Fanciful Forme is Finished, Finally!

Okay, well after tripping over the parts for this thing for months, I’ve finally finished the colonial forme (joined bench). 

The forme is really nothing more than a joynt stool elongated to “bench” length.  Upon sitting, most folks will immediately be struck by the fact that it is significantly higher than our normally accepted seating height.  In fact, it is 22″ high.  This may sound a bit uncomfortable.  But, in fact, it forces the “sitter” to keep most of his (or her) weight on his legs.  There’s been a lot of speculation about the height of joined stools and benches.  These pieces were very utilitarian in nature, though many of them (particularly in England) were very ornately carved.  They may have been used for other purposes along with the primary function of seating.  It is possible that they saw service performing tasks as varied as acting as a saw bench or a coffin bier.  Webster sites the meaning of the word forme as a small bench being used by a cobbler (shoemaker).  This type of bench was common in English private schools.  Many grade levels would have been taught in a common area.   Expressions like, “He has been promoted to the third forme” may indicate that a student was assigned to a bench (or group of benchs) being used by students who were studying a particular curriculum.

An edge treatment was carved on the top to add a little “cheap ornamentation” .  Many of you will immediately recognize the pattern as being taken from one of Frederick Wilbur’s books.  Thank you Mr. Wilbur.  The top is made from quarter sawn red oak that has a lot of character and a little staining along the edge.  There’s gotta be a little shot, nails or staples in there, somewhere.  Strechers, aprons and legs are made from honey locust.  These were some of the gnarliest boards I’ve ever worked with.  But the results and the color variation are very pleasing.  The finish is two coats of tung oil/turpentine/50/50 then two coats of heavy tung oil and finally a good coat of paste wax.

The torus shape on both the inside and outside surfaces of the stretchers was accomplished by roughing with a rabbet plane then finishing the shape with a scratchstock, made from an old saw blade.  Everything was draw pinned together.

In coming weeks I’m going to be concentrating on ways to improve the performance of springpole lathes and the construction (finally) of the Sidewing lathe, so stay tuned……

Sidewinder Lathe Project Update

Well, I’ve completed a number of “required” projects and now I can get back to the “fun stuff”.  The Sidewinder lathe is taking on “a life of its own”.  I’ve done some re-examining of my goals for this project.  Here’s the current list of things that I’d like to accomplish by building this lathe:

• design and construct a lathe that is human powered, but still capable of a range of speeds that will allow for high quality execution of the work on a reasonbly broad range of diameters, up to eighteen inches;
• be able to turn pieces up to sixty inches in length on a fixed bed (perhaps longer with a bed extension);
• minimize the footprint, by positioning the driving wheel parallel to the lathe bed;
• utilize contemporary work holding devices

In short, the goal is to build a big lathe that will be capable of turning large parts using modern chucking while occupying a small amount of floor space and – DO IT WITHOUT A MOTOR!

Okay, so I’ve got to start somewhere.  And, it seems to me that the logical place to begin is with the drive mechanism.  This, it would seem, would consist of the power supply (Me!), the power transmission apparatus, and the speed control system.  Alright, you’re right to ask the question – if I’m using a treadle, which is driven by human power, why do I need a speed control system?  Can’t I just increase or decrease the treadle speed as required?  Well yeah, I could.  But if anyone has every ridden an old single speed bike up a hill, you’d immediately know why some method of speed control (or more appropriately power control) would be so desirable. 

I plan to use a large drive wheel, forty-two inches in diameter.  From working on my springpole lathe, I know that about one hundred treadle strokes per minute is a pretty comfortable pace.  The math is realatively straightforward, I’ll be able to generate a pretty good amount of speed.  Ahh, here’s the problem.  The springpole lathe, you see, is all about torque.  It is a “torque monster” (as Underhill says, great for cutting multiple threads).  The “big wheel, high gear, high speed” lathe won’t be very torquey.  It’ll be kind like when Honda brought out their 250 cc four cylinder motorcycles to the race track.  Everyone thought their little rubber bands would break (but they beat everything in sight).  However, when I’m roughing in a large piece of stock, I’m going want to run at a slower speed with adequate power (torque).  Therefore, the need for some type of gear change mechanism.

So for the past few days, I’ve been thinking about methods of gear changing that I might use.  The whole issue is pretty well complicated by the fact that I have a right angle change of direction in the “power supply” line.  I thought about a step pulley arrangement but that would require the use of some kind of tensioning device (idler, etc.).  That device would not only take up valuable space, but it would also alter the direction of the power transmission (spliced rope or round leather belting).  Then there’s the problem of the type of belting I would use between the two step pulleys, as I invision them as being supported at both ends, not cantilevered.  Then, EUREKA! – a flash of insight.  Why not use two cone pulleys with a transfer idler?  Truly variably speed.  After a little simple mathematics; Speed of drive pulley X Diameter of drive pulley / Diameter of driven pulley = Output speed,  I figure that if I pump the treadle 100 times per minute, I can realize spindle speeds of between 175 rpm and 2950 rpm by simply moving the transfer idler.  Here’s a diagram of the “theory”,

So…If there’s anyone out there in “Lalaland” who’s as goofy as I am, let me know if you think that my theory holds up.  I’d be most appreciative of any input.

Obviously, this little project isn’t going to be completed within the next couple of days, so I’ll keep you posted.

Sidewinder project update

“Coupe de fleur’, who in reality is friend, workmate and nationally recognized expert and author on Craftsman furniture, raised a question on the Sidewinder’s drive arrangement and whether or not I planned to use a tapered drive and a multi-diameter headstock pulley.  He also mentioned the possibility of a set up that would allow for the use of a shell auger.  Fact of the matter is that I am contemplating using a MT2 drive and some type of quill set up in the tailstock that will allow me to use a live center and permit me to thru-bore.  Still doing a little contemplating regarding the need for anything other than a single diameter headstock pulley.  Here’s a “cartoon” of the reeving pattern.  If anyone sees any obvious flaws, please let me know.

Also, I’d like to thank Roy Underhill.  I asked Roy if he was familiar with this style lathe and what he felt was the best material for the drive connection.  He responded the next day, identifying the machine as being very similar to the one on display in the Norwegian Folk Museum and, in his experience, round leather belting was the best choice for the drive connection.  Roy is a “national treasure” and he proves the old adage that if you need something done quickly, ask a busy person.  Thanks again.

THE “SIDEWINDER” LATHE PROJECT

Call me irrational, illogical and a spendthrift, if you will.  But I’ve concluded that one can never have too many treadle driven lathes.  After all, God saw fit to give us two feet, so…  Over the next month or so, I’ll be working on a “sidewinder” style, continuous rotation lathe.  This is a curious configuration, with the wheel sitting parallel to the lathe bed, that offers a number of distinct advantages and challenges.

The advantages of this design are; the wheel diameter is only limited by the number of pulleys that are required to create the appropriate reeving path.  The larger diameter wheel can generate much higher spindle speeds with fewer treadle strokes.  The crank link will be in the center of the treadle.  This will allow me to build a trapezoidal treadle which will be both stronger and lighter than a “side load” treadle (type seen on most treadle lathes).  The actual depth of the lathe will be much narrower than one with the wheel perpendicular to the lathe bed, therefore saving valuable floor space.

I’ve only seen two partial photographs of this style lathe.  If anyone out there has any information that they could share with me, I’d certainly appreciate it.  Stay tuned.  We’ll doubtlessly uncover some arcane information about gear ratios, reeving, pulleys, bearings and rope splicing.  Should be fun.