Here’s a bunch of tips that will help you make any number of chips look exactly the same – or, more practically, enough of them, no one will notice the difference.
Let’s start with the raw material, the billet. Also known as a blank, this is the square of the wood in the lathe chuck, making it your turn. Accurate grinding blank completely square and the length of the same emphasis on how can not be overemphasized. In order to achieve this goal, I ran the face and an edge of the board I would take the billet from the contact person and then put the square opposite it with a good carbide blade in my desk saw. I get consecutive squares.
Sometimes I crosscut the jointed plank to length first and then rip finished billets. Other times, I rip squares and then crosscut finished billets from the squares. It depends on the wood and the length of the billet.
While it is tempting to cut billets 1/8″ to 1/4″ oversize with the idea of creeping in on the largest diameter, this is a mistake. I mill to about 1/32″ over the diameter of the piece. Turnings such as table legs will have a square area called the pommel at the top. This is where the aprons will be mortised in to form the frame of the table. While the extra thirty-second does not affect diameter much, it gives me some cleanup room to hand plane the pommel nice and smooth after mortising.
You will need to accurately find the exact center of both ends of your freshly milled blank. I use a machinist’s center finder and a sharp awl to accomplish this: a pencil line marks to the side of the center finder, while an awl hugs it. I then center punch the exact intersection of the two resulting lines and catch the punch marks with my centers when I chuck the billet.
Chucking off-center decreases the diameter you obtain by the mis-centered amount. Chucking on-center gives you the full diameter of the blank without measuring; simply turn until the blank is just round and you have the major diameter of the piece. No need for calipers; just lightly touch your fingers to the back of the rotating piece until you feel the flat spots just go away.
Accurate Layout is Key
The human eye is much better in picking up differences in the height of key elements on several turnings than in judging differences in diameter. Of course, the larger the turning’s diameter, the more irregularity you can have without anyone noticing. Most furniture turnings are between 1″ and 2″ in diameter, so my comments address this size range. While no one will notice a 1/8″ difference in diameter between several turnings, 1/32″ in heights of any of the elements will bring scrutiny. Precisely placing all of the elements on a turning boils down to accurate layout. Here are some methods that will help immensely in achieving that goal:
Master Part: Turn a good example of what you want or what the plans suggest. Display this master turning in front of your lathe by either hanging it on the wall or setting it on a shelf or stool. All measurements are now taken from the master turning, and it acts as a comparison to guide you in turning the rest of the pieces.
Rulers and Tapes: I do not use tapes very much, as they are hard to hold against a turning and bend around turnings with large differences in diameter, giving a false reading. I like folding wood rulers much better. Measure key elements on the master and transfer these distances to the piece you are turning with a sharp pencil. It is generally best to only measure from one end; measuring from both ends can introduce errors. The longer the turning, the more this is so. An exception is where you want a tenon of a specific length on one end but are measuring from the other. In this case, using dividers to mark the length of the tenon is fine if all the billets are of exactly the same length.
Calipers and Dividers: Both these instruments are necessary to duplication. You cannot have enough of these stalwart friends in a variety of sizes. The ones that woodworking stores sell today tend to be big and clunky. I have good luck finding really good ones at house sales, flea markets and antique shops for reasonable prices.
As outlined previously, you can obtain the major diameter of a piece by milling the blank to that size. I set a pair of calipers at each of the lesser diameters on the master turning. (Actually, I set them about 1/32″ larger so that I have some room to finalize each diameter.) I use dividers extensively to set the width of coves, beads and tenons, as well as the distances between elements. I use my largest caliper or dividers for the greatest diameters and distances. I then try to graduate them size wise as the diameters and distances lessen. A perfect caliper for tenons is an open-end wrench. It will give you a press fit with a drilled hole (1/2″ hole, 1/2″ wrench).
This will aid in long-distance running (50 or more) or on regular intervals. First draw the full size part; the paper shelf favors long chips. The key elements of the expansion line and the glue thin piece of wood. Reducing the resulting large diameters of the blocks to turn, with small steps, each row satisfying the edges. You can now turn this story stick, pencil in the appropriate cut and draw a line of work every time in exactly the same place. You can also set the calipers and separators directly to the critical diameter and distance of the story. Drill a hole and hang it on the wall.
Do not touch your tools ability: you need a good Turner copy, but you do not need to be a trump card. One of the biggest mistakes I’ve seen people make is sticking to the final smoothing of the oblique column sections, or worse, reducing the beads. Tilt is a tough tool to use often, and a poor time to get the necessary skills to use it and calm is when the legs you intend to complete the day after tomorrow. I very much believe that the spindle is drafted with a gouge and a spindle chisel 1/2 “. It is very good to grind the spindle to draft the round chisel very difficult to have to catch and will finish practically as good as tilting.
Use the appropriate speed: 1 “2” spindle wave, 800 – 1600 rpm is a good speed range. I usually work at 1200 to 1400 rpm but slow down for ramps 600 to 800 rpm. Too much speed can cause vibration to generate chats that are at work. However, too slow to invite. For sandblasting, the lathe can be accelerated. But keep it in 1800, then put your time and sand.
Often someone asked me, “What is the best for my lathe copier?” My answer is, “You!” You can buy copy paper, but a budget fan in the workshop is a pity. It only replicates flat tools with scraping tongues, reducing burr-free. These tools do not produce smooth finish or deep grooves between the elements such as beads. For small production runs of four to eight pieces, you will spend more time than needing to set the copier’s handle. Repetitive work also requires a lot of sand, from 60 – 80 – perseverance. This further erodes the crisp elements, leaving a very dim chip.