Watchmaker's Lathe vs Vintage Hobby-lathe for making spinning tops

[blueice]

Hi, I am looking to buy a lathe in order to make small (<5cm diameter) precision finger tops, and as someone new to machining I would love to get advice on what to buy.

These are my (non-negotiable) requirements -

1. Accuracy - The more balanced the top is, the longer it will spin. I believe the things to look out for are spindle play, runout and tailstock centering?
2. Cost - <500 USD for everything excluding cutting tools.
3. Size - Longest dimension about 30-40cm max. Yes, that means micro-lathes only.
4. Material - Needs to be able to bore a hole into the centre of tungsten stock (or at the very least, high density tungsten alloy). I don't care if it takes forever, it needs to be able to do it.

These are things I don't care about -

1. Maximum capacity - Basically any lathe out there will be large enough to machine the spinning tops I want.
2. Repeatability - I will not be mass producing tops, so I don't need to hit exact dimensions/shapes.

Here is what I am considering currently -
1. Watchmaker's lathes - I would assume lathes made for crafting watch parts would have very tight tolerances. I do not know the superior option between WW with cone bearings and Boley.
2. Vintage micro-lathes - Brands such as Unimat and Wizard. These have the advantage of having more mass than watchmaker's lathes and more solid contact with the ground, and are often sold with chucks to hold thick stock, as well as cross-slides and toolposts.

What would be my best bet here? WW, Boley, Unimat, Wizard or something else? I don't mind replacing a motor or disassbling the lathe for cleaning, but not much more. Or maybe go for something new, despite the poorer build quality (extruded aluminium beds and all)?

 

[Eddyde]

Hi, Welcome to HM.
Hum.. drilling tungsten, I'd think that rules out a watchmakers lathe. From the requirements you describe, a more rigid machine is what you should probably look for, that would rule out the Unimat, IMHO. I'm not familiar with the other brands.
Something like this might work well.

https://www.amazon.com/VEVOR-x14-Benchtop-Variable-Precision/dp/B09FDVMYXS/ref=asc_df_B09FDVMYXS/?tag=hyprod-20&linkCode=df0&hvadid=532655541111&hvpos=&hvnetw=g&hvrand=6784637178969507625&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9004769&hvtargid=pla-1431643506711&psc=1&mcid=eda566f2c0c83bf78a6fc96a4fa36c9a&gclid=CjwKCAiA0bWvBhBjEiwAtEsoWyQyvNwjvoVwZNpHaWhaXGwxOaGihyTiQKQZyOCL3q7W_Y_lgE1jvhoCXg0QAvD_BwE

 

[blueice]

Hum.. drilling tungsten, I'd think that rules out a watchmakers lathe. From the requirements you describe, a more rigid machine is what you should probably look for, that would rule out the Unimat, IMHO. I'm not familiar with the other brands.
Something like this might work well...

Oh I would certainly get a new mini-lathe if I had the space, and it is even cheaper than a used watchmaker/hobby lathe. But lathe size is not something I'm willing to compromise on. You seem to rate Unimat style lathes over watchmaker's lathes in terms of rigidity, so that is pretty much my only option then. Just out of curiosity, how would the spindle slack/tailstock alignment compare between the lathe you linked, a watchmaker's lathe and a vintage unimat micro-lathe? Are they on the same grade in terms of accuracy, coming down to unit variation/condition?

 

[silence dogood]

I own an Unimat lathe and once owned a Levin watchmakers' lathe. The Levin in my opinion was more rigid and accurate than the Unimat.
As for machining tungsten, I would suggest a tungsten alloy. Usually, it consists of 90% tungsten and the rest is iron and nickel. Pure tungsten is extremely difficult to machine. Much easier to machine the alloy and costs less. There is a "chatter free tungsten" alloy that supposed to machine like grey iron. Unfortunately, I've have had very little experience in machining tungsten, so this information is mainly gained from other sources.

 

[blueice]

I own an Unimat lathe and once owned a Levin watchmakers' lathe. The Levin in my opinion was more rigid and accurate than the Unimat.

Interesting. Did your Levin have one off-centre contact point with the ground, or 2 with one on each end? I see they come in both types. I wonder if the isolation of motors in watchmakers' lathes is part of what makes watchmaker's lathes more accurate. Less vibration to worry about.

As for machining tungsten, I would suggest a tungsten alloy. Usually, it consists of 90% tungsten and the rest is iron and nickel.

My first choice is MT-185, the number indicating its density. Being 97% W it should be harder to machine than most alloys but easier than pure tungsten. The real issue is finding sellers willing to sell like 500g of the stuff without ridiculous markup. It is comparatively easier to find pure tungsten, sold as element collector cubes or cylinders.

 

[silence dogood]

Blueice, I'm not sure what you mean by "off-centre contact point with ground". It did come with dead centers and an almost complete set of WW collets. Both the lathe and its' tailstock were unusual. The lathe had a longer bed, and the tailstock had a sliding mechanism so one could do indexing (I think). Checking out the history, it was originally used on a WWII navy ship. The original purpose, I have no idea. I traded it with my friend who is a certified clock repairman. He has about 10 watch makers lathes and a Unimat with all the accessories. He never uses the Unimat. The Unimat is a good lathe but is just does not cut it for his type of work. One thing that I learned from him is to be very, very careful if you take the headstock apart on a watchmaker's lathe. The lathes usually have many little, tiny ball bearings that are not in a cage but loose. The first chance that I get, I'll talk to my friend and tell him what you are trying to do. I'm curious myself of what he has to say.

 

[blueice]

I would certainly be interested in what your friend has to say. To rephrase my question, can the Levin lathe stand upright if you put it down on a flat surface?

 

[silence dogood]

If I read your last thread correctly, as long as the lathe is bolted to a rigid plate, bench, or whatever, you could run it upside down. My friend also has a Boley (beautiful machine) that he also uses a lot. He has other lathes. but I don't remember what brand and how often he uses them. Gary (my friend) also does architecture work, so I'll have try to catch him between things. One thing that I will mention is that many watch maker's lathes are built with a single base. The Levin that I had was unusual since it had two supporting bases. I really don't know if that would make any difference in your case. Any way as soon as I get a hold of Gary, I'll let you know.

 

[blueice]

Yes, base is the word I was looking for. I know most watchmaker's lathes have just a single off-centre base as you said, and even if you support the tailstock end with some wood, it would likely not have the ridigity of an equally well built lathe with 2 bases like your Levin. However, such watchmaker's lathes don't really come up on the market at my price range, so my best bet is probably still a Unimat type lathe.

The most common unimats I see are the DB200, the SL1000 and the Unimat 3. How do they compare with each other in terms of rigidity and accuracy?

 

[jwmay]

I’m no help. But why tungsten?

Atlas made a little 6x12 metal lathe. They’re hard to find, but I’d keep my eyes out for one. I gotta believe it’s a step up from the unimat.