Recently we came across an old type of bow-saw which had been sent to a veteran village carpenter for repair. Its precise origin could not be traced except that, a couple of generations ago, it had come from the estate workshop of a north-country peer. The feature of the tool is an ingenious method of tightening the saw when special rigidity is required. As, too, the saw frame could be made at home, a brief description may be of interest.
The arms (A), of 7/8 in. beech, are about 21-1/2 ins. long, shaped as indicated. Width at top (extreme) is 1-3/4 ins. and at the blade end 1-1/2 ins. The arms are chamfered as shown for comfortable handling, bored for the 1/4 in. top rod, slotted for the saw and notched for the cross stay (B). This latter is of 7/8 in. by 5/8 in., the 5/8 in. width showing on face.
The saw blade is 2-1/4 ins. wide, toothed as shown, and the threaded straining rods have the type of swivel indicated for tightening. The saw may be used for any kind of cross-cutting, plank or round timber, up to a thickness of over 9 ins.
Tightening Device. Turning to Fig. 2, it will be seen that this bow-saw is provided with a second cross-stay (C) which, with the saw shortened, can be fitted to exert special pressure on the blade.
This extra stay is the same as (B) except that it is shaped from a length of beech 1-1/2 ins. wide full by 5/8 in., the swell in the middle being required for piercing on the bevel. This bevel is shown in detail. The stay (B) passes through the bevelled aperture in stay (C), extra notches being cut in the arms (at E) to receive the short tenons on the stays.
The advantage of these crossing stays will be obvious. When the saw blade is adjusted to length, the cross stays fitted and the straining rod tightened, extra strong pressure is applied to the arms at the points XX and the saw will remain rigid for the heaviest work.
In its normal position (Fig 1), the frame, over all, measures fully 2 ft. 6 ins., the height being about 1 ft. 8-1/2 ins.
On the saw described the extra cross stay (C), instead of being thicknessed at the middle, is fitted with an iron collar 4-1/2 ins. long, as at Fig. 3. The opening in this collar has bevelled sides through which the other stay (B) passes. The stay (C) is of course in two parts, both bevelled to fit tightly into the collar. It is believed that the original stay was thicknessed as in Fig. 2, and that the collar was added later as a repair. The collar itself represents an exceptionally neat piece of ironwork.
David Binnington Savage died on Friday, Jan. 18, after a hard-fought battle with cancer. David was an artist, writer, furniture maker and designer, and a father figure to me.
“Reluctant to give in, he fought to the end, and continued to talk of Rowden (his workshop and school),” his wife, Carol, wrote to me in an email. “A true artist to the core, he was even inspired by the new spring growth outside his window to draw a design in his notebook just days before passing.”
You can read more about David’s life and work in this profile by Kara Gebhart Uhl.
Joinery – that’s what this is about. Joints that hold components together. In this case, versions of one joint, the mortice and tenon. There are on this bench frame three different versions: stub mortices and tenons; through-wedged mortices and tenons; and through dry-tusk-wedged mortices and tenons. So that you can take this structure apart to move it, the tusk wedges are just friction fit, but the bench is solid as a rock when assembled.
To gain strength, we use wedges in two of the three joints. In the knockdown joint, the top of the mortice is angled – a wedge is driven in above it to hold the structure. But this is getting too complex too soon – let’s look at the simple through-wedged mortice-and-tenon joint.
Basically, a mortice is a hole. With hand tools, you can chop it out with mortice chisels or drill out the waste and pare to the lines. But we use a morticing machine, which saves lots of work. This is basically a drill bit that cuts slightly ahead of a square cutter that chops out the corners.
First let’s get into marking-out mode. This diagram gives you the idea. Mark distinctly both the component position and the mortice position. Mark the mortice with a mortice gauge, with the knives set 30mm apart. As always, mark from the face side of each component.
This is the type of drawing that I like to see every student make before making a joint – it helps one to think about what is being done, and to think about the mechanics of this joint. This is not just a peg in a hole with glue; it’s a mechanically effective joint that would hold up without any glue. The two small wedges turn the tenon into a dovetail, splayed wider at the outside than the inside. It’s as tough as old boots.
First make the hole (the mortice) then the plug (the tenon) to fill it. Our morticer cuts pretty cleanly; I like and use machines that save me time and do a better job than I could. Chopping out a mortice by hand is nice and sweaty work – and some of you will be happy doing it.
The tenon gets marked out with the same mortice gauge setup (30mm, marked from the face edge). We use a setup on the band saw to cut those tenon cheeks to exactly the right size. Because this joint gets cut a lot, a dedicated setup for it makes good sense.
Have a careful look at the drawing above right, noting the stop and spacer at the bottom of the page. This stop is simply a block of wood cramped to the band saw table. Next to it is 31.5mm-wide spacer against the fence. The fence has a stop at the end to prevent you from going too deep past the shoulders. The idea is this: After the first cut, you need to move the fence 31.5mm to make the second cut and get a 30mm tenon. Try it out with some scrap. Cut one tenon cheek, take the spacer out, move the fence then cut the second shoulder. Does this give you the tenon you want? If not, cut a new spacer, thicker or thinner, as needed.
