Spindle

First impression is that is severely underpowered.

yawn deleted

t slot is 2 1/2 inches long. 7/8" inch gap and the rest of the dimensions are all a quarter of an inch. measured off a hercus clone.

why dont you just buy a southbend and refurbish it ....or just use it to death as it is.

flats and v's on the carriage are a very close fit to the bedways. the bedways are easier to measure :-)

did I miss anything? Stealth Pilot

didnt notice that. yeah try 1 1/2 hp single phase as a minimum.

I can still stall a cut with a quarter inch square tool bit in free cutting steel with 1 1/2hp.

Staelth pilot

You need at least 1hp, 1.5 would be better. Get an inverter rated 3-phase motor and VFD. The machine will run much smoother and will have infinite speed adjustability over a range of at least 10:1 without moving the belt(s). Are you planning to have a backgear?

Randy

May be underpowered. For home use 110v/1p input make sense. I suggest you look at the VFD drives that have 110v/1p input and

bed length or center distance? Will you have gap bed or sliding bed to allow largest possible face plate? With 5-7/8 cross slide movement you can face an 11 inch part.

Why not make the spindle large enough that it takes a 5C collet without an adapter. 3&4 jaw universal chucks are available with a 5C mount.

Slightly larger to accomidate a 5c internal bore spindle. For home shop use you will want a face plate.

Wider is better for milling.

Why ballscrews? $$$$ -- Steel leadscrews with brass/bronze or even babbit half nuts are well proven and last a long time. With the long bed a bigger leadscrew [under tension] would be a good idea. For power cross feed you will need another power feed shaft or a slot milled in the leadscrew to drive a gear.

Low production/high precision bearings are big bucks. In commercial operation they are justified. Have you considered using automotive/truck front wheel bearings. Plenty of load capacity, and are available large enough to take a spindle large enough for a standard 5C collet seat.

Use 5C -- very common and square/hex holes are available.

bigger is better and costs very little. Make it big enough for a

Check the Hardige late. Flats only.

Belts can be a pain to replace depending on how they mount. A linkbelt has lower vibration and are easy to fit/replace.

bigger is better. try to design so it is under tension. You will need a slot milled to drive a geat for cross slide and longitidunal feed or a seperate power shaft [generally square 1/2 to 3.4 inch.

Be aware that it is not considered good practive to use the lead screw as a "feed screw" because of the additional wear, although for home/hobby shop use this should be fine. You should have finer feeds available.

A one-off quick change box will be $$$$. See what you can adapt, or go for change gears. Change gears are far more flexable for metric and diametric/module pitches.

Lindsay books [see below] has many lathe instruction book reprints.

============ Nice fantasy project, but the machine tool makers have been doing this for 200 years. With the time and effort you are sure to expend, you will be far better off to simply buy a good used Hardige.

Before you get too much invested [either time or money] get the Gingery "make your own lathe" book and see what is involved. see

There is always the danger of reinventing the shell or rediscovering fire.

Unka' George [George McDuffee]

------------------------------ Watch out w'en you'er gittin all you want. Fattenin' hogs ain't in luck.

Joel Chandler Harris (1848-1908), U.S. journalist. Uncle Remus: His Songs and His Sayings, "Plantation Proverbs" (1880).

Umm, why don't you just get an Atlas or Atlas/Craftsman 10" lathe? It would save you a LOT of time! If you don't like their bed, you could change that, and might still be able to use almost all of the pieces with a little machining.

These are plain ball bearings? What is the axial load rating of them? How much load rating is left after the preload is applied? That's why the Atlas uses Timken tapered roller bearings. They come in two pieces, a "cone" with the roller cage, and an outer race. You can combine the two parts to hit the right ID and OD.

If you really are going to make your own spindle, go larger so you can fit

The stuff from McMaster-Carr is good enought to not bind up in a nut, and is designed for elevating heavy pieces, not as a machine tool leadscrew. Note that crossfeed screws are traditionally left-hand thread.

You could put a variable speed gearmotor (either DC or universal) on the screw for really fine feeds.

Yes, buy a quick-change box off a suitable lathe being scrapped. You'll save yourself hundreds of $ as well as aggravation.

I shouldn't ask, but why are you doing this?

Jon

So tell us... Why do you want to build your own machine?

Regards,

Robin

Mine was that he's putting ABEC 9 or 7 bearings on a 9 inch swing lathe thats 4 feet long. Unless he builds it a little heavier than a Chevy truck, it'll flex far more than the bearing tolerances. :-)

But that's OK, he's having the bed ground at the local shop that probably is using a machine older than he is.

He wants a 4 foot long capacity to turn 12 inch pieces.

He wants to use tooling compatable with a 9"South Bend.

And I ran out of things to say about someone that would go out of his way to choke down his spindle bore to 3/4 inch to fit collets that each cost somewhere near the price of a 10 pound box of 5C collets.

I am in awe!

Good friggen' greif.

Listen to the voice! It says "buy a lathe!" and "quit pissing around!"

My second impression is that if this guy is serious, he either has more money than brains, or he's spending tax dollars on this one.

