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Different lathe..... CNC teach?

 
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  #15  
Old 07-08-2013, 12:54 AM
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Re: Different lathe..... CNC teach?

one thing to keep in mind, if you are serious about a CNC or programmable lathe or mill is that the better ones are 440 volt three phase. You need at least eight inches of good re-enforced concrete under them with lag bolts! Most require a good pneumatic system to boot (plenty of volume). Lighter weight machines like a Southwest Trac might get by with six inches of concrete, and not much of an air system. A Clausing really needs the eight inches of concrete under it, and of course the lag bolts. You need the lag bolts to stress the frame of the bed to make it cut strait. Otherwise you'll end up chasing your tail all the time. Plus a strait bed on a machine uses less power to run it, and is proven to last longer.

gary
  #16  
Old 07-08-2013, 06:58 AM
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Re: Different lathe..... CNC teach?

Is it true that it's better to have them on an isolated piece of floor? I am going to be building a shop in the next few months so I could easily form and pour seperate sections for 2/3 machine pads. I was thinking about doing it anyway just to keep it from cracking all over the place.
  #17  
Old 07-08-2013, 12:53 PM
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Re: Different lathe..... CNC teach?

Quote:
Originally Posted by lazylabs View Post
Is it true that it's better to have them on an isolated piece of floor? I am going to be building a shop in the next few months so I could easily form and pour seperate sections for 2/3 machine pads. I was thinking about doing it anyway just to keep it from cracking all over the place.
let me take you from the day you order in the machine, to give you a rough idea what the steps are. Then maybe you can make the decision. Most lathes do not need an isolation pad, but they still have their own set of issues which we'll deal with later.

Lets say you buy a new machine center from XYZ Machine Tool company. When you get the order placed and after they receive their first deposit, they should send you a foundation print. Some will call out a spec on an isolation pad, while others will simply say something like 12" of re-enforced concrete with a density spec. I used the same grade of concrete they used in road building, no matter how thick they wanted it made. But there actually is a grade that's better, but not needed 90% of the time. In that drawing you'll see the actual layout of the machine including stand alone hydraulic tanks and the coolant system if it's also stand alone. You'll see how they prefer the CNC control to be placed and usually give you a couple of options as well. They will also give you the layout for the leveling pads and lag bolts (this must be done correctly!) I usually got this print about six to eight weeks before delivery.

In the above drawings you can start to lay out where you want to place the machine, and of course start to build an isolation pad if needed. By doing this ahead of schedule, you actually save a lot of time and money. But of course do it right. Otherwise you'll have to move the machine twice! I've poured isolation pads from 30" thick to 156" thick (beyond stupid!) Bought rebar by the flat bed truck loads (multi at that). I've done rebar by the old wire it together method, and the weld it all together method. That welded rebar is better. Don't skimp on the rebar, as it's important. If you have an existing floor, and have to install a pad, keep in mind that the pad is always one solid piece of concrete. Never set a machine on a pad that's less than two weeks old and really a month is a lot better. You want the surface finished as smooth and flat as possible, and this alone will help your installation. Doing the pad of course starts with a concrete cutting operation (I always do it with a saw). Kinda messy, but the nature of the job. Lets say you need a 10' square pad 36" deep. For starters it's best you find a concrete company that does road work or something that is critical by nature. You'll pay a little more, but save yourself a lot of grief 24 months later. You figure out you best location (remember there has to be access all the way around). I always went by the rule of the thumb that said to tale the axis travel and add two feet to it for added room. This will save you from cutting a hole in the wall, or even worse (and have I seen this one in person!) OK we have the 10' square laid out on the floor. Now add a minimum of one foot all the way around (I always recommend 18 inches or more). Have you guys cut the square out of the floor and pull it sections. Now we dig the soil and gravel out of the hole. Go about 48" deep (more is OK). I always put a layer of pea gravel under the pad, and tamped this down to where it's fairly solid. Limestone works well too (wet it down and tamp it a lot). Now we start to build the frame work for the outside ring around the pad. I will use a little bit of rebar with this part as well. Then pour the outside walls (you'll want them strait for a reason.). OK you got that part done and they've setup for a couple days. Now it's time to get serious. Pull the frame work. The next step is to install an anti vibration material that sorta looks like generic Cellotex, but it's not! You can install this all the way around with a Ramset. Put a layer on the floor if it makes you feel better (I never did). Now it's time to start welding rebar. If the machine will have a coolant flood system that goes in the floor you'll have to take care of this part as well. I always used a stainless steel trough, and poured up to it. You want several vibration devices to keep the air pockets out of the concrete. I always used a concrete pumper truck. Now comes the tricky and also a critical part. You need to install the lag screws. I like grade eight all thread. Some manufacturers will send in their own style of lags, others will tell you what they want. Most are simply L shaped threaded rod. Put them in the wet concrete as soon as possible. Four inches above the concrete is about right with at least eight inches in the concrete. Just make sure they are 90 degrees to the concrete, and are located right! After the pad is poured you just wait. I always covered mine with a roll of plastic, and hosed the pad down twice a day with water. After a week or ten days you don't need to be doing this anymore. Now you just wait a few more days. OK we've been a week now, and we're bored stiff. Pull the plastic, and clean the floor one more time (no acids please). Wrap every lag bolt with a couple layers of Ductape. In the drawings you'll see where all the leveling pads are placed (some use wedges and are far better) Lets make good leveling pads! I usually used 3/4" pads, but 1/2" thick pads are fine for light weight equipment. While your at it, cut between four and six 1" thick pads that are only spacers to help you position the 3/4" pads during installation. Take each pad and run a two flute end mill in them about 1/4" deep with about 1/8" clearance for the leveling bolts. This way the pads will stay in place. Roughly lay out your pads on the virgin concrete, and mark the new floor with a spray can of paint or even a magic marker. Buzz this area with a body grinder and sand paper to remover any bumps (there will be some).

