Build your own CNC  Bluechick

I use these building classic bikes, like this and sell some custom parts and tools on EvilBay.  I have used a commercial sign shop for routing, but wanted to be able to prototype and do one offs at home.

First, a word about importing into Canada.  Most US shippers use USPS or FedEx, or the US Postal Service.  UPS and FedEx have what I would have to call predatory customs fees - they make it very easy for the shipper, but on the other end the receiver may pay as much  as $65 'documentation' charge as well as collect the duties and taxes, then charge you a fee for doing so.  USPS delivers to Canada Post who charge $5 handling fee and collect the taxes, however USPS has dropped the affordable international parcel rate and now only has the expensive expedited rate for international addresses.   On a larger item like this, the best way to go (IMHO) is to use a customs broker with a US warehouse - the shipper uses his cheap domestic shipping rate to deliver to a US address, and the broker completes the paperwork and brings it into Canada.  You pay them a brokerage fee, reasonable freight and of course, duties and taxes.  I used Summit Customs Brokers, who have an Oroville, Washington warehouse and a Vernon BC office.  Total charges were very reasonable, and much less than international shipping would have been.  If you happen to have an Amerifriend (EBay speak for someone on the south side of the border who will reship to you) that's even better.

It took about a month from ordering to get everything in my hands, which isn't bad for a pre-release order over Christmas.   In the meantime, I acquired a PC to run the machine by going to a company I'm associated with and asking if they had any computers for recycling.  I got two- both without hard drives, which is common for security purposes.  The later model was a Pentium 4 at 1.4 GH and 500 M Bytes of memory, in a compact tower with dvd and CD burners.   I also got an older 14" LCD display, keyboard and mouse - all free, saving them the trouble of hauling to the recycling centre.  These were all older technology, EIDE drives and slow memory, etc.  A new EIDE 80 GB drive cost me  $80, although it was hard to get it working with the old tech, new drives do a lot more of their own management and it wasn't ready when the OS boot sequence asked it for the MBR.  Adding a mem test to the boot sequence gave the hard drive time to initialize, and it works fine now.  That cost a day or two.  I stripped the other machine and intended to use it as housing for the drive electronics, but changed my mind- more on that later.

I downloaded the Mach3 demo and ran drivertest, had a few problems, which were eventually solved by using the older, noapic parallel port driver.  It now returns a very steady, 25,000 hertz result.  Now all I needed was a CNC kit.

The kit arrived on Thursday, and it was essentially assembled by Saturday morning.
 

There are a couple of stains in the MDF from the oil in the Z axis bearings, so a word about MDF is appropriate.  Medium Density Fibreboard is a free machining wood product made from ground up wood fiber glued together under high pressure.  While it has high compression strength, no grain issues and is dimensionally very stable and consistent, it has little tensile strength, i.e. it doesn't like being bent.  It is also extremely porous and has little or no 'edge strength'.  It will 'split' very easily if a nail or screw is driven into the edge of the board without a pilot hole.  Working with it is a more like working with masonry than wood - design with compression only, and plan on drilling every hole.  It is also a sponge waiting to absorb water or oil.  If it gets wet, it will swell and become very weak.   I sealed my machine with three coats of oil based varathane, which it soaked up like a post desert camel, after assembly.  I had to take the major assemblies apart (Z axis router mount, Z/Y plate, gantry and table) to get at everything but it was well worth it - a spilled cup of coffee can ruin the machine without it.

Patrick's assembly videos are very good instruction, and if you watch them carefully, cover everything.  One thing to keep in mind is the orientation of the major parts, I had to take a few assemblies apart (that's when I was glad I decided not to glue anything...)  to get the orientation right.  If you have the drive side of the table (the side with extra space for the motor underneath) facing you, the high table end should be at your tight, and the low end at your left.  The

antibacklash nut mount, you can grind one side flat  to get clearance.
 

99681-2VGA

This is the wired machine installed in the workbench
  

The electronics and keyboard, etc. are in the drawers, like so (and I know I will have dust management issues, more to come on that) 


I used GE surface mount network junction boxes for the motor/harness connections instead of soldering - just take out the guts and they have 8 screw terminals to attach to.  Very handy and cheap at a couple of bucks each.  Limit switches are all on the gantry, except for the Y axis which are tucked in behind the rails and activated by #8 bolts attached to the rails.  

They're not real obvious, but you get the idea.

A couple of things of things about setting up Mach3.  I followed the book instructions,  and one thing it leaves out is that after setting the pins and ports settings for the motors, you need to set them all to active low.  Also, the Bluechick uses timing belts, not lead screws, so the correct motor settings (thanks to Patrick) are