First "Clockmakers" tools - broaches, pivot file..?

[Horology101]

I have just purchased Colin Thornes book - Clockmaking for the Model Engineer which is really excellent. I am preparing to make Colin Thornes - Skeleton Timepiece and this will be my first clock build. I`ve been wanting to do it for ages and I`ve got a neat little workshop up and running with most of the "normal" tools required for making engines and such.

I`m trying to get the basic tools I`ll require for making this clock, any that I can make I will do but those I that I will need to buy I want to order now in preparation.

Ok, so I`m hoping to compile a list but a few things I would like to question:

1. Colin Thorne says that a set of broaches are the first thing one should buy and a set 0.5mm to 10.0mm. Now I`ve been looking into this and considering a small set is 0.5mm to 3mm and a medium set 1.5mm to 4mm, I`ve not come across any set with such a wide range and to cover this range would cost quite a bit. Can anyone suggest a suitable set. I understand why the range is needed since I`ll be using them from pivot holes on plates to driving wheels on collets. Just seems like a lot of broaches or can you get them with a larger taper to cover a greater range - I haven`t found any. Any suggestions - UK supplier ideally.

2. Collin Thorne also suggests that a pivot file is needed, but they are £40 and apparently a right and left handed file is needed.

3. Any recommendations as to a good pair of tweezers?

4. Any other necessary tools?

I`ll be making the depthing tool, Jacot tools, burnisher, bench stakes, gravers and clockmakers throw.

I`ve been interested in model engineering a short while now and know that quality tools do the job and last longer so suggestions would be really helpful especially from a UK supplier.

Appreciate any advice.
Chris

[Jerry Kieffer]

Chris

Since you are in the UK and are into model Engineering, I would suggest attending larger model engineering shows if you have not. The last one I attended had a strong Horological showing. This would allow you to evaluate tools in person and solicit advise from those who are displaying movements/clocks they have built. I have not attended a Horological Show in the UK so I can`t tell you what to expect.

Since you are asking for advise, I would like to offer another perspective for consideration since you have indicated you have machining skills/equipment.


Building a Watch or Clock movement is no different than building any other mechanical item including Model Engines. In fact watch/clock movements are machined during manufacture in the same manner as most anything else. If you have everything required to machine a model engine, then you probably already have everything required to build a clock movement. Fits and finishes in clock movements are generally less demanding than properly operating model engines especially internal combustion. While the tools you are asking about and the skills to use them can certainly be and are used to build a clock movements, they are generally associated with maintaining and repairing existing movements.
As an example. Cutting broaches are very handy for many types of work, but it makes little sense to broach a tapered pivot hole if you already have the ability/tools to drill/bore a straight, round proper fitting hole.

I would suggest you look at the work you have to do with a open mind.
There is no right or wrong way provided the work meets the standard it has meet to function properly. And of course to a quality standard.
Another example if I may. While there is certainly nothing wrong with using a graver, It will have little or no advantage if you are already proficient machining on a machine type Lathe. (Model Engineering skills on quality proper size equipment)
If you have a Milling Machine it can easily perform the function of many specialized tools as was/is the case in movement manufacture. It is just a matter of setup and the same thought process as required in model Engineering design and construction.

You are correct in that the highest quality tools will provide the highest quality results. This will be especially true for the purchase of your tweezers.


Jerry Kieffer

[Dave B]

When I started this game, in 1979, the first things I bought were three pairs of tweezerzs, ( fine, medium, and heavy duty) and a couple of Bausch and Lomb loupes (2"-5x and 1 1/4"-8x, with an auxillary screw in lens to go to 18x). It was close to a year before I got into anything that required broaches.

[Horology101]

Dave B - I am on my way to cutting my first wheel and I have made an arbor, collet and pinion. I will soon be at the stage of staking it all onto the arbor so I can imagine some of these tools will be needed shortly.

Hi Jerry, I totally appreciate what you are saying and if I may quote Colin Thorne from the book, this is what inspired me to ask the question:

The only specialist tools you should get before you start are a couple of sets of clockmakers' broaches. These are tapered five-sided cutting broaches, and are used for enlarging holes for fitting pivots in plates, also for forming drive fit holes for fitting wheels on their collets, etc. Use them only for cutting brass. You will ned a selection of sizes, from about 0.5mm up to 10mm.

So, for example, in this instance I can`t imagine what I would use to produce an acurate tapered hole without the broaches.

I appreciate your reply.

Chris

[Mike Phelan]

Chris
Jerry is spot-on about the ME events and using good tools; there are two at Harrogate every year and also a few more around the country. (cf Google for dates)

I only own one (LH) pivot file which I've had for about 30 years; two of them are not essential, as they are expensive, and I manage by reversing mine and holding the end.

Broaches are essential, and unique to clockmaking. There's no substitute, but they will last for years. M&P have a good selection. Same with tweezers - cheap ones will soon end up in the bin.

[Horology101]

Hi Mike

Thank you for the advice.

Regarding the broaching set - I have looked on M&P but they seem to have small sets as I mentioned in my original post. Colin recommends a set from 0.5mm to 10.0mm which is a massive range and would be very costly. Is such a set needed do you think or are there any sets which cover a larger range?

Chris

[Jerry Kieffer]

Originally Posted by Horology101

Hi Jerry, I totally appreciate what you are saying and if I may quote Colin Thorne from the book, this is what inspired me to ask the question:



So, for example, in this instance I can`t imagine what I would use to produce an acurate tapered hole without the broaches.

