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Mini mills - are they worth it and which ones

Discussion in 'A BEGINNER'S FORUM (Learn How To Machine Here!)' started by theoldwizard1, Aug 1, 2014.

  1. theoldwizard1

    theoldwizard1 United States Active User Active Member

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    Well, my intro is out of the way, so here is the really reason I came here ! Are there any "mini mills" out there for less than $1,000 that are really worth buying ?

    I would be working in plastic, aluminum and some mild steel. Mostly simple things like slots and holes. I want to learn the "traditional" methods. I am concerned that the DC powered minis just don't have enough power. Vee-belts slip and I can't say that I have ever seen a cogged belt drive.

    A used Bridgeport or other full sized machine is just not an option. Too much space and no access to 240V. Plus I would have no idea how to check/adjust it to bring it into reasonable tolerances (+/- 0.002-5 is likely all I will ever need).

    Of course at my age, it is not going to get a lot of use (good thing I can afford to buy more material after an "Ooppss" !)

    What say the experts ? Or how does one go about finding a "garage" machinist in your area ?
     
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  2. pebbleworm

    pebbleworm Active User Active Member

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    I'm very happy with the Harbor Freight X-2. For what I paid for it it seems nicely finished, runs true and was easy to clean, set up and get running. I did fill the column with epoxy, which just made sense and sprung for an inexpensive set of collets. At the very least it's a a damn fine drill press. For the hobby stuff I do it works just fine. There are a couple of fettled/improved versions available from Micromark:
    http://www.micromark.com/MicroLux-H...CeYBn69BpDfqEtP8zeR2hyAs05cmO_dHF4BoCFQLw_wcB
    And the Little Machine Shop:
    https://littlemachineshop.com/3900
    but both are almost twice the price of the HF unit if you watch for a sale and have one of their perennial coupons. Each one does have useful and valuable improvements. Since they are a Sieg X-2 they are man-portable and fit on a benchtop. I have no regrets about the HF mill, but your mileage may vary. Check out this and other boards for more info, and there is a yahoo group for these mills too.
     
  3. Baithog

    Baithog United States Florida Machinist Group Moderator H-M Supporter-Premium

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    Motor power is not a problem if you are not doing production work. I have had my X2 for several years and I have never stalled a bit. Rigidity is another mater. It will cut steel, just lighter cuts than a knee mill. Of course the mini mill doesn't have that ton of cast iron the knee mill has, or the costs.

    My mill is from Harbor Freight. It has been converted to CNC. I'm finding it hard to justify the cost of the CAD/CAM software. I mostly run it in Semi-auto mode. Grizzly tends to have higher quality machines than HF, and more variety. Both the G8689 and the G0758 are in your price range.

    This is a photo of the dovetails for a boring head I'm making. They were cut in 2 inch mild steel with my wimpy X2.

    IMG_0999[1].JPG
     
  4. Travis7s

    Travis7s Canada Active User Active Member

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    Don't underestimate the V-belt, even some large-ish knee mills use them, and they don't really slip unless something very bad is happening.

    V-belt is actually the upgrade for the X-2 style mills. If you ever crash your stock X2 or leave the spindle locking pin in (guilty) you can kiss the plastic gears goodbye.

    You could also look into the Rong Fu mill drills, the RF25 is close to your budget and is a 400lb machine.

    Keep an eye on your local craiglist, you may come across a good deal.
     
  5. theoldwizard1

    theoldwizard1 United States Active User Active Member

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    Very impressive. I would love to see a video of your X2 in action, especially cutting that dovetail !
     
  6. Baithog

    Baithog United States Florida Machinist Group Moderator H-M Supporter-Premium

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    I'm impressed with the dovetail, too. I've never cut one before. There is no video. Maybe when I cut the dovetails for the tool grinder that I'll tackle next. I tried to shoot video of cutting the gib slot tonight and almost ruined the part with my camera fiddling. I'll have to try shooting some dog videos to figure out the process.

    I cut the male dovetail first, then used it to fit the female. Everything that could be hogged out with an end mill was. I have better luck with this light mill by running cutters as fast as I can get away with, and using 3 or 4 flute mills for steel. The machine seems to damp higher frequencies better. For the dovetail cutter, I ran it at 2200rpm, cutting .02/pass at 3ips. That is excruciatingly slow, especially for someone used to running a ton of cast iron. The power feed capabilities really help with keeping the feeds consistant through the boredom.

    My moto is: slow is better than broken tooling and ruined parts when it comes to these little mills.
     
  7. theoldwizard1

    theoldwizard1 United States Active User Active Member

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    What is the difference between a mini-mill and a drill-mill ?
     
  8. 12bolts

    12bolts Global Moderator Staff Member Active Member

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    A mini mill is just that, a smaller lighter mill, but still a mill.
    A mill drill is more of a bench/pedestal type drill with an x-y table to enable some milling applications. Like any combination tool they are generally not suited to "real" work outside of their original design scope. That being drilling holes in this case.

    Cheers Phil
     
  9. jatt

    jatt Australia Iron Registered Member

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    My unit is just a column mill drill. Machine spends most of it time ruining perfectly good hunks of MS with it and some ally.

    Its a manual unit, so lots of hand turning the X-Y table and Z, but it was never intended to be a production machine.

    Rigidity, well it weighs in at approx 360 Kg (790 lb), so its hardly a big unit. For myself I wouldnt go any smaller. Seem to use a lot of the table up with what i do with it and am pushing its limitations more than i care to admit.

    Like anything work within the limitations of your machine. If its a little one take lite cuts.
     
