| by Kenneth Chase | No comments

How To Make A Clock In The Home Machine Shop – Part 7 – Making The Barrel

G’day chris here, and welcome back to clickspring. With the main wheel complete it’s time to make the barrel assembly. So in this episode I’ll use a length of this tubing, and these offcuts, to make this. This is how the barrel fits into the clock design. it mounts directly onto the large wheel, and the whole assembly rotates around the barrel arbor. So I need to make 2 end caps, as well as the barrel wall, which has a recess at each end to accept the caps. The rear cap bushing must be a slip fit for
the wheel. But the front cap bushing doesn’t have to
fit anything, it just has to look good, so its given a nice rounded edge. So lets get started. I think it’s much easier to turn the caps
to fit the barrel wall, rather than the other way around, so I’ll make the barrel wall first. First up is a trip to the band saw to cut off a section of tubing The tubing is mounted on lathe chuck with the jaws lightly gripping from the inside, and the stock sitting clear of the back of the chuck jaws. and then its given a little bump with this centering tool, to set it true. Once its running true on the chuck, the jaws can be tightened. The rough edge was then tidied up with a facing cut. And you can see from the long stringy
chips, this is not a free machining brass, but rather a lead free variety. It’s not my
favourite brass to machine, but with the right speeds and feeds, it does give a good result. Both the inside and outside were given a skim cut to true up the surfaces, and then I machined the recess for the rear cap, taking quite light cuts to get a good finish. This section was then parted off, a little over length, to allow for machining of the other end. It was then remounted on the chuck, this time pressed up against the back of the chuck jaws. A quick check shows it’s running fairly true. Now the part needs to be faced to final length, and to then have the front recess machined. So I completed the facing cut. And then machined the second recess with a slight back taper, by feeding in with the compound on a 3 degree angle. The barrel cap will be made with a rounded edge, so this taper will give it a nice snap fit in the barrel. That’s the machining for the barrel wall complete. Now for the barrel caps. I started by cutting out two oversized blanks from these offcuts. Now these caps will need machining on both the edges and the front surface before we’re done, so it’s a perfect job for a super-glue arbor. If you’re wondering what the grooves are for, it’s to make sure that the glue has enough air to fully cure. Without the grooves, the perimeter seals off the glue in the middle, and it stays liquid. The first machining step for the caps is to knock off the rough edges of the blank, and turn down the diameter, leaving it oversize for now. The center hole was then drilled, slightly undersize. I plan to manually broach out these cap holes later, using a clockmakers cutting broach. That way the holes will fit the barrel arbor precisely. I’ll give you some more detail on this in the next video of this series, when I make the barrel arbor. I then got on with the job of roughing out
the full profile of the cap. Now super glue arbors work very well, but
they’re not without limits, and I did push my luck a bit here with the depth of cut.
You can see the part get the wobbles about now. I generated quite a bit of heat, the heat softens the glue, until it fails. I re fixed it to the arbor, gave it a quick cut to true up the bore …and were back in business. Now that the part is in basic shape, the bushing is reduced to be a slip fit for the main wheel bore, with a good undercut to give the wheel a clear seating on the cap. So with a good fit with the wheel confirmed, I faced the flange to final width, and then gave the front of the bushing a littler whisper cut as well. And before moving on, I made another quick check that the wheel seating was still good, after that last facing cut. The perimeter of the cap was then reduced to exact diameter, to give a nice slip fit for the back of the barrel. And thats the rear cap complete for now. A bit of heat breaks the super glue bond, and that rear cap can now be permanently fixed into place in the barrel. I’m going to bond it with loctite, so the parts need a good clean with lighter fluid before applying the glue. The inside of the barrel recess needs to be clean too, to get a good seating for
the cap. After a few minutes the excess glue can be wiped off, and the part set aside to cure. The front cap was machined, to begin with, in a similar fashion. And I bored the center hole on this one too, just to be consistent with the rear cap. The difference with this cap though, is that when close to diameter, the perimeter was brought to final dimension with files, and
it was given given a radiused edge. As I mentioned earlier, the objective is to
get a good snap fit with the tapered recess in the barrel. The last operation on the lathe, was to use these gravers to turn the radiused edge on the front bushing.. And thats the front cap done. Now the cap fit is OK. but it does have a slight amount of play in it, more than I’d like. The solution is to lightly hammer the perimeter to expand it a small amount, and after doing this, the fit is much improved. This cap also needs a little prising slot
cut into it, so it can be levered off the barrel when the clock is serviced. And thats the barrel done for now. In the next episode, I’ll make the barrel arbor, and broach out the barrel cap holes. Thanks for watching., I’ll see you later. If you enjoyed this video, here’s a few more I think you might like. I post regular home machine shop project video’s like these, so be sure to subscribe. And have a look at the clickspringprojects website too, for more toolmaking info. Thanks again for watching, I’ll catch you on the next video.

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