Member postings for Will Robertson

Here is a list of all the postings Will Robertson has made in our forums. Click on a thread name to jump to the thread.

Thread: Cos-Par Alfa 1 Universal Divider - Universeller Teiler
13/04/2023 20:19:22

I sent the person who'd sold me the divider the information that people on here had found - he used it to have a search around his workshop and found this: smiley

Gears For Cos-Par Alfa 1 Universal Divider

Thread: Name of Tools Used for Mill Tool Holder Retaining Bolt
03/04/2023 23:26:58

I eventually found the right set of 8 tools - the seller was selling them as "Spannschlussel" so I don't think he was sure of the formal name for them either - Spannschlüssel covers a fairly wide range of tools in German. Would also have been fun to make them on the lathe and mill.
Spannschlussel

Thread: Does anyone know what this is
03/04/2023 23:15:49

As well as a home-made general purpose divider my guess is that it would be handy as a quick, home-made way of cloning any given gear that could fit on the left hand side - guessing that the precision wouldn't be wonderful - it looks like that pin is spring loaded rather than being threaded to lock in place - but might have been enough for some things.

Thread: Cos-Par Alfa 1 Universal Divider - Universeller Teiler
03/04/2023 23:09:31
Posted by DC31k on 31/03/2023 08:19:14:

Possibly the most relevant publication at vintagemachinery is this one:

http://vintagemachinery.org/pubs/detail.aspx?id=27825

Thank you very much.

That's a very valuable reference and one that I'll definitely use in the future - for my CNC generation there were a lot of techniques like differential dividing that weren't taught.

It's very valuable for me as well to know the general technique of when I cannot find the manual for a specific piece of equipment searching for a manual for a piece of equipment which is based on the same principle.

03/04/2023 22:49:59
Posted by Nigel Graham 2 on 31/03/2023 00:00:23:

Wow! One lucky find!

Hi Nigel,

Yes - I was lucky to find such a beautiful instrument. I work as a climbing arborist and one unusual requirement of the work is very fine control over enormous muscle power - I suspect that others may have been put off bidding for equipment like this by being unable to lift it.

I bought it in Switzerland so guessing that it must have been made near Milan then labels made in French, German and Italian for the Swiss market.

> still square-edged, not bashed about by hammers and makeshift drifts!

Yes - makeshift drifting is one of my pet hates.

> I have just had a far-out thought, looking at the labels on this dividing-head. Recalling that strange "circular slide rule" that had us all foxed a couple of years ago now, might that have been some sort of highly-specialised gearing calculator?

Yes - it looks like differential dividing - which until Andrew's explanation above was a technique that I'd only known very vaguely about (I'm from the CNC generation...).

Will

03/04/2023 22:29:13
Posted by Andrew Johnston on 31/03/2023 21:15:14:

Lovely bit of kit; did it come with all the gears, brackets and a tailstock?

It can be used for direct indexing using the plate behind the chuck, simple indexing using the division plates and compound, and differential, indexing for divisions not available using the standard division plates. As stated above, in conjunction with a universal horizontal mill it can be used for milling helical gears:

Hi Andrew,

Thank you very much!

Those are wonderful photos of helical gear making!

Although the indexer itself seemed in very good condition (there was a little backlash but I think that can be adjusted away, addressed by locking before each cut or addressed by always cutting in the same direction) the tailstock, gears and brackets were all missing - one of the direct indexing wheels had a few teeth missing but I think they were intended to be replaceable so that custom direct indexing wheels could be made for frequently used sequences.

My guess was that I could run without the tailstock if I kept the cuts very light - or should maybe try to make a new tailstock for it?

With the gears and brackets missing would it be better to replace them with a stepper or servo motor and driver and use electronic synchronisation?

The part that fits into the notch at the top looks like it was designed to be easily removable and replaceable - is that simply so that it can be removed when using a gear train to move the indirect indexing wheel for differential dividing? What does the second notch cut into the back of the dividing wheels do?

