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IndustryArena Forum > MetalWorking Machines > CNC "do-it-yourself" > Single Purpose Lathe Conversion-Gang Lathe Setup
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  1. #1
    Join Date
    Apr 2007
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    11

    Single Purpose Lathe Conversion-Gang Lathe Setup

    I’m looking for a little reality check and I figure you guys are the right guys to ask (gals too).

    I make a specialty product from silicon bronze that needs to be tapped 1-1/2" NPT. We were sending them out and that got to be pretty expensive $15 each, and really crappy work, so I started doing them on a friends lathe, and it’s a real pain. Had to make a special everything, tap holder, I use a 2 foot, torque arm, and even after reaming the hole with an NPT ream, and using a skip tooth tap, and a lot of cutting fluid, it will stall a 7.5hp lathe. Silicon Bronze is 30% the machinability of steel. It is not friendly to this type of brute force process, that’s why it’s silicon bronze.

    So back to another machine shop, now it’s $17.50 each and it’s still a pain in the rear, they do good work. But small passes and a single point is the way to go, but of course it never loads the machine, because it’s single point.

    So, I’ve made my fair share of CNC machines back in the day, I’m looking at sacrificing a Grizzly G4002 - 12" x 24" with a cam-lock spindle to the project, just get a new chuck with replaceable jaws and make custom jaws. Don’t need extra length, and really, how much HP do you need to do a bunch of clean up passes with a boring bar and then single point the thread? About 2hp. So what, it takes 10 minutes each, fine. Centroid Acorn, DMM hybrid drives, everything fairly straightforward. The part is only a few inches long, it can be held in the jaws.

    The question comes to tool changer…

    I figure I need 2 tools minimum, but 4 would be really nice. A little facing, a boring bar, and a single point, plus one extra.

    Quick change tool post is NOT an option, me standing there is less of an option.

    Here are the options:
    Is there an automatic tool post out there, perhaps from China, that can be wired in?

    OR..

    Convert it to a gang style machine. Get a Grizzly G8750 X Y Table, deck the entire top carriage of the lathe flat, deck the underside of the X Y table, removing the entire Y axis from it, a little bolting magic and now I have 12” of travel! Mount some tools right side up, and the back half tools inverted. This way I never travel that far off center. Basically a gang style setup.

    It only has to hold .002” this is an NPT thread, it can probably be .005 and still be fine, I’ve paid for worse.

    The machine needs to be less than #1000 said and done, moving in a few years and freighting a Mori isn’t in the budget.

    It will run basically one single program its entire life, thread a 1-1/2" NPT into Silicon Bronze.

    So I would be interested in a sanity check of my idea, or is there a better way to skin this cat.

    We will tap this hole a MINIMUM of 600 times next year. 50 times a month, maybe more.

    Interested in hearing ideas.

    Thanks
    Aaron

  2. #2
    Join Date
    Dec 2013
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    5717

    Re: Single Purpose Lathe Conversion-Gang Lathe Setup

    Either idea that you propose would work. I like the idea of the gang tooling set up. Your parts list seems reasonable.

    Another option is a CNC mill, just thread mill the part. Wouldn't take a lot of machine to do that job and might be easier to convert than the lathe. Might even be able to find one already converted at a fair price. A tool changer would be really nice, but maybe you can work around that.
    Jim Dawson
    Sandy, Oregon, USA

  3. #3
    Join Date
    Apr 2007
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    11
    I really kicked that around, concerned about concentricity, then I come back to the weighs 4 tons problem. I looked at a great looking Mori Seiki 150 Slant bed, great price, great everything. 9000 lbs of fun. Rigging and moving it in 2 years would make it impractical.

    I did find a 4 post indexer from China, same like you see on these other econo-CNC lathes, I asked them to quote me. That and a small industrial PC, I can have a dedicated threader for under $6k.

    Lots of options.

    Thanks for your input.
    Aaron

  4. #4
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    Dec 2013
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    5717

    Re: Single Purpose Lathe Conversion-Gang Lathe Setup

    When I mentioned thread milling I was thinking more about my 450 lb EMCO Concept 55, 4 axis mill. I think it would actually do the job, just not very fast, but it does have a 6 tool changer. It's almost portable. I also have a Mori sized slant bed lathe that would do a fine job either thread milling or single pointing, but it is a bit hard to move around. If I were running your parts in my shop that's the machine I would use.

