Gathering pallet

Hi.

I am building Alan Timmins 8 day long case clock and at the point on the striking train where I have to fit the gathering pallet on the arbor. Timmins method is to use a 1 degree taper (2 degree combined). I have turned the taper on the arbor but stuck on how to machine the tapered hole in the gathering pallet which is 60 thou at the large end. I would like to hear from anyone who has built the clock or has similar experience and how they solved the problem.

Thank you.

David.

You need a taper pin reamer don't you? They can be bought, or you can make another arbor with the same taper out of silver steel, file nearly half the diameter off longitudinally, polish the face and harden/temper to make a d-bit reamer.

Since taper pin reamers are used in clockmaking e.g. for making holes for taper pins holding pillars in plates, Timmins may have designed the arbor taper to fit a standard size.

Hmm.  Tracy sell such reamers that seem to be 1:50 or 1:48 and are horribly pricy.  Maybe remake the arbor to a standard taper?

Will send you a PM.

Edited By John Haine on 20/01/2020 16:43:50

I wonder if Timmins meant to use clockmakers broaches? These come in cutting and smoothing types an a typical taper is 1mm in 100mm.

These are available from the usual suppliers of clockmaking materials and are not expensive.

Brian

Clockmakers and jewellers tend to use the term 'broach' for what we might call a reamer (of a particular type). They are five sided, hard steel and slightly tapered, and you use them as you would a conventional reamer. The edges where the ground flats meet are sharp enough to scrape a brass hole, and they are available from jewellers supply firms. I have used them to make unavailable carburettor jets.

Try this for an example:

https://www.ebay.co.uk/itm/A-Pair-of-Very-Fine-Tapered-Hand-Reamers-1-6-1-7mm-diameter-1-16/392460023495?hash=item5b6070b6c7:g:wwgAAOSw~AFdlOle

Regards - Tim 

Edited By Tim Stevens on 20/01/2020 17:41:19

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Sorry, David ... I am not familiar with the Alan Timmins design

May I ask : Does he use round tapers ?

My understanding is that the typical gathering pallet fits on a tapered square.

Grateful if you could post a scan of that detail from the book, for my enlightenment.

MichaelG.

I've not made the Timmins clock but my standard method with all such items is to make an extra tapered component while the lathe is still set to the particular taper and then use the second one for making a 'D' cutter so that the female component might be easily made to an exact fit......

Thanks one and all for your replies. I did make a 'D' reamer, the problem is that the thin end of the taper is 50 thou and the thick end is 60 thou as near as I can measure. The taper and the taper reamer were turned at the same setting. The problem for me was that the only available method I have to file to the halfway mark is a filing rest on the lathe and the reamer becomes very fragile as I neared the halfway and bent away under the pressure of the file. It took a long time and I am not sure that it is really a good job. It really needs a method of supporting the reamer along its length while filing.

I do have some pivot broaches but their angle is less than 1 degree (2 inclusive) I think they are 1mm taper per 100mm length. I also have some commercial taper reamers that would be small enough but these have a more obtuse angle, between 3 and 4 degrees inclusive. Since this has to be a locking taper I wonder if this angle would be suitable? I wonder is some someone with more knowledge on this matter could advise me?

Alan Timmins does mention that the original clocks had a square taper as someone mentioned but said that filing a square hole this dia. is difficult and I would concur. He changed his design to a round taper. I will scan the page in and upload it tomorrow.

I will take a look at Tracy's catalogue that I have and thanks for your help.

David.

Don't overthink it....you only need a very short length of 'D' cutter to taper the hole so don't get too carried away filing up a long taper flat...... Just harden the end of the piece and temper to 'straw' then work on the edge of a fine stone until you can see that you are half way....may need to use a glass to see properly, then ream the hole and keep testing with arbor until you are pleased with the fit.

..............For a 1 degree tapered hole you could, alternatively, simply turn up the taper in brass, coat with an abrasive such as 'autosol' and just polish the inside of the hole until you get a nice fit......only do this in the lathe or similar so that it's accurate and the pallet sits nice and square.

.

Thanks for that, David

MichaelG.

I used a standard clockmakers broach and in 35 years it's never moved

Roy

Hi

I was going to post a page from Timmins book showing the gathering pallet but only JPEG files are accepted and my files are PDF. I'll convert them and post later.

There are a lot of good ideas here. The use of the clock makers broaches is a consideration so I calculated the taper angle based on 1mm reduction in dia per 100mm of length. It worked out to be 35 minutes, quite a lot smaller that what Timmins wants. It raises the question of am I right in my assumption the 1 degree taper is the angle between the centre line and one side of the taper. The included angle would be 2 degrees.

My thoughts that the D reamer was too fragile led me down another path, that a 4 sided reamer/broach would be stronger. I'd like any feed back on my thoughts. I tilted the filing rest to 1 degree using a small digital level I use to set the angle of the blade on my saw table, it's not really accurate but that doesn't matter as I will use the reamer in the lathe collet chuck to set the cross slide using a dial gauge. As suggested a little Autosol would finish any imperfections.

Thank you for your patience, as suggested I'm probably over thinking this but I must get it right.

Kind Regards.

David.

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Thanks, David ... much appreciated

MichaelG.

Timmins didn't care what the angle was. It is just a case of making it smaller at one end so it goes into a hole and jams instead of gluing, soldering or welding. Then the hole doesn't need to be a matching taper as the brass will distort to fit. The hole doesn't need to be tapered at all but there ain't no other way of very gradually opening out a hole to just the right amount. So clockmakers invented their tapered broaches to meet the need.

If you are going to make more clocks it is worth getting some broaches, just make sure the executors of your estate realise they are valuable. If it is the only one turn a bit of mild steel to a couple of thou over size about 2 inches long and while spinning it pinch it with emery paper moving along to put a small taper on it. Then put the flat on as described before. It may only last for a couple of holes but even mild steel is harder than brass so can cut it.

Bazyle

If I remember rightly the gathering pallet is steel not brass

Roy

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Traditional ones are ... [ but I don’t yet know how far Mr Timmins strayed from tradition ]

MichaelG.

MichaelG I followed Timmins book when I built mine and it has a steel gathering pallet. I've just checked it

Roy

Thanks for that, Roy

MichaelG.

What is wrong with this site. I just spent half an hour typing a reply after signing in and clocked on add posting and it kicked me off and I had to sign in again and the post isn't there. I'll try again tomorrow.

Regards David

Edited By JasonB on 24/01/2020 06:53:35

Thanks for posting the scan, David ... it makes the situation, and the difficulty, much clearer.

Mr Timmins suggests broaching ... but ... whilst the clockmakers’ five-sided broach works nicely on brass, it is not well-suited to steel !!

MichaelG.

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Note, for general reference : The more conventional arrangement is shown here:

https://www.davewestclocks.co.uk/gathering_pallet.htm

Edited By Michael Gilligan on 24/01/2020 07:21:41