Cos-Par Alfa 1 Universal Divider - Universeller Teiler

Will

30/03/2023 23:11:44

I was extremely lucky and bought a very beautiful Cos-Par Alfa 1 Universal Divider - I'd thought I'd be outbid but guessing that I was very lucky and others either didn't know what it was or couldn't lift it.

I'd initially thought that it was a direct and indirect divider with 2 dividing wheels for indirect dividing and the option to use off-the-shelf or custom made custom dividers for direct dividing.

Looking at it in more detail though I realized that I'd got something more special in my hands. It can be attached to an external drive and I think the idea is that a blank divider disk can be made and slots cut in the reverse side of it so that it can act as some sort of programming wheel to allow the indirect divider to be programmed to automatically move through a predefined sequence of steps. It's more sophisticated than any other mechanical divider I've seen though and I'm having difficulty working out how to use it in fully automated mode. I can't find anything about it online. Does anyone have any details?

Here are some photos then a video with the indirect dividing disk removed to show the mechanism in action :

Cos-Par Alfa 1 Universal Divider - Universeller Teiler

Cos-Par Alfa 1 Universal Divider - Universeller Teiler

20230330_172001.jpg

Cos-Par Alfa 1 Universal Divider - Universeller Teiler

Cos-Par Alfa 1 Universal Divider - Universeller Teiler

Cos-Par Alfa 1 Universal Divider - Universeller Teiler

Cos-Par Alfa 1 Universal Divider - Universeller Teiler

Cos-Par Alfa 1 Universal Divider - Universeller Teiler

Cos-Par Alfa 1 Universal Divider - Universeller Teiler

20230330_172018.jpg

20230330_172038.jpg

Cos-Par Alfa 1 Universal Divider - Universeller Teiler

Cos-Par Alfa 1 Universal Divider - Universeller Teiler Video

Edited By Will Robertson on 30/03/2023 23:15:22

Edited By Will Robertson on 30/03/2023 23:16:06

Thread: Name of Tools Used for Mill Tool Holder Retaining Bolt
25/03/2023 17:34:01

Thank you very much!

We've got a whole cupboard of those arbours at all different sizes - 10 or 20 in total - so need a set of tools for them or one adjustable tool.

Thanks for mentioning mill arbour spanners - agree about the 4 points - all the mill arbour spanners that I could find had 4 points not 2 and the geometry of the points was different.

An adjustable pin spanner might well be a way to do it - I hadn't seen the characteristic two round holes for a pin spanner so I hadn't thought of that and the adjustable pin spanner I have here is for much smaller, lighter things.

There also seems to be a much heaver duty version of a pin spanner - an adjustable gland nut wrench - intended for the glands at the ends of hydraulic cylinders - so I've ordered one of those. The pins are round not square so not a precise fit but might be good enough. I'll see how things go with it and if it doesn't seem robust enough I'll turn down a piece of stock to the right diameter for each arbour then mill the two teeth in the ends of those.

Thank you all very much for letting me know that they're proprietary - I was beginning to wonder if I was going crazy not knowing any standard tool for them.

The original tool or tools got parted from the mill and arbours before my friend bought them.

The mill is a Reiden HF30 Mill:

Reiden F30 Mill

Reiden HF30 Mill

24/03/2023 19:23:00

I'm really sorry to ask such a basic question. What's the right name for the tools used to loosen or tighten the retaining bolt on these tool holders for the mill? It's a European mill and metric.

It's my generation - we were just taught to always expect a hex / imbus retaining bolt on tool holders and I don't know what the tool is called for these.

milling tools 20230310_103508.jpg

Thread: Detailed Repair or Restoration Manual for a Mikron Watchmaker's Lathe - How to Repair Headstock Bearings
24/03/2023 14:35:10

T&LM info here just for interest.

The T&LM does not have wicks, the Mikron does so be careful not to ruin them. Oilers like these seem to stay clean


Thank you very much! I can see the similarities with the T & L.M. headstock now.

