Dark Lady Clock

I've read somewhere that clock pivots need to be ever so slightly rattly because when the relatively high loads from springs or weights are applied to the relatively thin pivots they bend ever so slightly, and so if they were too good a fit in their bearings they would bind. I assume this wouldn't occur with ball races, which can accomodate a (very) small amount of misalignment

Nearly there now

Edited By John silver on 06/09/2016 08:04:39

Looks smart John.
Now I've been using it for a bit I've found a couple of tweaks. If the counterweight has a point at the top it's less likely to foul the driving weight as they pass. Likewise if you can keep the diameter of the driving weight down it helps.
I fitted the ball race to the weight pulley as suggested, it did make a difference.
The screw that holds the click was a bit proud and caught on the cord sometimes.
Otherwise it's running ok and will go indoors soon.

Cheers john

I'd like so find some info on making a lathe tre-panning tool - I managed (with great effort) to cut the dial using a narrow "Vee" shaped tool (I guess it is a threading tool).

I've made most of the strike works parts, so it's just the hands and weight to do next

All the best

John

.

This looks a very useful little tool grinding jig, John.

**LINK**

http://bbs.homeshopmachinist.net/threads/45764-Homemade-trepanning-tool-grinding-jig

MichaelG.

To make the tool, grind up a bit of HSS (size it to suit the size of the work) a bit of 1/4"sq would do for most stuff. With the cutting end away from you grind the left side to a bit past half way, now this side needs to be tapered in to accommodate the circumference of the circle. In use be careful as you near penetration as it rarely goes through in one go, and if the tool catches up it can ruin a good bit of metal, and make one say bother. looking from the front, it looks like a parting tool with one side vertical, and the other with clearance.

There you are, I know what I mean, I'v got to make one tomorrow.

Ian S C

I used a 55 deg HSS thread cutting tool as I had one handy. Light cuts from each side of the V not just plunged in.
The brass sheet was stuck to a bit of ally waste then both stuck to the faceplate with carpet tape.
I gave it a polish first to get a 'satin' finish on the brass.

All finished, it only runs for a little bit then stops. But i haven't added any clock oil to any pivots or the foliot???

Edited By John silver on 12/10/2016 15:39:24

Looks good.

Brian told me they take a while to run in. A drop of light oil helps on the rubbing faces. Mainly round the verge bearings.
What weight are you using?
I ended up with 3.5 kg on a double fall, with a ball race in the weight pulley.

I also fitted a smaller adjuster on the foliot. One turn of the original weight was too coarse.

Edited By john carruthers on 13/10/2016 08:37:17

Well done John!

Good work. Very impressive for a first project.

Dave

Greetings all,

I'm a bit stuck trying to get the clock to run OK. Lifting the verge causes the gears to spin as the weight falls as expected so I have been looking at the profile of the pallet.

I took the photo in Brian's notes and drew around it scaling to the correct diameter around the bolt head. This is shown in red.

The blue shows the layout of the various lines on the 14mm wide metal strip and the purple basically what comes from it.

As you can see there is quite a difference between the position of the 3mm curves to the threaded hole on both variants.

I'll post this to Brian for comment too

I have a shorter radius, so a deeper curve in the working faces.

John If the pallet fouls one tooth of the escape wheel, might I suggest that the fault lies with the tooth rather than the pallet