Bob Graham Round memento/keepsake

Making an unofficial memento for completing the 24 hour BGR across the Lake District fells

Background: the Bob Graham Round is a 24 hour challenge to visit 42 named summits on a 66 mile (106 km) unmarked circuit with 52,000 ft (15,850 m) of height change, that starts and finishes at the Moot Hall in Keswick, England. It is not a race, except against the clock, and runners can attempt it at any time of the year. The Bob Graham 24 Hour Club keeps a record of the 2,000 or so runners who have successfully completed the challenge since 1960.

I wanted to mark a friend’s successful round by making her a little memento. It isn’t for sale, or in any way official or sanctioned by the Bob Graham club, but I’ve included full details & downloadable plans in case you want to try making something similar.

The memento is a plinth of Lake District slate, topped with a piece of clear acrylic laser-cut into the shape of the hills on the route.

Laser-engraving the slate plinth

I was keen to use a material of the Lake District, so a piece of slate mined locally at Honister Slate Mine was the obvious choice (or some wool from Herdwick Sheep?

Slate would normally be engraved by hand or with a CNC cutter machine, but I was interested to see if small lettering could be engraved using the 40W laser at Access Space in Sheffield. I used a piece of scrap roofing slate for a series of test cuts at different power/speed levels. At first it didn’t look promising, but by cranking up the laser to 100% power and setting it to repeat 3-4 times, it cut to a good depth. The slate is noticably warm when it emerges!

I used the free Inkscape application for 2D design, ready for exporting to the laser cutter. Each colour is a different pass of the laser, at different power/speed levels, so the pink lines are etched first to mark the acrylic stand and 5mm drill locations, black is the main text that is engraved and finally blue is just a placeholder to locate the edges of the slate (not sent to the laser cutter).

Download files for laser engraving (152×64mm slate):

Painting the slate plinth

I wasn’t sure if such small lettering could capture paint. The advice I found online was to “flood” the area with an acrylic paint, which I took to mean use a small paintbrush to cover all the engraved text with a decent amount of paint. You don’t need to be accurate.

Then after 5-10 minutes, wipe the excess paint by using a slightly damp (lint-free) cloth wrapped around something flat and rectangular, like a glass coaster. Wipe several times in the same direction, and don’t press too hard. The goal is to remove some of the excess paint from the surface of the slate, while leaving paint inside the etched lettering.

After 12-24 hours the paint should be completely dry, and use a fine sandpaper (P600 then P2000 grit) to lightly sand the surface of the slate to remove the rest of the excess paint. Again, you can wrap the sandpaper around something flat and rectangular, and this should leave the painted lettering intact.

Any colour of paint should work, but I liked the ‘traditional’ look of light grey lettering.

Drilling the slate plinth

I had assumed that slate would be tricky to drill (like ceramic tiles) so I clamped the slate into a power drill press at Access Space, and used a HSS bit. It was actually very easy – even a battery drill works fine if you go slowly and don’t put too much pressure on the slate. I ended up making two 5mm holes for the M4 screws, and counter-sunk the base with an 8mm drill bit to conceal the nuts.

A minor niggle is that you can see the screws at the back through the clear acrylic, so possibly an opaque material would look better, or use glue instead of screws to join the slate & acrylic? I needed this one to be easily dismantled & packed flat for flights.

Laser-cutting the acrylic hill profile

I started by making an altitude profile of the 42 hills in the Bob Grahram Round from a GPS track of the route, smoothing the bitmap and tracing it into a set of vector lines in Inkscape. Geek that I am, I originally wanted the name & height of every summit shown on the profile, until I quickly realised just how large it would have to be made for it to be readable! In the end I settled for naming the road crossings.

Again, each colour is a different pass of the laser, at different power/speed levels, so the pink lines are cut first to make the profile and screw holes, green are extra cuts to make it easier to extract the jagged shape, black is text that is etched and finally blue cuts the outside of the flat panel. I used a 3mm thick transparent acrylic (perspex) sheet, but it could easily use a different colour or thickness, or even a different material like wood or stainless steel.

Download files for laser cutting (requires approx 150×110mm):

Bending the acrylic – With the protective film left on the flat acrylic sheet, I clamped the bottom of the sheet in a vice and used a heat gun to soften the material along the line I wished to bend on. Using a straight piece of scrap wood I slowly pushed the top section of acrylic just past 90°, to form a stand with 2 laser-cut holes that matched up with the drilled slate.

Bill of materials

An easier option might be to ask at Honister Slate Mine if they would be interested in making something like this memento, already engraved & painted with the wording you want?

this corner was reserved for an announcement that the author had succeeded in their own BGR. Up to the time of going to press, however, such an announcement cannot be made.

Honister Lake District 152×64×10mm natural slate, smooth edges	£8.50¹
3mm extruded clear perspex 150×110mm	£0.37
Laser cutting charge	n/a
M4 nylon pan head 13mm screws+nuts (2 of each from 10 pack)	£3.69
Acrylic paint light grey (5ml? from 59ml)	£1.89
Total, excl P&P	£14.45

¹Unfortunately Honister charges £9.50 for delivery of a single small piece of slate, so you can get a much better deal if you collect the slate in person, or put in a larger order.

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Nick Smith, August 2016.