Very interesting, Comfy. This is the kind of thing that fascinates me. My imagination is so convoluted and complex that I can’t imagine a way to overcome lack of machinery and high end ($$$:money_mouth_face: tools. Your solutions remind me of the simple old world solutions that people come up with in my wife’s home country of Costa Rica. I often see how people manufacture of repair things there and wonder why they have something set up in that way until I see what they are doing and I am dumbstruck by their genius of simple solutions to complex problems. I envy that ability to cut out the noise and identify the problem and come up with a solution that is simple and robust. I was looking at rotating tables but the cheapest one that I could find was for $250 on Craig’slist and was a huge version of one of these.
Perhaps or maybe better, please consider posting a thread of how to machine like comfychair. It would be a big help for those of us on a budget that lack a practical imagination.
Well, each situation requires its own novel solution. It's like, how do you give instructions on how to be creative, how to repurpose 'found' objects to solve a problem? I used that 4-up bezel-thing as an example, just because that was one that took me a good bit of thinkin' before I hit on the solution, mostly because I was trying to make it more complex than it really was. To cut something round, you only need a stable & accurate reference point (it only varies a little whether it's on the inside or outside of the workpiece); in that case it was as simple as using the four center holes that would later be cut out and discarded.
That fixture thing I made to hold the stainless pins I use for probably better than 90% of everything. It's just two pieces of 1/8" thick aluminum angle, clamped in the vise, and then six holes drilled only partially through, so the pins don't fall out the bottom when the vise is loosened, and to hold the pins at the same height even if you move the pins to a different set of holes. I have a bunch of the long stainless pins (scavenged from old CD-ROM drives, they're the guide rails the laser pickup slide on), and cut them to length (height) if I don't have something already made up that will work. You could just as easily use various diameter TIG welding filler rod, it's available in about every material you could imagine - stainless, titanium, inconel, aluminum, silicon bronze, etc.
For milling a flat surface on top of something with an endmill it's a lot harder, the cuts have to be really shallow or else it bites and flings stuff across the room. Whenever possible, especially since a lot of these parts are small and that puts soft fingers uncomfortably close to very sharp fast-spinning metal, I try to bolt the object down onto a larger baseplate that gives a more stable surface to slide around while making the cut. For something like a pill that's taller than it is wide, that helps a LOT.
That was done without being clamped down except to the square baseplate, just sliding the baseplate around under the endmill. Taking very very shallow cuts (no more than about .010"), measuring, then raising the table a tiny bit and going at it again until it's close enough to finish off with a file and then wet sanding.
This is a spare pill from a different light that was already made up with a matching cut-down 3XP board to fit inside the pocket, it fits with very little slop but still spins easily. Just used as a fixture to allow rotating the TIR in a consistent, concentric circle, at a fixed distance from the tool bit. The repeatability of that distance between the center of rotation of the workpiece and the tool bit is what determines the accuracy.
I could churn out a dozen of those 17mm TIRs with a finished OD variation of just a few thou. The catch is, it helps to do them all in one go, without moving any of the fixturing... if you move on to a different setup for machining a different part it's hard (but not impossible) to get back to the exact same setup to do another TIR that comes out the same size as the first ones. But again, it depends on how carefully you set it up, not so much on the tools.
DO NOT EVER WEAR GLOVES when trying any of this crazy shit! Gloves will not protect you, they will just get snagged and wrap your whole hand around the bit, instead of just giving you a little nip.
In case you ever wondered why the switch on a drill press or mill is where it is, in that awkward location right out in front of the headstock, it's so you can bang it 'off' with your forehead while your hands are being devoured by the spinning tool bit. This is not for the faint-hearted!
Did you have the triple glued down? How did it not fly off when you were working on it. As for gloves, yeah I learned that lesson about 13 years ago on a jointer table. Didn’t lose any fingers but I still learned.
Glued down? Hell no, it has to be rotated by hand! Like, with fingers! Push the part towards the cutter, it stops when it hits the two clamped pins (or the single pin thru the center, depending on which part is being worked on), and then rotated as it cuts. When you can push it towards the bit and turn and no more is being cut off, it's finished.
Not a high jacking so much as a complimentary post but how about recommendations for a cross-slide? The harbor freight models seem to have a good deal of play. Are there any that rotate?
Get a X-Y table made for a small mill, the cheap cross slide vises are junk, at least for doing work like this. They're also extremely awkward - the vise jaws being one piece with the base means your setup options are extremely limited. You may need the vise jaws oriented in a way that's physically not possible.
One of those with a standard low profile drill press vise clamped on top is much more versatile. You can get the same results without one, you just have to be more picky about positioning the vise on the drill press and adjusting the table.
Glued down? Hell no, it has to be rotated by hand! LOL, sassy pants. I was referring to the carclo or triple lens being glued to the PCB. I just figured that the holes that the lens interface with would be too loose and the lens would flex and pop out while turning it to the smaller diameter. It just looks too easy.
Also don't want to hijack, but what do you recommend for milling bits? I'd love to get a mill at some point, but for now is it best just to use Dremel bits on a drill press?
JohnyC, have no fear of hijacking. Your question absolutely contributes. (I wouldn’t be irked if it didn’t to be honest, but you read my mind).
I received an iPad mini for Father’s Day, totally destroyed my budget but I’m loving it. Now the drill press is on my August birthday wish list. If that falls through I’ll have to get it on my own.
I really appreciate everyone’s input as this is a tough choice on a budget, so thanks everyone.
I just picked up a new set of drill bits because I assumed the HF set I had was all bent, because on my Menards Performax drill press I got from a friend for $50, the bits wobbled. Well, it's actually the chuck. It's a JT33 taper and I hammered it out with a pickle fork, and measured runout on the tapered spindle to be less than .001" (that's as precise as my dial indicator goes). I ordered up a keyless chuck that should hopefully be better bilt.
So this is just an FYI that while the spindle runout might be fine on the cheaper drill presses, it might pay to buy a better chuck.
