We're located north of Baltimore, so probably a tad far to go from College Park. But if you still want the recommendation we use Callan & Palmer, a firm of about 7-8 people, 4 of whom I believe have their CPAs.
BUT, they know very little of the specifics of the production business and I don't think it's all that important that they do. What is important is having a good handle on small, closely-held businesses in general. When it comes to accounting and taxes I doubt there's much difference between what we do and what a small machine shop does. We both require an investment in machinery which is amortized over as few years as IRS rules will allow. We both can have employees, or not. And in both businesses the purpose of a knowledgeable accountant is to help you get the highest return from your business LEGALLY.
Hope this helps and glad you liked the 12 Things piece.