Laser scan

I’m being slow at organising my data, but today I managed to re-sample the NMI Carolan harp laser-scan, and uploaded it to Sketchfab. This allows it to be easily embedded in web pages.

NMI Carolan harp (National Museum of Ireland) by Simon Chadwick on Sketchfab

Sketchfab does allow downloading of the low-res model but I have also made a link to the full-res version: OBJ mesh file. I use the MeshLab app to view and manipulate the OBJ mesh file

The scan data is marked cc-by (attribution) on Sketchfab but I think it is really public domain, since it is just a digital reproduction of a public-domain publicly owned artefact. You don’t need to attribute it to me – please give attribution and credit to the National Museum of Ireland, who own the original object and gave permission for the laser-scan to be made.

Here’s the video of Elaina Sugrue of Accuscan, making the scan back in the October 2018. You can see how the point-cloud, captured by the scanner, is rendered real-time on her laptop screen. This scanning process generates a huge amount of point data, which had to be processed, and separate passes with the scanner “registered”, to generate the finished mesh file.

I think it is important to be able to release this kind of primary data, as part of the project to understand the old harps more. This scan is a wonderful resource, but it needs a lot of further study to be of practical use. I have made many slices and renderings, which in due course I will publish.

This harp, being very damaged and distorted, requires also a lot of theoretical reconstruction work. Hopefully in time we can also publish reconstruction drawings. I am still thinking about how best to go about this.

I remembered my old post, Archaeological copies of old Gaelic harps from back in 2016. We are not moving at the rate I suggested of one per year, but this kind of study and documentation is an important part of this kind of long project.

The header photo is by Brenda Malloy, and shows myself and Elaina Sugrue at the National Museum of Ireland in October 2018

A typology of tuning pins

There are a number of different styles of taper harp tuning pins. I am trying to categorise them so that it is easier to be specific when talking about the different types. Up to now I have talked about the “old” style with fat drive heads, and the “modern machine-made” style with narrow heads. But I see now that these are rough categories, which can be broken down more subtly.

I think the most distinctive and diagnostic thing is the relationship between the drive and the shaft. The drive is the square- or rectangular-section end of the pin, which is where you put the tuning key on, to turn the pin. The shaft is the conical main part of the pin, which is embedded in the wood of the neck, and also which carries the string at the far end. The shaft is always, and the drive usually, tapered rather than parallel-sided.

Basically I think the first diagnostic is whether the head is wider or narrower than the shaft; in other words whether there is a step up or a step down to the head from the shaft.

I’d suggest Type 1 pins have a step up from the shaft to the head; Type 2 pins have the head about the same size as the shaft, and Type 3 pins have a step down from the shaft to the head.

We could have sub-categories; sub-type a could have a sharp step at about 90°; sub-type b could have a clear transition at about 45°; and sub-type c could have a very smooth flat transition. We could also append R for pins with rectangular (not square) drives.

Suggested typology of harp taper tuning pins

Because both head and shaft taper away from the centre of the pin, and because there is often a gradual transition from shaft to head, it can be hard to state at what point the diameter or width of each part should be measured and compared. So while it is easy to think about comparing the width of the head with the width of the shaft, it is often difficult in practice to choose where to measure. So my idea of looking for the nature of the “step” between shaft and head might prove more useful.

Left to right:
Type 3a (modern #5×3″ steel pin)
Type 3a (modern #4×3″ steel pin)
Type 3b (steel pin from Arnold Dolmetsch harp no.10, c.1932)
Type 2c (iron pin made by Simon Chadwick for a replica medieval Gothic harp, 2018)
Type 2cR (iron pin made by Simon Chadwick for the replica Queen Mary harp, 2014)
Type 2cR (brass pin made by Simon Chadwick for the replica Queen Mary harp, 2007)
Type 1b (brass pin made by Simon Chadwick for the replica Carolan harp, 2019)
Type 1c (brass pin from county Monaghan, c.17th century)

I think that previous attempts to document tuning pins have not been specific enough about where the measurements have been taken. The scheme below suggests where to measure:

Point A is the extreme end of the pin
B is the smallest diameter of the conical shaft of the pin
C is the largest diameter of the conical shaft of the pin
D is the largest width across the flats of the drive
E is the smallest width across the flats of the drive
F is the extreme end of the pin.

The following measurements can be taken to record a pin:
1. Distance A-B
2. Diameter at B
3. Distance A-C
4. Diameter at C
5. Distance A-D
6. Width across flats at D
7. Depth across flats at D
8. Distance A-E
9. Width across flats at E
10. Depth across flats at E
11. Distance A-F

From these measurements we can calculate the taper of the shaft, the range of sizes of tuning key socket which will fit the head, and the nearest standard taper hole that the pin will fit in. We can also work out the nearest standard taper blank to use for making a copy.

Irish libraries

I’ve been working in a lot of libraries recently. I love seeing inside different library buildings – the ambience and atmosphere and architecture sometimes seem as important as the collections.

Armagh Public Library was set up by an act of parliament which stated that it would always be called the Public Library, but they changed its name recently and it is now called the Robinson library after its founder, Archbishop Robinson. It is a handsome 18th century classical building stuffed full of handsome 18th century leather-bound volumes. This is the most elegant and beautiful library but is the hardest to make practical use of because its collections are so old-fashioned! I did check out their copy of the Memoirs of the Marquis of Clanricarde, to understand more the preface which famously mentions the performance of bardic poetry with harp accompaniment.

I had previously seen a copy of this book at Luggala. I remember somewhere reading an opinion that Garech Browne’s was the finest private library in Ireland, but I never managed to get to see inside – there was always some excuse, or distraction.

In contrast, the Irish and Local Studies library in Armagh is hidden round the back of a council building, entered through a basement door at the back of a car park. It has excellent collections of journals and newspapers – I never even got to go into the rooms with books! I found some very interesting references in very obscure 19th century periodicals here.

The other interesting library in Armagh is the Cardinal Tomás Ó Fiaich Memorial Library and Archive. I have not done proper research here, only browsed, but it has interesting local studies collections.

In Dublin I have been working at the National Library of Ireland, and also at the Royal Irish Academy. Both have beautiful buildings, and excellent collections; I have mostly been looking at specific unique items there. I have especially been reading the RIA minute books from the 19th century – I have not found what I am looking for in them, but that in itself is kind of interesting. They are really fascinating objects, full of the signatures of the Great Men like Petrie and Wilde. I have more references to follow up especially at the NLI, but it is harder to do because they are not so easy to get to.

In Belfast I have been using the Linen Hall Library and the McClay Library at Queens University Belfast. The Linen Hall library is a lovely old building full of lovely old collections, while the McClay is a really impressive new building with a tower that reminds me a little of Cambridge University library. The McClay holds the Queen’s Special Collections, including the Bunting manuscripts, and so has been extremely useful for me.

A library I have been involved with creating for over a decade now is that of the Historical Harp Society of Ireland; this library unfortunately remains merely a collection of books, since it has no librarian and no building. Maybe in time that will change.

There are other libraries which I would like to get access to. Another private library I have been in, but not used, is that at Clonalis House. There is Marsh’s Library in Dublin. And there is the curious local studies library at Benburb – it was closed when I visited, but I should try again.

I am sure there are others that I have missed…