Step 5: Make the anti backlash screw blocks

Take the three pieces of 2 1/2" x 1 7/8" plywood (you could also use Delrin or MDF) and cut them according to the drawing. Drill and counterbore the holes for the mounting bolts. Drill and tap the 1/4" Aluminum rod for the 4mm bolts and insert them into the blocks (make sure you can see the threaded holes.) If you use Delrin to make the parts you can skip the Aluminum inserts and just thread the holes in the blocks for the 4mm bolts that hold the metal plate that retains the ACME nut.

My blocks were cut by hand- and it shows! The best way to cut the 1/2" wide slots for the ACME nuts is to make a jig and cut them using the router table. Clamp the screw blocks in the jig and then run the jig over the router bit to cut the slot. Don't try to cut the slot to full depth in one pass- just slowly increase the bit height and make multiple cuts until you get the desired depth. Cut the slot for the non spring side first and then flip the piece over to cut the other slot- that way both of the ACME nuts are guaranteed to be in perfect alignment.

Now make some 3/4" x 1 7/8" retaining plates for the front by drilling holes for the mounting bolts and a 5/16" hole so the ACME rod can slide through.

Check the fit of the parts by assembling it as shown in the drawing. The spring should be 1 1/4" long ( or close to that) before being compressed.
<p>please can you suggest me what outcome is possible after making this machine</p>
You can mill small parts in wood and plastics but not metal.
<p>Hello, <br>At the moment, I'm making a CNC machine to drill PCBs's holes but I'm having some problems related calibration because the measures from the gerber file (.drd) are in millimeters and I need to adjust it for the maximum resolution (X, Y) of the my machine. My work area is 208mm X 284mm and I'm using labview software to control this plant. Can you help me ? My address e-mail is: fabio.pinheiro.mail@gmail.com</p>
Unfortunately I don't have any experience with this or Labview. Have you tried the CNCZone forums? That's honestly probably the best place to go to get help with your problem.
awesome project<br>
<p>What happened to your new milling cnc?<br>you only posted one picture of it (in construction status)</p><p>I am trying to make one... some ideas of yours? advices? pictures of yours?</p>
I'm still working on it- LOL! It got pushed on the back burner as I've been working on so many other projects. I'll eventually finish it. :)
<p>can anyone please help me out with the details of electronics part??</p><p>i have purchased sanguino controller which uses atmega644p, but have no idea how to interface it with stepper motor (nema17). also we will be using eaglecad, pcb-gcode wizard and pronterface software(s) to make the pcb design, convert it in gcode and send the gcode to the controller respectively.</p><p>someone suggested us to use L293D stepper motor driver but we are not sure how to interface it with sanguino controller.</p><p>we are quite clear about the mechanical section but are unsure of the electronics one.</p><p>kindly help me out.</p>
How long did you spend on this project? I'm trying get approval from my boss to build one of these for our prototyping workshop, he likes the component cost but wants to know how many labor hours I would spend building it .
Maybe a couple of weeks at least? It's hard for me to remember since I built it a while ago.
what a beautiful machine~ i love it. maybe i'll make one~ I have a old printer, maybe i can use it~
Can u please tell me the spindle's minimum requirements for milling jewelry wax? I am building a cnc router for making master models from wax. The motor is 50watts 2500rpm 220volts. You have used 12v motor, how many watts is it and amperage?
Wax is really easy to mill. A motor this size, or anything over an amp or two should be able to handle it easily.
I have already bought a spindle motor from china and with proper settings it can handle even aluminum. It is 12-48v 300w 12000rpm with ER11 collet.
I no longer have that motor since I am building a new machine. 50 watts@2500 rpm sounds pretty low unless you are using a very small cutter at high rpm. The problem with using very small cutters at high rpm is vibration- minimizing vibration in the spindle is very important.<br> <br> Have a look at this thread for building a low cost variable speed spindle using a RC brushless motor-<br> <a href="http://www.rcgroups.com/forums/showthread.php?t=1175772&page=2" rel="nofollow">http://www.rcgroups.com/forums/showthread.php?t=1175772&amp;page=2</a>
Awesome mill Honus! Did you figure out how accurate it turned out to be? I imagine it is only as accurate as the tools you used to build it with. I already have a tabletop manual mill, now you gave me the idea to try and make it a cnc mill for easy operation. Thanks so much for taking the time to document this for the community.
