K2CNC Summary

[Cutloose]

I've followed the K2CNC thread (for what seems like years...) Sometimes it seems like a love-hate relationship going on. First someone proclaims there love for the units....next they're pissed about some poor machining or something.

I must give Tauscnc credit for following through and posting the good, bad and the ugly...without getting personal.

It seems to me that K2CNC is trying very hard to make things right, but before laying down the cash, I would like to get a recommendation from those who have K2CNC machines.

1. Don't buy under any circumstance
2. Conditionally buy if you have some CNC experience and patience
3. Buy these products....best value for money
4. Unconditional BUY.

Any other comments that were not covered in the K2 Thread appreciated.

Tim

[tauscnc]

Hey Tim,

Somehow you knew I was going to respond to this thread right Man that other thread does seem like it goes on forever I have had my K2 for sometime and have gotten to use it a pretty decent amount. I would not say very much but a decent amount.

I think they fill a part in the machining industry as far as price. There is not much out there in this range and price. The one great thing is they stopped producing that awful roller bearing design machine and seem to have gone all too linear bearings. The linear bearings they use, I think, I are VERY nice.

I think in your list of 4 things 2 would be first then 3.

If you get the upgraded ballscrews/ballnuts, which I think would make my machine much nicer then you really could have one great machine (pending all else is up to par like shipping). I wish I had known more or was offered, "hey tauseef, now we can upgrade your ballscrews....". Many times I pass the "upgrade" pitch but in this case it would of been educational. The machine works quite well but you will need to have some tinkering know how, but to be fair I think this would be required on almost any machine you buy. I swear the Sherline is one great machine but it has need it occsional tinker (the customer service is what blows the competition away). I know of a couple guys on the net that are running them 8 hours a day cutting 3D wooden guitars and they say they are doing well (they have their servo setup too).

If I was to reorder one I would consider the following (KG-3925)

- Get extra cross braces; 2 or 4 more. It comes with one in the middle. I
got 2 extra so mine has a total of 5. They didn't charge much at all.

- I would strongly consider seeing if 2 side by side aluminum rails would be possible on the Y axis. That would be awesome. So you would have a total of 4 Y aluminum rails. I don't know if this is really needed thou.

- I am MOST unhappy with the gritty and loud ballscrews/ballnuts that came with my machine. If I recall, when I ordered mine it said Thompson ballscrews but the machine came with Nook. I don't know the difference but assume the Nook are cheaper. I do not know the charge for upgraded ballscrews. The biggest problem is the Nook don't have dust covers but I am working on that myself.

- Some type of dust wipes for the ballnuts and THK type rails would be
nice. The linear bearings and rails are very nice...they have wipers.

Of course this all means the machine would be more. I think for the price it is still a good buy. I have not heard from Ron for many months and only hope the customer service is getting stronger.

Hopefully others will write also that have been using the machine and give a review.

I would not sell my machine as it does what I need it to do and I think it does the job well (hobby based things, like RC airplane parts, rc heli frames, wooden signs, light aluminum work, etc. for me). I have plans to try wood buring with it soon

Hoped that helped.
taus
www.cuttingedgecnc.com

[Cutloose]

Hey Taus,

Yeah...I was kinda hoping you would respond so that I could see if you were still happy. As much work as you did on that unit, (and the review in that thread) they should have made you a paid consulting design engineer.

I like the overall layout of their units, but if I'm going to start adding extra rails on the x axis, upgrade ball screws, additional cross members...etc. I might as well think about building my own.

Did you have any experience in mechanical engineering or metal working before you bought this unit?

I would love to put it together, but I don't have access to much metal working machinery. Maybe I should pay someone to make me some parts.

What do you use the Sherline for? Aren't they all smaller units?

Thanks for your response!!

Tim

[Cutloose]

One more thing...... Why would you like an extra set of linear rails on the x-axis? Are you having some trouble here?

[tauscnc]

Hey Cutloose,

I am NOT having any "real" problem with the unit after they changed out the ballnut mounts. My X axis ballscrew is really quite silky and the Z is great but the Y is gritty. I wonder if the mount for that is just a little off still. It works so I leave it. I was doing some tests yesterday to see if I could get good repeatability out of the machine but my measuring tools kept moving. I will try again today and report back soon on backlash etc (something Cbass asked about months ago.)

As for the extra rails and such that is just personal preference...nothing else. I don't really know if it would help either. Jason has one of these also and runs it 8 hours cutting guitars and I don’t think he has anything other then upgraded ballscrews and the servo motors.

