[skipper]

Hi Folks,
I've seen several Harbor Freight 33686 and Grizzly G1005 mill/drill CNC conversions that used Geko steppers controllers or servo motors. Has anyone converted these or similar sized mills using the Keling controllers and stepper motor package? I would like to use their 495 in-oz motor package but am not sure if it will work. I have not come across anyone who has used Keling kits to run this medium size mill.
And yes, I have asked on the Keling forum site but got zero responses.

Thanks for the help,
rene

[nlancaster]

I have not bought a mill yet but that will come after my CNC router is done, so these are opinions based on what I have read.

I am going to be using the Keling 495 oz/in motors and controlers on my CNC router, they seem like a good deal and well thought out combo package.

Both of those machines have one huge problem from the CNC stand point, Round Columns. This means that moving the head up and down to get more Z-axis movment will cause it to lose position in X-Y plane. Otherwise you are limited to 3-5/8inches of Z spindle travel.

How about considering these 2 mills,

http://www.grizzly.com/products/G0463
X3 many people have converted these and there are also prebuilt upgrade kits for CNC that add ball screws and preloaded ball nuts. Saving you the time have having to engineer all those parts yourself. Also has 15inches X travel x 5-3/4inches Y travel. While the Y travel is slightly lower then the 2 round colum milles you are looking at. Also the round colum mills you are looking at do have a more powerful motor at 1HP vs. .75HP on the X3.

http://www.grizzly.com/products/G0519
Another option if you are looking for a bigger mill that will not break the bank is thise one from Grizzly. I believe it is a clone of the Rong Fu RF45 that is used by Industrial Hobbies for the basis of thier mills. Larger table then any of the above machines with large work area, more Z travel, and 1HP motor that could easily be replaced with a more powerful Motor and VFD control for higher RPMS and Horsepower.

I am trying to decide between these to mills for my next big purchase. I like the work area of the G0519 but it is almost 2x the price of the G0463 and I think I can do everything I want on the X3. Or at least everything I can think of right now.

[Ron111]

Skipper,

It’s a fair question, and I feel comfortable giving you an answer. Making the assumption that ball screws and ball nuts are used, and that the stepper motors are driven with bipolar drivers which delivers the maximum rated torque, and a supply voltage at least 36 VDC (Assuming this is with in the Keling Driver voltage range).

As far as the machines, the Grizzly 1005 (435 lbs. Shipping weight) is smaller than the Harbor Freight 33686 (706 lbs. Shipping weight (620 net weight)). So, the HF will require more energy to move the axis.

The Grizzly 1005 is about the same size as the X3, and also the table size. As far as stepper motors on cnc’ed X3's, several have used Keling 425 in/oz steppers with good results. Some have direct coupled and some have used a 2:1 gear ratio which would effectively double your holding torque to 990 in/oz. Either way, these motors should work just fine.

The NEMA 23 motor does not have the heat dissipation that the NEMA 34 does.

I would think that the Keling 495 in/oz would provide the power for the HF 33686 if a 2:1 or a 3:1 pulley ratio was used which gives 990 to 1485 in/oz.

Assuming 500 rpm stepper motor speed, and a .200 pitch/inch screw would yield rapids of 100 ipm with a direct drive coupling.


Assuming 500 rpm stepper motor speed, and a .200 pitch/inch screw would yield rapids of 50 ipm with a 2:1.

Assuming 500 rpm stepper motor speed, and a .200 pitch/inch screw would yield rapids of 33.3 ipm with a 3:1.

Steppers can generally run around 800 to 1000 rpm, but using 500 rpm should provide margin in your calculations.

I have used the Keling 425's with Gecko 201's on a lathemaster 9 X 30 lathe, direct coupled with a 5/8", .200 pitch screw, and had rapids in excess of 125 ipm. (Some had advised that the 425 NEMA 23 would not have the power or the heat dissipation for the long Z-Axis of the lathe)

Personally, with the HF 33686, I would choose a size 34 motor somewhere around 600 in/oz with a 2:1, but I think that the 495 in/oz would work just fine.

Ron

[skipper]

Hi,
If I knew then what I know now, I would have bought a square column mill, but, what I do have is the Harbor Freight 33686 round column mill. I am trying to find out if anyone has converted this mill (or similar in size) to CNC, specifically using the Keling motors and controlers. They look like a great package but I am worried that they may not be strong enough for my type of mill. What I have come accross for this mill is people using Gekos or servos but I would like to use the Keling 495in/oz package.

Thanks,
Rene

[Ron111]

Skipper,

Just went to the Keling website, If I went that route, I would substitute the KL-201-24 24V/8.3A power supply with the higher voltage KL-320-36 (36 V/ 8.8 Amp) power supply.

The drivers can handle 40 VDC (including BEMF, also the drivers are spec.'ed for overvolt protection so you are well within the spec.'s) so the 36VDC power supply would do better than the 24VDC as far as performance.

The motors draw 3 amps and with 3 motors and you figure about (.67 X 3A X 3 motors = 6.03 Amps) so the power supply has the capacity.

The 36 VDC power supply is $16 more, but the performance will better.

The motor's were spec.'ed around 3.5 Volts and the max motor voltage is around 20 X 3.5 or 70 VDC, so 36 VDC is well within motor spec.'s.

My take on it,

Ron

[Ron111]

Skipper,

By the way, I see some of the guys using these mills and they turn out some pretty good work. You just have to plan ahead as far as your Z-axis, just so you don't have to reposition the head (if you do you have to rezero all the axis. Bubba has some hints on his website about this and his conversion, if you can stumble upon it, it's a good site.

Ron

[skipper]

Thanks guys,

I think I will give it a go. I do plan on using 5/8 ball screws and probably a 2:1 reduction. I was thinking that if I can mix-and-match controllers and motors, I can use a high amp Geko driver and larger motor just for the z-axis. I can interchange drivers and motors right?

rene

[Bubba]

rene,
to help you "stumble on my site"

http://bellsouthpwp.net/A/r/Arts_home_page/cnc/

Be glad to help if I can.

[Ron111]

rene,
Usually you would fine you larger motors on the X & Y axis, because they are moving more mass, and generally you want higher rapids (moves between actual cuts), where as in the Z axis you are most likely moving to clearance on rapids and you are moving much less mass. I see Bubba paid you a visit, check out his site and his method for preloading ballnuts.

Keep digging,

Ron

[erikj180]

This thread is pretty old.

I have the G1005z and inspiration to convert to a 3 axis CNC. Is anyone aware of a compiled kit that will work *well* with the G1005z? I'm lacking in knowledge on what ballscrew/nuts and motors to order best suited for my machine.

[native34]

I converted my HF 33686 Round column mill to CNC using 3 Gecko G203V drives, 2 Kelinginc Nema34 906 oz-in stepper motors direct coupled to 5/8" ball screw .200 lead 50V 20A toroidial power supply from antekinc.com CNC4PC C11 Multi function board. I am not to happy with limited Z axis movement but all in all the thing functions well and is very repeatable.

[Bubba]

Mine was done with servos and geckos with 5/8" Roton screws on the X&Y axis with the existing quill down feed being the mechanism used on Z. There was additional work done to reduce the backlash on the quill to an acceptable level. Power supply was home built un-regulated using a microwave transformer that was rewound. It was also wound with an additional winding for the 5V and 12V supplies.
The biggest problems over the years have been from Operator error!