# LMS 4962 vs 3990



## personman12905 (May 29, 2020)

Hey ya'll, I have yet another, "what mill should I buy?" question. I used to have access to some big mills and lathes (bridgeports, jets) from my university, but recently graduated so no longer have access. I'm looking to start building up my own empire of dirt and wanted to start with a mini mill. A little tight on space right now (and power available in said space), so a larger mill isn't really an option. I'm really only looking to work with aluminum and softer materials, no steel.

After looking through some other "what should I buy" posts, I've noticed there's fairly high praise and recommendation for the LMS 3990. However, I've noticed that there isn't much mention of the LMS 4962 (Sieg X2D) at all, which is the mill I'm currently leaning towards. Is the lack of mention due to it being a bad/poor mill, or just few people owning one to make adequate comments on it? From LMS's comparison page, the two are identical on paper, aside from the motor. If that's the case, I'd be willing to save a few dollars now and do a motor conversion later on down the road. But if there's something detrimental about the 4962 that I just haven't found yet, then I'd rather save up a little more for the 3990.

I'm also open to purchasing an older used machine, but haven't had much luck finding one online in SE US (craigslist really). However, I'm not sure what sort of machines might even be out there that would be worth investing in. I'm looking to do a CNC conversion down the road, and I've read that round base mills make that difficult/impossible. I had found recommendations for the Rong-Fu lineup, but it sounds like the round base makes it a poor candidate for a CNC conversion. What other brands/models that I should be on the lookout for that would be good for a conversion? Also, how often do mini mills seem to pop up on craigslist? Is it every few weeks, or every few months?
Thanks for the help!


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## silence dogood (May 29, 2020)

I have a LMS 3960 and have been very pleased with it.  If you check out" multimods for a minimill", you can see some modifications that I've done.  You could get the Sieg, but it would cost you an extra $600 or more to upgrade.  So I would just get the 3990. Also LMS sell the tooling kit that can go with it. I did and it was worth it. I believe the kit goes for about $250.


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## homebrewed (May 29, 2020)

My impression is that the 4962's gear noise (from the 2-speed gear shift mechanism) eventually goads the owner into upgrading to a belt drive, so why suffer from the noise and lower power?  That's my take anyway.  For full disclosure, I own the Micromark X2S, which has a belt drive 500W motor so I haven't heard what the gear drive actually sound like.


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## Road_Clam (May 30, 2020)

personman12905 said:


> Hey ya'll, I have yet another, "what mill should I buy?" question. I used to have access to some big mills and lathes (bridgeports, jets) from my university, but recently graduated so no longer have access. I'm looking to start building up my own empire of dirt and wanted to start with a mini mill. A little tight on space right now (and power available in said space), so a larger mill isn't really an option. I'm really only looking to work with aluminum and softer materials, no steel.
> 
> After looking through some other "what should I buy" posts, I've noticed there's fairly high praise and recommendation for the LMS 3990. However, I've noticed that there isn't much mention of the LMS 4962 (Sieg X2D) at all, which is the mill I'm currently leaning towards. Is the lack of mention due to it being a bad/poor mill, or just few people owning one to make adequate comments on it? From LMS's comparison page, the two are identical on paper, aside from the motor. If that's the case, I'd be willing to save a few dollars now and do a motor conversion later on down the road. But if there's something detrimental about the 4962 that I just haven't found yet, then I'd rather save up a little more for the 3990.
> 
> ...




I don't have the 4962, but I do have the 4190 (the 3990 with a DRO) .  Spec for spec the 2 mills are almost identical, the major difference being the 3990 has a brushless motor. Looks like the 3990 also has a much beefier head assembly.  Brushless motors offer superior low speed torque over a conventional motor. People don't realize that running your drills and mills with low rpm's and light cuts extends your tool life substantially. most of my drilling is done around 500 rpm's and depending on my mill tool diameter anywhere from 300 to 2000 rpm's . I bought the optional high speed gears  and in hindsight that was just a total waste of money. I also like to start a threading tap under power held with the drill chuck. This ensures a perfect straight entry of your tapped hole. This is easily done as there is enough torque at low (100) rpm's to drive the tap into the material before the spindle stalls.  The 3990 is an awesome platform to upgrade in the future as your needs change. So all this being said, I vote you buy the 3990.


