[dexter4000]

8020 T-Slot Milling CNC

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Im planning on building a CNC Milling machine out of t-slot frame for cutting aluminum and mild steel.
Does anyone have one or has any suggestions in building one for milling metal and if its sturdy enough?
Also , what is the best spindle for milling metal? Are the china ones good ?

Thank you.

[TechGuy5002]

8020 T-Slot Milling CNC

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Im planning on building a CNC Milling machine out of t-slot frame for cutting aluminum and mild steel.
Does anyone have one or has any suggestions in building one for milling metal and if its sturdy enough?
Also , what is the best spindle for milling metal? Are the china ones good ?

Thank you.

That largely depends on the work area. Unless your work area is tiny (just a couple inches), it will not be sturdy enough to cut steel. Perhaps an alum t-slot mill will be OK for very thin sheet steel. If you plan to have a reasonable work area measuring 10s of inches the machine will need to be constructed out of steel or perhaps stiff alum (like 7075). A machine would have considerable mass measured in many hundreds to thousands of pounds.

High speed Chinese Spindles are way to fast to cut steel. They will probably work OK for alum.

[dexter4000]

the area of work im thinking to be a 30' x 25' .
The china spindles are variable so speed is not a problem when cutting im thinking more of torque. I also thought that aluminum will not be a problem but steel is a totally different animal.

Thanks for the input.

[TechGuy5002]

the area of work im thinking to be a 30' x 25' .
The china spindles are variable so speed is not a problem when cutting im thinking more of torque. I also thought that aluminum will not be a problem but steel is a totally different animal.

Thanks for the input.

Its likely the the high speed spindle will not put out the same torque at low speeds. A better option wound be a 3 to 5 hp three phase AC motor. using a belt fed spindle and a variable frequency drive.

I think you mean 30" (inch) by 25" (inch) not 30' (feet) by 25' (feet).
In either case, alum. t-slot will not be rigid enough for milling steel. You need to go with a steel frame. With a 30" by 25" inch work area you will likely need the stifness equivlent of about 8"x8" solid steel construction. either a single vertical column of 8x8 or a pair of 6"x6" columns. Even the 8x8 column will limit milling cutting depth to avoid excessive tool chatter. You could use steel flat bar (perhaps 6x1 and 8x1 bolted or welded) and filled in with epoxy and granite to avoid using solid steel columns. The table could be constructed using a torsion box. Perhaps if your milling thin sheets you can get away while less stiffness, but I suspect you intend to machine more robust work pieces. If you intend to mill just alum. you might be able to get away with a 6x6 or 5x5 solid steel column. FYI: I am assuming a Z travel of about 10 to 12 inches. Go look up specs. on a typical manual mill to give you the scale of how rigid the frame must be.

FWIW: if you already don't own a manual mill, I would recommend getting one first. This will provide you the means to lean and provide the means to construct your CNC mill. Manual mills are extremely useful, even if you had a working CNC.

[dexter4000]

It is 30" X 25", sorry for the typo.
Im gonna be milling steel just on small parts everything else will be aluminum and wood.
I was gonna do the frame either way from steel because its much cheaper than buying aluminum.
Thanks for the input. Much needed.