I appreciate your reply.

Chris

Chris
Thank you for asking the question. This is one of my favorite subjects.

First to answer your question. I can think of several methods of producing a accurate tapered hole especially with machine tools.
A fast accurate method would be with a reamer that is easily made as follows.

First chuck a piece of round drill rod (Or Silver Steel) in your lathe. Then machine or file a desired taper. From that point, highly polish the taper surface, harden and temper and grind the taper half round. This will make a reamer with a sharp cutting surface, that will produce a very nice finish far better than the rough surface produced by a scraping Broach. The highly polished taper surface is what will produce the really nice hole surface finish.

However this is not the important question that should be asked.

The question that should be asked is why on Gods Earth would you want to install a round straight pivot in a tapered hole ?
I would like to have Colin Thorne or anyone else Explain this. Are the companies that have manufactured movements for the past 150 years all wrong I am sure that some manufacturer must have produced a tapered pivot hole somewhere along the line, but I have never seen one.
In addition, tapered holes to fit wheels to a hub will of course work, but it is a unsound mechanical procedure for that type application.


The use of taper broaches for this type work has been part of traditional repair methods in Horology for hundreds of years as indicated by Mike. If I had to guess I would suspect that it comes from the fact that in the early days, materials were extremely expensive. A broach could be made using little material to make a wide range of hole sizes. Be it a sound procedure or not.

Unfortunately in the World of Horology, to some people, it is sacrilege to even think about questioning any traditional procedure no matter how unsound it may be.

My point to you was that with a model engineering back ground and equipment, you have the ability to produce a movement in the same manner as companies like Howard or patek philippe.

Having said that, I of course own several sets of broaches and use them on a regular basis. I would also suggest everyone have at least one set for all kinds of work, but only used where they will not compromise quality work.

Jerry Kieffer

[Horology101]

Jerry,
I don`t mean to sound rude, I`m know I`m the one asking for help and advice only you said:

The question that should be asked is why on Gods Earth would you want to install a round straight pivot in a tapered hole ?
I would like to have Colin Thorne or anyone else Explain this.

Colin actually directly answers this question in his book, quote:

The hole is initially drilled undersize and then opened out from both end with a taper broach until the pivot falls home freely ... The reason for the tapered hole is twofold:

1. When assembling the clock, it is often necessary when fitting the second plate to have to locate the pivots one at a time, particularly in an older clock, because the pivots will be slightly floppy in their holes in the other plate, and therefore do not all stand up nice and straight. The plates are obviously not parallel at this stage, and therefore the pivots are slightly out of the perpendicular to this plate until it is finally pushed down onto the ends of the pillars. The slight taper to the holes assist this assembly procedure, having said that it should be noted that when assembling on a level surface, it is quite possible, even lightly, that the second plate will sit right down over all the pivots and pillars with no "fiddling" at all. One gets a great feeling of satisfaction of a job well done when that happens.

2. We are back to the problem of reducing friction: with the hole tapered from both ends, the pivot is bearing on a very small area near the center of the hole. Wear will eventually increase this bearing area, but at least we start off with the ideal.

-------------

Jerry, I totally appreciate your advice in terms of the fact that there are various solutions to problems and tools can be used or made to get the job done. "There is more than one way to skin a cat" comes to mind...

[Jerry Kieffer]

Originally Posted by Horology101

Jerry,
I don`t mean to sound rude, I`m know I`m the one asking for help and advice only you said:



Colin actually directly answers this question in his book, quote:

The hole is initially drilled undersize and then opened out from both end with a taper broach until the pivot falls home freely ... The reason for the tapered hole is twofold:

1. When assembling the clock, it is often necessary when fitting the second plate to have to locate the pivots one at a time, particularly in an older clock, because the pivots will be slightly floppy in their holes in the other plate, and therefore do not all stand up nice and straight. The plates are obviously not parallel at this stage, and therefore the pivots are slightly out of the perpendicular to this plate until it is finally pushed down onto the ends of the pillars. The slight taper to the holes assist this assembly procedure, having said that it should be noted that when assembling on a level surface, it is quite possible, even lightly, that the second plate will sit right down over all the pivots and pillars with no "fiddling" at all. One gets a great feeling of satisfaction of a job well done when that happens.

2. We are back to the problem of reducing friction: with the hole tapered from both ends, the pivot is bearing on a very small area near the center of the hole. Wear will eventually increase this bearing area, but at least we start off with the ideal.

-------------

Jerry, I totally appreciate your advice in terms of the fact that there are various solutions to problems and tools can be used or made to get the job done. "There is more than one way to skin a cat" comes to mind...

Chris
You are certainly Not rude. If anything my straight forward and blunt responses are probably considered rude by many even though they are never intended to be.

First I must say I have not read anything written by Colin Thorne nor have I ever met him or seen any of his work.
If the comments above are actually word for word from his book, then we clearly have a difference in philosophy.

Personally, I could never endorse not correcting or creating a unsound and less than quality situation for the purposes of assembly.

I wish you luck and many enjoyable hours on your clock movement project.

Jerry Kieffer

[harold bain]

Just an observation, but I think you are talking about two different holes. The hole that you fit a bushing in should be tapered for a more secure fit.. The hole that the pivot fits in, perhaps not.
However, this thread discusses some clocks where both the bushing hole and the pivot were purposely tapered:
http://mb.nawcc.org/showthread.php?t...t=taper+pivots