Project still in design phase

The only component you need is money. :-)

Sounds like you need a servo c> I have a design in my head, and I am wondering if some of the elements of it

I think the whole thing is simpler than CNC, but should be a poor man's single plane manual cnc type thing.

Initially I was considering the table be free moving (though constrained to move along track or slide rail) not "bound" by the micrometer, but rather having the micrometer provide a "stop" at some position then freely move the table forward to the stop, then return to the zero position. In either direction once the position is locked movement in the other direction should be free. Does this make is simpler?

I am not sure I follow what you suggested with pins.

No!!! :) No servo anything, all manual manipulation.

Imagine something that could produce a small saw blade by knowing the teeth per inch and the depth of individual teeth, or a key. In actuality, it is to be an improvement on an existing product that is used for just that key origination from code. There is currently a very inexpensive machine that does just this but with a rocking carriage instead of a straight feed. It has a micrometer depth stop for cutting to the correct depth (fore/aft) and a micrometer that sits along the side to gauge the left/right position. None of these positions bind the carriage, beyond giving it something to lean against. The idea though is that you have to calculate the movement and manipulate 2 separate micrometers for each cut. Secondary to the more accurate straight feed carriage, I want to come up with some kind of stepper methodology. In both cases once you have your initial position, you are moving by some set increment such as .092 or whatever. Depth (fore/aft) works the same way, once you have the beginning, each subsequent depth is a multiple of something. At the time of use one would know the initial position and the incremental value. But I'd like to get away from having to calculate each position. I know I want to move another .076 or .092 or whatever. Of course even if I can come up with the straight feel sliding table I could certainly guide it in the way the current one is guided, even that would be an improvement.

I want to build a more accurate and convenient to use "carriage" for this as an accessory.

I am trying to bridge the gap between a $300 piece of equipment and a $1600 piece of equipment that basically do the same thing. Obviously if it costs close to 1300 to do it, then it would serve no purpose :) But if it could be done for even a couple hundred dollars, then it would be worth the effort.

It sounds as though the positioning could be accomplished with micrometer heads and gage blocks (or similar accurate blocks). If you need to reset for numerous different increments, the block method could become troublesome. It's not clear to me if you'll need 2" of travel, (or 4" or more).

Some micrometer heads are bidirectional, numbered for both directions, and have resettable zero set on the thimbles. Mitutoyo has heads that adjust in

The other recommendations for resettable stop/index pins and coarse/fine adjustment methods are also worth consideration. Since you're at the design stage, you can determine the cost effectiveness of accuracy and versatility.

A small X-Y table with dial indicators would be relatively inexpensive, but would require counting and frequent resetting of the zero/add/subtract points.

WB ..................

Ned --

Sounds like a good day at the library :)

I have forwarded the book suggestions on to my home email, and I will certainly look them up.

I am not necessarily opposed to servos, and stepper motors, it is just that I have never worked with them and just assumed they would be more expensive than a manual solution. Am I to assume that the stepper would drive the micrometer head?

Ok, how about suggesting some sources for these:

Inexpensive Slide Tables Stepper Motors Ball Screws

Perhaps Berg, or "Small Parts".. "radio shack"?

I don't see much reference to "slide tables" is there another name for that?

Keep looking:

You can find used stuff inexpensively too.

Jim

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How about using some ordinary fine screw threads to move the table and use a couple of cheap dial or digital calipers, modified to the task, to determine positioning? That would get you out of issues such as backlash, just read the table's position directly and the screws are incidental and need to be only of adequate quality to move smoothly. Seems that some of the digitals are able to zero from any position, if that would be a plus then you'd have it.

John

My newsfeed has been down for several days, so I've missed the start of this. However, small X-Y or X-Y-Z tables are made for optical table work, if you don't need sufficient rigidity for machining.

But -- unless you luck into them used, they will *not* be cheap.

Good Luck, DoN.

An inexpensive source of 1" - 2" linear motion devices used to be old 5.25" floppy disk drives; they usually have a stepper motor, a carriage, and slides. An old 3.5" floppy disk drive has a smaller range, much smaller motor, etc., but might work for your purpose.

Regarding a mechanical solution, a pair of pantographs would allow for use of indices with fixed spacing. With a row of holes drilled at even spacing, moving the input arm from one hole to another would step the output arm by the pantograph ratio. One pantograph would do x-axis steps, and one would do y, and the x one would ride on the y one or vice versa.

-jiw

-jiw