Rebuilding an Atlas Horizontal Milling Machine

I’m reaching the tail end of the rebuild on my US Machine Tool mill, and looking for the next project. I’ve got plenty of plans for different things to do, but someone spotted my old Atlas in the USMT rebuild blog, and asked about it.
I bought the Atlas about six months ago from my friend Rich. I had put out some feelers for a small horizontal mill, and Rich had this one sitting in his shop collecting dust. The machine had been rebuilt previously, and by the looks of it, been put away pretty much unused. It is in need of a good cleaning, and a tweak here and there.


I had the mill home for about a half an hour before it dawned on me that it was just too small for some of the Neanderthal cuts I am inclined to take. The machine has been sitting idle for quite a while now, and its time to do something with it. I had planned on selling it “as-is”, but decided to fix a few cosmetic problems, and make some more arbors for it. The dried way oil makes operation a little stiff, so it will benefit from a good detailed cleaning.

As you can see; it looks pretty good already. I made a few cuts with it after I bought the USMT mill, and was surprised at how well the Atlas works. I’ve been trying not to “fall in love” with it (successfully) for six months now, but have come to realize why Atlas owners love these things. Its small, but makes a good cut, and the thing is real nicely built. There are a few things I plan on making “better”, but plan on keeping this mill as original as possible.

The plan is to make this nice enough to sell for some decent money, and gain some much needed floor space. I don’t really NEED three milling machines, and I’m sure I can find something else to spend the cash on. I don’t plan on going overboard on the “rebuild” timewise, and won’t have to spend a whole lot of money on it; the hard work has already been done. This project probably won’t get started for a week or two. More later……….

12/12/2011: I started to take the mill apart tonight. This is how it came apart (took about a half hour).

These are the gib adjusters for the table. Take these out, and the table will slide off (to the left).

Turn the table lever (counterclockwise) to move the table to the left.

Grab the table gib before you slide the table off, so that you don’t lose it.

Heres the bottom of the table. The grease is really thick and stiff.

The saddle comes off by first removing the Y axis adjusting screw. First you unscrew the large collar that screws into the saddle. This will only come out so far, then you will have to screw the handwheel (clockwise), to remove the screw.

Maybe you can see the two threads here: the fine thread on the collar is right hand thread, and the ACME thread is left hand thread.

After removing the gib lock, remove the gib adjusting screws.

Push the gib to the front, then lift the saddle straight up.

This is the saddle up-side down, with all the parts that were removed.

These sheetmetal guards slide with the saddle, and pull off, towards the front. Both will need some work to smooth them out.

You need to remove the knee height stop screw before you remove the knee. Its on the left side of the knee.

The knee will hit the back gear eccentric, if you raise it far enough to remove it. I took it off by driving the taper pin out part way, then rotating the lever.

Pull the pin all the way out (after rotating), and remove the eccentric.

Remove the two screws from the knee way chip guard, and lift it forward, and up. At this point, if the gib is loose enough, you can lift the knee up and off.

Heres the knee (viewed from the top) with the gib in place. I pulled the knee with the gib in place (the grease made it stick in place).

As clean as the machine was, there was a ton of crud on the ways, and the knee screw rack. I’m thinking that when I straighten the chip guards, this problem will not be quite so bad.

It didn’t take too long to clean up the rack and ways. I picked most of he junk off with a rag, then scrubbed it with a toothbrush, then cleaned it with acetone, and polished it with a ScotchBrite pad. The cleanup went real quick.

After I got it apart, I took inventory, I came away real impressed with the quality of the machine work on this machine. Before I started working on this mill, I thought of Atlas machines as toys; boy I was wrong. This is a real machine tool, just smaller than the ones I’m used to seeing. More later………..

1/9/2012: The old Atlas has been sitting, waiting for the holidays to be over, so I can get it back together. I had some free time today, and decided to get some work done on some neglected projects.

Heres the bottom of the saddle, all cleaned up and smoothed. Some moisture had gotten trapped in the grease, and caused some corrosion. Nothing drastic, but it was bound to have caused friction. It got polished off. The hand wheel got a trip to the wire wheel after it came apart to be cleaned and lubed.

This the easiest way to install the saddle; just set the left way, then drop the saddle straight down.

Now you slide the gib in from the front, and install the gib locking screws on the right side of the saddle.

The saddle screw comes next, after a nice coat of way oil. You will have to run the screw in part way (left hand thread), then thread the support collar in (right hand thread). Sounds complicated, but you’ll figure it out.

The saddle screw looked so much better than the knee screw, I had to take that one out and clean it up, too.

Both screw supports cleaned up real nice after a few minutes on the wire wheel.

I put a little thick grease on the back of the table gib, just to hold it in place while I was sliding the table on the saddle. Needless to say; the table got a good coat of way oil before it went on.

With all the parts back on the base, I adjusted all the gib locking screws to nice and snug. The machine is so much smoother it ain’t funny. I tend to get a little overboard on “clean ups”, but this was well worth the time invested. The machine works alot smoother, and will be much more fun to use. Properly adjusted gibs add to a machines accuracy, also.
The next step is to free up the back gear in the spindle head, so that low gear can be used, and work out a few kinks in the belt tensioner, and the see what kind of interest I can get on Craigslist. More later……….


12-7-2012:  I feel a little guilty about not updating  this blog in a while, but space became a critical issue, and a fellow CAMS member asked if the mill was available, and it went down the road. I’m sure Fred will get more use out of it than I did, and hope he has as much fun as I did have. On to the next project…………………….

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2 replies
  1. Robert Palmer
    Robert Palmer says:

    Do you have any videos of the rebuild? I just bought one of these fine machines myself and I would like to know more about how to restore one of these gems.Thank you.

  2. admin
    admin says:

    Sorry, Robert; I don’t have any videos of the “rebuild”. I’m getting dangerously close to doing some videos on some stuff going on in the shop, but nothing yet. I would check to see if Yahoo has an Atlas group, I’m sure they do. That will probably be your best source of info. I agree with you; They are gems, just a little small for my needs.


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