Not exactly a mini-lathe question

[lilricky2]

In my former life I was a machinist/millwright. Now. with health problems, I am working out of my home shop. I have a converted cnc benchtop mill. Since I am finally starting to get the hang of cnc, I would like to acquire a lathe that I can eventually convert to cnc. I need something that can handle aluminum carbon and stainless to @ 3 inches in diameter. Larger than 20 inches between centers but smaller than 40. I would prefer 220 single phase and it must be metric thread capable. Quick change gearing would be nice but not absolutely necessary. I would not be able to beef up the screws or spindle bearings for a while, since I would need tooling first. Price is a factor. I have been looking at the Lathemaster 9x30 and the Grizzly G4003 12x36. I will be working on rifle barrels, cutting pump shafts and sleeving bearing housings. I have never dealt with these little machines so any direction/advice would be greatly appreciated.

Thanks,
Rick

[Dan S]

Rick,

Are you going making things 3" in diameter out of stainless? If so based on reading of the specs, I think you would be pushing the upper limits of a 9x. I think a 12x36 or a 13x40 (if the budget allows) would be better suited for the type of projects you are planning.

Please note I own an 8x12 and have never used a 9x, but based on weight and motor hp, the 9x doesn’t seem suited for your projects. Hopefully I won’t get flamed by any 9x owners.

[BobWarfield]

I have a Lathemaster 9x30, and I am successful turning stainless on it. One concern would be the spindle through hole dimension when looking at rifle barrels. You'll want to look that over carefully and make sure it is satisfactory for your application.

Best,

BW

[lilricky2]

I don't want anyone flamed over this. I am just looking for good advice on these smaller machines. Dan, 3 inches would be the extreme outer limits for what I am trying to set up for, but that is the type of advice I am in need of. I am used to machines larger than this. Our small machine was a LeBlond 14x40. Bob, you are correct, 3/4 inch spindle bore is not nearly large enough, but I could make do as long as I have at least 28-30 inches between centers. Anyone favor a brand or is one as good as another. I would like to convert it to cnc later when I can afford it.

Rick

[wizard]

All sorts of questions and coments come up here.

First make sure that the lathe has a spindle noise suitable for CNC. Screwed on chucks and such are not suitable. Chucks should either bolt on or use a cam lock arraingement. You do not want to give up the ability to run in reverse.

Second as has already been mentioned the thru hole in the spindle is important. Determine what you need and then add a few percent to that. Do not accept a lathe with a smaller bore.

Allied with this, if you expect to do bar work the abilty to use 5C collets to the full diameter can be an advantage.

If price is a factor it pays to shop around and be patient. Look for deals on new stuff, but more importantly look to the used market.

Not to detract form your CNC interests but do realize that a CNC conversion of a manual lathe leaves a lot to be desired! It is no where near as usefull as a CNC conversion of a manual mill. So consider finding a used CNC lathe of small size. I say this for a number of reasons. One is that you will not often gain much in speed for limited lot sizes. Another is that for larger lot sizes the abiltiy to handle bar or to chuck automatically is important. Another issue is spindle control, both positoning and speed.

Don't get me wrong there have and will continue to be a number of succesful CNC conversions of manual lathes. For specific applications it can work out well. But don't look upon a conversion of a lathe as being as usefull as a conversion of a mill, there is more missing on a lathe for production CNC work.

If you have experience with larger machines you do run the risk of being disappointed with the smaller machines. They can be very good when operated within certain capabilities, but those limits are hit quickly.

Thanks
Dave

P.S.
As an aside it might make more sense to pick up a largish manual lathe with the intention of keeping it manual. Buy a smaller 7x 12 lathe for CNC as a learning platform and very light duty machine. I'm generally of the opinion that an unaltered manual lathe is good to have in any shop.

D.

[BobWarfield]

Originally Posted by lilricky2 I don't want anyone flamed over this. I am just looking for good advice on these smaller machines. Dan, 3 inches would be the extreme outer limits for what I am trying to set up for, but that is the type of advice I am in need of. I am used to machines larger than this. Our small machine was a LeBlond 14x40. Bob, you are correct, 3/4 inch spindle bore is not nearly large enough, but I could make do as long as I have at least 28-30 inches between centers. Anyone favor a brand or is one as good as another. I would like to convert it to cnc later when I can afford it. Rick

Don't worry Rick, I certainly won't get flamed over any of it. I would not settle for less than a Lathemaster style 9x30 or possibly an 8x12, though it sounds like your requirements eliminate the 8x12. From what I can tell, these are the most rigid of the smallish lathes. By all means look at the step larger, such as a 12x36 as well. I think the spindle hole may well be the deciding factor for rifle work.

