After a run through the online jobs landscape looking for relevant manufacturing employment opportunities, it looks like you're gonna find one of two things - sites with a tight focus on manufacturing and few jobs, or lots of jobs but a loose definition.
Now, manufacturing is by its nature a pretty broad topic. To make it even more plainly obvious - look around you ... EVERYTHING is manufactured. Consider all of the industries that manufacture within their own standards, cultures and processes, and it's as convoluted a category as there is.
Add to this the various administrative and professional services that medium and large manufacturers employ - accounting, HR, IT - and the numbers become REALLY deceptive.
To help with this, I performed two searches on each site - one for "manufacturing" and one for "manufacturing + cnc" to test the representation for a specific sector. (After each property name below, these numbers are listed in parenthesis, respectively.)
But what I found was still compelling, even looking at such a broad topic. If you're looking for a job - or just thinking about it - maybe this snapshot of the online employment space & quick review can help you in your search.
LinkedIn (1,690 & 11) - Oddly, the strength of LinkedIn isn't its jobs listings. Odd, because many consider LI the online employment Mecca. What makes LI so powerful are its networking & relationships platform. It's meant to be WORKED - consistently, even when you're not looking for work. And LI has a rep for being more white collar than blue collar. So, I wasn't too surprised to find less "manufacturing" jobs listed. But ELEVEN jobs for CNC? To be fair, a search on "machinist" returned 43 results. Bottom line: If you're active on LI, that's good. If you're looking for a quick gig, you might want to look elsewhere.
CareerBuilder (11,251 & 952) - CB has become one of the best of the "traditional" job posting sites, and the numbers show it. Most all of its manufacturing listings are indigenous to CB - they aren't shared or ported in from other sites. That can be good or bad, depending on your requirements. Bottom line: Include this in your search for manufacturing gigs, as you're likely to find something here that isn't anywhere else.
Monster (>1000 & 72) - My, how the mighty hath fallen. A few years ago, Monster was the darling of the online employment sites. It's still formidable and, like CB, there may be unique postings here. But the numbers are not strong for manufacturing postitions. While sites like LinkedIn and Social Media are erroding the value of these sorts of sites, it looks like Monster has taken an especially hard hit. Bottom line: You may want to leave Monster out of your assembly of online go-to job sites. Manufacturing just doesn't appear that strong.
Simply Hired (183,705 & 3,367) & Indeed (150,765 & 3,630) - SH and Indeed are Google-like search engines that include results from every online job site you can imagine. For shear volume, you can't go wrong with these models. Of course, you're not looking for 3,000+ jobs - you're looking for THE ONE. But if you want the biggest bang for the time spent looking, these aggregators can expose you to the most options the quickest. Bottom line: Strong for manufacturing, any way you slice it - but they lack the more sophisticated tools & associated services of LI, CB & Monster (i.e., resumes, salaries, etc.).
Yahoo! Jobs (4,587 & 244) - Another once-huge titan of the employment Interwebs, YJ appears a bit anemic on the manufacturing side of the house. Yahoo! is still one of the best-visited sites but its lack of specific jobs for our world is perplexing. Bottom line: Do you Yahoo? I don't think so.
ManufacturingJobs.com (2,843 & 2,246) - This site is a targeted platform with ONLY jobs specifically from and for the manufacturing industries. That's really good for you, since there are fewer unrelated jobs to hunt through. Bottom line: Limited tools, but strong focus on manufacturing makes this site a valuable option for your manufacturing job search.
ManufacturingWorkers.com (23,234 & 884) - Not as targeted as some, but better than others. This site is part of the Beyond.com network of career sites - so you're going to get some bleed-over from other industries. But not much. And the tools here are on a par with (but not quite as robust as) CB & Monster. Bottom line: Not as strong for relevance as some, not as volumous as others, with tools a little less complete as you'll find elsewhere. Beats a poke in the eye with a sharp stick.