John Parslow skeleton clock

I've made a bit more progress. Wheels and pinions now cut. Will start on the arbors tomorrow. Don't have a pivot file so I will polish after turning with 1000 grade wet and dry and hope that is good enough (any thoughts?).

I have put a few photos in an album here to show progress.

Russell.

Hi Russell

Wish I could cut gears like that looking at your pic's lovely work and must take a lot of patience.

bob

It's not cutting the gear teeth that takes the patience. It's the crossing out!  Done by hand - no cnc (yet).

Russell.

Edited By Russell Eberhardt on 19/04/2012 09:20:59

Well done Russell, I admire your patience. As a half way measure to CNC you could, as I did, use a rotary table, see here

Harold

Nice one Harold. You always come up with good ideas.

My mill has X stops but no Y stops. Having seen this I must fit something similar.

Russell.

Russell.

Although 1000 grade wet'n'dry might give a decent finish on a larger area, it'll look like ploughed field on a pivot.

Make yourself a pivot file/burnisher by using a 600/1200 grit diamond stone or file, to apply a grain across a piece of 3mm wide HSS (a graver is good for this, because its lozenge profile allows access to the root of the pivot) , or an old reworked hand file, whilst being careful to keep the surface flat.

Then either spin the arbour in the lathe, or rest it against some wood in the vise, and apply this new tool until the surface takes on a polish - a little thin oil helps, as does keeping the pivot clean.

Martin.

Hello Russell.

I agree with the comments from Springbok & Harold Hall. Things are looking very good. Well done.

I never got the hang of using a pivot burnisher myself so used 1600 grade abrasive paper and polished until the abrasive was really shiny and then inverted the paper and coated it with `Autosol` metal polish then ran the lathe at full speed to polish the pivot to a high shine.

`Autosol` polish may not be available in France but jewellers rouge may do the job, but its messy.

John.

Thanks Russell, I find the Y axis stops very useful, they are of course not so definite as the x stops as the stop plate, even at 6mm thick, tends to flex a very little. Even so, results within +/- 0.05mm are easily possible and if better is required then using the feed screw dials to back up the result will achieve this. This is much easier than attempting to see, amongst all the swarf, when the cutter is getting near the end point required.

Even the X axis was poor when i purchased the mill as the stop bar would be pushed left and right, note the dowels that I added to stop this.

Regarding polishing the pivots, I used Micro Mesh in grades up to 12000. for details see here and here

Axminster sell this but only in sets of sheets. DEP I found very helpful and they will sell you individual sheets and even cut sheets. As a guess, from memory, a sheet is about 300 x 150 and they will certainly sell half sheets.

The sheets can be washed when they have been used and it certainly works at the courser grades but is less effective at the finer grades, but still works up to a point.

I have used the material to finish the clock frames.

Harold

Thanks for the suggestions regarding pivot polishing. The finest wet and dry I have been able to get is 1000 grit. I have some rouge powder, it is recommended for non ferous metals but I will give it a try.

Micromesh looks interesting although the website is a bit confusing. They show a micrograph of 400 grit "sandpaper" beside 1500 grit Micromesh and the Micromesh looks rougher to me! However I see it is recommended for refinishing acrylic windows so I might be able to find something similar in one of the nearby boat chandlers.

I see M & P (who have an outlet in France) sell "Diamantine " powder for polishing steel in medium and fine grades - anyone tried this?

I can see some experimenting coming on. I'll try making a burnisher as Martin suggests and try various polishing mediums and see what gives the best finish.

Russell

Time flies - a month since my last post here.

Well, I tried making a burnisher as martin suggested but couldn't get decent results.

I ordered some 2500 wet and dry and some Micromesh from Axminster (thanks for the tip Harold) and get good results following the wt and dry with micromesh. Can't find Autosol here and not sure about metal polishes that may contain silicone so I finished the pivots with Yacht Rubbing, which is used for finishing fibreglass boats, on a lollipop stick. That gave a good mirror finish.

I've added a few photos to my album to show that I am making some progress.

Russell.

One quite good fine abrasive is tooth paste, I'v used it for polishing steel samples for microscopic inspection, and also for finishing the bore of hot air engine power cylinders. The stuff I use is the free stuff you get on airlines (it tastes awful). Ian S C

I'm not a clock man but when I was an apprentice millwright in a power station in the '50's one of my tasks when working with the station Instrument Maker was stripping down and overhauling "bourdon" pressure gauges.

I was instructed to polish the pivots with "pith", no I haven't got a lisp either.

I don't know who the supplier was or even which plant the "pith" came from but the finish on the pivots was astonishing, so I was told. I suppose that technique isn't used any more!

Incidentally, I have used Solvol Autosol to polish Buffalo Horn handles on competition quality walking sticks and you could acheive a mirror finish eventually, but it's bloody hard work.

Len. P.

P.S. I'll be surprised if this post doesn't elicit a few bawdy responses.

There is no pith available these days due to all the pith takers.....

couldn't resist! sorry!

A bit more progress. All wheels now planted and running smoothly, (picture added to album). I made one planting error and had to bush the plates and try again but all's well now.

Next task is to sort out the escapement. At the moment I can't get it to work on the depthing tool so more investigation is needed.

Russell.

Although it is a few years since the last post on the subject of the Parslow skeleton clock, I hope that someone may see my post and offer some advice.

I am in the process of attempting to make this clock using the book and plans, however there seems to be a discrepency with the size of some arbours or the wheels centre holes. The plan on page D4 fig 5 says to ream centre hole on intermediate wheel 0.1875, but the section of the arbour where the wheel sits is only 0.118.

Maybe I am missing something but hope that someone can advise me on the correct action to take.

Dave

Hi David,

The intermediate wheel doesn't sit on the arbour but is rivited onto a machined taper section on the intermediate pinion. In the magazine article this is shown in Fig 12. I'm not sure if it is the same number in the book.

Russell

Hi Russell,

Thanks for that information and I now understand how it is done.

I must also thank you for the information you gave me on another thread when I asked about turning silver steel. I purchased the inserts as you suggested and am amazed how easy they have made the task.

So thanks again for your assistance.

Dave

For the pivots, use papers 2000 and then 2500 (to remove ALL hint of the previous 2000) then use diamantine on a carefully prepared steel burnisher made from a small file...make sure to keep edge straight and 'sharp to the flat.

Dimantine can be bought on line form any of the big sundries houses such as Cousins or Walsh. Best place to get fine abrasive papers easily is from branches of Halfords who do a pack of two sheets each of three fine grades; 1500, 2000 & 2500 for about £7, if I recall....be sure to keep the papers clean and only take out what you are going to use as these grades are well into the 'contamination zone' and any foreign body on the paper will cause you extreme grief!......don't ask how i know

If you really can't get dimantine then (i have found) ordinary 'T-Cut' for car body finishing makes a good substitute

At Epping forest Horology Club we have a tutor, one Francis Brodie formerly horological restorer at the Science Museum who tells us to polish pivots to the limit of our endurance and intelligence!...then look at the pivot under a good light/good glass to examine the highlight thereon........if you can see properly again out of that eye within 6 days then you did not polish adequately........

Edited By Bob Stevenson on 04/10/2019 18:17:53