Now we're ready to set the machine on the pad (finally!). I always recommend hiring riggers for this work, as they usually will set the base of the machine without tearing up the lag bolts. (I had a team of seriously good millwrongs out of a Michigan auto plant that wouldn't even scratch the paint on the machine!) Now some folks like to use anti vibration pads ontop their leveling pads. This is good, and this can cause grief. I've tried them under the pads, and it didn't work as well. Plan on cutting a hole in them, unless you buy them with the hole in them. No big deal. Wedges are the best thing for machine centers, and use a good anti vibration pad ontop them (I like Machinery Mounts). Have the guys set the machine on the thicker pads (1.25" is about right for a vibration pad and a 3/4" steel pad. It is critical about where you place the thicker pads (I've even used wood blocks) as the machine frame will flex a good bit.

With the machine set, your work is just beginning! You'll need at least two .0005" levels that are at least ten inches long. But if you have to you can get by with one. After you have the machine on the leveling pads, and the thicker ones removed rough level it to about .001". Now the electrician can do his conduit and you can start plumbing it in. I always lag down the hydraulic tank (s), and filter units

It is very important that the machine frame never sets over a crack in the concrete! Even more critical with a lathe or a grinder! Otherwise they just move all over the place. Most CNC lathes work well with 8" of re-enforced concrete, but some of the bigger ones want 12". They really don't need an isolation pad. But grinders like the isolation pad. I do recommend that you recheck the machine level daily till the frame quits moving. The level is not aligning the machine to make it cut strait and square, so don't get rooked into that though process! It's just the start of things to come. I used a 12"x12"x16" granite H block for most of the smaller machines. But I had a 48" long cylinder square for the bigger stuff. I liked using Federal electronic levels after the machine was running, but a good laser will do just fine. It's just easier with the electronic level. Plus you can work as close as your heart desires. For just about anything anybody here will buy, the two .0005" spirit levels will do nicely, but also will not help you square up the column if needed

I know this post is lengthy, but trust me I just glossed over it and told you the easy parts. You can have five machines that are identical, and all five will level and align differently. Once again the nature of the beast. I would not bother to pour a pad for a lathe. Just a nice thick floor with zero cracks will do fine. You can sink high grade lag bolt anchors in the concrete (they get expensive, and you'll need a good hammer drill). When you new machine is delivered, either leave it on the pallot, or set oak blocks where each leveling pad would be. A warped machine frame is not fun, and a warped cast iron one is a beast to deal with. (often takes months to get the warpage out). Lastly, be sure to use jam nuts on every lag bolt with a cad washer under them. Very important.
gary
  #18  
Old 07-08-2013, 06:44 PM
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Re: Different lathe..... CNC teach?

Thanks for all the info, I appreciate the time it takes to educate us that are unfamiliar with industrial kind of setups.

I will be talking to the power guys soon and will ask about 440 but at this point I am just hoping that 3ph 220 is going to happen.

Thanks again!
  #19  
Old 07-08-2013, 06:55 PM
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Re: Different lathe..... CNC teach?

For a small machine like the TL1, you can forget about the discussion above. The newer machines have massive castings that are much stiffer than one had on older machines. Yes of course it wants to sit on concrete and unquestionably, in a huge factory with forklifts and all sorts of heavy things driving around an isolated foundation is superior. However, for a home type shop with 1 operator, none of that is needed unless you live within 50 yards of an active railroad line or a few other funky places.

I know of many shops operating machines larger than the TL-1 where you will not find a single lag bolt and in fact they often change the layout of the shop every 6 months. Not an ideal situation, but they still produce parts that satisfy the customers. If your customers are having you make parts for turbines and you have to machine superalloys, yes you probably need every trick in the book to get it right and make money doing it. Which is what kept people like Trickymissfit occupied over a lengthy period.

However, none of the esoteric stuff is needed to turn out bolt gun receivers...
  #20  
Old 07-08-2013, 06:57 PM
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Re: Different lathe..... CNC teach?

If you can get 230V 3ph. coming in, all it'll take is a transformer with a good line conditioner. What kind of gunsmithing work are you planning on doing, if you don't mind my asking?
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  #21  
Old 07-08-2013, 09:27 PM
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Re: Different lathe..... CNC teach?

I am doing just general gunsmithing stuff and building other things at random. I have a chance to step up from pure manual to a hybrid lathe and want to do it the right way. I wouldn't call tricky's suggestions B.S....... there is a best/ideal way to do things. He did mention that a normal reinforced concrete floor would be sufficient. If I am building a floor from scratch with the intent of placing machine tools it requires no extra work to build isolated pads for each. If that offers any advantage It seems like the prudent thing to do. I think I will end up in the middle...... I am going to get as much power as I can to the "shop", once again get all you can the first time and try to prevent re-work. I am going to pour a sectioned floor 3/4 work places in one end and the rest of it in one piece but thicker than a "standard" garage floor. I am not a "pro" but I did stay at a holiday inn express'.... and have barreled enough guns that shoot under 1/2" to want to build more and get better! I just enjoy building guns to the best of my ability, might as well try every method that is available to you.........
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