    I just looked at those little stepper turrets, kind of cute. Looks like what you need and the price seems right. I wonder how stable they are? I like your lathe mod idea, I think it will work fine and your budget is realistic.
    Jim Dawson
    Sandy, Oregon, USA

  5. #5
    Join Date
    Mar 2004
    Posts
    413

    Re: Single Purpose Lathe Conversion-Gang Lathe Setup

    Quote Originally Posted by Aaron Moss View Post
    ...........So back to another machine shop, now it’s $17.50 each and it’s still a pain in the rear, they do good work. But small passes and a single point is the way to go, but of course it never loads the machine, because it’s single point.
    600 x $17.50....... do the math.

    I wouldn't "Grizzly" ANYTHING. You will spend valuable time and money making this work for you and you might just be disappointed in the end ( an honest review of hundreds of G0704 conversion discussions reveals this fact)

    You are going to spend money regardless, so why not go out and find a used OMNITURN. It will be a very capable investment you can put to work immediately and also use reliably for years to come. A "GT-Jr" is only a little more than your 1000 lb concern, and a lot... and I mean a LOT more capable. People that have them swear by them. I can only WISH I had one.
    Chris L

  6. #6
    Join Date
    Feb 2008
    Posts
    521

    Re: Single Purpose Lathe Conversion-Gang Lathe Setup

    On the face of it, it's a no brainer, but, - potential cost of machine inc tooling - $10k, set up and wastage parts - $500, part time employed labour to watch machine / change tool bits etc - $10k, interest / repayment on loan for purchase - $1k per yr.? Electricity and consumables - $500 . . . . . so rough total $22,000 / 600 and each part in 1st year is $36.50 ie double what it is costing to outsource and for two years you will break even. Taking the machine purchase out of the equation of just running costs = $12,000 / 600 = $20 which would be a $2.50 loss on every part - not so attractive now. This is why machine shops just don't set up a machine to do one part unless it can be run 24/7 for volume production, if idle, its not earning its keep. If you renegotiated with your supplier to do a run of 600 pieces instead of 50 / month you might half the per unit cost? All the figures are guesstimates for the illustration.

  7. #7
    Join Date
    Mar 2017
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    411

    Re: Single Purpose Lathe Conversion-Gang Lathe Setup

    I bet my Precision Mathews PM1228 could do that part without difficulty. I CNC'd it a year ago and was looking at adding one of these.

    https://youtu.be/EBXyO_Fw4GU

  8. #8
    Join Date
    Apr 2007
    Posts
    11
    Jim,
    EMCO Concept 55 looks pretty good, really thought about milling. Still kicking it around, I've thread milled thousands of parts in aluminum, but the silicon bronze...is a lot tougher than it looks.

    Found a deal on a Takang TNC-5 CNC Flatbed Lathe, really kooky machine, but priced to sell, with an estimated weight of 4000, but pretty small overall. It's pushing the weight limit, but it is forkliftable.

    We'll see how motivated to sell he is.

    Thanks

  9. #9
    Join Date
    Apr 2007
    Posts
    11
    Datac,

    An OMNITURN GT-JR is a good looking machine, just the right size, price is good too. I like the fact the spindle is exposed and easy to get to. I'll keep it on the list of options.

    Thanks

  10. #10
    Join Date
    Apr 2007
    Posts
    11
    Kawazuki,

    I used to run a machine shop, and I'm pretty solid on the numbers, but the demand is ONLY 50 per month. So we are going with a dedicated machine approach. It's substantially cheaper in the short and long run. We'll be at less than a 2-3 bucks a part after the first year, and no operator. Mostly after we "179" the machine on the taxes.

    The machine can sit idle, put in a part here and there throughout the day and easily keep up with demand, we'll get a BBQ cover for it when not in use.

    It's a very different way to look at machining, and the way you describe works great for job shops, and high volume guys, but it's a death sentence for small specialty manufacturers.