My Mikron seems to have very fine metal tubes to syphon the oil from the oilers down into the bearings rather than fiber wicks. Are those fine metal tubes referred to as wicks as well?

Thread: Mikron F75
11/03/2023 15:08:46
Posted by old mart on 06/03/2023 21:18:17:

The bearings are bronze and adjustable, they are bored with a cylindrical hole and the spindle will have a plain diameter where the bearings run. The spindle definitely is removed to the right. That thrust race is only there to counteract tailstock thrust and ensure the spindle has minimum end float for turning. Not at all scary, of delicate they are very similar to the spindle bearings in a Smart & Brown model A, bulletproof.

Thank you very much.

That's very helpful to me to know about the roles of the bearings and thrust race.

What lubricating oil would be appropriate for the bearings of this sort of lathe? Would a modern low viscosity fully synthetic or part synthetic engine oil be appropriate?

Thanks for mentioning the similarity with the Smart & Brown model A - I hadn't known about that lathe.

Will

Thread: Detailed Repair or Restoration Manual for a Mikron Watchmaker's Lathe - How to Repair Headstock Bearings
09/03/2023 17:07:11

I was able to collect the lathe and get a micrometer on the headstock and the radial play on the headstock bearing that it measured was 0.25 mm - not the "a bit over 1 mm" that I'd guesstimated by hand - apologies for my grossly incorrect manual guesstimate on that. 🙈

06/03/2023 10:52:07
Posted by Dave Halford on 05/03/2023 21:09:28:

Looks like a T&LM style split cone head stock though the bed is very different. You edge them tighter as in 'loosen the back and tighten the front in small amounts with a C spanner till the play goes. It's very likely the bearings are fine, but they have been loosened to mess with the belt .

If there are felts in the bottom slot they are best left in place, they swell up and will not go back.

Hi Dave,

Thank you very much.

>Looks like a T&LM style split cone head stock

Does there tend to be there more information available about T&LM lathes than about Mikron lathes?

>You edge them tighter as in 'loosen the back and tighten the front in small amounts with a C spanner till the play goes.

Thank you very much - that's an enormous help - I hadn't been able to find any documentation on it so it's enormously valuable to know that that's how to adjust the bearings. Is it reasonable for me to expect to be able to get rid of c. 1 mm radial play by adjustment alone? Should I attempt to clean out the bearings with solvent then compressed air to remove old oil and other debris then lubricate with fresh lubricating oil before adjusting?

I don't even know at the moment what lubricating oil specification would be suitable for bearings like this.

>It's very likely the bearings are fine, but they have been loosened to mess with the belt

Thank you very much. I don't fully understand "to mess with the belt" - unfortunately my generation were taught CNC and got no training in belt driven equipment. The motor and belt drive hardware that would have originally powered the lathe was all long gone when I bought it so I'm planning - without making any modifications that damage this historically significant lathe - to power it from a modern variable frequency motor and variable frequency drive that I have here or to buy a modern geared stepper motor to power it - hopefully if I get it right the geared stepper motor would have the advantage of allowing the lathe to be used as a divider and simple machining centre as well as a traditional lathe.

Thank you very much again for your help!

Will

Thread: Mikron F75
06/03/2023 10:16:01
Posted by Hirschli27 on 31/03/2020 23:42:43:

I can give a little bit of help for the disassembly of the internally geared Mikron T90 and F75 headstocks.

Starting with what you should not do: DO NOT turn those two small screws that seem to go directly into the bearings. They have flat sides at the end that go into slots in the bearings. If you turn them they either break or damage the bearing slots.

You also do not habe to remove the bearings (unless you have to adjust for radial play). Realigning them to the spindle is somewhat time consuming when you put them back.

The spindle comes out at the front. There are two rings around the spindle at the front side. The first is partly hidden and has a small screw. This screw ends in a slot on the spindle and prevents it from rotating. It should not be tightened as it should be moving along the spindle. If it is tightened just loosen it a little (it does not have to be out completely).