I also tend to agree about the threaded on chucks, though the 9x30 uses a quasi-camlok arrangement that I prefer to a thread on chuck. As to the bar feeder, only you can say whether your appetites require such a beast, and whether that means you work from a real CNC lathe (lots more money), or try to provide the equivalent on one of these smaller lathes over time. I do think the idea of a collet system is very attractive and would benefit both your accuracy as well as productivity, but these are readily available for all of your lathe options.

One last comment RE CNC. A quickchange gearbox is a significant expense in the manufacture of the lathe, and will likely be discarded in a CNC conversion. One nice thing about chosing a lathe without one is that the extra cost of the QC box is often applied to a sturdier lathe, which I think is the case for the Lathemasters.

I'm personally a lot less convinced about the need for a manual lathe if you have a CNC lathe. The conversational capabilities of Mach 3 seem awfully good for a lathe, and a lot of what gets done manually is frankly just repetitious without being beneficial. If you think you'll have need of a lot of exotic setups, you might want the manual, but for the basic operations, the CNC is sure nice. After all, why should you have to deal manually with turning to a particular diameter when the CNC can do that for you? If you don't CNC, you're going to want a DRO and certain tooling that is rendered un-necessary with CNC. Another great example is turning tapers or balls. Who needs those attachments if you have a CNC?

Best,

BW

[lilricky2]

Great points! I was just thinking of repeatability + speed with a cnc machine. I've spent weeks turning hundreds of inconel gas burner ferrules thinking "a cnc lathe would be nice right about now". I was also thinking I can store rifle barrel and pump shaft profiles on my computer, and once they're written, they're always ready to go. A bar feeder would be great addition but I'm not in a place to afford those type of niceties yet. You guys are right about spindle bore though, 1.5-2 inches would facilitate about 90% of my needs.

Rick

[BobWarfield]

Rick, you said the "I" word, which is a word I'm not sure one can ever say too loudly around the small Asian lathes. If you think you will have to do much Inconel or other exotic or obstreperous alloys, it is probably yet another argument for the larger machine.

Best,

BW

[wizard]

It is funny but I come to the opposite conclusion that Bob comes too, re the need for a manual lathe. Most of the manual work I'm familiar with on a lathe is not repetitious at all, it is very much a new adventure each time one walks up to the lathe. What I do is machine maintenance related so that is part of the issue and time is always wanting. So I can't see the benefit of having a manual lathe possibly your only one, converted to CNC.

What Rick is telling us below is another story altogether and indicates he needs a CNC lathe for production runs and lesser runs where repeating a pattern is required. Frankly this has not been a task for manual work in some time. Even before CNC gun barrels where being turned on tracer lathes. A Long Long time ago I work very breifly on a repair of a tracer made by Seneca Falls Machine that was a tracer for gun barrels, interesting how that was done. So while we are talking about manual lathes the reality is that sort of machine is far from what is required.

As I see it a do it all lathe for what Rick needs will be pretty expensive relative to a 9x20 or 9x30 lathe.

The first problem to look at is barrel profiling, this requires a lathe with a bore large enough to pass the barrel blanks or a good distance between centers. (I do not believe that 30 inches is enough, though that depends of course on a number of things. One of those things is where his barrel making interest lay, a bench rest barrel for example would require a bigger lathe than a barrel for a 10/22. Rick seems to think that 30" between centers will cut the mustard so lets leave it at that. So if the barrel is swung around to work on the chamber (after profileing) how far will it go into the spindle. Ideally it would go far enuogh in so that the chamber end is fully supported by the jaws or collet. As you can see a lot depends on exactly what Rick is doing and what he would like to do in the future. At this point I would have to say that the 9" class lathes are to small. That is for things done manually. CNC'ed would present even more problems if more than profiling needs to be done.

The second issue is the production runs of small parts. I'm not sure what size of ferrule he is talking about here, as I can imagine everything from 1/4" swagelock type ferrules to something completely different. Here I'm tempted to say a smallish machine CNC'ed might do the trick especially if the stock can be handled via a collet and collet closing system. There is also the issue of maintaining quality which admittedly may be a problem on a small lathe. The problem is that this application cries out for a lathe that can handle bar, it may also require more tooling than running a profiling run on a gun barrel. Most manual lathes simply don't have the nice tooling indexers, nor room for them, purpose built CNC lathe have these. How well ganging tooling on the cross slide will work is an unknown at the moment.

