How To Make A Clock In The Home Machine Shop – Part 3 – Making The Washers And Screws
G’day Chris here, welcome back to Clickspring With the pillars and frames completed, its time to finish the frame assembly by making the washers and screws. The washers are as you’d expect, a simple disc, but with an ornamental groove around the edge. I need 5 like this, and then an additional one with a countersink, making 6 in total. Its a fairly straightforward piece of turning, and I found it easiest to turn them all in the one sitting. The first one I’m doing is the one with the countersink, followed by the 5 with just the simple clearance hole. Wilding recommends in his construction manual that they have a slight undercut at the center of the underside surface, so they seat well on the plates. To do that I turned up a quick cement chuck on the small lathe, bonded the washers on with a little super glue, and then set up for a very light taper cut. Just a few degrees, and then took a facing cut across the underside of the washer. A little bit of heat breaks the super glue bond, and now the washers have a slightly concave base, and should sit nice and snug at the perimeter. So with the washers complete, its time to take a look at the screws. The clock has 5 of these large flat head screws, which are kind of a nice visual feature, all made from mild steel. Again a fairly straight forward turning job. First I roughed out the shape, then undercut the head, and finally I used a die to cut the thread. I parted them off just a little bit overlength to leave a bit of metal for finishing. So next I needed to put in a screwdriver slot, across that top face, and I figured the best way to do it was
to use a slitting saw on the mill For once that little tip left over from parting off came in quite handy. I used it to line up the saw blade with the center of the screw. At this point the screw form is basically complete, it just needs to be brought to final di mension and then polished. So its back to the small lathe for the final operations. Off camera I turned up this little filing guide to help me keep the edges of the screw square during sanding and polishing. Here I’m making a start on those edges using fine grit emery paper stuck on to a brass polisher with adhesive. This is a tailstock polishing tool I made for my small lathe, I’ve tried to emulate the classic screw head polishing tool used by watchmakers. I’ve made discs of both brass and soft steel. Emery paper and wood can be fixed on with adhesive, or the metal discs can be used directly with various grinding and polishing pastes. The lap aligns nicely with the surface of the screw head, and can be lightly rotated to bring a fresh cutting surface to bear on the work, but I’ve found that under power its a bit too aggressive. probably causing more problems than it solves. Operated by hand though, with a reasonably fine grit, and it does a good job. In this case, I’m using a 3000 grit disc of emery paper on the steel disc. After just a few strokes it leaves the surface in quite good shape to start the polishing. Now I plan to do the polishing with Diamantine powder, and I must confess I haven’t had much success with it so far. I can get it to polish, but I always seem to get these little scratches that ruin the finish. So with these screws I was determined to sort out what was going wrong. I figured I would try out different polish consistencies, and a few other things, and see what I could learn. So first up I tried a fairly wet mix on a soft wood lap. Most of the texts also make mention of a putty consistency to the polish, so I tried that too. In both cases the polish cut ok, But I could see that the wood I’d chosen was less than ideal. Its too soft, and slightly rounding the edges of the screw, which I definitely don’t want. I had moderate success with the edges, just using this simple oak polisher. But eventually though, I hit the same snag which put me off last time. The surface was polishing, but I was picking up some nasty scratches too. By the size of them, they weren’t being made by the polish. It looked like contamination of the lap or maybe the paste. It was clear I had to make some changes to what I was doing. So first of all I went back one step to remove the scratches with the emery paper. Then I resurfaced the wooden disc. I tried out a few different types of wood, but I found mdf had an immediate positive effect. I also I charged it using a lot less polish. I got serious about cleanliness, covering up the paste after mixing, and cleaning the work thoroughly after every step. And finally I disconnected the lathe belt. Which allowed me to back right off on the pressure, and to better mimic the action of the classic watchmakers tool. Now I know that the results are far from perfect, but the deep scratching problem all but disappeared, and for the first time, I was starting to see the surface pop out the way I had read in books. Its a huge improvement on my previous efforts with diamantine, and at least now I know what I’m aiming for. Anyway, with that little adventure behind me, I blued the screws to finish them off. And now its time to have a bit of fun and see what it all looks like so far. I’ve got to admit its kind of motivating being able to see the clock start to take shape. That’s it for this week. Be sure to hit the subscribe button if you haven’t already. In the next video, I get started on the wheel cutting. Thanks for watching, I’ll see you later.