[Berceli]

I recently purchased an NM-135 with no electronics (no controller, drivers). I have been in contact with Jeff from Novakon, who has said it is a very old machine. He does not have any manuals or spec sheets.

My plan is to use the existing axis motors and hook up new drivers and controller.

What type of drivers are compatible with the installed motors? I am thinking something like a DM556. Thoughts?

If anyone has any information on the machine I would appreciate any links or info.

Thanks - John

[metalmayhem]

I'd lean more to dm860 drivers since they can handle higher voltages

[Berceli]

I'd lean more to dm860 drivers since they can handle higher voltages

Do you know what voltage/amp settings I should be using?

[metalmayhem]

I don't know what motors are used on an nm so I have no idea what is ideal . The motors should show the rated amps and a voltage to work from . If they don't and novakon doesn't remember then I'd replace the motors since they are fairly cheap .
Lets say if you use 48v power supplies which isn't uncommon then your pushing the other drivers to their limits

[joeavaerage]

Hi,
I built my own machine. I use Mach4 as CNC software and an Ethernet Smoothstepper as motion control board mounted on my own design/build breakout board.
I have been using this combination for nearly ten years and Mach3 prior to that. Mach4 is light years ahead.

You need to decide whether you get servos OR steppers. There is nothing wrong with well chosen and spec'ed stepper, but if you want fast, powerful and high resolution; then get servos, and don't be tempted by the cheapest
no-name Chinese brands, you want something better. I use 750W Delta B2 servos, a Taiwanese brand made in China. They are superb. I pay $438USD per kit (servo, drive and cables), have done for some years.
They eat ANY stepper ever made!.

Craig

[metalmayhem]

Hi,

You need to decide whether you get servos OR steppers. There is nothing wrong with well chosen and spec'ed stepper, but if you want fast, powerful and high resolution; then get servos, and don't be tempted by the cheapest

Craig

I believe these mills are basically sieg x3's though I may stand corrected . I'm willing to bet it's a rebranded sieg cnc from way back , it sure looks like them . I think a decent set of steppers would do fine . It's not enough of a mill to justify servos and it's overkill in my opinion .
I looked at a test video that novakon put out and it is very slow .

edit
I just looked online and the sieg is apparently the same mill . Google Sieg KX3 CNC Mill and there is some info that can be found . The rapids are only 40ipm so if it were me I'd change everything .
I considered buying some of these when little machineshop was selling them but by then they weren't carrying stock

[joeavaerage]

Hi,
for such a small machine steppers will be fine.

If you go to buy new ones (recommended) then DO NOT BUY HIGH INDUCTANCE steppers. All the manufacturers have high torque steppers and they sound very attractive until you consider the
inductance, in many cases too high to be of any use in a CNC machine. The manufacturers know that most first time buyers don't understand inductance, so they make these models cheap albeit with high torque
just to catch the newbies.

All steppers lose torque the faster they go, that's physics and there is no getting around it. Inductance is a reasonable measure of how bad that degradation will be, the lower the inductance the better.

For 23/24 size steppers look for 1mH to 2mH, 1mh preferred and reject anything over 2mH.
For 34 size stepper look for 2mH to 4mH, 2mH preferred and reject anything over 4mH.

The best steppers are seldom those with the absolute highest torque but rather those with moderate torque but low inductance.

The other classic method to overcome high inductance (sluggish) motors is with high voltage drivers and power supply. You should get drivers that are at least 80VDC and a matching power supply,
preferably a linear supply, as they are much more forgiving of short term overloads.

https://www.antekinc.com/ps-10n80-10...-power-supply/

Don't be alarmed or put off by spending a little bit more on steppers, drivers and supply now. If you buy well you'll have them for twenty years, and probably outlast this machine and maybe your next one too!.
Buy unwisely and you'll be contemplating replacing your poorly chosen items within a few months. Been there, done that.

Craig

[Berceli]

Thank you everyone.

I got the old steppers working with some drives I had. Yes, they are slow. Noted on new stepper motors. I will up grade since I get the spindle working.

I am now working on the spindle. It is a little “crunchy”. I am trying to remove the spindle from the casting that holds the spindle. I can not figure out how to remove it. Photos attached. I either need to rebuild it with new bearings or replace with a new spindle. I am not sure if that is an option.

Suggestions?

Hi,
for such a small machine steppers will be fine.

If you go to buy new ones (recommended) then DO NOT BUY HIGH INDUCTANCE steppers. All the manufacturers have high torque steppers and they sound very attractive until you consider the
inductance, in many cases too high to be of any use in a CNC machine. The manufacturers know that most first time buyers don't understand inductance, so they make these models cheap albeit with high torque
just to catch the newbies.

All steppers lose torque the faster they go, that's physics and there is no getting around it. Inductance is a reasonable measure of how bad that degradation will be, the lower the inductance the better.

