ShopSolutions “When we bought the Studer from United Grinding
Sample of spindle shafts, some with three, four, five, six or more diameters and shoulders, that are ground at AME showing the super finishes, multiple OD diameters, and thread grinding that are required of the Studers.
Technologies [Miamisburg, OH] in 2006, we were looking at two machines that were rumored to be very good,” said Sam Schubert, grinding supervisor. “However, if you bought either one you’d probably want to buy a second machine because of the commonality in controls and training issues, and the ability to cross train. If you have a variety of machines, with a variety of different controls, you tend to have operators who don’t want to leave a particular machine, because they’re familiar with that specific control.” Recently, AME took delivery of a Studer favoritCNC cylin- drical grinder to provide them with the technology, along with the Studer S40, to grind spindle shafts. Lately AME has been grinding an increasing number of spindle shafts, a job they hope customers will place them on their supplier short list for. “I consider what we do to be small-volume work. One to
five shafts, and then every once in a while a 20 to 30-piece spindle shaft order. Nothing in the hundreds,” said Schubert. “Normally the spindle shafts are 8620 carburized and hardened steel. The shafts are from 6 to 50" [152–1270- mm] long, and almost all of them are going to have OD bearing diameters that will be ground on the Studer. The shaft diameters can be straight or they can be tapered. The tolerances on the shafts come from the bearing manufac- turers. If it’s 100-mm diameter, we’re going to be held to 0.0003" [0.008 mm] total tolerance on bearing diameters. Some shafts are going to have three, four, five, six or more diameters, plus some shoulders. “Basically, what we do since all of them are heat treated, is prep them, meaning we will grind the centers. Then we rough grind and grind thread diam- eters. What we’ve found is that through rough grinding we take some of the tension out of the shafts, especially the longer, thinner ones. After rough grind- ing, the shafts leave our department and get threaded on the lathes and possibly milled to cut keyways. Then they come back and we do our finish OD grinding.