The Gun Counter

So the X2 is technically feasable, but just barely, making it a hassle to use. I thought it would work, but then I rarely use mills that small.

So, the X2 is not big enough. What would the next-size-up, the just-big-enough machine be?

Windy Wilson wrote:So, the X2 is not big enough. What would the next-size-up, the just-big-enough machine be?

Forget the "next size up" - when buying machine tools, always buy the biggest work envelope you can afford/have room for, because invariably you'll have a job that's too big for the machine soon enough. I suggest an IH mill. As a bonus, the column mill design is better for CNC conversion that Bridgeport style machines, as the Head setup is stiffer.

Just machining out the trigger trench looks non-trivial to me if you want precision parallel interior surfaces.
properly space apart. I would guess you have to have a pretty rigid spindle that can handle a large enough diameter end mill that won't chatter or push off at the bottom of the cut. If you were just doing the trigger trench what would be the recommended size of end mill??

I remember a number of guys that started projects that got ruined on the price of the cutting tools they needed. I remember one guy with his own shop with a really large lathe that he used to bid on projects from other shops that didn't have a big enough lathe to do. He said he bid on one off and per contract he had to mill one slot in the piece and found he had to go out a buy an end mill. It ate up about half his net profit on the job.

I remember many moons ago trying to find a GSA surplus tool and cutter grinder. Even a pretty worn was just too expensive.

2K is what you'll get for a smallish bare bones machine. A KO Lee with a decent number of accessories? You're looking at 5 grand and up. Frankly, any machinetool you can buy used for less than 2 grand tend to be either too small, too thrashed, or so obscure/obsolete nobody wants it(case in point: Large shapers and frequently screw machines often go for scrap these days).

Well, thank you all for the very thorough answers. It got really esoteric really fast, but you all laid it out pretty clear for someone who has never done any machining at all (I've built some crude things out of wood). I was able to follow along (to my mind) pretty well, even though my only exposure to non-woodworking machinery was a glimpse of an auto-insertion machine and a solder tank(?) in the Automation Lab at *** aerospace company.

HTRN:
The last time I laid hands on a shaper was in 1983, and that was after 1965 in a training school. They were tricky to set up, and didn't have the versatility, IMHO, of a milling machine but the had the advantage of just using a single tool bit. You could shape the tool bit for rough out work or finish work. In the training school I used one to machine out a large V-block and finished it on an old hand powered surface grinder. My last job using one was to cut an internal key slot on the inside diameter of a large pipe. They'd made an extension bit holder so it could get inside the pipe. Eurk! I just flashed on a shaper with digital read outs.
http://en.wikipedia.org/wiki/Shaper
If you want a new shaper you can get one from India IIRC. errrh.....

Shapers do certain, VERY limited jobs well, mostly involving cutting recesses/keyways that have to be square, rather than radiused. Stuff that would otherwise have to be done with a sinker EDM or a broach setup(may not be possible in blind holes). Other than that? They're boat anchors. I will say the smaller ones are usually more valuable, as they're popular with hobbiests - up to maybe 12 inch, mostly stuff in the 8-10" range. The big 20" shapers? scrap for the most part when they come up for auction. Planers are in a similar situation(Interestingly, planers are popular for cutting pressbrake dies, because they induce less stress in the work, causing less distortion).

:jacked:

You had to go and mention planers. We were using planed large flats of hot roll for jig and fixture tables. We started getting plates that not only were rough as cobs but that we couldn't get level. They were warped. We sent some spies down to the tooling machine shop and the problem was the "operator" would just clamp the plate down then start hogging material off of it. He wouldn't put shim under the parts where he clamped and the plate wasn't touching. Then he'd turn the plate over and hog it again. So to use the plate we had to shim or get parts ground down for locators, drill jig plates, and stuff. It made putting tooling reference point on fun also. It was a union shop and we couldn't get him to do it right, moved or fired.