Lathe Too Big?

tmcd · Post by **tmcd** » Thu Dec 31, 2009 10:27 am

I have a need to produce some small items for a couple of projects that require turning and tapering. A small lathe such as one of the Taigs or Sherlines is more than big enough for the parts I want to produce. However, either of those could of course have limitations in the future due to their capacity.

Is a larger lathe, with appropriate tooling, "too big" for small work or am I better served getting a small machine that is suitable for the planned tasks and adding a larger machine if my needs change in the future?

Of course I know the real mans answer is that you can never have too many tools.

Thanks for sharing your experience. I don't post much since I'm so inexperienced at most of this but I have learned an incredible amount from these forums. Hope everyone has a healthy, prosperous 2010.

Tim

Bill_Cook · Post by **Bill_Cook** » Thu Dec 31, 2009 10:48 am

The only limit as far as turning small parts on a larger lathe is speed. Watch parts can be made on a 36" by 288" lathe if time isn't a factor. The accuracy is there.

BC

SteveM · Post by **SteveM** » Thu Dec 31, 2009 11:31 am

You didn't say how small diameter the parts are, nor the material, both of which will make a difference in what you need.

Aluminum, cutting at 200 sfpm for 1/4 diameter with HSS tooling will need (if my notes and calculations on my spreadsheet are correct) about 3,000 rpm, which you are not going to get on a 16" South Bend. Steel requires a lot lower speed than aluminum, so carbon steel would need only about 1,200 rpm for the same size. Brass requires speeds closer to aluminum.

Personally, I would see if a bigger lathe can do the job. You can get small South Bend 9" lathes that don't take up a lot of room. Some prefer the 7x12 minilathes. There are a lot of options, both new and used. The Sherlines, by all accounts I've heard, are not bad machines, but small and with lower limits than other machines. They appear to be good for very fine detail work.

Steve

CarlD · Post by **CarlD** » Thu Dec 31, 2009 1:00 pm

I have turned some very small parts on a 16" lathe so I don't see a problem.

Richard_W · Post by **Richard_W** » Thu Dec 31, 2009 2:43 pm

The beauty of a small lathe is it can be stored under a bench or on a shelf. This leaves room for the larger lathe, so you could have both and use the one best suited for the job at hand. The smaller tool bits can be used in both lathes. Many people do this, since the 7" X 12" HF lathe is $499 and they have a 4" X 5" for $299. Both can be put away until needed leaving room for a larger lathe. (Not an endorsement for or against the HF lathes. Just an example for size comparison.)

In my case I choose to only have one big lathe, since most everything I want to do is larger. I guess it depends on your space, budget and what you want to do with it. For most people I would assume a 4200 pound lathe like mine is to big. Yet I must admit it would be nice to have 12 or 14" lathe with the higher RPM and a collet closer.

I would say if you have the space and funds to have both, then get both.

Richard W.

Post by **Harold_V** » Thu Dec 31, 2009 3:37 pm

The one consideration not being mentioned is the holding of materials. A large lathe, while capable of making small parts, would be a poor choice where holding is concerned, to say nothing of the limited spindle speeds, and, often, unwelcome coarse feeds. Large chucks can't close down to hold small items, plus they are dreadful to work around for small items. Dangerous, too, because you tend to hover over the parts so you can see what you're doing.

I specialized in small work when I ran my commercial shop. A 12" lathe with a top speed of 2,000 RPM was adequate, but I can't tell you the number of times I wanted more spindle speed. I would have welcomed, with open arms, a spindle that ran 4,000 RPM. As it is, I altered the feeds of the machine, cutting them in half, in support of the comment about feed rates, above.

If you intend to limit yourself to small work, definitely orient your shop that direction. Regardless of the size you choose, you will NEVER be able to handle everything that comes along, so make your shop comfortable for the work you'd commonly do.

Harold

tmcd · Post by **tmcd** » Thu Dec 31, 2009 3:51 pm

Harold_V wrote:The one consideration not being mentioned is the holding of materials. A large lathe, while capable of making small parts, would be a poor choice where holding is concerned, to say nothing of the limited spindle speeds, and, often, unwelcome coarse feeds. Large chucks can't close down to hold small items, plus they are dreadful to work around for small items. Dangerous, too, because you tend to hover over the parts so you can see what you're doing.

<snip>

If you intend to limit yourself to small work, definitely orient your shop that direction. Regardless of the size you choose, you will NEVER be able to handle everything that comes along, so make your shop comfortable for the work you'd commonly do.

