If you're not filing as a business, forget about deductions here. If you are, it's probably better just taking it as a one-time expense rather than depreciating it because it's way less complex that way. The only exception might be if it was very expensive and you don't have enough other income to offset this expense (i.e. in effect most of the deduction in this case would be "wasted" from a tax standpoint). In general though, you're better off expensing small equipment purchases of a few hundred dollars or less. For example, I bought a new solder iron last year for I think $90. It's not worth it trying to research if such equipment can be depreciated, what the normal depreciation schedule is for such a piece of equipment, and then bothering with the record keeping to do so. Ditto for things like computer parts. Easier to just write off this in the same tax year under maybe repairs and maintenance or office expense. After all, my business is electronics, not accounting. It's bad enough doing taxes once a year. I don't even want to think about them the other 364 days. Large purchases of many thousands of dollars though are another story, but I don't anticipate ever needing stuff like that in my line of work. If I ever got that big, then I would be able to afford a CPA to do this stuff for me.
Another thing regarding filing as a business-the IRS is getting wise to people who file Schedule C for what is essentially a hobby, and claim an overall business loss against their other income year after year. Unless you really are in business with the intention of making money, you're better off not filing as a business with the intention of deducting machinery purchases. Without knowing your situation, I can't advise you any further. To me it sounds like your accountant maybe thought you asked if you could write off the mill and lathe on Schedule A (itemized deductions). Obviously you can't, even on the "miscellaneous deductions" line.