As Rick has described his applications, I can see a CNC'ed lathe helping somewhat if the modifications don't harm the manual usability. Barrel profiling should work rather well on a converted lathe. The ferrules and some of his other projects though may not fair as well, there might be a partial productvity boost but surely not an optimal boost. I focused on the word productivity because that is important for a task that you could loose to somebody else. Further it seems that that is one of Ricks goals personally.

As I see it he could very easily use a converted lathe to CNC his barrels unattended. Doing the ferrules on a converted lathe won't allow him to step away and work on other things in my estimation. Unless of course he fills in a lot of the misisng spices that make a real CNC lathe shake and bake. That would be automatic bar feed, turrets for tooling and parts and scrap handeling.

I don't want to sound negative as it is clear that for some usage he will make out well. I just don't see a converted lathe spitting out ferrules all by itself every ten seconds. In other words ones expectations should reflect the reality of the converison and the work to get to where he'd like to be. It might be more sensible to look to the possibility that two different lathes are required here. A cheap CNC converison for barrel profiling and a more elaborate CNC for the other parts. I do believe that a task specific conversion for barrel profiling could be very cheap.

Dave

BOB: I'm personally a lot less convinced about the need for a manual lathe if you have a CNC lathe. The conversational capabilities of Mach 3 seem awfully good for a lathe, and a lot of what gets done manually is frankly just repetitious without being beneficial. If you think you'll have need of a lot of exotic setups, you might want the manual, but for the basic operations, the CNC is sure nice. After all, why should you have to deal manually with turning to a particular diameter when the CNC can do that for you? If you don't CNC, you're going to want a DRO and certain tooling that is rendered un-necessary with CNC. Another great example is turning tapers or balls. Who needs those attachments if you have a CNC? Best, BW AND FROM RICK: Great points! I was just thinking of repeatability + speed with a cnc machine. I've spent weeks turning hundreds of inconel gas burner ferrules thinking "a cnc lathe would be nice right about now". I was also thinking I can store rifle barrel and pump shaft profiles on my computer, and once they're written, they're always ready to go. A bar feeder would be great addition but I'm not in a place to afford those type of niceties yet. You guys are right about spindle bore though, 1.5-2 inches would facilitate about 90% of my needs. Rick

[lilricky2]

Dave,

I am not even remotely disagreeing with you. Your points are the exact reason I am sking for direction with this. I had completely forgotten about bore chambers in my last post. This makes spindle bore a critical issue. I appreciate the reminder. The ferrules I was referring to are about a foot long, 1,25 inches in diametwr and contoured on a lathe to fit large acetylene burners used to manufacture nylon. You are right though, I do want to be able to do small production runs (maybe half dozen at a time) of standard ANSI pump shafts like Goulds ST or XT and Durco Group I and II and be able to switch over and turn a barrel with as little confusion on my part as possible. The fact is, I will be running it manually for some time. I just hope to find a machine sturdy enough to turn a 3 foot pump shaft, precise enough to face a rifle bolt or ream a chamber with the potential to be cnc converted that will fit comfortably in my little 16x16 wood frame shop. I also need it to be (dare I say it) affordable. I may just be asking too much. I just don't want to regret my choice and wish I'd gotten something else instead.

Rick

[jorgepease]

I would think if you are going to be doing some heavy turning, which requires you make more/lighter passes, then CNC would have merit. Just let it run and walk away. Your not going to be churning out the work with a little lathe anyway.

I think a CNC retrofit has allot to offer. I would not want to lose use of manual operation but dont understand why I would. I just ordered the lathemaster 9x30 and want to add CNC. I am looking at Flashcutcnc. Their system uses double shaft motors so you can keep your handwheels. Just unplug the motors when using manually. Then at least you can eliminate some of the tedious parts of the job.

My machine will be profiling, adding grooves, and chamfers to alum tubing as well as cutting delrin balls in production runs between 50-100 pcs. If I can have it my way, all I want to do is chuck the piece and push a button.

[lilricky2]

Ideally, thats where I'd like to end up. Unfortunately. a cnc retrofit looks to be a little expensive unless someone has a parts list and DIY installation they would be willing to share. Fortune did smile and I bought a 12x36 Harbor Freight lathe new in the crate from a local individual for under $1300. I used a 20% off coupon for the stand and am setting it up in my shop this week for about $1475 so far. I am looking for tooling suggestions, where to buy, brands, pricing. Since I no longer work in a commercial shop, I have to buy my own tooling. I am going to pipe and valve my coolant tank over from the mill and hang some more/better lights. Once I make a liitle money, I'd like to start accumulating parts for a cnc retrofit. I think I could make good use oc a cnc capable lathe with what I want to do. Anyone with advice or suggestions, lay 'em on me!

Rick