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Watchmakers Lathe Or Mini Lathe


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37 minutes ago, Squiffything said:

I recently went for the U3 and upgraded motors. Like you I begin a steep learning curve and am looking for projects to try. 

Plenty here

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Written with humor and human touch. 

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I'm reading the machining articles of Dean Williams, no-nonsense and he praises a lot the use of leaded steel. So I went out and bough some at the metals shop, probably the only one in my city - not even my city anymore, thanks Heaven I'm now 1hr away from it. There are millions of steel types, each country use their own codes, names, nicknames and one could read equivalences for hours. Of that many the shop has maybe three types, and the leaded in round bars only <_<

First I tried turning and I was able to to make 0.10mm cuts in facing a 28mm round bar, even if probably I'm not using the correct cutter and speed. Then I put it on the press drill pictured above (which I paid €32 at the 2nd hand shop), with a menacing black HSS 13mm bit. I was unsure of the result since I had been struggling with much smaller holes before. It went down as if it was butter. I had sprayed some cutting fluid but it wasn't even necessary. And the swarf is amazing. Threading, boring or anything else will be very easy on this material, no need for super-special tools.  Not the strongest, better looking steel on earth, but if you want to go easy on your micro-lathe and not using Aluminium, that is what you want.

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Oooo nice looking swirl :) how’s its strength for what you are making? I have a lump of steel that I’m trying to turn and it’s hard going. But so far I’m not using a center piece to hold the other end which I think will improve it. I also meet a rotary Ed to do the milling job that I need to do. 

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I w

12 hours ago, Squiffything said:

Oooo nice looking swirl :) how’s its strength for what you are making? I have a lump of steel that I’m trying to turn and it’s hard going. But so far I’m not using a center piece to hold the other end which I think will improve it. 

I was referring to what is called 12L14 in the USA, from what I read is good for most practical uses.
The rule of thumb is no more than 1 and 1/2 of the diameter hanging, otherwise need a center or rest.
Now I learned to be wary about mistery metal, they can be very bad for small or big machines.
The common advice is to scour machine shops for scrap, I went to see the one which looked more like an arranged tractor salvage, I offered to pay for 1 or 2 small pieces but he declined to give me any. So I'm now buying the stock, at least know more or less exactly what I'm getting. 

Edited by jdm
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I’ve got a mate who is an engineer/troubleshooter and has a workshop in his back yard. When I say workshop that is a bit of an understatement in that it consists of five separate buildings around half a dozen big lathes two or three mills saws that can cut girders etc etc. He has a barn full of metal and he lets me go play. He’s in his seventies so he doesn’t have to take much work anymore but he still gets asked to sort problems out for people so he keeps his shop running. 

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On ‎4‎/‎19‎/‎2019 at 12:42 PM, jdm said:

Correct.
This low-cost attachment enables you to machine thirty-six different unified thread pitches (Pitch range from 80 to 5 threads per inch) and twenty-eight different metric thread pitches (Pitch range from .25 to 2.0 mm). It also allows you to cut them as either left-hand or right-hand threads.

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     thread pitches;  S.A.E. or MM ?   vin

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12 hours ago, jdm said:

e wary about mistery metal, they can be very bad for small o

 

On 6/8/2019 at 12:43 PM, jdm said:

Written with humor and human touch. 

Indeed.  From the golden era of model engineering, those authors were all regular contributors to Model Engineer and they both really knew their stuff and had a friendly and pleasing voice.  Model Engineer and one point was weekly and was popular enough that many made their living at it as authors.  Worth noting, the Tubal Cain of ME and those books is not the youtube video person who took the same name.

With a definite horology connection, Model Engineer ran numerous clock builds over the years

A classic that should be on everyone's bookshelf, at least everyone interested in making things, is "The Amateurs Lathe" by Sparey

Edited by measuretwice
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4 hours ago, Squiffything said:

I think this is something I will need to invest in otherwise it becomes an unusable item. Added to the list together with a rotary table.