Cheers Trevor Jones

My third impression is that I just got sucked in by a troll.

DoH!

:-)

Cheers Trevor Jones

greg dimensions of the ways. (just in case your post wasnt a troll)

/\_= /\_/\ | | | |

in ascii art that is the general arrangement

Come, come, Trevor! No troll - Naw ! It's the same guy that built a steam-powered V-8 for his pickup.

And uses 4 of those cylinders for an air compressor.

Ok. After watching the thread gather several replies, here's my next iteration. Yes, this is not a troll posting, although you may have it started to sound like one.

It's come to my impression that I'll need to design and build something a little bigger. I'd like no bigger than a 13" lathe. Most of the round stock I have comes in 12" cut lengths.

Why? Well.. yes I could go out and purchase one, or bits and pieces of one to put together to make what I want. But, that would be just too easy. Second is, that I have a South Bend 9" that I use a lot, though it's on loan to me.

For finances, $1,500 is my starting budget. Next month, I'll have more, probably half that more.

My first question, is that I've been hearing a lot of people want 5C in their spindles. Yes, I could do this, but.. why?

I figured it would be underpowered, but I still need to keep the same belt for now. 3VX375. Ok, so 1-1/2 HP. I planned on getting my pullies from McMaster-Carr. There's a good Dayton distributor in town, and could get other brands. Any ideas on which model? I've also added plans to purchase a VFD. Again, which one?

My feeds are still the same at crossfeeds of 0.0005" to .0056" and longitudinal feeds of 0.0021" to 0.0162".

One of my original ideas was, a larger threaded spindle (2.00" or bigger), or a D1 style spindle, maybe even a L type spindle? I couldn't find dimensioned drawings of D1 spindle noses, or instructions on how to homebrew one.

My headstock and tailstock going to be a bit "boxy" / "squareish". (I like things square! LoL)

Stealth Pilot, thanks for the dimensions!

I saw great plans for follow and steady rests too. I'll incorporate those.. once the design is built.

Yes, I'm going to probably have a backgear. I've used backgears the one I have for a long time now.

I really would like the lathe to be able to handle a reasonable 6" /

The spindle bearings I had looked at originally were Timken Tapered Roller Bearings, with a 1.7716" bore.. roughly 45mm (for you metric nuts).

My original thoughts on materials used for building this lathe was stressproof / tooling plate in the 8600 series steel or stressproof

Boston Gear has been helpful in the past when I started building other projects that required gears. But, Yeah, I could take a QC off a SB or something like that, and mod it to work.

I figured ballscrews on a lathe would be a bit too much, but I could do that later on in the lathes history. Rockford Ballscrew offered to grind / roll my leadscrew with the correct LH pitch ACME on any size I chose, and include the required half nuts, etc.

Given how I've had my other lathes motors mounded, either underneath the lathe and behind the lathe on the bench. I found that behind the lathe was the best. I'd be open to other mounting styles.

About much finer feeds? What would you consider best?

I wouldnt need to mill or put anything on a face plate that would be bigger than what would fit on a 8" faceplate, at least not yet. Although, I just figured that 5-7/8" would allow me good access.

One thing I do regularly is drill 17/32" holes (0.53125") with a

Thanks for your help!

Any other comments?

Greg

Just one. A fool and his money, are soon parted. Good luck at the soup kitchen.

Cheers Trevor Jones

Just the response I thought was going to appear.

Gee whiz.

Greg B.

You have $2300 and a Southbend lathe, and you want to manufacture another complete working machine capable of doing useful work?

Even if you had all the machines necessary (and you most certainly do

I'm not sure very many people here will have the time to explain the absurdity of your project (the list is *extensive*). You might be able to make a machine slightly larger than the Taig/Sherline machines with that kind of budget, but you won't be able to use any castings I'll wager...

Good luck with everything anyway.. It's at least a good mental exercise..

Regards,

Robin

Really?

Have you actually priced out any of the stuff that you are speccing ?

Start with the ABEC 7 and 9 bearings.

Follow that up with a quick price and availability check for 5c collets. New ones. Good name brand stuff, hardened and fit for accurate use. And 4C, and 3C. Check the availability of different sizes and shapes too. You may just figure out why 5C is the recommended choice.

Get a firm quote on exactly how much that ground lead screw is going to cost, too.

Then start getting firm quotes on the grinding time to grind the ways.

When it's all added up, you are blowing smoke up your own arse thinking that you could somehow reinvent the 1950's lathe, except with parts and tooling that are even harder to find, and made more complicated than it needs to be.

If that does not give you any clues as to why you have been treated like a troll or a lunatic, then nothing will.

You have some money. Buy a lathe. Make changes to the geartrain as you need, from cataloged parts and minimal custom made bits, likely such as an expanded gear quadrant to mount said gearing.

Or piss away $30K or so to build something that likely will end up the equivalent of a $1500 used lathe.

If you are just fantasizing , at least have better than mediocre goals in the fantasy.

Cheers Trevor Jones

Yes, just as I suspected.

Greg