Anyone built their own hobby/mini metal lathe? Don't have the funds or space for a serious lathe, so was thinking of trying to build one with angle iron for the bed and using a variable speed bench grinder to drive the chuck with a couple belts. I don't have any welding equipment beyond a spot welder, but I have a drill press and don't see why I couldn't just bolt everything together.

It sounds like a neat and ambitious project, but in the long run you would probably be better off buying a cheap, small Grizzly or Harbor Freight lathe.
There is a web site that rates all of those smaller machines (I'm hoping someone will list it here, because I forgot the URL) and there are many tips on how to get good performance out of them.
If you want to experience the build, then go for it.  If you want to get right to machining, one of those lathes will get you up and learning quickly.
Just think of the things you could do with a lathe that is almost ready to go.  

Sell me on it.

I need inspiration to get me into this

Barrel reprofiling, threading, form 1 suppressor parts; not to mention you can make cool metal candlestick holders!

I hear you on having a professional machine. Looks like Harbor Freight has a sale coming up soon, so that may be the better choice by far.

Look for some old american iron.   Its usually not terribly difficult to find old metal lathes fairly cheap.  

I have a grizzly 12x36.  Kind of wish I had spent the $ on an older american made machine.

IMHO, horrible idea

The bearings in a cheap bench grinder cannot hold up to the force of cutting metal with other, harder, sharpened metal blades; even if you do get a little life out of the bearings you will have HORRIBLE accuracy because they aren't precision bearings.

The angle iron for bed-ways is also horrible. It just doesn't have the rigidity, and rigidity is crucial to machining. Even hobby level lathes have heavy castings for the ways/head-stock etc. Notice I said CASTINGS; cast-iron is much more rigid than hot-roll or cold-roll steel. Steel is strong, but flexes, cast-iron is stiff, but breaks. There is a reason castings are used, angle iron will most definitely not hold up to the cutting forces, let-alone keep it's shape (flat, true, straight) as varying loads are applied at different places on the bed.

What will act as your saddle and how will it effectively engage the "angle-iron bedways"? How will you crank the saddle? How will you make a cross-slide for the lathe? How will you hold tools?

Plan to cut threads etc? You need a lead-screw, half-nut and thread-dial, how will you adapt those on?

You will be MUCH better off doing a little research on mini hobby lathes, even if they are Chinese trash you will save a LOT of time, frustration and money in the long-run to buy a piece of garbage from China before you pursue this idea.

Sorry to poo on an idea, I value outside the box thinkers, but this idea is not a good one.

Have you ever run a lathe before? Have you experienced tool chatter and it's effects? Cheap ones will chatter bad enough to kill parts, tooling, your hearing, and ultimately the machine itself (vibration is a bitch). Even quality lathes can chatter if they setup isn't proper or the material is just one of those materials that chatters no matter what. An angle-iron lathe will chatter and break tools so badly that if you use it even somewhat regularly your cost on wasted materials, broken tools, repairing the parts of the lathe that are killed by vibration will all exceed the cost of a real lathe in no time at all...

Really bad idea.
Worst case get a Harbor Freight.

All I got is find an old South Bend on craigslist, then watch this guys videos.  https://www.youtube.com/user/mrpete222/videos

He's a crusty old buzzard, from a bygone time.

Mr. Pete is awesome. I showed his videos to my old timer neighbor who has a hobby machine shop for restoring Classic cars. His face lit up when I told him they were basically TV shows about machining.

I bought my father a 9a Southbend in 2013. Date code said it was made in 1928.  Heavier than ten hells, but amazingly accurate. If you're going to build a redneck lathe, you might as well just put your stock in a drill and hold it in a vice. Tool holder? You got hands right?

These machines are out there.  $400-$800 for a good older 12x36, depending on looks and tooling that goes with it.
Spend your time looking, rather than figuring out how to use an engine block as the headstock.

If you want to drive to Missouri, I'll give you a fixer upper.  I've never measured it but I'd guess it about a 8"x30".  I bought it for a few bucks years ago at an auction to keep a scrapper from getting it.  I don't think there's a motor on it but I beileve it's pretty complete.

I'd hate to see what you'd say about a real machine then... IIRC the SB 9A should be less than 500 lbs... which is consider quite anemic for most lathes.

FWIW, I'm not dogging on the SB 9", I have a light 10 (10K) which is basically a glorified 9". I just thought your comment about their weight was funny because they are one of the lightest weight lathes that are generally considered usable. Even cheap import ones weigh more than the SB 9"...

Here is what you may be looking for.
http://openbuilds.com/?category=cnc-lathe-builds&id=297

The family that runs Open Builds are very nice people (Mark and Trish Carew). I built a CNC router from one of their early designs, mostly intended for RC hobby use, but I was able to cut MDF for router templates for my woodworking.
I have been accumulating parts to build the OX CNC router (2x4 table), and have most parts except the driver board, and time.  Eventually I want to build a laser cutter.

An old metal  lathe is something I'd like to get someday.  Just manual.  i want something for building bamboo fly rods (turning the ends so that the ferrules fit tight, turning the butt so the reel seat fits, etc).  When I built my first one we just used a little sherline, it worked well, but there are some bigger things I would like to try making someday, like fly reels, etc.

Little machine shop is way more betterer . they have a page that compares each model.

On the phone so I can't link. Google mini lathe.
Fwiw, all think lathes are made in the same factory in China, even the harbor freight.

I read darn near every page on mini-lathe and littlemachineshop.com, then bought the Grizzly G8688. It got here 3 days ago.

SE Arlington. Bring it over. I should be ready in a week. Cutting tools arrive Monday. Still need either a bullnose live center or preferably a 3 jaw Chuck for tail. Looking this weekend for one.

There's always this classic.

There's a forum out there somewhere of people building the whole Gingery machine shop.

Not saying it can't and shouldn't be done, I've seen plenty of good results where people have cast their own base or created granite ones.  That being said, it is a large undertaking, and I'm not sure what what you have on hand (i.e. mill) for building the mounts for the motor, spindle, leadscrews (or ballscrews).  Lets not forget about ensuring the rails are true to one another and FLAT.

Here's the link to a homemade/DIY slant bed CNC lathe, while CNC, most of the basic design principles remain the same:  http://www.cnczone.com/forums/vertical-mill-lathe-project-log/51688-cnc.html

Zach

http://en.wikipedia.org/wiki/Multimachine

http://machineshop.olin.edu/resources/documents/Prison%20Camp%20Lathe.pdf

What kind is it?
 

Back gears for threading are going to be a PITA to complete.

It is a real job to get them meshed correctly for pitch accuracy on older equipment.

A single broken gear can spell the commercial death of an older lathe.
It is simply not worth hobbing a new gear to replace a damaged one.

Old

I shortened the barrel and gas system for this FAL with that lathe.  It is usable.  

How much do you want for it?
 

As long as you're taking it to use, it's free.  Just pay it forward.  

Well I already have a little South Bend 9 in the garage, so I don't really need it.