I Have a Novakon NM-200. Questions anyone?

[cjjonesarmory]

Hello all,

I run a small shop and do various work, some gunsmithing, some woodworking, and some just screwing around :-)

I purchased a Novakon NM-200 a few months ago. I plan to write more about the mill sometime in the near future when I have more time (I'm kind of busy with getting our home ready for me and my wife's first child), but I saw that there are a couple of guys out there that may have questions. I'd be happy to answer any specific questions you may have. You can email me or post your question for everybody's benefit and I'll respond either way.

I don't have any images online to link to. Not sure if the images can be somehow uploaded to CNCZone. If anyone knows the answer, let me know and I'll put up a few. You can sort of see the mill in my "avatar" pic.

Anyway, I'll do my best to get back to any questions promptly.

-Chris

[independent-cnc]

Hey Chris,
Sounds nice. I'm planning to purchase a machine but probably a bit smaller. Maybe the NM-135, X4 or bf20(X5). I think I will benefit from the higher speed spindle of the Novakon for cutting modeling board.

For uploading pictures, I think you just click the "insert image" icon on the message page as you write your post.
Looking forward to seeing more of your machine.

[tbas]

Hi there:

I am thinking about buying a Novakon mill also. For my own work it does not need to be too accurate but I am hoping to do some work for others on the side.

My question is what sort of tolerances should I be able to expect assuming all is adjusted and the mill is not pushed to hard? within a few thou? 1 thou?

Have you tried machining any of the harder materials? 4140 or maybe some 316?

Thanks for taking the time to answer our questions.

Tom

[Mark A Johnson]

I find myself trying to come to a desision on what to purchase. What was it about the NM-200 that made you pick it, and what other machines did you consider?

Thanks,
Mark

[cjjonesarmory]

To independent-cnc:

My NM-200 has an advertised top speed of 4000 RPM, in actuality I've seen only 3000 RPM, but there was a problem with a bearing in the spindle that may have limited the top speed. Let me just say that Novakon's Customer Service is pretty darn good! They've worked dilligently with me on the mill's issues and have so far resolved all of my satisfaction. I am currently waiting for the replacement bearing, but it should arrive any day now. Very responsive customer service.

Anyway, back to the point, even at 3000 RPM and using a 0.0625 (1/16 inch) ball end mill and a 15 FPM feed rate, I have successfully cut embossings from 10" diameter to 3" diameter in several wood species including pine, aspen, maple, oak, and even MDF with no problems. I'm not familiar with what "modeling board" is (I'm primarily a metal person). The only thing I can think of that was a problem with wood cutting is a little bit of "fuzzing" in the embossings when the bit gets a little dull. It just doesn't shear off the wood cleanly at 3000 rpm, in actuality it should be turning at more like 20,000 rpm. I have successfully made a router mount for the mill so that I can use my Porter Cable fixed base 27,000 rpm router in place of the milling head. I am still developing some improvements to the attachement, but so far it's been fantastic. When I'm done, to change from mill head to router attachement, it's just removing two bolts, disconnecting the electrical, using a shop crane (aka engine hoist) to remove the milling head and bolting up the router attachment.

I'll put up some pics of the attachment when I have time.

To the other folks who posted questions: Gotta run for now, I'll reply to some more soon.

[cjjonesarmory]

To tbas:

Accuracy is (for MY needs anyway) pretty good. Repeatability and accuracy is about .0005 (half-thousandth) at low feed rates (say 5 to 10ipm). At higher feed rates, it's a little unpredictable. Although (or because) it has a large bed, the column is not completely stable. Don't get me wrong, it's a fantastic mill for the price range, but when going to feed rates above around 10 or 15 and when there is a lot of rapid x and/or y movement, I notice the top of the mill sort of wagging back and forth. I would say that 50% of the movement is movement or rocking of the machine as a whole, and 50% flexing and movment of the column.

