John Wilding Elegant Scroll Skeleton Clock

We featured Glenn Bunt's clock depthing tool in MEW 227 & 228.

Neil

The John Wilding type is much easier to make!

Russell.

Thanks Neil I think I will subscribe to the MEW I used to take it "years" ago.

As I have fitted the wheels to the Arbors Russel I will have to use the conventional gauge.

John.

I have the same book, but it shows different dimensions. Are you using an up to date copy? My copy is date d1998.

From the full-size plan, measurements for centre distances (sadly, in old units) starting from the barrel arbor are shown as:

3.25inches, 1&17/32inches (which is the dimension that is troubling you, I think), 1&5/32, 1&3/32, 1&3/32

John Wilding is very helpful and, in my experience, responds to letters. I do not have an up to date address, since he moved, but you might be able to contact him through RiteTime, or the British Horological Institute (of which he is a member. He had an article published in this month's BHI Journal.)

Marcus

John Wilding's depthing tool is a simple but useful tool. Plans were included in the BHI Journal around 1979 or 1980, as I recall. It was in the instalments of the first of three clock designs intended to be made on the Unimat 3 (or larger lathe, of course). The clock you are building was also published in instalments in the BHI Journal, as most of John's clocks have been. That's perhaps the source of the reference to the "1st series".

I made that first clock, which was based on a 16th Century one-handed clock, and I made the simple depthing tool as well. The DT design has appeared in several places since then, I believe. And others have published similar designs of DT too.

Marcus

Yep, but the OP needs a tool that can depth gears already fitted to their arbors.

Neil

Hi Marcus thanks for the reply

The measurement that is giving me concern is the 1 5/32" it measures 1 7/32" plus the pattern for the rear plate cut out is different from the front profile!

John.

One of the problems with the dimensions is that while they are all in imperial units, cycloidal gears are usually dimensioned in Module (M), which is a metric measure.

42DP is approximately the same as 0.6M, but not exactly. So if you convert calculations based on 0.6M to imperial units, there is a small error. The same would be true if you did it the other way around, of course.

Using the Thornton's guide to wheel and pinion cutters,

Module (M) = twice the centre distance in millimetres / sum of teeth in wheel and pinion

Or: centre distance = half of sum of teeth x M

= 98 x 0.6 = 59.8 giving a centre distance of 29.9mm

1&5/32 is 29.36875mm and 1&7/32 is 30.95, so you can see that either imperial figure is a compromise and, as the drawing says “approx”.

It is not unusual to vary the depth of cut on a clock wheel, just a little, so I would use a 0.6M cutter, and increase the depth just a touch. That ‘touch’ could probably be calculated from the Thornton’s guide, or perhaps by using Gearotic (which I think now includes cycloidal gears). That thins the teeth slightly, but not enough, in this case, to cause a problem.

I have seen a clockmaker’s depthing “tool” which allowed meshing to take place without disturbing the dividing setup used to cut the teeth of the wheel, so that the correct depth can be judged at that stage. They are not common, and would not be required for this job, although one would be jolly convenient.

It would be worth calculating all the centre distances, as a check, to see if any others need a slight adjustment, or if the errors cancel out as you progress up the train.

Marcus

The pinions for this clock are stated as being "best" made out of blued pivot steel. I disagree strongly. Pivot steel/Pinion wire has a poor finish on the surface. Try abrading it lightly with a very fine paper, and you will see the surface is like a ploughed field. The wire will be uncut, so that's not going to provide the low-friction surface you need. Carbide rod or HSS rod would be much better.

Marcus

John. If you were to make a depthing tool as the John Wilding pattern and instead of having points, Drill holes the same size as the arbours through the adjustable screws you could depth the wheels and pinions then put a point made from the same stock as the arbours through the screws and mark out that way. ( I hope this makes sense, I know what I mean )

Roy

Thanks Marcus that has given me a bit to ponder over and I hope it all resolves it's self when the Depthing Tool is sorted!

Thanks Roy that is a thought !!!

John.

Hi guys back on trying to finish the clock!! I have got to the stage of the plates all done not polished the train is done and running, the bit I am stuck on is fitting the strike components there is no mention in the book I have of how to fit them? can anyone help with either a scan of the section covering this or sell me the latest edition IF it covers this? my edition is No4. Thanks John.

.

Marcus,

Please permit me to question your strong disagreement.

Blued pivot steel is a raw material, from which things are made

... It is not intended to be used 'as-is'

MichaelG.

Does your edition have Fig 114 showing the bracket in which the hammer is to be pivotted? The bracket is to be fixed to the front plate with 2 screws. The 3 sections of the bracket can be pressed together or soldered.

The trip pin on the minute wheel should be approximately 4mm (5/32" in from the edne of the wheel, andf aligned with the minute hand. Make the lifting piece over length, then trim it so that release occurs exactly on the hour. I would take care to allow enough material to remain so that the arm can be given a final polish but still release on the hour. Longcase clocks often have bent pins to compensate for wear...

Fig 116 should show dimensions of the lifting pin. The pin is held on the shaft using an M1.8 x 0.35 (10BA) screw, bearing in a flat on the arbor (also shown in fig 116).

The tail of the hammer arm rests against the stop block on the bracket (shown on the un-numbered fig. entitled 'bracket components' and shown in the photograph Fig 115a. I am guessing that photo may have been a later addition, as it shows the assembled parts. Fig 115 itself shows the Parts of the "one-at-the-hour" striking gear.

Marcus

Yes; but my objection is that it is widely recommended for use in the as-supplied condition when making lantern pinions. If the surface is polished, that reduces the diameter, which then means the specified matching drilling diameter is wrong. Lantern pinions have merits of their own, but, when used instead of cut gears, the blued pivot steel is used as a convenience, so one would expect the drilling diameters to be correct for the finished diameter of the rod. That diameter is variable, if the rod is polished or turned.

More modern materials may be more expensive, but are dimensionally more accurate, and have a surface finish which means they can be used as-is. They are also harder than pivot steel. I guess pivot steel was the most convenient workable hard material 100+ years ago, but I am inclined to move with the times, except when restoration demands the use of age-appropriate materials.

Marcus

Thanks for the clarification, Marcus

MichaelG.

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P.S. For small lantern pinions, decent quality sewing needles make very good trundles.

Hi Guys I have moved on a bit the clock is all rough assembled not polished yet!! anyone any idea of what the click spring on the barrel looks like? again nothing in my book! I can do something to do the job but would like to do it as it should be. There are a lot of things missing in the book like how/where the bracket for the alarm is fitted, the maintaining dent arbour no mention of that either etc etc

Thanks.

John.

Hi John, the ratchet on the mainspring barrel doesn't have a spring, the pawl is initially held away from the ratchet teeth during initial setting up, then engaged and locked tight once the mainspring pre-load is set, it isn't moved again unless necessary to reset the spring preload,
The mainspring is then wound via the fusee cone which winds the chain/wire off the barrel, the barrel arbour always remaining stationary

The spring on the fusee wheel holds the ratchet pawl against the teeth on the ratchet wheel adjacent to its train wheel, this can be fashioned out of strip brass, a common repair on antique longcases and fusees when they work harden and break,
I'll have a dig into my repair archives and try find an example,

John.

Hi John that's great thank you and it all make sense any info is much appreciated

Kind Regards,

John.

Cheers John, I've found some photo's of a replacement spring I made for a longcase movement I Restored, it was for a 5 pillar 8 day 'Pinchbeck' clock with a small 'refinement' not normally seen on run of the mill stuff, so it may suit the skeleton, I'll get them into my albums and post them up for you.

John