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Thread: Getting in the market for a milling machine and metal lathe

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  1. #1
    Join Date
    Feb 2007
    Location
    southeast Michigan
    Posts
    679
    I think you'd end up being unhappy with the LM3990. At 177 pounds you would have to anchor it to a solid, heavy stand or bench. But the real problem with it would be small X & Y travel distances. One of the things you mentioned in your first post was machining bolt hole patterns. The Y axis travel on this machine would severely limit limit you for that operation. There are ways around that but they are time consuming and less precise. I bought my G0759 not just because I never intend to turn it into a CNC machine but because I wanted the DRO. A DRO removes any backlash issues and has several other good features, most notably for me is a bolt pattern function. So easy to use. You can always buy any kind of mill but for what it sounds like you are going to use it for a DRO is highly preferable. And it's usually better to have it factory installed. Power is another issue with smaller mills like mine and I upgraded mine to a 2 1/2 HP treadmill motor. There are kits out there to do this too.

    Once you start using a mill at home you'll get into a lot of projects that you are not anticipating right now. So my advice would be to buy a mill with the most travel, especially Y, and weight that you can afford to fit in your space. I know a massive Bridgeport, or clone, might be nice to have but they were built primarily for a production environment where reliability and machining speed were important. In a home hobby environment you don't need a machine that will run for 8, 16 or more hours a day for many years. And if it takes you 2 passes to make a cut instead of 1 on a Bridgeport, so what. You're using it for enjoyment, not work.

  2. #2
    Join Date
    Jan 2007
    Location
    New Hampshire
    Posts
    2,797
    With the LM3990, I'm not worried about the weight or being able to secure it to a heavier base. That is solvable. I've read lots of decent to good things about the LMS tools, which is a plus. The smalled X and Y size is a concern. Actually the head clearance (not the head travel but distance from the bed to the chuck) is something else I have been watching and wondering how much I need. How much Z is lost when using a (good) vise, a dividing head, or a rotary table? I'm thinking neither of the last two or going on anything from LMS.

  3. #3
    Join Date
    Feb 2007
    Location
    southeast Michigan
    Posts
    679
    Head clearance can sometimes be an issue. The top of the jaw rails in any vice you would use is roughly 2 1/2 inches from the table. A 5 inch dividing head, which would be appropriate, for these mills is a little less than 4 inches from their centerline to the table. And a rotary table, 6 inch for instance, is going to be about 3 1/2 inches from the table to the top of the rotary head. Of course, there are times when you can fasten the stock directly to the table, leaving a bit or clearance underneath. And keep in mind that using a drill chuck or a boring head will also greatly reduce head clearance. Using R8 collets with end mills or matching drill sizes not so much. Since many of your operations will likely require using twist drills another way to minimize head space is to use an R8/ER32 collet set like this: https://www.ebay.com/itm/36345601769...rchantid=51291. ER collets, by design, have a greater clamping range per collet than R8 collets, and they grip better. Of course you can use end mills with them and not even need a set of R8 collets. Get yourself a set of stubby drills and you can further minimize head clearance.

  4. #4
    Join Date
    Sep 2016
    Location
    Modesto, CA, USA
    Posts
    10,093
    A word of warning, double ended endmills and drills are too long to grip well in some collet systems.
    BilL D

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