    I was at a friends shop, and he had 20'ish Brown and Sharp screw machines, old cam machines, all staggered so they fit in a 1500 sf shop. Sounded like like a bunch of clocks running. A machine would be set for months and just slowly whittle through the bar, one little part at a time. He wasn't rich, but his wife didn't work, owned his home, and put his kids through college.

    Just a different way to do the math.

    Thanks

  11. #11
    Join Date
    Apr 2007
    Posts
    11
    maxspongebob,

    That was what I was looking for, that is REALLY good looking, better than the Chinese stuff, it Czech stuff!

    The Mathews doesn't look a whole lot different than the Grizzly.

    I have no doubt you're machine will do it, doesn't have to go fast, just has to keep going.

    What CNC setup did you use? Mach, Acorn, or other?

    Thanks for the tool changer.

  12. #12
    Join Date
    Dec 2013
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    5717

    Re: Single Purpose Lathe Conversion-Gang Lathe Setup

    Quote Originally Posted by Aaron Moss View Post
    The machine can sit idle, put in a part here and there throughout the day and easily keep up with demand, we'll get a BBQ cover for it when not in use.

    It's a very different way to look at machining, and the way you describe works great for job shops, and high volume guys, but it's a death sentence for small specialty manufacturers.

    Thanks

    I understand completely, I have about 40,000 lbs of iron sitting on the floor that only runs about 6 months out of the year. We also make a speciality product, and once the annual production needs are met the machines don't run except for the occasional side job or small project.

    I haven't even run that little EMCO mill yet. It was given to us about a month ago and all I did was fire it up to see if the wheels turned. Seems to be fine, and is in showroom condition. Still not sure what we're going to use it for. But the price was right.
    Jim Dawson
    Sandy, Oregon, USA

  13. #13
    Join Date
    Apr 2007
    Posts
    11
    I've seen a lot of shops like that, and that kind of math gets really spooky.

    Did you look at that tool changer maxspongebob shows the video of? That is a really good looking piece of equipment.

    I think I'm going to go Acorn over Mach, nothing against it, used it quite a bit, but Acorn looks a little more production orientated. So I'll contact the tool changer people to see if they interface with that as well, but I can envision building a rack 3 lathes stacked one on top of the other. Each specialized to build a specific family of parts.

    I think I could get to $7k per machine gang tooling, and $8k with a tool changer. So I can have the rack done equipped for $25k, 3 smallish lathes, ready to go. All you would have to do is 'wake up' the machine you need, run a range of motion program for 30 minutes, and you're in business making parts. Not a bad concept at all.

    I still do have an Enco turret lathe for all the really small pieces, the CNC wouldn't be for that, I don't want a chucker setup yet.

    The idea for the CNC lathes is getting better every day.

    Thanks
    Aaron

  14. #14
    Join Date
    Apr 2007
    Posts
    11
    I've seen a lot of shops like that, and that kind of math gets really spooky.

    Did you look at that tool changer maxspongebob shows the video of? That is a really good looking piece of equipment.

    I think I'm going to go Acorn over Mach, nothing against it, used it quite a bit, but Acorn looks a little more production orientated. So I'll contact the tool changer people to see if they interface with that as well, but I can envision building a rack 3 lathes stacked one on top of the other. Each specialized to build a specific family of parts.

    I think I could get to $7k per machine gang tooling, and $8k with a tool changer. So I can have the rack done equipped for $25k, 3 smallish lathes, ready to go. All you would have to do is 'wake up' the machine you need, run a range of motion program for 30 minutes, and you're in business making parts. Not a bad concept at all.

    I still do have an Enco turret lathe for all the really small pieces, the CNC wouldn't be for that, I don't want a chucker setup yet.

    The idea for the CNC lathes is getting better every day.