The second ring is a nut screwed on the spindle and it is for adjusting the axial play. Remove the screw. Under it appears a small piece of bronze which on the bottom has the same threading as the ring. DO NOT touch this bronze piece - you will never get it back in at the right angle if you move it.

After removing the screw it should be possible to turn the ring somewhat. On the opposite side of the screw there is a hole that is useful if you have to use some force to move the ring in the beginning. But be careful not to insert any rod into the threaded hole to get the ring moving. Also be aware that the ring is rather soft and the also unthreaded hole can be easily ruined with to much force. The ring should move easily - do not use force and stop before it touches the pulley. If the ring is turned to move towards the back of the headstock the hole will be partially covered by the pulley. It is not necessary to screw it that far to the back now. Just leave it where it is for the moment.

Moving to the pulley: You must loosen the screw with the square hole. This screw locks the pulley to the spindle for turning without the internal gearing. If you use the internal gearing the spindle and the pulley turn at different rpm (3:1) and so this screw must be unlocked for this purpose. The other screw on the pulley is for oiling and can stay where it is.

At the backside of the pulley is another ring with two screws on opposite sides. They have pointed ends and fix the ring to the piece underneath. Before you remove those screws check if one of them and the threaded hole in the ring are marked (punched dot or x or similar). If this not the case you really should mark one of the screws, the matching hole, and also the piece under the ring. If you do not you risk that when putting it back together in a wrong combination the internal gearing will block completely (I can tell!). Both screws must be removed. Now the ring should turn freely. Do turn it 90° and look into the threaded hole: underneath has appeared another screw in each of the holes. Unscrew these, too. Now the pulley should be able move a little. You can now can gently turn the second ring at the front to unscrew it from the spindle. It should move to the back along with the pulley and the spindle can be drawn out at the front as soon as the ring reaches the end of the threads on the spindle.

Be careful when you lift the pulley after the spindle is out: The internal gearing drops out very easily if it is not too dirty.

I have two of these internally geared Mikron headstocks. With one this procedure has worked perfectly well without the use of any force - so I can tell it is the way to do it. With the second headstock I followed the same procedure - and the pulley does not move. I think it is stuck because of dirt or hardened oil.

Kind regards, Kaspar

Hi Kaspar,

Thank you very much for providing such detailed and valuable information - particularly on the things that should be avoided.

I've just bought a Mikron T90 watchmakers' lathe with a bit over 1mm radial play on the headstock bearings and I'm trying to do as much research as I can before attempting to adjust, repair or replace the bearings. I don't think it's got internal gearing though so that makes the situation simpler.

If you've got any other information on repairing the Mikron lathes and milling machines I'd be very interested.

Thank you very much,

Will

06/03/2023 10:01:06
Posted by Pete Rimmer on 04/12/2018 21:08:41:
Posted by Bill York on 29/10/2018 11:39:54:

, I have heard people say that all information is out there on the internet, you just need to look for it, well that's not true, I spent almost a week contacting the original makers, the import company or whats left of them and many knowledgeable sites in various countries all to no avail

Bill,

Did you see this page?

**LINK**

Hi Pete, Thanks for the link - the link is giving an error now but I was able to extract the original URL from it

https://www.usinages.com/threads/petite-fraiseuse-precis.20287

That's very helpful for me - I'm trying to restore a beautiful Mikron T90 lathe that I've just bought - it's had a very difficult life and has a bit over 1 mm play on the headstock bearings so I need to work out how to adjust, repair or replace them.

06/03/2023 09:55:22
Posted by Jan Nieuwenhuis 2 on 04/12/2018 16:16:13:

Check out this site:

https://www.usinages.com/threads/mikron-t90.21964/

Try translating with google (Site is is French).

You will have to subscribe first to be able to see the pictures, but I think it will help you to solve the problem.

If not, I will try to remember how I did it with my Mikron T90.

I think is is the woodruff key that might block your attempts.

