In the majority of instances, you will hold a workpiece in a three or four jaw chuck, a collet if really high concentricity of a very accurate round workpiece is required. These methods will work perfectly well with round, square and even rectangular stock. When it comes to holding irregularly shaped workpieces, you will need to put a faceplate to work.
A faceplate is nothing more than a flat, round and usually threaded, spindle held plate with either slots or holes machined on its face to accept all sorts of fastening devices to clamp the work to it. The object to be machined is placed on the surface face of the plate and clamps are slid through the slots or are directly screwed if there are threaded holes. Once you are satisfied with the work's position, the clamps are securely tightened and the face plate is screwed to the lathe spindle. If the work has to be milled, there are little adapters that are nothing more than a threaded short solid rod with a "T" base that will fit in the "T" slots of the milling machine table. To use, you insert the adapter and position it where you want on the milling table and screw it down tight. The faceplate or even a lathe chuck with matching spindle thread can now be screwed onto the adapter and worked on in whatever fashion you desire.
Another very common use of a face plate is to drive a round workpiece mounted between centers with the use of a " dog ". A lathe dog is a device that clamps around the work and has a tail that is inserted in a slot or hole on the faceplate. In use, the faceplate drives the dog which in turns drives the work. The reason for mounting a worpiece between centers is to maintain concentricity even if the work is removed and re-mounted during extensive machining operations. The head stock center used is no different than a tail stock center. They both have a 60 o point that match that angle produced by the center drills. The only difference may be the way in which they are installed. Some lathes will have a Morse tapered spindle as with the SHERLINE while some will have the spindle bore tapered to accept a specific type of collet. In the end, the method of installation will not matter much as long as the two resulting center points are facing each other in perfect horizontal and vertical alignment. Center drilling a workpiece is done by chucking the work and supporting it if needed with a steady rest, facing and center drilling the first end, reversing it to repeat the same procedure on the remaining end. The center point on the head stock will not provide enough friction to drive the work, being there simply to hold and keep the work aligned. It must be driven by the drive dog. In industrial applications, dogs will come in many sizes to handle a multitude of diameters. For our model making or miniature work, we will not really need a traditional dog and can instead, drive the work with an adjustable clamp that screws to the faceplate and simultaneously clamps around the workpiece. Even an automobile hose clamp and a piece of rod can be brought into use to drive some work. Simply insert the rod into the driving hole or slot on the faceplate so the rod is parallel and in contact with the work held between centers. The hose clamp is slipped and tightened over the work and rod to lock them together as a single solid unit. As the spindle turns, so will the work, driven by the rod and clamp. Of course more sophisticated drivers can be made but I like to keep things at the their simplest.
Faceplates are also used in general woodworking to also hold irregularly shaped pieces as well as short round and square stock. The difference here is that wood pieces are usually screwed to the faceplate from behind. This is fine for full size workpieces but in miniature work, we can use much simpler methods of attaching work to faceplates. I prefer several of newer non traditional methods like glue, double stick tape and the waste block system. Each method being specific to each need. When I say " glue " I mean the instant variety such as " Crazy Glue ". I can either glue or screw a piece of 3/4" thick pine to the faceplate from the back with relatively short screws. I would then machine the pine so that it is round and has a true face. I can either double tape small work pieces to the pine face or glue them to it. As the work is finished, it can be carefully pried away from the faceplate if taped, or just parted off with a cut off tool if glued. Round scale miniature table tops are easily made on the lathe with the use of a faceplate. I prefer the 2" diameter faceplate offered by TAIG for this purpose. You will have to drill mounting holes yourself but that is not a problem. The table top blank can either start as a square piece or you can roughly saw it round, for later trueing up on the lathe. After the rough stock is double taped to the faceplate and clamped for about ten minutes to insure a good bond, you can lightly face what will become the under surface and sand it to a fine finish on the lathe. Remove and flip the work and face off and finish sand the top surface. Turn the top round and cut any edge decorations now while it is still mounted on the lathe. That is all it takes to produce a perfectly round miniature table top.
Since we are on the subject of faceplates and making table tops. I recently was on one of my metal scrounging tips to my local metal scrap yard when I came across a large bin containing what must have been rejected machined aluminum parts and other components that surely came from some local machine shop or production company. In today's highly technological world, few machinist actually turn parts by hand. Almost all industrial machining is done by Computer Numerical Control or CNC for short, where the dimensions and other relevant parameters are pre-programmed and the machine's X - Y - Z axis so the tool just performs what the computer tells it to do. You would think this would be the fool proof way of producing perfect parts in high numbers. By the amount of waste parts being scrapped at my scrap yard, it does not seem to be that way. You know what they say, " somebody's trash is someone else's treasure "! In this pile of junk metal I have found perfectly machined disks of many diameters. Some with center holes and some without. Some are pre-drilled with perfectly spaced rows of holes around their circumference. To utilize one of these turnings I simply use a standard 2" diameter TAIG face plate and mount the scraped part to it. First I chuck the turning so what I have decided will be the rear face is toward the tail stock. I machine a 1/16" to a 1/8" deep recess that is a perfect fit to the diameter of the small TAIG faceplate. As I near the correct diameter I check the fit with the actual faceplate. The perfect fit is a slight press fit. When I achieve that, I machine a few concentric grooves from the center to near the edge of the recess. These are needed to allow a few air gaps so the crazy glue we will use to join the two parts together will properly cure. Smear the two mating surfaces with the glue and press the two together in a vice. After about 15 minutes, the joined parts can be further worked by screwing the faceplate to the spindle and taking a light facing cut across the front and a truing up cut around the circumference. You can bore out the center to match the faceplate center hole or just leave it as is. If I am making 3" diameter table tops, I make 2-3/4" diameter faceplate to provide as much support to the stock and prevent flexing during the facing operations. It also allows a 1/8" overhang to enable you to work and shape the edge and its underside without the danger of marring the edge of your faceplate. Use double stick tape to attach the table top blanks to the faceplate. Apply the tape in on a single layer to the faceplate and trim it to the edges of the face. Peel off the paper cover then stick the wood blank to it. Waste blocks can also be attached to this face plate and used in other rminiature turning projects. If you are skillful at woodturning, you may want to try miniature turning of bowls, vases, platters, candlesticks, etc. A thicker waste block tapering to about an inch at the face, makes an excellent glue block for the items just mentioned. A small bowl or round box can first be hollowed and finished on the inside, parted off and reversed onto a pressure chuck which is nothing more than another waste block that has had a shallow slightly tapered tenon turned on its face onto which the reversed bowl or vessel can be pressed on by its opening. If the fit is just right, the outside and underside of the bowl can be worked and finished. I make a habit of always having several faceplates ready to perform many different jobs.
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