Big Lathe vs Small Lathe

Linghunt said:
Cut and paste the program elements of different tools. Each tool by itself is easy to do , If you know how the machining should be done. and tool order. Biggest trick is the transition from tool to tool and not hitting anything. I'm pretty good about this now, but had my learning curve.

I got a "duty cycle" of about 40% on it running if not less. I got boxes of parts that need to be finished or 2nd Op-ed. I can't keep up with it. Granted I do have many other hats to wear , but it's a repeatable machine that performs like the specs say. Tech support has always been top notch.

I could ***** about little stuff, but nothing major. Buying one is economics and work projections. I had mine paid off in like 8 months. that included learning time.
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Program every operation around the tool like its your only tool, and make a safe retract of the carriage as part of your tool change macro? Might be a little slow for long parts, but are you likely to be turning really long parts and using gang tooling? I don't know. I've been struggling with the logistics of this as well since I am in the process of turning my mini lathe into a CNC gang tool machine.
 
Linghunt said:
Cut and paste the program elements of different tools. Each tool by itself is easy to do , If you know how the machining sho.uld be done. and tool order. Biggest trick is the transition from tool to tool and not hitting anything. I'm pretty good about this now, but had my learning curve.

I got a "duty cycle" of about 40% on it running if not less. I got boxes of parts that need to be finished or 2nd Op-ed. I can't keep up with it. Granted I do have many other hats to wear , but it's a repeatable machine that performs like the specs say. Tech support has always been top notch.

I could ***** about little stuff, but nothing major. Buying one is economics and work projections. I had mine paid off in like 8 months. that included learning time.
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Thank you, I have no experience with such a machine, I suspect it costs way less then a Swiss screw machine even with a C axis control
 
Bob La Londe said:
Program every operation around the tool like its your only tool, and make a safe retract of the carriage as part of your tool change macro? Might be a little slow for long parts, but are you likely to be turning really long parts and using gang tooling? I don't know. I've been struggling with the logistics of this as well since I am in the process of turning my mini lathe into a CNC gang tool machine.
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Short parts like 1 - 3 inches are ideal. Here are some lessons / tricks I have learned off the top of my head.

-1- You want to do your cutting next to collet, so you can add stock feeds in the middle of program ( e.g. a 6 inch part , but after feed you just do a part off, or a thread on that end prior to part off. ) you can get in trouble in "thinking" with stock hanging out hitting other tools.

-2- Do long retracts for tool transitions and don't worry about speed. Dial those down after you got it running and watch part cycles in real time.

-3- Long tools like reamers, tap heads can be worse than long stock. I try to put all of those items on end of tool plate.

-4- Parts and chips falling on and hanging up other tools impacting their use. I leave part off tool on top for this reason. Plan to add another output for an air blast, but not done yet. I plan to do this with electrical upgrade for air spindle and various Dc motors with feedback meters etc. Still building up the E box.

-5- If possible align all tools on same Z . easier thinking , Z is the same on all tools.

-6- Make alignment tool for Y on tool height. This was a must for live tooling. Align a drill on center without a gauge.

-7- CNC folks know this one, it can be over looked thou. if your part has a taper from stock flex. The final pass you can program a taper to fix it. When I thought of that one, I was like "what a dumb a$$" for not thinking of it earlier.

-8- Transition moves, keep them orthogonal , diagonals are quicker, but easier to make errors. I'll do diagonals when I'm trying to shorten part time. Attempts to get a second off a 10 sec part is hard. not worth the effort unless you are making 1000's of that parts. but run the economic numbers to know.

-9- Know your cost base. Operational cost etc. This will help in knowing how far to go with code and setups for time and also helps with quoting. Business 101 stuff.

-10- Don't slam the stock on bar stop when feeding for next part. I place it away from stock by .010" or so, open collet then jog for length I need, then close collet. Delays for some operations are a good idea too. This can get you in trouble too if prior part didn't part of correctly and now is in the way.