In regards to the vibration of the whole machine: The feet are adjusted properly (they are the regular feet not the type that bolt to floor) and everything is bolted securely, but the very large bed is a LOT of weight to be throwing around rapidly. I can feel the concrete floor shake and vibrate with the incredible power of the machine when it's running at say 30+ fpm and there are rapid x and y movements. So I wouldn't even doubt that part of the wagging is movement of the floor (it's a concrete garage floor) under the machine. I had played with the acceleration settings in Mach3 and tried various settings for the x and y motors down to as low as 6 (original settings were 25 for x and 18 for y) and it did decrease the vibration significantly, but as a result increase the machining times. I decided to let the settings remain at original as it did not significantly impact tolerances (again for my own needs) and it increased machining time.

I think due to the vibration and variability in the x and y movements that the accuracy and precision tolerances are maybe up to .001 inches (one thousandth), but again depends on lots of factors including feed rate and amount of rapid changes in direction.

Another thing I did was remove the motor/milling head shroud. I thought that reducing the top-heaviness of the machine would help. Unfortunately it was about that time that I started experiencing the bearing problems and did not do any more tolerance tests after that. (See previous post for details).

I have not cut any 4140 yet on the NM-200, although I will when it's back up and running. I have primarily been cutting wood and aluminum (6160) since I am fairly new to CNC. Once the milling head is back in action, I plan on doing some more metal stuff. In the mean time, I've been playing with doing wood projects such as house address signs, embossings of 3d models in wood, etc... since the router attachment works great. I've found a lot of demand for wood products from the general public. I think it would be a good way to make some extra cash from the machine by doing wood projects.

By the way the continuously variable speed AC motor is very nice. Sounds like the starship enterprise when it's spinning up :-) I can't wait to test it again with the replacement spindle bearing. I'm hoping it will run smoother at low speeds with the new bearings. Basically, the problem with the bearing was that it had some metal contamination and/or moisture contamination most likely from the chinese manufacturer. The bearing was toast toast toast when I pulled it out.

[cjjonesarmory]

To Mark A Johnson:

Well, there were a couple of lower capacity units that I looked at from flash-cut, but the price wasn't quite what I thought it should be for a converted mill/drill machine. I've got a Grizzly G3616 full size manual milling machine with an Easson ES10-3M5 DRO (from DRO Pros <-Great company by the way), and the thought of getting a mini-machine just didn't feel right.

I considered converting my G3616, but I can't have my mill out of commission during the conversion and I figured I'd NEED a mill to fabricate parts for the conversion anyway, so that was out of the question. It was going to cost several thousand for the conversion as well, and I just wasn't that familiar with CNC at the time and figured I'd probably end up breaking something and never getting the performance I really wanted and buying a new machine anyway :-)

I initially was looking at the same mill from Smithy, but later found Novakon had a drastically lower price, and came with Mach3 instead of whatever the Smithy Ez-trol thing is.

I had also considered financing a true full sized machine from KBC Tool or Grizzly, but after thinking long and hard, decided that I didn't want to fork out twice the cash for a machine that had the same capacity. The extra accuracy/ridgidity that the machines had with bigger columns and parts was not really necessary for me.

My MAIN reasons for going with the NM-200 from Novakon (besides price) was the capacity of the machine, and the fact that (as far as I can tell) the machine is purpose built for CNC (not a conversion), size of axis motors (106 lb-in which if I am thinking correctly converts to 1696 oz-in), and variable speed AC motor.

I can't say plus or negative about Smithy's service, but Novakon gets an A+ in customer service. The problems I experienced with my machine was most likely caused by the Chinese manufacturer, not Novakon, and Novakon has done an excellent job of addressing my concerns.

On the data sheet from Novakon about the mill, one part of the document says that table travel is 24 inches on the x axis and 15 inches on the y axis. There is a red "revised" label next to this statistic. In the specs above the listing of the x and y axis travel, there is a spec for "Work Cube" which lists 22"x11"x10.5" for x, y, z. The machine came configured with 20"x10"x10". I do not think it's possible to get 24" from the x axis without relocating the y-axis homing switch configuration (not adjusting the switch positions but moving the WHOLE assembly out of the way). The motor assembly for the x axis will run into the y axis homing switch assembly at this length of travel. Currently, I've got it set up with 20" of travel between limit switches on x. I think relocating the y axis homing switch/limit switch configuration could get a little more maybe up to 22", but I just don't really see getting 24 inches of travel safely under any circumstances.

