[i_am_fubar]

Ahh, god bless the philosophy of jumping in the deep end. This is the first of my projects on this scale. As you can probably tell my the pictures, it will become a CNC mill. The travel is 240x220mm on the X and Y respectivly and 150 on the Z.

The X and Y bearing are THK SR20's and the Z will use HSR15's. I'm aiming to use a splined shaft to transmit power from a motor at the back of the Z colmn so the excess weight isn't being lifted every time the cutting head moves up and down.

The core of the base is a large chunk of ground cast iron. it has two 25mm plates bolted to the sides and the rails are mounted on that. The table is a spare part from a TaigX3, modified to take the bearings.

Z design is on its way.

Out of curiosity, I'm only 21 and wondering if there's many people my age doing this sorta stuff.

anyway, heres some nasty pictures from my phone, enjoy.


The base of it so far. all steel and iron.


Close up of the front of it. the handle is there for testing only.

[RICHARD ZASTROW]

fubar, You can't be the same one I had to live with in the US Army!!!!
Your project is looking fine. Your spline idea solves one problem and could create another. Just be sure to have a spline shaft/nut without slop. There are applications like this out there. They are fine till the spline/nut interface wears and then strange harmonics etc. show up, even on surfaces you machine. I,m not saying it's not a good idea, just be aware.

[dansutula]

Good Ideas and Good Start!
I believe that you are well on your way to building an exellent mill.
From the look of you work, I'd guess that you have had either design/engineering experience or have a natural knack for design, or both.
Regarding the stationary motor/ spline-driven spindle, I have also contemplated this idea. It is similar to a Bridgport wherein the quill is moving but the motor is stationary. Perhaps you could scrounge some Bridgeport parts and or design elements. Due to their past popularity, there are lots of used BP parts available at low costs and even some of the retro kits (such as ballscrews) are available far below the cost of individual custom components. The BP components are a bit larger than benchtop scale but may be worth considering.
Good Luck, and keep us posted!
Dan

[i_am_fubar]

Yea, the workshop technisions (am using the Uni workshop) were a little confused. I have no qualifications in mechanical design or machining. But I'll soon have a degree in cybernetics and electronic engineering.

Something I was trying to work out. As the position of the spindle rotation isn't a critical measurment, is the slop only a concern for when the the motor is spinning up and down?

As to the components I'm looking at using, they are the ones shown here :-

http://www.huco.com/products.asp?cat=202

I need to start work on the motor drives and assemblies, all I have at the moment is a very big, heavy and over engineered XY table.

Sam.

[RICHARD ZASTROW]

Sam, I guess it's a matter of what the application will be. I would think that if you intend to do helical interpolating, solid spindle (rigid) tapping under CNC control, there could be a problem with thread leads. You could get some "spindle bounce" (recoil) as well.

[DennisCNC]

Out of curiosity, I'm only 21 and wondering if there's many people my age doing this sorta stuff.

Well, im 24 and this is what my dad and I built, I did all the wiring

http://www.cnczone.com/forums/showthread.php?t=27147
http://www.cnczone.com/forums/showthread.php?t=27570


Nice start on the base!!!

[i_am_fubar]

Wow, thats cool. I really want to see if my mill will be able to engrave marble/granite and the such when its done.

I will keep in mind what you've all said about the splined shaft and provide concept drawings ASAP.

Sam.