Getting things together.. What IS a lead screw?

[Zagroseckt]

Hay folks. I'm new here and i'm Gathering the meterials to build a chapcnc like rig.
I'm just stuck on a few points

Like what the (explective) Is a lead screw?

I minchen this at my local hardware store and they look at me wierd.!. i don't like being looked at wierd

More questions to come i asure you.
Sorry if this is in the rong spot.

Oh ya HELLO ALL

[Chagrin]

Lead screw: "A device consisting of a threaded shaft and moving carrier such that the carrier moves equidistant intervals for each rotation of the shaft"

For hardware store purposes, just ask for "threaded rod" or "allthread".

[Zagroseckt]

Oh thank you i at least i know what allthread is i Might even have some but im not sure of it's condition . Thanks allot

Now next question.
Since I've never used allthread in this manner befor.
What kind of barring should i use?
Any suggestions or is it users choice.?.

And should i prepair it in any special fasion

[DR-Motion]

Hi Zagroseckt,

check out this link to my website, although it doesn't show the cheapest components it might help you get the picture in your head... http://www.cnc-hobby.com//cnc-kit-components.html .

After a while you get used to the "hardware pro's" looking at you funny and when you start to educate them you get more respectful looks.

regards Gary

[Zagroseckt]

Wow thanks I'll look this sight over

As for the first page my only reply is EESH!

and here i was allmost thinking of using a few carage parts from an old large printer....

all thooo i could probly still use some of it. i do know that preticular printer literly squashed a 2x4 into splinters when it was in use (alltho the 2x4 did ruin the print head... well not realu ruin just knocked the plastic retainer off the pinshild...

It still prints if you dont mind it ripping the papper up but not for long regardles im using those stepers...... THERE HUGE!

[rvan]

Originally posted by Zagroseckt Oh thank you i at least i know what allthread is i Might even have some but im not sure of it's condition . Thanks allot Now next question. Since I've never used allthread in this manner befor. What kind of barring should i use? Any suggestions or is it users choice.?. And should i prepair it in any special fasion

First off, A standard Threaded Rod (English or Metric) is not ideal for with Milling. You want to either use a ACME screw or a BallScrew.

ACME Screw
http://www.nookindustries.com/acme/....meAssembly.jpg

BallScrew
http://www.nookindustries.com/ball/....lScrewInch.jpg

These are designed to push loads using a Nut. With a standard threaded rod, you will run into problems, because they are designed to support non-movable loads.

You will also need a special nut in order to reduce or eliminate backlash. Backlash will decrease the accuracy of your mill.

Before you start buying stuff to build your mill, I would highly recommend you read up on Mill construction. There are lots of Web sites showing and explaing how a DIY Mill is created. You save your self a bundle in purchasing mistakes. I would also recommend that you write up the dimensions of your mill, what type of materials you intend to Mill, How fast and how accurate will it need to be.

Then make a list of all of the components you will use, and include sources and prices. You'll be surprised how quickly the costs will add up.

[Zagroseckt]

Oh and to ancer one question i see on your sight.
I want a CNC for 3 things.
1. i cant cut a straight line.... without a ripguide
2. i cant cut a curved line well not a good one providing i dont loos controle of the drimmel
3. I'm a moder ( i mod electronics) i love taking opjects and using them in maners the manufacture never designed them for. I've done many projects and alltho they sufice they quite frankly look like crap. And the Moder in me DOSN'T like things that look like they wor made by a 4 YO with a hammer and some chewing gum.

I'm tierd of asking frinds to cut out brackets to hold lights in computer cases. Tierd of making mods that dont look profecinal.
My goal is for when some oen sees one of my mods they go "Wherd you buy that." not Neet you made that yourself....

Arguible a SLA system would probly be faster but im not a millionare so I'm gona be doing 3d rapid prototyping on a slow CNC and ill be estatic the first time it takes me 30 hrs to make one case... my first project will be to take a GBA mod i've done (replacing the 1.6" screen with a 5" screen w/ moved cartrige slot tv transverter and a built in game riper (eprom emulater) wich i have planed out and working aside from assimbling and putting it in a nice designed case.

I have autocad and im looking into a program called alibre.
I also have 3dsMAX wich is more for 3d grafix than solid modling altho it can do it.
I KNOW how to use max im lerning Acad and alibre

With my luck my first pices will be replacement parts for the router (it's probly gona look silly if i do the cutting)
Any sugestions?

[Zagroseckt]

I shoudl have spell checked that

[yukonho]

Although acme leadscrew or a true ballscrew with anti backlash nut is nice, threaded rod will definately work well enough for your purposes. My current machine uses 1/4-20 threaded rod and I use cuttingboard material (HDPE) for the nut. I threaded it with a standard hand tap. I use my machine about 3-4 hours every day for my small manufacturing business. The repeatability and accuracy are more than adequate for this purpose and way better than you could ever dream of getting by hand.
My whole machine from scratch cost around $400 Canadian to build, including all electronics and hardware, everything.
Do a lot of research and read the forums extensively to see what can be done and what options you should consider for your machine.
co

[Zagroseckt]

Ok now for the tool itself.

I have a rather overpowerd drimel (not the REAL name brand but it uses drimel bits and chuks) I've used it for a few years now at full speed it can definintly leve ones hands numb.
My question here is how much vibration should the tool put out.
(note the vibration is when running at full speed) i rarly have had to spin it up THAT much.

Should i go with another kind of router if so keep in mind alltho im not "cheep" i only have about 100 buks a month to spend.
I'm Visualy impard and on SSDI

[chuckknigh]

Since I've never used allthread in this manner befor. What kind of barring should i use? Any suggestions or is it users choice.?

Here's the bottom line. Go to your hardware store. Grab some allthread, and a mating nut. Now, it's time to play.

Put the nut onto the allthread. You probably did this by holding onto the nut, and spinning the threaded rod. This is exactly how a leadscrew works.

The threaded rod is held stationary, and then spun by the motor. This results in the nut moving in a linear fashion, up and down the threaded rod.

You attach a table to this nut, and the nut pushes it around! Simple, isn't it?

Now, there's a little bit more involved. You have to hold the table level (otherwise it'll just spin around the screw) and you usually do this with a bearing surface on each side. Since friction will rob you of power, you want to support the table on some sort of bearings.

One thing to use for bearings is rollerskate bearings, rolling on gas pipe. At the other end of the spectrum is super expensive precision ground linear ways with mating low friction bearings.

Take a look around this site, and look at the details of how these machines are built. CNC machines are amazingly simple, mechanically. It's the electronic interface, and the programming, that can get complicated.

You might also take a look at the pictures on http://www.crankorgan.com for a few ideas...he has great pictures, and some pretty good ideas for some pretty cheap machines.

-- Chuck Knight

[Zagroseckt]

ok but how do i get the allthred to spin freely inside it's mounts.

(Items perchesed so far.) Bunch of MDF small sheets. Pack of cutting blades for drimmel. 4 rod's of allthred. marker caliper verious nuts and bolts. box of ye old ballberings (i use this in other projects )

Work done so far (Wire raped controler board for steppers All 3 stepers are responding to basick commands.)
Looked at MDF in bewildermint wondering how high or short or well you get the idea

I realy dont want to "Buy" plans half the fun is in the playing but i dosnt mein i know how high the gantry should be... Oh boy is it gona be fun trying to line up everything. think im gona borrow a drill press for that part