I felt the same when I first started out. I tried to stick to "generic" geometries like CNMG or APKT. I ended up with some proprietary cutters, like the Sandvik coromill which uses an R390 insert and I really liked it. That one I used a lot and went to ebay to get inserts for about $11ea, which is half of what MSC charges.
But back to my original question; I asked about margins because I'm considering if it would make sense to start selling some of the same tools I use. The overhead is already covered so it would just be a matter of the initial outlay in a good amount of stock, and then of course marketing and selling.
The trick is, "dealers"/distributors don't stock hardly anything. Any why would they? Carrying their own inventory would eat up tons of cash, for very little markup/margin to cover it. They let the manufacturers hold the inventory, and then drop-ship the items. It was a big selling point for me to brag about how close our warehouse was.
Don't forget, that manufacturer & distributor rep's full-time jobs is to be out selling. Are you going to run/work your shop full time, and then re-sell the same cutting tools that you're using in your shop, on the side? Good luck... Like I said - sales is a full time job...
There's no reason why you couldn't have a successful business re-selling tools, but I don't think it's something you could do "on the side." You'd have to be out knocking on doors during normal business hours.
Regarding margins - that's the 4-billion dollar question.
(About the sum-total of the cutting tool market in the U.S.) If you were going to invest your cash into stocks, what's the minimum amount of return you'd be willing to accept? Remember, this R.O.I. percentage has to fuel your growth as well... The selling price of your product should be above that figure by several percentage points.
And the market has become hyper-competitive, especially after the 2008 mess.
Also, don't forget that you're most likely going to be dealing with shops paying net-30. Someone places a decent order, and then skips on the bill, it's your job to collect now.
(No different than any other business either, but that goes on in the cutting tool world as well...)
Just food for thought...