There's truth to that.  You often see people holding an end mill in a drill chuck (gasp) or three jaw.  It can work, but is problematic in that the tool can slip which if excessive can even damage the chuck.   These chucks get no bite in endmills which are hardened end to end.  They're intended for work or drills (the end of which is not hardened) where they get enough of a bite so they can hold.   You really should have a collect chuck or end mill holder for end mills

I've a collet chuck for a U3, very simple affair - basically a screw on ER chuck.  Probably wouldn't take much to have a batch made and sell on the fleabay

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19 minutes ago, measuretwice said:

They're intended for work or drills (the end of which is not hardened) where they get enough of a bite so they can hold. 

Is there a way to see if something is hardened? And if only partially? I've got (cheap) coated drill bits, who knows what they did to them? As simple they appears, there is an universe of complexity associated with drill bits. 

Quote

I've a collet chuck for a U3, very simple affair - basically a screw on ER chuck.  Probably wouldn't take much to have a batch made and sell on the fleabay

Exactly my thinking, because this specific MF14x1 chuck currently isn't available anywhere. I want to make my prototype first and then the batch. 

Another guy insist that faceplate + chuck like arceurotrade sells is the way to go because the faceplate is finished on your lathe. But I don't see how a single piece chuck can be worse if manufactured correctly.

In the meanwhile I have no choice but keep the endmill in the three jaws. Well that isn't long since Taig milling attachment arrived just yesterday.

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On ‎6‎/‎10‎/‎2019 at 6:05 AM, vinn3 said:

     thread pitches;  S.A.E. or MM ?   vin

   buying attachments for a lathe -  be careful.    an example;   the head stock (what you screw the chucks onto,) on an U S lathe  is 1/2 x 20 thread.  tooling made for a metric head stock WILL NOT FIT !  vin

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33 minutes ago, jdm said:

Is there a way to see if something is hardened? And if only partially? I've got (cheap) coated drill bits, who knows what they did to them?

The shank on a drill shouldn't be hardened - you might have noticed if you've ever had a one catch and pull a burr up on the shank, these are easily filed off because its not hardened.  You can tell if something is hardened by running the corner of a file over it....skips and its hardened. starts to cut its not.

 

Edited by measuretwice
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On 6/11/2019 at 3:25 PM, measuretwice said:

You really should have a collect chuck or end mill holder for end millsI've a collet chuck for a U3, very simple affair - basically a screw on ER chuck.

I've researched. I think ER collet aren't right to hold an endmill:

  • Force is angular to center line of tool holder
  • Less gripping area results in lesser accuracy

https://www.bilz.com/products/cnc-tool-holders/super-collet-chuck/

At least a 3-jaws chuck grabs the entire shank. A mill collect (MT2 with drawbar) look like below. Not cheap, even the Chinese one. And can't be used direct on the C0/U3 which has no taper. Maybe would be good devise something that can use holding slot on the shank.

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Below the C0 with TAIG milling attachment. The device footprint is exactly the same size of the cross-slide, and its existing holes are just a bit off the T-slot. The slide has a sink where the compound pivots, the attachment could be milled to accept a bushing to made it rotate precisely.

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4 hours ago, jdm said:

I've researched. I think ER collet aren't right to hold an endmill:

If not end mills, what are they are for?  ER's are primarily a tool holding system (vs workholding).  That super collet might have advantages over ER, (or could be hyperbole)  but take a look at a tool changer on a typical cnc - I would say ER's are the most common way to hold end mills. 

Whether one is a bit better than another imo doesn't matter - anyone is 500x better than no collet for hardened tool holding.  While ER's have the advantage of being able to hold a wider range of sizes, if I had a choice, I'd prefer a spit collet or ER.  Nevertheless, availability, cost, small form factor and that its such a simple thing to mount on an existing spindle make them an easy and practical choice.  

As for length, so long as you grip enough so its solid, it doesn't matter that much - grip is a function of the coefficient of friction and force applied, it doesn't depend on surface area.  As I said, point loaded chucks like a three jaw or drill jaw are intended for, and really only effective with soft material where they can get a bite so they don't slip under load.  I suppose in engineering terms bite means the point load imparts a slight elastic (or often with work plastic) deformation of the surface under the jaws so the jaws don't slip.  that doesn't happen with the higher tensile strength of a hardened piece.

