Click “Fetch”. This uses the geonames service to find the name of a nearby location. This will be used in the name of saved files. You can edit/change this in a text-box.
  • (the segment of the geological map should appear)
  • Save the map and a Quo calibration file
  • In Quo “Explorer”, select the “Loaded Maps” tab and use the document-with-green arrow icon to import the map image. This will cause the image AND saved calibration file to be read. I usually now change the transparency to 80%. You should see the geological map in Quo.
  • You can “query” the map one layer at a time to find the kind of rock (etc) at a given point by clicking the mouse on the image. This information is remembered and can be saved out as a GPX file containing “waypoints” for each location. Import this into Quo and set it to show the waypoint “note” and you will get geological labels showing.

There is a “settings” button which can be used to alter the save location, image size etc. Take care and NB that the BGS WMS server will sometimes return a blank image if your image size/map size combination are out of its range. A known bug also means you need to restart the programme if you change the save location. I recommend you change the save location as the first thing you do. Also, watch out for your firewall blocking web access; if you get an error on “Fetch” this is the first place to investigate.

I would like to acknowledge Paul Dixon ( as I adapted code of his (GPL Open Source) for the coordinate transformations that are used. This is JavaScript whereas I used C#.Net. I’ve uploaded this for use, adaption or what you will under the same licence: DLL, Source code.

If you would like the C# source code for the “WMS2Quo” app please contact me. Similarly, I’d like to hear of any bugs (you know what I mean by “like”).

Orrery and Gear Spreadsheets from Mike Shuter

Thanks to Mike Shuter, who commented on the previous entry, for sending me his two spreadsheets with Orrery gear ratios and the “continuous fractions” method of determining wheel/pinion pairs. He has permitted me to post them here but please contact “m [dot] shuter [at] ntlworld [dot] com” if you find them useful. Please do not repost without contacting Mike as he is the creator.

Mike Shuter’s Spreadsheets