Aluminum Casting X-Y Axis Acme Nut Trap from 3D printed models.

X axis acme nut trap. 

I am using 3/8" acme rods and nuts for my X and Y axis.  Nothing I could find would fit my custom cnc build,  so I decided to 3D print some models out of ABS and cast them out of scrap aluminum. 

Models and Machined acme nut Traps. 

 After casting the parts in a sand mold,  I machined them on a 12" drill press using an X-Y table and a CNC straight cutter.  Slight modifications to make them fit exactly how I needed them. 

Y Axis acme nut trap. 

Right now there are only a couple washers/nuts locking the nut to the trap.   Once the cnc is up and running  I will machine a couple clamps to lock them to the nut traps. 

Aluminum Casting CNC Z-axis carriage

It's been a while since my last post, but there is a really good reason.  I was building a foundry and teaching myself mold making for aluminum casting.  The real hard part was getting a 3d ABS print to create a clean mold.  A problem since it is not a smooth surface.  I found a solution and will be making another post to explain how to do it.

  The video above shows the casting process for 1 of the 6 parts that make up the Z-axis/carriage for my CNC.  It included the spindle mount I designed for the ryobi circle cutter spindle.  There are 2 smooth rod holders for 8mm rods, 2x bearing mounts for 15mm OD 8mm ID bearings.

  It turned out really well with very tight tolerances. No play at all.

Sand cast mold of the 3d printed part.

Comparison of the 3d part alongside the aluminum casting.

Aluminum Cast smooth rod mounts.

The complete Z-axis carriage assembly.

Almost to the electronics. Just have to install the Acme screws/nuts, Design mounts for the limit switches. Then I can start on the electronics assembly/setup.  It is coming along really well.

Recycled parts for my CNC

I am all about reusing,  recycling junk in my builds.  The cutter/spindle motor is no exception.   I've been shopping around for my spindle motor for my cnc.  Estimated this would cost me $70-$150 for this part alone.  Then while looking for some hardware in my junk box,  I came across the perfect motor! 

This is a Ryobi SS180 speed saw/circle cutter that I purchased as part of a Ryobi tool package almost 10 years ago and has never been used.  I cracked it open and found the perfect spindle for my cnc.  Perfect especially since it is FREE! 

The motor is rated at 26,000 @ 18v dc.  I can hook this up to the cnc controller or more likely,  I will connect it to it's own DC PWM controller for manual speed control.  It has a 1/8" and 1/4" reversable collet sleeve already on the shaft as well as a high speed bearing.  It appears the shaft is hardened tool steel,  so it should work  very well.  Also is air cooled (fan). 

 Mounting threaded screw holes on the body and the beefy 32mm bearing on the shaft will make mounting extremely easy. Never know when you will be able to use something in your junk drawers!

  Another new addition to my shop is a Grizzly G8750 compound slide table for my drill press!  Until now I have been doing all my metal machining freehand.  I wish I had this when I started my build.  It makes everything so much easier and precise! Next upgrade will be a new drill press.

Bearing and motor mounts in t6061 aluminum are so much more precise with the X-Y compound table!  It's a dream! 

Minor update,  installed the 5/8" acme screw for the X axis using a 3/4" push bearing in the uprights.  NEMA 17 motor connected with a 6mm to 5/8" coupler. .  Z plate has 2040 openbeam installed.  Next step is to mount the Y axis acme bolt,  motor and hardware.  

This is the current state of my CNC build. The X and Y axis are complete, using 12mm Rods and bearings.  I am waiting for delivery of some 20x40mm Openbeam to start the build on the Z axis.

  The Z axis will be removable to swap different cutters/heads that can easily be bolted onto the 2040mm openbeam..  After that, the only parts that remain are the 5/8" threaded rods and the electronics.

The initial setup will be Sainsmart tb6560 4 axis 3.5amp controllers using 3x 17hs24-2104s Stepper motors and Mach3 Controller software  running on an old IBM Thinkpad (for the serial port) running WIN-XP. Not sure of the cutter head that will be used, but initially going to use a palm router with an electronic speed control unit.