-11- In tool setup and programing, think about what happens if a tool doesn't do his job, you can trash a few tools before it stops. ( turning tool breaks as it clears area for thread tool ) that tool is toast as well.) No way around some of it, but good to think about.

Hope that helps. Triple check tools are tight, that kinda stuff too LOL.
 
I was planning on trying to make it a lot simpler than that. Three boring/drilling tools and no more at any one time. All mounted in the middle of the T slot table. To start with a single turning tool on the forward end of the table, and an inverted parting tool on the back of the table. Z height should be no different than programming a tool table for a mill. Every tool IS a different length. X offset is where I run into trouble. I'm planning on Mach 3 for control to start with so I'll see. An automatic 4-tool tool post may be added down the road, but live tooling likely would not. I did come up with a simple idea to control and connect only when in position live tooling on a multi tool post but I have to think about that some more.

I've been playing with ideas for an optical position sensor for tools, but they fall victim to chips just like proximity sensors and micro switches do.

One of the problems I often see is over thinking the number of tools and tool holders we need. How many hobbyist and home shop videos have you seen where the guy has 40 tool holders for his QCTP. One for every tool and insert tool he owns. Seems cool on the surface of it, but we only need one for every tool we are going to use for THIS job. Maybe a couple extras for tools we use on most jobs. Admittedly I have about 20-25 tool holders for my big lathe so I fall victim to that thinking as well. On the other hand my mid size lathe has five tool holders and I use ONE (1) of them for 99% of the jobs it does. And it does the most paying work right now of all of my lathes. LOL.

Anyway, my thought is the same for a CNC setup. Just setup the tools for the current job. The main point for most folks of CNC in my opinion is to crank out identical parts one after another. Not necessarily to have massive flexibility during a single job. Of course I have to add that the main thing I use CNC for is massive flexibility in a single job. LOL. (milling) I make mostly custom one off casting and injection molds. Often a single job will run all day.

I want to CNC my little lathe because there are some secondary markets where I can make and sell a few parts, but its not worth it to stand there and turn the handles all day. Production runs would be small, but 20 to 30 minutes turning handles for the market price of the part makes it a poor use of my time. If it works out I may also CNC my mid size lathe. The big one will likely always remain a manual machine, because it is just so much faster to turn a single part by hand sometimes than it is to program it.
 
You are on the right track. If a tool isn't needed for a job, I take it out. Can't break it with it in tool box. I was thinking of posting some setup pictures, but this thread got high-jacked. Perhaps I will start a new one in the right area.

Take videos and pictures of tools, a good way to document, I'm terrible about do that consistently.
 
silence dogood said:
Unless someone bought it, the worlds largest lathe is for sale. It's a Waldrich Siegen 3000x 13000mm(118'x512') . Unfortunately, my shop is too small(14'x12'), so I had to turn it down. I guess that I will have to put up with my 8"x14".
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Here is a small lathe for sale. An under floor wheel truing lathe, for $650k. Not bad, but just a little bit bigger than my 9x18" junior. Should be a screaming deal.

https://www.ksl.com/classifieds/listing/45442671
 
silence dogood said:
Unless someone bought it, the worlds largest lathe is for sale. It's a Waldrich Siegen 3000x 13000mm(118'x512') . Unfortunately, my shop is too small(14'x12'), so I had to turn it down. I guess that I will have to put up with my 8"x14".
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You are off by a factor of 12. It's 118" x 512", or about 10' x 42'. Still, bigger than my shop.
 
cjtoombs said:
You are off by a factor of 12. It's 118" x 512", or about 10' x 42'. Still, bigger than my shop.
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I saw a big one in Napa, Ca. several years ago that makes that one look small, it would swing 14 ft. and bed length 150 ft. had two carriages that the operator rode on and was retrofitted for CNC and either carriage and all functions could be controlled from either carriage platform; the tailstock had a power mover and power quill travel. I was being used to make a long hollow shaft for seismic features on the new Bay Bridge on San Francisco Bay. The shaft was about 5 ft. diameter, how long I do not remember. The lathe was originally made for trepanning marine tailshafting.
 
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