I think the answer to my question is that the shop may eventually have two lathes. Besides enclosure openings most of what I do now with the mill is small brackets, etc. A small lathe will let me make custom shafts, reducers, etc. I know that for any project I currently have in mind and those I would normally tackle a smaller lathe is more than adequate.

Someone asked about materials. I very rarely use anything other than aluminum or some type of plastic. The plastics are typically when something needs to be electrically insulated.

Harold's comments about holding small parts and getting too close are quite valid in my case too.

Tim

PeteM · Post by **PeteM** » Thu Dec 31, 2009 9:25 pm

I have three lathes, ranging from tiny (watchmaker's) to pretty small (Austrian Emco) to a not very big (13" Harrison) with a 20 to 3000 rpm speed range. Most of my work is not very big and the Harrison is perfect for it. For example, it will turn something as small as a 2-56 screw thread as well or better than the smaller lathes. Below that, it's probably time for the watchmaker's lathe.

What I'd suggest is getting a well maintained (not sloppy) lathe with around a 1.5" spindle bore and the ability to take 5c collets, plus a speed at least somewhat above 2000 rpm. Even with this somewhat larger lathe, you'll feel comfortable getting close to work held in a 5c collet. What you definately don't want to do is work on fiddly little stuff held in a 12" 3 jaw spinning at 600 rpm.

SteveM · Post by **SteveM** » Thu Dec 31, 2009 11:44 pm

PeteM wrote:What I'd suggest is getting a well maintained (not sloppy) lathe with around a 1.5" spindle bore and the ability to take 5c collets, plus a speed at least somewhat above 2000 rpm.

Good advice. 5C collets are plentiful and you can get really good ones used for reasonable prices. They can hold up to 1-1/8". 3C and 3AT collets only can go up to about 1/2"

My dad has a Clausing 5914, which is a 12" lathe. He also has a Pultra watch lathe, and he never uses the Pultra. He does do some small work (currently working on an Allchin 1-1/2" scale traction engine), so small work is possible.

Aluminum and some plastics will require good spindle speeds, so you might want to look at roller bearing spindles instead of babbit bearings. Either way, check the spindle speeds.

Steve

Jose Rivera · Post by **Jose Rivera** » Fri Jan 01, 2010 3:53 am

Speed, speed, speed.

I have used a 18" Monarch at UCB that was just as accurate as the EE10 that I had ... one could have used the large lathe, but it was useless for small diameters.
Not enough speed.

Most Asian lathes do not have enough speed.
Anything above 2500 RPM is starting to be good for small diameter turning.

steamin10 · Post by **steamin10** » Fri Jan 01, 2010 12:42 pm

I agree here on large spindle bore and larger size for the envelope. For myself, turning a 12 inch wheel is not possible on a 6 inch lathe. If you think it is, try it sometime, and find all the compromises that work in to get it done. My 9 wont take a 3/4 inch bar down the spindle, so working axles come to the larger lathe, or goes between centers. (prefered).

I sadly have three iron head SB lathes in 15, 9 and 6 inch. The Nine inch is my work horse and most work comes from it. I have some small 4" chucks that get chucked into the 9 inch for 'Micro work'. The 4 jaw can anything deadon in a jiffy, including the micro work.

With the iron heads speed is an issue, coming short of 2k rpm. You need roller bearing headstocks for service with high rpm, and they are much more available than when I started my tool collection. If I ever go to work again, a roller head is on the table.

lakeside53 · Post by **lakeside53** » Fri Jan 01, 2010 2:21 pm

I have three lathes right now...

A beautiful 1930's watchmakers lathe with a full 8mm collett set - not really in use. Can't sell it as it's an "heirloom" from the wife's side.. Might convert it to a tig tip grinder.

My second is very nice Emco V10P... Wonderful lathe but I was always needing something more for larger parts.

So.. I now have a Polamco 14x40 (built like a 16x60...) that has a 28 to 2500rpm speed range. Yes... great lathe with a host of wiz-bang features, but I need a set of smaller chucks to use it on small work. My 8 inch chucks just don't close down enough. Sure wish the Emco (8tpi mount) and Polamco (D1-4) shared the same chuck mount...

Ignoring size related issues, having two lathes is very useful. Many times I've has part in one and to make something else, or... for a "second operation' setup.

I'd really like another about the size and accuracy of the Emco - and dedicate it to tool post grinding... I have my eye on a $700 Emco Compact 10 (D1-4 mount)... Such a waste of a fine machine, but...