Thank you very much Jan - I've just bought a beautiful Mikron T90 Watchmaker's lathe that's had a very hard life and has a bit over 1 mm play on the headstock bearings so I've been trying to find out how to repair or replace the bearings - I don't think I've got internal gearing so that makes the situation simpler but I am having a lot of difficulty finding documentation on how to adjust, repair or replace the headstock bearings so the article in French that you gave a link to is an enormous help! If you have any other information definitely let me know!

Thread: Detailed Repair or Restoration Manual for a Mikron Watchmaker's Lathe - How to Repair Headstock Bearings
05/03/2023 20:25:45
Posted by Michael Gilligan on 05/03/2023 16:37:32:

I thought I remembered seeing something about the bearings … check the post by Kaspar on this page:

**LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=138694&p=2

MichaelG.

thumbs upthumbs upthumbs up Thank you very much Michael! Just scanned over that and it looks very useful - I'll re-read it in detail. I'd seen the "F75" in the title and thought that it was about one of the Mikron milling machines (milling machine is "Fräsmaschine" or "Fräs" in German and Swiss German).

05/03/2023 16:15:11

I've just become the very happy owner of a very beautiful Watchmaker's lathe made by Mikron in Biel, Switzerland - Mikron were better known for their hobbing and milling machines than for their lathes but were one of the manufacturers who - together with Schaublin - pioneered modular precision lathe systems - I think some of the Mikron T90 lathes made it over from Switzerland to the UK - there's some more information about them here:

http://www.lathes.co.uk/mikron/

and here

http://anglo-swiss-tools.co.uk/mikron-t90-lathe/

Before buying the lathe I tried the headstock bearings and they were in fairly terrible condition with a bit over 1 mm wobble. Overall, the lathe has had a very hard life and there's wobble on the saddle that I'll also need to address. I know that Mikron made this lathe with the intention of the headstock bearings being adjustable, repairable and finally replaceable but I'm having difficulty finding a manual with details and specifications of how to adjust - and if necessary replace - the bearings. I've got access to high quality bronze stock to make new bearings if needed, a larger lathe and a mill but I didn't want to attempt to adjust or replace the bearings until I'd studied the details.

Does anyone know where I could get a suitable manual or instructions for replacing the headstock bearings and restoring the lathe in general? (I can read English, French, German and Italian.)
Will

watchmaker lathe 02.jpegwatchmaker lathe 01.jpeg

Thread: Lathe alignment
31/03/2013 22:31:47

Hi Jan,

I've got much less experience than most folk on here so please treat my two contributions with a pinch of salt:

From the 0.3mm test piece taper you mentioned I'd guess that this is due to tailstock misalignment. It would be best to clean the ways, clean the tailstock taper, ensure the taper of the centre is free of any bumps and then adjust and perfect the tailstock alignment before starting any adjustment of the lathe bed.

A piece of swarf caught between the tailstock and the ways might throw the tailstock significantly out of alignment but I don't know your lathe in detail so I'm not sure.

You mentioned 'mild steel' - steel sold as 'mild steel' can vary a fair bit - some of it is easy to machine to high precision and good surface finish and some of it is impossible to machine to precision and good surface finish - this can cause problems when making precision measurements like this. A specific grade of free cutting steel (or something cheaper - e.g. aluminium) designed for good machining properties may help.

Will

 

Edited By Will Robertson on 31/03/2013 22:32:37

Thread: Cylinder Boring Techniques for Steam Engines
30/03/2013 21:01:01

Apologies for the pause - work became heavier than usual and I had to do a re-design of the cross-slides so that they could be machined sensibly from the stock I can buy. Also spotted errors in the design that needed attention.

I've run into an unexpected problem - I can't find anywhere that sells metric cylinder drain valves (formerly known as "cylinder drain cocks" but I think we're not supposed to use that any more because it's not politically correct or something). I'd thought that one supplier over here sold them but I can't find them in their catalogue. I can easily get drain valves with non-metric threads but everything else is metric and I'd like to stick to metric (my generation...).

Any ideas who might sell them?

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