  10. theoldwizard1

    theoldwizard1 United States Active User Active Member

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    I'm getting excited now after a lot of research ! Biggest problem is I need a place to put my new toy ! The garage is too cold and damp in winter and to hot and humid in summer. Looking at build a nice 8x12 shed/man cave, insulated and heated and cooled.

    From my research I am leaning toward the LMS 3990 HiTorque Mini Mill with one of their packages. One thing that bothers me, is that using a milling vice and parallels for through hole boring, you loose Z axis space. The obvious solution is 2-4 1" steel spacers mounted under the column and attached with longer bolts. Obviously these would have to be milled and lapped to provide a true flat parallel surface.

    Anyone do anything like this ?
     
  11. maker of things

    maker of things United States Hermit H-M Supporter-Premium

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    I have a G0704 that I have cnc-ed. Grizzly also has the short bed version, G0758 with stand for $895. I primarily work in steel and found it to be lacking in power and rigidity even as (or especially due to me being) a neophyte. Aluminum is another story, I have made .2" deep full width rough cuts with a 3/8 2 flute cheap chinese hss endmill at 20 ipm! I did very little to the machine save adding steppers for control. If you google "mill size comparison" Hoss has a page with several pics of various mills next to another mill and/or people for size reference. I found it impossible to visualize how big one mill is compared to another by the size specs on the websites. For example an X2(3990) is tiny next to the G0704/bf20.

    Something to possibly consider on these small machines with a dc variable speed motor. The motor has a controller board that increases the rpm of the motor when it senses a load to try to keep the cutter at the same rpm. This works nice when you are milling a slot, for example. If you do as I and try to drill a 1" diameter hole with a silver and demming bit, the board has a difficult time working out what to do, and effectively make the drilling with anything but the lightest pressure difficult to dangerous. The large bit tends to "cog" nearly stopping at 180 degree intervals. If using a drill larger than 1/2 is a high priority, a belt drive might be worth a thought.
     
  12. shocktower

    shocktower United States Iron Registered Member

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    I picked up a Rusnok, I really love this thing, small precise smooth as butta, I got a real bargain on it and parts ares till made in the good old USofA
     
  13. Silverbullet

    Silverbullet Active Member Active Member

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    I take a bit of offence , the size of the machine doesn't mean it can't do really great work with tight tolerance. To say a mini mill is to small or a drill mill won't do the job of 99 percent of the hobby machinist. It's not the machine it's the machinist. There are machinist who have built machinery without any machine.
    Shaper , milling and LATHES. And I'm sure there are others.
    Don't ever under estimate a machine if you know how to use it.
     
  14. Rockytime

    Rockytime United States Active User H-M Supporter-Premium

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    I sold my Bridgeport and large lathe a couple of years ago because of old age. I replaced the mill with a Grizzly G0781 mini mill. It uses R8 tooling which I already had and meets every hobby machining I need. Love it!
     
  15. wrmiller

    wrmiller Chief Tinkerer H-M Supporter-Premium

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    I previously owned the LMS mill and will say that this mill can be as accurate as you need it to be. It's the operator, not the machine.

    While machining aluminum on the small machines is the easiest, I also machined 4140, stainless, and titanium on mine. You just have to think about what you are doing, and what you are doing it on, machine-wise. :)
     
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  16. dontrinko

    dontrinko United States Active Member Active Member

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    I have a Unimat setup as a mill. It works fine if you are not in a hurry. The 1/10 th HP motor makes small cuts necessary. All IMO; Don
     
  17. seanb

    seanb United States Active Member Active Member

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    I had a RF-31 clone as my first mill. It worked pretty good, Being lighter than a full size it had some trouble with stuff like fly cutting but it still did a good job R-8 tooling and a bigger work envelop. That's as small as I would go. I payed $400 for my RF-31 it needed some work but they are out there for that price.

    I have nothing against mini mills but i work on bigger stuff
     
  18. DaveInMi

    DaveInMi United States Active Member Active Member

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    I have 4 milling machines-- 2 vertical and 2 horizontal. The smallest is a Taig manual. It all depends on what I'm working on which machine works the best. The Taig is the go to unless I need more size.
     
  19. Ryan383

    Ryan383 United States Iron Registered Member

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    I have used a few different Bridgeport mills, of the "generic Bridgeport size"
    The column mill I have now (probably a JET JMD-18) seems just as tight, and rigid. The Z axis is not as easy to use as a knee mill, but using the tensioner to take out the lash can still be very precise. BUT I wouldn't consider my column mill "mini" as it is about 700 lbs. I would pick up a used mid sized mill over a new tiny mostly aluminum and plastic mill. I only paid 300 for mine used.
     
  20. kd4gij

    kd4gij United States Active User Active Member

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    Don't tell this member that.
    http://www.hobby-machinist.com/threads/ford-302-v-8-engine-1-3-scale.14387/
     
  21. rtp_burnsville

    rtp_burnsville United States Iron Registered Member

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    I owned a X2 for several years and my main complaint was rigidity. The basic design is akin to a wet noodle, just looking at it and the thing moves around. The very limited Y axis travel was a limiting factor in what can be machined. However, it was easy to extend the Y axis travel an inch or so which greatly helped.

    The head and spindle worked just fine and the variable speed was very handy. My mill had the R8 spindle which made finding reasonable priced tooling a plus.

    If I were to buy another similar sized mill skip the X2 and look for an X3 or one of the other mills position between the X2 and X3 in the market. (Grizzly has a couple models as an example and they are discussed on several forums.) Rigidity is very important if one expects to get a quality finish on parts and the X2 is very much lacking in that requirement.

    Robert
     

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