    Thanks
    Aaron

  15. #15
    Join Date
    Mar 2017
    Posts
    411

    Re: Single Purpose Lathe Conversion-Gang Lathe Setup

    I use Mach 4 with an Ethernet Smooth Stepper and ClearPath servos. Here is my build thread. I also have a Grizzly G0704 and did a conversion on it as well. After a bit of experience with it, I am not too impressed with the Grizzly.

    https://www.cnczone.com/forums/verti...-software.html

  16. #16
    Join Date
    Mar 2017
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    411

    Re: Single Purpose Lathe Conversion-Gang Lathe Setup

    Quote Originally Posted by Aaron Moss View Post
    maxspongebob,

    That was what I was looking for, that is REALLY good looking, better than the Chinese stuff, it Czech stuff!

    The Mathews doesn't look a whole lot different than the Grizzly.

    I have no doubt you're machine will do it, doesn't have to go fast, just has to keep going.

    What CNC setup did you use? Mach, Acorn, or other?

    Thanks for the tool changer.

    Odd, my reply didn't show up. Lets try again.

    I use Mach 4 with an Ethernet Smooth Stepper and ClearPath servos. Here is my build thread. I also have a Grizzly G0704 and did a conversion on it as well. After a bit of experience with the Grizzly I am not impressed.

    https://www.cnczone.com/forums/verti...-software.html

    - - - Updated - - -

    Quote Originally Posted by Aaron Moss View Post
    maxspongebob,

    That was what I was looking for, that is REALLY good looking, better than the Chinese stuff, it Czech stuff!

    The Mathews doesn't look a whole lot different than the Grizzly.

    I have no doubt you're machine will do it, doesn't have to go fast, just has to keep going.

    What CNC setup did you use? Mach, Acorn, or other?

    Thanks for the tool changer.

    Odd, my reply didn't show up. Lets try again.

    I use Mach 4 with an Ethernet Smooth Stepper and ClearPath servos. Here is my build thread. I also have a Grizzly G0704 and did a conversion on it as well. After a bit of experience with the Grizzly I am not impressed.

    https://www.cnczone.com/forums/vertical-mill-lathe-project-log/381622-cnc-software.html

  17. #17
    Join Date
    Feb 2008
    Posts
    521

    Re: Single Purpose Lathe Conversion-Gang Lathe Setup

    Don't have to repeat yourself again and again LOL!

  18. #18
    Join Date
    Dec 2013
    Posts
    5717

    Re: Single Purpose Lathe Conversion-Gang Lathe Setup

    Looks like this thread is alive again. I have seen this happen before.

    Quote Originally Posted by Aaron Moss View Post
    I've seen a lot of shops like that, and that kind of math gets really spooky.
    A bit spooky, but it works for us. It really only works if everything is paid for so the bank isn't breathing down your neck. Our overhead is close to zero when the wheels aren't turning.

    Did you look at that tool changer maxspongebob shows the video of? That is a really good looking piece of equipment.
    I did. That looks like a nice little turret system. Looks well designed.

    I think I'm going to go Acorn over Mach, nothing against it, used it quite a bit, but Acorn looks a little more production orientated. So I'll contact the tool changer people to see if they interface with that as well, but I can envision building a rack 3 lathes stacked one on top of the other. Each specialized to build a specific family of parts.
    If I had to make that choice, I would also go with Acorn. Looks like the interface should be simple, 1 digital output and 2 digital inputs I think. That and a bit of control logic would get it going. Not sure how to to that with Acorn, but I'm sure there is a way of doing some kind of PLC type programming in Acorn.

    I think I could get to $7k per machine gang tooling, and $8k with a tool changer. So I can have the rack done equipped for $25k, 3 smallish lathes, ready to go. All you would have to do is 'wake up' the machine you need, run a range of motion program for 30 minutes, and you're in business making parts. Not a bad concept at all.
    An interesting concept, I like it.
    Jim Dawson
    Sandy, Oregon, USA

  19. #19

    Re: Single Purpose Lathe Conversion-Gang Lathe Setup

    Quote Originally Posted by maxspongebob View Post
    I bet my Precision Mathews PM1228 could do that part without difficulty. I CNC'd it a year ago and was looking at adding one of these.

    https://youtu.be/EBXyO_Fw4GU
    Got any pictures or video's of your CNC lathe? I was thinking of converting one also.

  20. #20
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    Mar 2017
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    411

    Re: Single Purpose Lathe Conversion-Gang Lathe Setup


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