What kind of screws should I get?

[Robotics Guy]

I'm a student in high school just starting to make my own PCBs. When I make a PCB I have to drill over a hundred holes with a dremel, and these holes are really small making the dremel bits very easy to break. To solve this problem (and to have another fun project!) I'd like to build a very little, very cheap, CNC machine.

The boards that will be drilled with my dremel are only about 3"x4". What exactly do I need to buy to make the board move back and forth so I can plunge the dremel down and drill the hole?

I'm looking at some 12" screws on e-bay right now (I'm assuming a 12" screw would be long enough, since my board is only ~4" long?): http://cgi.ebay.com/eBayISAPI.dll?Vi...m=330332172328

Thanks for the advice!

[veteq]

Hee there,

Better to buy some second hand ballscrew on ebay, cheaper.
most include bearingblocks.
they where new very precise and more still far more precise than the leadscrews you linked to.

expect to pay at least 1000 dollar for a working machine.
you need
mach3 160 dollar
stepper drives+stepper 200
ballscrews ebay 200 can cut them to the lenght needed.
linear guides 200
a bit alu and milling 200

if you would like i can make you a nice concept design tommorow??

regards,

Roy B.


http://search.ebay.com/_W0QQsassZyishi_xingtaiQQhtZ-1
http://search.ebay.com/_W0QQsassZjak8858QQhtZ-1
http://stores.shop.ebay.com/d-kwa252...34Q2ec0Q2em322

[Robotics Guy]

Roy, thanks so much for helping!

I was hoping to build this for around $300.

This is a hobby project, for learning and having fun, so I'm planning on writing the software myself. Meaning that I won't need the Mach3 control software.

I got some stepper motor drivers free as samples, which I think will work with these cheap stepper motors: http://www.alltronics.com/cgi-bin/ca...brand&start=30

The ballscrews you linked to on ebay are only about $30 dollars each, with $20 dollar shipping. Do I need more then two screws? If not, it looks like the screws will cost about $100 total.

Would it be possible to make the linear guides myself, from cheap metal tubing or something? The boards I'm going to be drilling weight almost nothing, so the guides do not need to be very sturdy.

a bit alu and milling 200

I have a dremel that should work very well for drilling PCBs, does that eliminate the "milling" cost above?

if you would like i can make you a nice concept design tommorow??

That would be great!

Again, thanks so much for your help!!

[veteq]

if its low budget you can make it youre own,
just read a lot on the forum.

thinks you will nead 3 screws.

regards

[venomx999]

If its just tracing and drilling boards. You oughtta check out www.instructables.com They got a small cnc made from pipe metals. It would be the least amount of $ spent on the project.

[pminmo]

Actually for a small pcb machine, plain old all thread 1/4-20 is fine.