After trying to mill circuit boards I just wasn't satisfied with the results so I started building a new CNC that is much more rigid- plus it will print 3D parts as well.
What are the dimensions of the extruded aluminum?
The extrusions measure 1&quot;x3&quot; and 2&quot;x4&quot;. I really need to get going on this again...
Any instructable on this?
No yet- I'm still working on it.
how much did the linear rails cost<br>
I don't remember the exact amount since I got them a year ago but I think they were around $600.
The word is &quot;Torx&quot;. :)
Yes- but most every wood screw company labels them as &quot;Star&quot; drive screws- I didn't want people saying &quot;I can't find Torx screws- I can only find Star screws.&quot; LOL!
I recently obtained two small motors from a vacuum cleaner. one is about the size of a roll of Kodak film, the other is larger than a film canister. This also came with a 6V power supply. Seeing as how the vacuum cleaner didn't do well after years of use, could i use the motors for making my own mill or lathe? or maybe some other tools?
I honestly have no idea. Without having some specs on the motors it's impossible to say.
can u teach me how to program..?
Sorry but I can't. You might have a look at CNCzone.com.
good and useful idea
Good link for CNC supplies.<br><br>http://www.kelinginc.net/
Cool. I noticed you had issues with accuracy with your build and started a much more expensive one. I was wondering if the slides were where you think yo lost accuracy. I was wondering to make the oversize and shim them to suit while using bolts through the outisde face of the aluminum to maintain the parallel integrity.
Here are my x &amp; y slides retained on the spacer from the outside. I plan on making my delrin a bit oversize and shimming my rails to suit.
Progress with larger spacers due to my different aluminum C-Channel. Anyone need the old ones?
That looks great! Are the spacers Aluminum?
yes. I have some resources that you don't ; )
It seems my aluminum c-rails are 1/8&quot; wall thickness instead of the called for 1/16. I am wondering if I need the plywood for the y-axis slide. It seems pretty rigid. I guess the design of the y-axis backlash mechanism would have to change to suit also....hmmmmmmm....
It probably won't be rigid enough without a base for the Y axis and the slide will bind under load. One thing you could do about the backlash mechanism is to use Delrin nuts for the lead screws instead as they take up a lot less space. Dumpster CNC sells them-<br> <a href="http://www.dumpstercnc.com/" rel="nofollow">http://www.dumpstercnc.com/</a>
It actually had more to do with rigidity and vibration- that's why the new machine build is all aluminum and uses very rigid slides. The most difficult thing with this build is making sure the slides don't have any slop in them while still being able to slide with as little resistance as possible.
I see the acem nut is only retained on one side. Is it necessary to make a retainer for the spring side or does the spring tension keep it in tune? thanks in advance.
The spring tension keeps in place- it can't rotate in the slot.
Yet another question. I am thinking of using 1/4-20 ACME rod instead of 1/4-16 and was wondering if there was a particular reason you chose the 16. thanks.
It's just what I found locally.
I have a question about the main z-axis laminated base. There seems to be a dimension missing that looks to be about 4&quot; on the left side of the sketch. Does that seem about right. Forgive me in advance if I am wrong and don't see it.......again : )<br><br>thanks in advance.
You are correct- it should be 4&quot; long. I had to go back and look at how the Z axis is constructed to make sure (the mounting screws are 2&quot; apart.) I also found a couple of other errors that I needed to fix. I'll make a note on the drawing- thanks! :)
No problem- I would have felt terrible if I told you to buy the wrong size material. Delrin is expensive stuff!
Yes it is expensive when you buy it from the plastic supply store in london (Canada). I wish that I had checked Forest City surplus first. They have it at a very reasonable price.
3D etchesketch anyone? :D
can u plz give the complete details of its working i am a diploma studentt in mechanical engineering and i m thinking of making this as my final year project
All of the information necessary is presented in the instructable. Is there a specific question you have?

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Bio: I'm a former bicycle industry designer turned professional jeweler. I like working with my hands and am happiest when I'm in the shop ... More »
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