Will a 3 jaw work with an end mill?  Yes you can get away with it to a point with extremely light use but it will be the first thing to fail and when it does you risk damaging the chuck jaws.  Its something you do if you have to, but its not the best or right way.

Finally, even if you have a soft shank, a collet is still a superior holder from the standpoint of runout.  A three jaw will have runout so that the endmill often would cut on one tooth; machining takes longer, there's a high chance of breaking an endmill and a poorer finish are the results.

If someone really want to improve the Unimat, a new spindle hardened and ground that accepted 8mm or even 10mm collets would take that machine to a new level.  iirc, such a factory spindle was available; too bad they weren't more widely picked up as overall they are a neat little platform

Edited by measuretwice
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On 6/10/2019 at 11:00 PM, measuretwice said:

Model Engineer and one point was weekly and was popular enough that many made their living at it as authors.

I've looked at the present product (I knew already that it has been the resource for home machining for a century) and while is still very alive and accessible, I was surprised to see how it has zero connection with the contemporary "maker" trend. I didn't expect a full "drones/3D printing/Arduino" kind of magazine but what about evolving a bit from steam locomotives to e.g. moving robots? These are very challenging and the serious ones require machining metal, not plastic. Think battle of robots in the USA, etc. So I'm in two minds if to subscribe, I'm attraced especially by the printed edition.
The forum is probably better with many lively discussions, how to start with 2/3D CAD and from there to CAM/CNC, but the forum format is horrible, straight from the 90's for small screens.
Call it Old England if you wish...

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  • 8 months later...

Well, I'm about to do it - 

pulling the trigger on a Sherline 4530A lathe, with a few accessories.

I went back and forth between a watchmaker lathe and the Sherline several times in my mind, and finally landed on the Sherline.

Reason being I want to be up and running making parts as easily as I can, and learning to use a graver freehand seems to be a bit of an impediment. I also have a manufacturing background, and am already familiar with using machine tools, although I'm not much of a machinist.  And, as far as I can tell, I should be able to make just about any part that I need to on the Sherline. 

Just wanted to post here to give anyone who thinks I'm making a horrible mistake to chime in :-)

Cheers!

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It won't be a mistake unless you'll want to take machine shop jobs , I had considered it as well, it has the best accessories and documentation, and reasonable price. In the end I choose something else (Unimat 3 clone) but I think our learning path will be similar. There is always room for a watchmaker lathe and the Sherline will be good to make tooling for it.

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It all depends what you intend to make on a lathe, I can tell you after you start and learn the ropes, you will want to progress in machining more complicated parts. Just make sure accessories  are available, they will also set you back a good sum of money.  

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Well I bought a Sherline everything. A lathe, milling machine, CNC rotary table, and oodles of attachments and tooling. I did this because I make clocks and cutting gears and such on a watchmakers lathe isn't the easiest, and frankly, getting the attachments for a watchmaker's lathe for such tasks isn't easy or cheap. 

Sherline quality and service are both excellent; they actually respond to emails with good solid advice, and they honestly seem to put the customer first over sales. They are also more than willing to discuss issues, and give recommendations, on the phone should that be your preferred form of communications. 

Having said all that, I still use a watchmaker's lathe on occasion, basically for anything that I use a graver for as it's easier and more precise for really fine work and its easier to hunch over and see the work closer up safely. I'd say I use  the lathe 95% of the time. I had hoped I could do away, aka sell, my watchmaker lathe and its attachment and do everything on the Sherline, but I don't think will ever be the case, well not for me anyway.

If I had to have only one, I'd choose the Sherline without hesitation but fortunately that's not a choice I have to make.

 

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Thanks, @Scouseget, I'm scheduled to receive the machine today, and I'm looking forward to seeing what I can do with it. It may not be a full blown instrument lathe, but I keep reading that with the proper techniques quite a lot can be done with the machine. That doesn't mean that *I'll* be able to make anything useful on it, but I'm going to try. :-)

My expectation is that I will still at some point acquire a WW style lathe, but I would really like to try my hand with a graver before I go through the time and expense of rounding up a decent watchmaker lathe. So far no opportunity has come up, but I should be able to put a tool rest on the Sherline  and give it a go when I'm ready.

And yes, I fully expect there will be a continuous flow of accessories showing up at the house :-)

 

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