[agnisflugen]

i found this thing in a bin at a thrift store, i was hoping someone might know what it is, and how it's used... it's kinda heavy, shaped like a rectangle...it says, "Bridgeport CNC" at the top, and it has designs etched into it such as a flowers, and something called a bolt circle....it measures 6 1/2 by 4 inches, and is 1/2 inches thick.....i took a picture of it too:

what is this thing? | Flickr - Photo Sharing!

thanks in advance for reading this

[dertsap]

it looks like promotional stuff which shows some examples of what the machine is capable of doing ,

[agnisflugen]

it looks like promotional stuff which shows some examples of what the machine is capable of doing ,

what kind of machine does it go to? i'm sorry, i don't know anything about this sort of thing....

[dertsap]

Bridgeport

[agnisflugen]

Bridgeport

but what does it do? cut metal? i've tried googling it, but this seems to be the most knowledgeable site......

[fizzissist]

what kind of machine does it go to? i'm sorry, i don't know anything about this sort of thing....

I know what it is. You should buy it. Quickly, before someone else does.

It's worth 6.5x4x.5 times the weight of aluminum in lbs/cubic in, multiplied by the current scrap price of aluminum.

Prior to finding a buyer, it should be mounted on a wall to help educate anyone as to the subtle aspects of the computer programming skills required to make a CNC milling machine productive.

Seriously. It's a set of examples of codes used, and different types of geometric approaches to generating a toolpath on a computer controlled milling machine, in this case a Bridgeport CNC.

Buy it. Donate it to a high school machine shop that has a CNC mill and take the tax write off for the real value. Some kid took a lot of time to create this, probably for a graded project. He did a good job.

[tr4252]

agnisflugen; It is a nice piece of work. Perhaps the person who made it signed it or left some other reference. If you can take it apart without damaging it, you may find some information.

Just so you know, a Bridgeport CNC vertical milling machine is similar to a router (I presume you know what a router is) in the way it cuts material. A milling machine however, is generally used to machine metal, with great precision. The CNC part means Computer Numerical Control.

Tom

[agnisflugen]

thanks guys! i bought the heavy mystery thing the day i saw it cuz it was only .50 and i thought it looked neat, i just had no idea what it was or how it was used...i came home and tried to look it up on the computer and that's how i found this forum. everybody seemed so knowledgeable and friendly so i joined, i'm learning so much already! :banana:

[agnisflugen]

agnisflugen; It is a nice piece of work. Perhaps the person who made it signed it or left some other reference. If you can take it apart without damaging it, you may find some information.

Just so you know, a Bridgeport CNC vertical milling machine is similar to a router (I presume you know what a router is) in the way it cuts material. A milling machine however, is generally used to machine metal, with great precision. The CNC part means Computer Numerical Control.

Tom

that makes alot of sense, thank you! i'm familiar with a router so now i'm able to visualize how it was used...i can't take it apart though cuz it's a solid hunk of heaviness...

[tr4252]

For 50 cents you got a nice bargain.

Tom

[agnisflugen]

i've been doing some research on vertical milling machines today, and i didn't realize there was such a following! is the thing i bought called a template? or is it just an example of what the machine could do?

i haven't seen another one like it, but then again i don't know what to call my part when i'm searching for it online...after looking at some pictures of other Bridgeport machines i recall there being other strange pieces of metal in that bin...a rusty clamp, and this long metal arm with a hinge, and in the corner of the store was a hodge podge of old junky looking shop equipment...i wonder if it all went together? they were having a 50 percent off sale that day, so things were kinda crazy...people bumping into my cart and what not....i'm just glad i go out of there alive cuz i was in a pretty ghetto part of town....but the ghetto thrift stores always have the best stuff!!

[fizzissist]

What you bought is worthless to you ( I don't say that to be derogatory), but precious to whoever made it, and meaningful to all of us here who program, set up, and/or run a CNC machine.

It was probably made by a student as a class project, or an instructor as an example of what's called "canned cycles". Those are the "G" codes you see, commands generally in the first position in a line of code after the line number, that tell the computer on the machine the nature of the movement of the tool desired.

Someone has gone to great lengths to first write the code, probably by sitting at the computer typing one line at a time manually, then running the finished program and cutting the part you have....each of the individual patterns a set of lines describing the toolpath.

For example, G79 is a command for that Bridgeport's computer control that creates a circle, where the tool starts in the center, angles out towards the edge, arcs to the outer circle, cuts a complete circle, arcs back towards the center, then rapidly travels back to the middle of the hole and retracts away from the part. Whew.

These days, that same process is most often done with the aid of software which generates the G-code automatically. (good programmers still know how to write it manually so they can catch funny things the yet-to-be perfected software does...which is why we respect the piece you have)

Here's a few videos to help visualize what's involved
[nomedia="http://www.youtube.com/watch?v=_CE6Jk_6DWg&feature=player_detailpage"]YouTube - CNC Programming Tools[/nomedia]

[nomedia="http://www.youtube.com/watch?v=hhHPvwW-7rw&feature=player_detailpage"]YouTube - OCC Bike Building with Mastercam[/nomedia]

....and on the very sophisticated level....
[nomedia="http://www.youtube.com/watch?v=139z62o6OhA&feature=player_detailpage"]YouTube - CNC Machining of a Motor Block[/nomedia]

[underthetire]

Demo part for sure. My guess would be for a early knee mill with a early control. I'm sure it came from a tool show, back when simple parts were ok to demo, and controls were quite limited. For 50 cents, it's worth the aluminum.

[agnisflugen]

wow! watching the motor block video really helped me understand the tiny grooves that are present in my piece, and after watching that motorcycle guy cut flames into a curved piece of metal i now understand when someone said to me this is a primitive example of what modern CNC machines can really do...thank you so much for those links, i'm a rather visual person and i've been reading articles about CNC machines this weekend, but i was having difficulty wrapping my head around what all the hub bub was about