The Vernier caliper – use

A Vernier calliper is simply a calliper which uses a vernier scale. The popular record suggests that the first Vernier calliper was invented by J.R. Brown, founder of Brown & Sharpe Mfg. Co. in 1851, with a resolution of 1/1000 inch. Below is an image of that calliper.

Fig.1: The original vernier caliper, by J.R. Brown.

A typical Vernier caliper has a movable jaw which slides linearly along the main scale. There are a few differing types of Vernier calliper. Here is an example with a Vernier calliper, “Tuna“, made by ABR Almkvist & Co, Eskilstuna, Sweden. This is quite a simple caliper, with both inner and outer measurements on the same scale. This caliper has both cm, and inches. The scale for the cm is 1/10 of 1/10, or 100ths, which is likely more than enough precision for most woodworking tasks (each mm is divided into tenths). The scale for inches is 1/8 of 1/16,or 1/128th inch. The “Tuna” also has a depth gauge, which is convenient.

Fig.2: Measuring the thickness of a piece of plywood.

The example in Fig.2 shows measuring the width of a piece of wood in both inches and cm, using the inside caliper. On the Tuna calliper, the reading for Fig.2 is 1.0cm+0.7cm+0.07cm=1.77cm. The reading in Fig.3 is cm is 3.0+0.8+0.0=3.8cm, or 1+8/16+0=1.5″.

Fig.3: A simple vernier calliper in both cm and inches

The classic caliper from Brown & Sharpe has a more complex vernier mechanism, with graduations for 1/1000th inch, and is likely more suited towards the machinist. It also has a much more precise measuring mechanism.

Fig.4: The classic Brown & Sharpe caliper

This vernier is the No.570, which takes both inside and outside measurements, graduated to read on one side for outside and the other for inside. The sliding jaw has two components: by locking the rightmost portion it is possible to finely adjust the main Vernier scale using the thumbscrew.

The main bar scale is divided into inches, and tenths of inches, while each tenth of an inch is divided into four parts. The smallest divisions are therefore 1/40th of an inch, or 0.025″.

Divisions of the main and Vernier scale

On the sliding jaw is the vernier line of division. This vernier is divided into 25 parts numbered 0, 5, 10, 15, 20, 25 and the whole length of these 25 parts is equal to 24 divisions (40ths of an inch) on the bar. Since the 25 parts of the vernier only cover 24 parts of the bar, one of these 25 parts would be 1/25 of 1/40 or 1/1000 inch shorter than each division on the bar. If the 0 of the vernier is placed next to 0 on the bar, the first line on the vernier would be 1/1000″ behind the first line on the bar, the 5th line on the vernier would be 5/1000″ behind the 5th line on the bar etc. Each line on the vernier when opposite a line on the bare therefore adds as many thousandths as the mark on that particular line of the vernier.

To read the vernier, look along the line until you find a line that is exactly opposite a line on the bar, then read the line on the vernier (not the bar). To read a vernier calliper with 1/1000 inch precision:

1. Read the whole inches on the bar.
2. Read the 10ths of inches.
3. Read the thousands of inches to the 0 of the vernier.
4. Add the reading of the vernier where it exactly matches a line of the bar.

For anyone interested in an extensive history of calipers, I direct you to The Origin and Evolution of Calipers.

Drawing – a lost art?

James Liberty Tadd in his book New Methods in Education (1899), insisted on the egalitarian worth of art education. He believed drawing to be the primary instrument in education.

“Drawing is an universal tongue. It compels observation, reflection, perception and conception. It opens the mental eye, the eye of the understanding, that looks all around, up and down. It enables one to understand the message that is printed in every natural, normal thing, that is stamped with everlasting lines on each side of every leaf and blade of grass, that is twisted into the architecture of every shell, and that shines in the hues of every crystal — a message of beauty, of proportion, of grace and of fitness. Drawing makes mind.”

Workbenches in art (iv) – late Victorian

The older renditions of workbenches in art worked largely because staked workbenches were likely found in the first century AD. Art which appeared in the late 19th and into the 20th century is more problematic because many of them depict workbenches of the period. A case in point is the The Holy Family in the House of Nazareth (1889), a piece of artwork by Modesto Faustini (1839-1891). Faustini trained as a carpenter in the orphanage at Brescia, before becoming an artist, and it shows. The entire image is festooned with European tools of the period. It is a beautiful piece of art, making the workshop seem quite glamorous. The bench’s front vice sports an unusual handle, which seems more like one of the simple screw vices which first appeared in the late middle ages. Although the wooden screw seems too large for the vice itself. The remainder of the workbench is very simple, almost the older splayed-leg bench with stretchers, and tool storage beneath.

Faustini, The Holy Family in the House of Nazareth (1889)

On a side note, the plane that Joseph is using seems to be about half the length of the bench (which itself is ≈200-220cm long, and has a height of ≈80cm). Another painting is that of French artist Giacomo Grosso, Sacra Famiglia (1902). It portrays the carpenter shop in Nazareth, not only with Mary, Joseph and Jesus, but also with some neighbours in the doorway present. While much of the scene seems quite authentic, the workbench is not.

Giacomo Grosso, Sacra Famig (1902)

Collectors in a throwaway society

Buy one thing, and it is an artifact, buy a second and it’s a pair, buy a third, and it’s the beginning of a collection. Why do we collect things? Sometimes it’s because something takes our interest. Books, block planes, vintage Swiss Army knives, wooden biscuit springerle, copper pans, baking tins, vintage camera lenses, etc. Are we drawn to preserving some aspect of history that is meaningful to us? Collecting is sometimes the adventure of the find, the hunt – finding that unique items amongst many at a tool show, or an antique market. Of course collecting isn’t always easy. There is a point where finding rare or expensive items can become prohibitive. Or collections can be overwhelming. Sometimes there is little or no information about an item anywhere, it just exists. Not everything has an elaborate backstory. Some have a story but no physical entity, either because it is so rare, or because it never progressed beyond the design stage.

Many people likely find the concept of collecting strange, but were it not for collectors, we would not have any notion of our past histories. The world has become a throwaway society, where very little is valued beyond its present use. Many of the tangible things we create today aren’t worth collecting. Is there a purpose in collecting things like computers? They are inanimate, and don’t really tell a story (except the story of their development). My vintage Exakta camera from 1954 tells a story, and still works. Old vintage things still work, and there is an inherent beauty within them. Maybe we collect old things because they were made by craftspeople, in a slower time. Not always more precise, not always with a more advanced materials.

Collecting generally involves three sensations: instinct, opinion, and knowledge. Everyone is born with some level of instinct, and we can all develop opinions, and knowledge, well that develops over time as we explore and analyze the things we collect.