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## ARC-170 (May 31, 2020)

+1 for the 3990. It has a better motor. I have one. I got it on CL. I've cut steel and aluminum. Works great. I find it to be a little small for me, but it has worked for everything I've needed so far. I've had to push it a little to mill stuff that was slightly too big. LMS is a great place. I live nearby and go pick my stuff. The people there are super nice and knowledgeable.


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## tonydi (Jun 1, 2020)

I have the 4962 and it's been a great little mill.  It'll be 5 yrs old in a few weeks and it's been bulletproof.  I worried about the gears before I bought it and was prepared to go with the belt drive but I'm glad I never needed to.  I made a spindle lock and would hate to lose that by going to the belt setup.  

I've never had a situation where I was disappointed in the performance and was wishing I had the better motor. As long as you realize up front that these little mills have limitations and you don't exceed those limits you'll be fine.


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## Aaron_W (Jun 1, 2020)

I can't help you between the 3990 and 4962 specifically, but on the what else to consider I have a few ideas.

I've been in your position and currently have a Sherline 5400 mini-mill and a Clausing 8520 (a small 6x24" knee mill) so I can share some of the thought processes I went through, and my opinions with the machines I now have.
The biggest issue in my eye to smaller mills is the limited Z axis (vertical) space, the 8-11" this class of machine typically has fills up quickly with tool holding (chucks), tools (drill bits, end mills) and work holding (vise). Rigidity is issue #2. Beyond that with appropriate care little mills are quite capable of working with most materials. I know of people using Sherline mills to work with stainless steel and titanium.

I don't have any experience with LMS machines, but as a vendor of machine tooling I've been pleased with them, and their machines do receive generally favorable reviews as the posters above highlight.

The actual physical space required for a machine is probably less important than weight and budget you have to work with. I have my Sherline mill mounted on a 26x22" tool chest which provides an adequate work space for it, as well as tool storage. My Clausing mill needs more space but not a great deal more (perhaps 36x36").

Budget is often the least flexible aspect.

Weight directly relates to rigidity, it also directly relates to how easily a machine is moved. Do you need to move the machine around easily, perhaps stored in an out of the way space and set up for use? If so weight is critical as anything more than about 100lbs becomes an issue. If weight simply relates to moving into its new home and the capacity of the bench or stand it sits on then it is of less importance, disassembling a machine one time to move it in, is not a big deal. When I bought my Sherline mill my "shop" was an upstairs spare bedroom, and I needed to be able to easily swap the mill and lathe on the bench depending on which I was going to use. Light weight was a big plus in my case at that time. The Sherline mill weighs less than 50lbs, the Clausing around 800lbs so it would have been a serious no go at the time. Things changed, I now have a shop space in the basement, space is still tight but machine weight has become much less important since I don't have to worry about wood floors or frequent moving of the machines.
I use both of my mills, the Sherline is capable of much higher spindle speeds, and is quite handy for very small work. The Clausing being a knee mill has some set up advantages and the weight results in much more stability.

With all that out of the way, and by no means dismissing either of the listed machines as options (either is larger than my Sherline which I have been quite pleased with), you might consider something a step larger / more expensive if the size, weight, budget allows. The Precision Matthews PM 25 or Grizzly G0704 (very similar machines) are quite popular, they are bigger, but still fairly small mills. They gain 2-3" in the Z axis which can be very useful, as well as just in general having a larger work envelope. LMS' 5500 is also of a similar size. The Grizzly G0758 falls in between the 5500 and 3990 so may also be worth a look. These are all more expensive by 50% or more so budget needs to be considered, could be worth watching for used if budget is fixed. Not a lot of vintage bench mills but there are some, Benchmaster is probably the most common, but there are a number of little known horizontal / vertical mills from the 1940-60s that do pop up, sometimes at very reasonable prices since few have heard of them.


I'm quite happy with my current arrangement, but if I had to have a one mill solution I think I could be satisfied with something like the PM25 / G0704.


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