Make sure your blade is good and sharp and that you run slowly into the blade. Chunka, chunka, chunka….
We cut the tenon shoulders at the table saw. The blade height will be the same for all; the shoulder position will be measured for all and a stop set up probably off the end length. Tenon lengths will be different for the different kinds of joints.
Registration opens at 10 a.m. today (January 21, 2019) for classes during the second half of 2019. Note that the registration form now requests (but does not require) a phone number. It would be helpful to provide that (and to double-check your email address); we’ve had a few emails bounce back…and if I can’t get in touch with a student after repeat attempts, I have to cancel the registration – which I hate to do. Thanks in advance.
If you’ve any questions, shoot me an email at covingtonmechanicals@gmail.com (please do not send questions about classes to the LAP help desk).
In 1744 John Wister built a summer house in Germantown, a rural area northwest of Philadelphia. The house later became the primary residence of the family and was known for its gardens, orchards and farm. When Charles Jones Wister (1782-1865), grandson of John, inherited the property he named it Grumblethorpe. He took the name from ‘Think-I-To-Myself’ a comedy by Edward Nares.
The Historic American Building Survey of 1934 notes, “Charles J. Wister had a taste for mechanics and in 1819, added a frame workshop.”
Wister’s workshop was on the second floor of the extension with a loft above. In the photo of the shop you can see the steps in the back left corner leading to the loft.
In the survey drawing of the second floor the workshop addition is at the very top, on the right is an enlargement of the shop. His shop was a generous 26’ by 10’-10’’ with a forge (F) connected to the chimney and a bellows (G) that was positioned below a cupboard.
The lathes (see photo) are under the windows in the back right corner. The cabinetmaker’s bench was likely on the left hand wall (under window #213?).
In 1920, a year before the workshop photo was taken, Jones Wister, great-nephew of Charles, published ‘Jones Wister’s Reminiscences’ with a chapter on his great-uncle. Here are excerpts with a brief description of the workshop:
”…The youngest of his family, born 1782, he early showed desire for learning and excelled at school and in college. He was celebrated as an astronomer, poet, lecturer and skilled mechanic.
Much time was given to his books and philosophical studies. His recreation was found in his workshop, where he had a forge, two turning lathes, and a cabinet-maker’s workbench, together with numerous mechanical tools.
At the last visit I paid my cousin at Grumblethorpe, I asked permission to revisit his father’s workshop, and found it just as I remembered and my great-uncle had left it, everything covered with dust, but intact, as it was sixty or seventh years ago. Nothing had been disturbed. He was to Germantown what the Weather Bureau is to the country. Three times daily he took the temperature, read his barometer, making careful notes, which were regularly published in the GermantownTelegraph, then owned and edited by Philip R. Freas.
He had an observatory, equipped with a telescope, through which he watched the heavens, and upon every clear day, observed the sun crossing the zenith. He issued bulletins of the time, and every clock in Germantown was set by his standard.
…He was a remarkedly versatile genius, for besides all his other accomplishments, he could repair clocks, and many which needed repairs were put into working order by his hands…
I should have taken more interest in my great-uncle’s educational researches, had not his shop possessed greater attractions. The long and short foot lathe, beautiful cabinet-maker’s bench, not to mention the blacksmith’s forge, won my enchanted admiration, and were much more to my taste. For here it was he turned the Wister tops, celebrated among all Germantown boys. These tops were made from dogwood, could not be split, but could split the tops of any playmate opponent, whose top was unlucky enough to be hit.
There are a few men still living today for whom my great-uncle turned a spinning top…He was a merry and humorous old gentleman, and when a new boy would be presented to him would astonish him by asking, “Why is a cranberry tart like a pump handle?” After the boy had puzzled awhile, he would quietly say, “There is no resemblance.”
The Bucks County Historical Society in Doylestown, Pennsylvaia has some of the tops make by Wister, other small items and some of his tools.
In 1820 Wister started a notebook to record his workshop activites and titled it, ‘Various Recipes & Formulae Used in the Shop.’ I believe the notebook is in the Eastwick Collection of the American Philosophical Society in Philadelphia with no digital copy available. However, in early 2010 an enterprising young intern at the APS posted several photos of items from the Eastwick Collection including this recipe from one of Wister’s notebooks:
Charles Wister was one of the early users of photography in Philadelphia and, according to notations in the APS archive, he took photos of Grumblethorpe. Did he take photos of his workshop? If so, and if they survived, the APS may have them.
What mysteries are waiting in the the various archives holding Charles Jones Wister Sr.’s notebooks and photographs? For now, we have one photograph taken 56 years after Wister died and a sparse account of the workshop that is dated around the same time. I will be sending a note to the Operations Manager for Grumblethorpe to find out what remains in the workshop and possibly get some photos.