Recommend a bench top drill press

Comfy, you think it won’t be able to take the ghetto mill action that I plan for it? I looked at some others but the price quickly triples. I was also looking at Craiglist for old ones that have endured the test of time and coming up with a lot of the harbor freight, sears drill presses. I like that price with the coupon, that was a nice surprise. I guess my question is do you think that it could consistently be accurate to a 64th of an inch? I suppose I could measure a smidge bigger, then sand and buff to tolerances…

It seems like it lost a lot of it’s torque over the winter, drilling into some steel last week and the thing kept stalling out. Thought maybe it was just a dull bit, but that was not the case.
Belt is good, no slippage so it just seems like the motor is laying down.

I really have not had a ton of hours on it since I got it.

But, hey with HF you have 90 days to see if it works for you, just keep the receipt and they will take it back if you are not happy with it.

As for mine, I am going to search for an older USA made beast at some upcoming community yard sales.
A guy up the hill from me used to have a garage full of the big stand up drill presses like we had in my high school.
Wish I would have gotten one from him. He moved now and I have no way to contact him.
But they are out there and I will find one.

Good luck with your search and let us know what you got and how well it works,
Keith

There's no way to set up the fixturing to give you a specific dimension, you have to guess, make a cut, measure it, and see if you need to tap the table/vise one way or the other. Accuracy in this case is down to how precise you are on the setup and learning how the machine reacts to different cut depths (if there's a lot of slop in the spindle/quill/headstock, making a cut can pull it farther in one direction depending on the type of cut you're making).

It's kinda like asking 'what's the accuracy on that hand file?' It depends on how much metal you take off! :)

comfy, I think he was trying to ask how bad the runout / slop / etc was. You brought that up earlier in the thread and I agree that it’s a valid concern… that said, there’s really no halfway on having tight tolerances. Either you’ve got what you need or you don’t. If OP can’t spring for the best, the HF may be a great option.

The slop or runout doesn't matter. Holding the workpiece at a stable, fixed point relative to whatever space the spinning tool bit occupies is what will determine the accuracy. Even if the shaft is bent and has lots of runout it still spins the tool bit in the same size circle every time it comes around. Machining round parts, the accuracy depends on being able to rotate the workpiece in a concentric circle, not the machinery.

I see what you are saying now.

First step, the four holes are the reference point for the first cut. The accuracy of where you put the holes and their size and their concentricity will determine the accuracy of the outer circle. It's like tracing a pattern. Any flaws in the master will transfer to the copies.

The starting points for the 4 holes were in the right places, the scribed circles were not! The holes are the part that matters.

Tapping the table left or right moves the fixturing pin closer to or farther from the tool bit. There's no measuring scale like on a feed screw on a X-Y table or a lathe tool post. You just have to tap, make a cut, measure, and see how much it moved and whether you need another tap.

Now that the outer bore is the right size, and round, the center locating holes are no longer needed. The outer part of the holes will take over the job of being the master for making the rest of the cuts. (also note I replaced the previous layer of masking tape on the aluminum angle with packing tape, to reduce friction)

The flashing left over is thin enough this part was cut freehand, it was very easy to cut away the leftovers without cutting into the finished part.

Again, another step is cut, using the un-cut part as the locating point for the clamped pins. If the surface used as the reference point is round and the right size, the new cut will be as well.

It's all about the fixturing, and being able to plan out a series of operations that will give you something accurate from the previous step to use as a reference for the next one.

That is one exceptional effort CC.

I use one of these
Dremel 220-01 Rotary Tool Work Station
by Dremel
Link: http://amzn.com/B00068P48O

There's another very important point: how you set up this stuff matters. A lot.

This is correct. See how if the workpiece moves away from the pins, it will cut LESS? And by pushing it up against the pins it'll cut more?

Same here, just it's a cut on the ID instead of OD. If it moves away from the pins it cuts less.

Same here.

Now, see this? This is WRONG! WRONG WRONG WRONG DO NOT EVEN TRY THIS, it will bind up and either fling the piece across the room or break the bit or maybe both. You absolutely MUST have it set up so you can slide the workpiece away from the pins (& the bit) while you reposition your grip. If it cuts deeper when the piece moves away from the pins, you will have a very bad not good day.

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.

I’m seconding this request. I think that could be a great thread!

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.

Turning down a 3XP & TIR from 20mm to 17mm:

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!

Holy crap! A Quad triple!

Please don't quote multiple pics like that, all my stuff is hosted on my home computer and once is more than enough already. :_(

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?