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Haas ST-28Y. Looking at buying

Mr. Atoz

Oct 5, 2022
We are looking at a lightly used ST-28Y. We have an old SL-10 that has served us well and a Haas horizontal mill, including other cnc lathes and mills. It seems I heard there were some bugs in the NGC . What do you think of the newer Haas machines, and are there issues that need to be watched for? I would like to hear from you if you have direct experience. We will be doing no heavy machining of difficult materials or super tight tolerance. Mostly in the +- .004 range. In addition, how do their robot loaders stack up to others?


Nov 26, 2021
The ST28 is kind of an interesting concept from Haas, I like the A2-8 spindle nose to help support larger work pieces, but a 12" diameter chuck and 4" bar capacity on a lighter frame turning center? It seems a little goofy if you ask me, but I digress as people have been buying them obviously. The NGC is hit or miss, the earlier versions of the NGC were all right, and I think some of the newest software versions are pretty decent as well, but it just depends. The biggest problem with the newer generation Haas lathes is the spindles are extremely loud and obnoxious, much louder than other belt driven machines on the market and machines with integral motors. If you are only doing looser tolerance parts on it, I think the Haas would be a good fit but I would also take a look at other machines in that same class from other manufactures, as what you find may surprise you. Anything from Okuma, Mazak, and some Doosans are going to be pretty solid. You may also have luck looking at something from Hwacheon or Smart Machine Tool, they all have their quirks though. I do not know a lot about the robot packages from Haas, but the integration with the machine directly seems to be a very good option.

Orange Vise

Feb 10, 2012
We have two ST20Ys and an ST35Y.

The ST28Y is basically a mix between the two.

Mostly in the +- .004 range
Easy. Ours will hold a couple tenths. Tool wear is much more likely to affect dimensions than machine inaccuracy.

What do you think of the newer Haas machines, and are there issues that need to be watched for?
Worst subspindle homing routine ever implemented in a machine. They use cheap limit switches that accumulate coolant and oil. In all three of our machines, the switches got stuck closed and the sub would home to the wrong position by an entire encoder revolution, so +/- 1/4". This has caused more than one crash. There's an easy workaround... every time you home the machine, jog the sub all the way up to the main chuck and verify its position. If it's off, add or subtract 1/4" to the B-axis work offset. Kind of dumb that I have to do this, but it works. Luckily I leave the machines on all the time so I only have to home them a few times per year.

Their barfeeders are not great. They error out frequently. But they're also really easy to use, so it's a bit of wash.

NGC works fine for us. They glitch out occasionally requiring a restart, but it's infrequent. Less so on the ST and VF machines, more often on the UMCs.