most important tool in your shop

This is an easy question. Just start a big project and work until you need a tool you don't have. Go buy it.

 

My brain and hands, everything else is a extension of them.
Of course sometimes my brain goes AWOL and I beat on my hands.

 

Yep, if they don't woop the snot out of you for leaving them lay around.

There are several pages on here and I posted once earlier but a guy starting out and trying to equip a home shop needs to look at what he will be doing in said shop and base his equipment needs on that.

If you don't have much of anything.

A good set of basic tools = XX piece Craftsman set on sale. I love my off the tool truck tools but Sears sets on sale will put a lot more tools in your tool box.
A decent tool box to keep them in and keep them organized in so you aren't hunting for them all the time.

A test light and multimeter.

A good 3/8 drill and a good 1/2 inch drill.

A 4-1/2 inch angle grinder. I have a pair of HF orange ones that I have used forever while the 80.00 Black and Decker sits on the shelf because it is missing the nut that holds the disk on and the size of the drive stud on it is wrong for the cup brush I have. My buddy buys 100.00+ Makitas and swears by them but he burns at least one up every year.

A decent floor jack and good jack stands.

A good vise mounted on it's own stand. Either my 4 inch Craftsman that is 43 years old or my 6 inch no name gets used every time I work in the garage with no exceptions.

Cherry picker or chain hoist. Either will lift, hold and or save your back and you don't have to offer them beer to get them to help.

A decent variable speed sawzall. Also a decent variable jigsaw. Quite often on sheet metal the jigsaw is a lot easier to control.

A torch set simply because you can do a lot with it.

An electric welder. I used a stick welder for a lot of years before I got my hands on a mig. My T bucket was built with my buddy's 225 Lincoln in Texas in the 70's and you can buy one of those used for 100 to 150 bucks and sometimes less. I don't use my mig as much as I thought I would but it is getting used more all the time and will get used a lot in the next few months.

A drill press. I find that mine gets used on most projects and it beats the hell out of trying to drill straight holes with a hand drill when you have a lot of them to drill.

A belt/disk stationary sander. I picked my Craftsman 6 incher with a 9 inch disk up for 40.00 one morning off Craigslist when a couple were selling off her dad's wood shop tools because they didn't do wood work. It gets used on most fabrication projects and the disk side gets used more than the belt.

An air compressor. a 100.00 3hp yard sale or craigslist unit will air up tires, blow of dust and spray paint until you can save up for the big unit.
As for air tools, my air chisel hasn't been out of it's box for over ten years and I don't use the impact much at the moment as I don't have enough air to run it. That may change shortly though. I've got an onsale electric 5inch orbital sander that gets used for body work.

A horizontal band saw. Mine was an 80.00 craigslist unit that I ended up putting a full set of bearings on for the blade and am still tweaking the blade to get a straight cut. The chop saw I've had for the past 20 years hasn't come out from under the bench since I got the bandsaw working.

From there you can go to the Tig, the two or four post hoist and other great to have but not a necessity of live as shop room and spending money allow.

Here locally we have a trade school and a couple of Jr colleges that have automotive programs within 75 miles and a few times a year someone who has dropped out of one program or the offers up a fairly decent set of hand tools for pennies on the dollar. I bought most of my body tools from a long time bodyman who had retired and was selling off almost all of his tool and equipment collection. I'm still using the 9-1/2" or so mostly 36 grit sanding disks that I bought a tall stack of for 10.00 I've got about 50 lbs of lead I got from him along with a vixen file and hammers and dollies. I've got a pair of angle iron saw horses that I got at a drag racers estate sale that one of his brothers said he sat his dragster frames on when he worked on them. They were pretty inexpensive but get used all the time.

When I was working in shops I had a standing personal rule that if I needed to borrow a tool twice in a week I needed to own one. Some specialty tools like ball joint presses or cooling system pressure testers you may not want to buy right off but rent or borrow from the parts house and take them back when you are done.

 

Handheld bandsaw is used more than anything.

 

Mr 48 chev gave the best list. I took me 40 plus years to buy up what he stated. now after buying tools for 55 plus years I am a tool junkie. After almost loosing my sight I have safety glassed every where. you can not walk 4 feet in my shop with out seeing safety glasses.. .......................Pawn shops are a great place to purchase tools. They stock the floors monday mornings.. I buy loose odd ball tools {craftsman or equal} cheap.. Make them a offer thats close they will sell. Last If you loan tool make a list other wise the borrower will forget. I have a black board in plane view of everyone.. .. Good Luck and enjoy our Hobby...

 

Asking a question like this is like asking what's the best road to take...it all depends on where you're going. I have always been a jack of all trades so most of the tools mentioned so far are ones I have and consider important but you will have to decide which of these meet your needs right now.
Over the years I have bought quite a few specialty tools, most never see the light of day but they are nice to have when they are needed. Some tools just become indispensible, like the jawhorse. The wife saw the info-mercial for this sawhorse/vise on the TV and bought one for me for Christmas a few years back. I didn't think that I would use it too often but what the hell, it was a gift so you have to make the effort. I use that rig on a daily basis...it holds parts for welding as well as having a sturdy flat top plate for use as an anvil. Folds up for storage or throwing in the back of the truck. It makes a great set of extra hands when I need them and it is almost indestructible. When I melted the nylon jaw pads while welding some parts, the manufactured sent me a new set no questions asked and at no cost.

 

A GOOD air compressor, torch set, floor jack and jack stands. Followed by 7" grinder, buzz box Lincoln welder, wire welder, chop saw, vice grips, table saw. Given the limits of my ability to measure properly, I can make about anything with that stuff.

 

I really didn't think it would get used much when I put it in, but the fireman's / stripper pole is plenty of fun and gets used quite a bit.
One could argue that it couldn't possibly be the most important tool or even a tool for that matter, but when its in use everyone forgets about all the other tools.