For 23/24 size steppers look for 1mH to 2mH, 1mh preferred and reject anything over 2mH.
For 34 size stepper look for 2mH to 4mH, 2mH preferred and reject anything over 4mH.

The best steppers are seldom those with the absolute highest torque but rather those with moderate torque but low inductance.

The other classic method to overcome high inductance (sluggish) motors is with high voltage drivers and power supply. You should get drivers that are at least 80VDC and a matching power supply,
preferably a linear supply, as they are much more forgiving of short term overloads.

https://www.antekinc.com/ps-10n80-10...-power-supply/

Don't be alarmed or put off by spending a little bit more on steppers, drivers and supply now. If you buy well you'll have them for twenty years, and probably outlast this machine and maybe your next one too!.
Buy unwisely and you'll be contemplating replacing your poorly chosen items within a few months. Been there, done that.

Craig

[metalmayhem]

my guess is that under the top flange there should be a nut . once you remove those then it should pull / tap out through the bottom

[Berceli]

There are two flanges one at the bottom, which can not be removed because the spindle prevents it and one at the top because the belt gear is in the way. The belt gear seems to be a interference fit as I cannot find a set screw. The belt gear is 1/4" or so from the top flange, so removing the top flange it will hit the gear before revealing a nut.

When I am with the machine tomorrow I will be more aggressive on removing the screws on the top and bottom. The screws are small and short and seem to just hold the flange.

Ideally, I would like to replace the spindle.

[joeavaerage]

Hi,
see the pics I posted earlier. I bought the spindle (new old stock) 3.5kW(S1), 3.4Nm(S1), 10krpm(rated), 40krpm(max), 400V, HSK32E tool interface plus ten HSK32-to-ER20 tool holders for $2000USD including
shipping (but not including the VFD) from Vietnam. ATC in particular has fundamentally changed my CNCing, for the better. While 3.4Nm is pretty modest I can run 6mm and 8mm endmills in steel quite
aggressively and with decreasing torque authority but otherwise usefully 10mm, 12mm and 16mm again in steel.

ATC spindles in this category, say 3kW to 7kW, are as cheap as I've ever seen them. My guess is that the Chinese economic downturn is prompting manufacturers to sell at cost or even below just to
secure sales.

Rebuilding or repowering an existing spindle might seem cheaper, but only seem cheaper.

Craig

[metalmayhem]

it's tough to tell by looking at 2 pictures . there should be a nut there somewhere thats holding it all together and adjusts the pressure on your bearing . Was the nut holding down the pulley , and have you pulled the nut off already ? .
You need to pull the screws form the flange . If the nut has been removed already then the pulley should pull off which may require a puller , it should just be a keyed pulley . From there it should push through the bottom once you pull the screws from the bottom flange

Replacing the bearings is easy , replacing the whole spindle probably won't be unless seig still provides parts for those mills

[metalmayhem]

here is a manual for a smithy (same mill) it has a parts breakdown which should be of some help

https://drive.google.com/file/d/1aOr...5anl5yxYc/view

[Berceli]

Guys, thanks for all the help. This community is fabulous.

The top flange and pulley came off together. It is a keyed connection. I then found the two spindle nuts I was able to remove and tap out the spindle. I found the trashed bearing at the bottom.

The trashed bearing has the markings “32907 qgg qx”. I found bearings that match the number but not the letters. How important will it be for the other markings? Where is a good place to order bearing and what brand?

Folks were correct, upgrading the entire spindle housing, will be a big job, so I can not do that. My goal is to get the mill running and then circle back on upgrades.

here is a manual for a smithy (same mill) it has a parts breakdown which should be of some help

https://drive.google.com/file/d/1aOr...5anl5yxYc/view

[metalmayhem]

all the letters on the bearing don't necessarily need to match as long as the new bearing matches in size and are angular contact .
Little machineshop might have matching bearings for that spindle . They carry some parts for the sieg kx3 which should be all the same .
It would be best if you can match up some nsk bearings

[joeavaerage]

Hi,

32907 is a taper roller bearing. The upper bearing is angular contact while the lower bearing is tapered roller.

Craig

[Berceli]

Thanks lads.

Bearings ordered.

Now I got to get the races out...

[joeavaerage]

Hi,
if you get really stuck, and I mean really stuck, and cannot remove a bearing shell then run a weld in the center of the ring with the MIG. As the weld contracts as it cools the outer diameter
of the bearing shrinks, and often by quite a margin, say 0.5%. Depends on how big the weld is.

I used this method often when doing wheel bearing on boat trailers. The salt water plays merry hell with the bearings and the hubs, to the extent that is was very difficult to remove the bearing
shells and the hub has rusted and increased the gripping pressure of the ring substantially. Through the summer months I would do this at least weekly as part of my job.

Do not under any circumstances miss the bearing ring and strike an arc direct to the inner diameter of the hub.....that ruins it and the chances are you'll never get that shell out. That's why I always
used the MIG, it is just so much easier to start the arc and weld in the correct location. I pretty much refuse to do it MMA.

Craig