I haven't played with the y axis, but my machine currently has 11" of travel on the y axis, with a little more room to play with if I need it. I just haven't had a reason to try and get more from the y axis yet.

Last, the z travel is a little more limited than I'd like. Not the overall travel, 10 inches is great, but I have to use 2-4-6 blocks to get parts bolted to the table. In other words, with a standard sized set of end mills (say 1/8" through 3/4") with approx 1.5 inches protruding from the end of the collet, you are still about 1 to 2 inches from the end of the end mill to the bed. I am going to play with the z travel after I fix the milling head. I think I can adjust the limit switches to allow the arbor itself to come within 1 or 2 inches of the bed, meaning most of the standard end mills should be able to reach the bed. Not that I want to machine the bed :-), but in machining, you can never fully forsee the best way to clamp a part to a machine, and once the machining starts, you don't want to move it. I want to have the extra travel if I need it.

[Mark A Johnson]

CJ,

Thanks for the reply. The good thing seems to be Novakons Customer Service.

Mark

[fineartlig]

can you tell me how difficult it was to get off the truck and in your garage?

What equipment did you need? a Fork lift is not in my shop.

DavidMunson@DavidMunson.com

[cjjonesarmory]

To fineartlig (David Munson):

Well, like you, I don't have a whole lot of equipment for lifting. It was an incredibly nerve-racking process.

I used a hydraulic engine hoist, lots of rope, cable, and a pair of 1,000lb capacity funiture dollys (the short square kind with 4 casters, not talking about a hand truck).

The stand itself is probably between 300 and 400 lbs. The machine is probably about 900 to 1200 lbs. The remaining portion of the 2000 lb shipping weight was the controller, and various accessories like the large coolant catch plate.

If I were to recommend one absolutely critical lifting accessory it would be a load leveler. The lift points of the mill itself are well below the center of gravity and the mill will definitely go upside down if not carefully lifted....

Second to that, you will most likely need something to keep the chains or cables off the upper section of the mill while lifting... It's a bit hard to explain, but if you have the four lift points on the maching attached to a single hook point, the chains will pinch some wiring and put some very heavy pressure on some of the sensitive components (motors, wiring, the table, etc...). I would recommend a square framework that would have 4 chains dropping down from the four corners of the frame to the 4 lift points on the machine. Basically, something to keep the chains vertical from the machine lift points to the hook point. So the chains would make a cube instead of a teepee shape. I hope that makes sense.

Last, I had trouble getting my engine hoist to get enough height. So if you can afford it or already have one, I'd recommend using a gantry type setup like the one that Harbor Freight sells for about $600.00 along with a chain hoist.

If you haven't already, definitely ask for lift-gate service. It would be impossible to get off the back of the delivery truck without it (taking into account the already mentioned lack of a forklift). I ended up having to go to the shipping terminal and have them put it in the back of my pickup because the delivery truck guy was too chicken to back the delivery truck into my driveway. But I guarantee that any delivery company is not going to let you take the crates apart while on the truck, and even if you did, the heaviest part is the mill section and for all intents and purposes is not able to be disassembled.

I hope that covers it. If you have any more questions, please feel free to ask! It took me about two days total to go from crate in my truck to fully assembled/leveled/etc...

[fineartlig]

1. Originally I was thinking the forklift bars (if I had a fork lift) could go under the table (attached to the lifting points) and under a pipe through the column. 2. I don't have a drawing of the side view to confirm that would work. 3. Can you tell me how high the table is.? 4. I might be able to get a pallet lift that goes that high.

5.Where could I buy a lifting load leveler? or do I make one out of kindorf ( uchannel with bolt holes?

6. Or maybe 2" x 2" angles welded togather. Scares me the the lifting points are far below the center of ballance.

7. Do you think that a 4 ton engine lift attached to a load leveler frame and a padded collar around the column would work?

8. Or maybe the best thing is to hire some equipment handlers?


Thanks in advance.

David.Munson@FineArtLight.com
St. Louis
314-369-3913

[cjjonesarmory]

I'll send you an email with some more details :-)