Uh physically go there and see what their capabilities are

The best shop I ever worked with was the one that quoted by delivery date. Don’t push your suppliers for better delivery than quoted and don’t expect them to hold that delivery for 60 or 90 days.

Gonna second Tasty Platypus here: go look at their shop.

Don’t look at the surface level. Yeah, clean and shiny is impressive, but what you’re actually looking for is the work flow. Do they have a massive pile of stuff waiting on too few lathes? Are the mills standing empty? Are there old and rusted toolboxes shoved into unused corners from ex-employees who never came back? Do the machinists all look like they’re about to fall asleep or collapse at any moment? Is your tour carefully rehearsed - guided to the Potemkin machine and encouraged to speak with just one guy?

That guy used to be me. That’s a big red flag. It was because nobody else gave a damn.

Go there, look around, and pick up the prints and packets. Look for dates. Are they all from two weeks ago? This shop is always late. Are they all for next week? That’s good. Are they from years ago? That’s not the due date, that’s something else entirely.

Don’t be fooled by floors that were mopped an hour before you showed up. You’re looking for signs of the culture and morale of a place, not how fast they can sweep when the bossman says a customer is coming. In fact, if you see freshly mopped floors and it’s NOT near a shift change or end of workweek, they stopped to clean up just before you got there - and that’s a big flag because it’s probably the only time they do.

Another metric that you can actually see with your own eyes when you go somewhere physically to a new machine shop is how well the people on the shop floor work together! It’s really the most efficient way to find out if a machine shop can do what you ask of it. If the people doing the actual work, don’t get along with each other OR the people who work in the office, you really should keep looking for a better place. I understand that there is somewhat of a disconnect between the shop and the office, specifically the engineers and salespeople. If the salesperson just says they can do it, no problem, without consulting with the shop Forman, probably should keep looking. It’s only when everyone there, works together as a cohesive group, that deadlines are made almost without question. When it’s a bunch of passing the buck, it’s someone else’s problem now, not my job, it’s not going to be reliable. The good ones leave, the bad ones stay, and the customers are who pay the price. Just my half a cent. It’s not even worth the full two cents.

Ask if they are willing to share the last 6 months of their On Time Delivery metrics.

I would do a full background check of the business. Verify licenses, certifications, and insurance. Check for business litigation, judgements and liens. Review financial health and credit. Request Bank references to confirm they pay their bills on time and maintain good standing with financial instutions.

Site inspection, qualification run, possibly staggered deliveries (do you really need 150 shafts at the same time?)