Harbor Freight 44991 CNC SUPER CONVERSION

[asammons]

Hello Everyone,

I'm new to CNC hobby and after stumbling around and reading for several months I feel that I am ready to engage into my own CNC conversion. Here we go.

THE MACHINE

The base machine chosen for the conversion is Harbor Freight 44991. It has a farily ridgid column and has proven to be a good investment after 12 months of use.

GANTRY

Stock gantry is very small. I have purchased a composite mini mill base from CNCbridges.com that gives 26"x9"x9" traversing, greatly increasing effectiveness of the machine. Gantry uses precision ACME screws with antibacklash nuts, as well as linear slides.

STEPPER DRIVE

HobbyPRO 4-axis drive will be used to drive 425oz-in unipolar steppers.

POWER SUPPLY

Toroid transformer with two secondary coils, rectified to 39VDC at 20A, should provide enough power for all 4 axes.

SOFTWARE

CAD: Alibre Design Expert 9.1 (SP1)
CAM: SprutCAM 4.0 (if I can find a correct post processor for Mach3)
NC: Mach3

POSSIBLE CONCERNS

Unipolar motors should have plenty ot torque. However, should I see problems with current lead screws I may choose to upgrade to ballscrews, thus increasing effectiveness of power transmission.

What do you think?

[SyilAmerica]

Sounds good.

Let me know when you are ready for the Mach 3 post for SprutCAM. I've modifiied one that works great.

[jacarpen]

Do any of you guys know of anyone that builds these Gantries for the larger benchtop mills. I would love to retrofit mine for one of these. I have the Rong Fu 31 or something similar to that.

[asammons]

Originally Posted by SyilAmerica Sounds good. Let me know when you are ready for the Mach 3 post for SprutCAM. I've modifiied one that works great.

I think I am ready for the Mach3 post! It's amazing you brought this up, I found the below Mach post processor for SprutCAM, but it may have issues:

http://www.download.sprut.ca/temp/Mach_.spp

[asammons]

BUILD PROGRESS: DAY 5

Well, electronics is coming together quickly.

New CNC Computer
I was thinking about building a computer for the CNC conversion, and then stumbled on DELL SX260, the smallest desktop ever. Specs:

Size: 9"x9"x3"
Processor: P4 2.66GHz 533MHZ BUS
RAM: 512DDR (Upgreadable to 2GB)
HD: 40GB Hitachi
LAN: 10/100/1000 (Yes, gigabit!)
Sound, usb, blah blah blah

Computer has a parallel as well as serial ports, and comes with a Windows XP Pro license. Perfect for CNC and all for $195 on eBay!

It's Alive!!!
Received HobbyCNC Pro 4-axis board in the mail couple of days ago, it was quickly assembled and tested using a scrap unipolar stepper from a UMAX scanner...Also salvaged some heatsinks out of an old ATX power supply to give it the finished look. Compare the 4-axix HobbyCNC Pro board to the computer it's attached to...go Dell SX260

[tobybirch007]

How's the conversion goin? I'm thinkin about doin this exact same thing. What power steppers are you using?

edit: I found the steppers, shoulda looked first...

[Vogavt]

Title says it all!

I was at a local HF yesterday and noticed their 44991 was marked down to $350 as a Close-Out!

Anyone else seen this?

I didn't get a chance to talk to the Manager, so I didn't get any details.

[asammons]

I wanted to follow up on this - finally got around finishing the project. CNCbridges failed to deliver the table, and we decided to make a Harbor freight 44991 / 33686 hybrid. All details are in this new thread!!!

Benchtop Monster is Born - Harbor freight 44991 / 33686 Hybrid CNC Conversion!!!