Me I just thought the frame looked a little “light” and wanted 2 extra cross braces (this really was for the 2525 machine I returned but they fit the 3925 also). I REALLY like them there. More places for me to put clamps on when holding wood if you don’t have a top fitted. I think they charged me $25 for the braces with screws etc. Not bad at all.

I did not mean the linear rails on the Y axis (I think the rails and linear bearings they use are awesome) but that 80/20 type aluminum extursion. It would be really cool to have 2 stacked side by side. Again just me.

THE ITEMS I MENTION THAT I WOULD GET ARE JUST PERSONAL PREFERENCE. I don't mean to say the K2 3925 needs them at all or turn this thread into a K2 needs to get this stuff done to there machines to make them better. Its just little stuff I noted but don't know if it is needed

The only MAJOR thing I think you would benefit from are upgraded ballscrews/ballnuts. I would do that hands down. All else could stay the same.

I think the other thing that would REALLY help is what do you want to make. Is it for hobby use or for production?

As for the Shelrine, they are smaller machines. I have used mine for years and love it. I made new NEMA 34 mount for the K2 off of it. I will post some pics soon. I have pics and stuff on my website with heli, airplane, etc parts.

Finally, I have no "real" education in mechanical engineering, metal working, electroincs, etc. Everything I have done/learned in the past years is self taught with many hours and many mistakes, etc. I burned through my first endmill in about 2 min as I had no clue what feedrate to use for aluminum. Its been a fun road and I would do it all over again. My bro was/is into electroincs and helped me out quite a bit...other then that its guys like you that I learn from. Many internet hours and "touching a wire here and touching a wire there" See here is a perfect example of make sure you know who your asking the question to before you believe any answers

Also, I had my machine sent apart because I did not trust shipping after my 2525. It was really easy to put together.

For the price and what I need it for I am happy with the 3925 (hobby and general "fun" use).

later
taus
www.cuttingedgecnc.com

[carlnpa]

I've had all the same issues that Taus has, I really wish I had been able to upgrade the ballscrews to the precision kind initially (I had to later). The x axis has way to much deflection in it as is, mine has an added 1/2" Mic6 aluminum plate that brings the deflection to .005 or so. Many of the screws are small for the torque needed to tighten (just rethread to larger size when they strip). I added a set of adjustment locks to square and lock the spindle mount. K2 has been good about continued support.
With patience you can make good product.

[tauscnc]

Hey Carlnpa,

Can you post a pic of the square adjustment mounts? How much did the upgraded ballscrews cost ya? What are you cutting in those pictures? Seems like cutting board material in the first or maybe delrin. Whats that your making in the second?

thanks
taus

[Cutloose]

Where is the deflection coming from? Is it due to the length of your unit? Just curious...what did the aluminum plate cost ya?

[tauscnc]

Hey I just realized why my post before made no sense and why my mach 3 setup is right but it just never made sense. I was saying the X axis would be great with 2 stacked together aluminum rails when it should be the Y axis. I have had the X and Y mixed up in my head all of this time on this machine. Gezz. I tell ya sometimes. Its amazing I got anything cut

The deflection comes from them using 1 rail for the Y axis and it is supported at the ends only. this rail is around 42-43 inches long. They have the linear rail bolted to the Y aluminum rail but there is quite a bit of weight from the X and Z carraige. I can see how adding a top would help fix this. Kind of like adding skin to an airplanes frame. I don't know if my machine has much defection so adding more rails might be overkill.

Here is a PICTURE OF MINE showing this. This is a back shot. You can see how the Y axis rail is held up at the ends and there is no support in the middle. To get middle support it seems like you would have to go to a dual ballscrew setup for the Y axis. That sounds painfull too

taus

[carlnpa]

The ballscrews themselves are PN XPR6320R48 (powertrac 0631-0200, <.001 in 12") $71.71, these need to have ends machined. The zero backlash nut is SEL10178 $169.48. The parts are bearing and wear plates for various ag machinery, the white are uhmw, the grey are Nylatron GSM and GS materials. The parts have holes, chamfers and pockets tolerance <.008.
The deflection in the x rails comes from the weight of the gantry and 1020 (1x2") extrusion .030+ deflection with 40lb load. K2 should be using 1530 rails on this axis. The y axis will deflect a fair amount also if loaded. If you loook carefully you can see the mic6 plate supporting the melamine cutting surface. That melamine is flat and uniform (+- .002) and makes a great cutting surface, its cheap and sealed from moisture.
The picture is trying to show the four setscrews I put in the spindle mounting plate to both lock the plate and allow tramming adjustment.

[ger21]

Originally Posted by tauscnc Hey I just realized why my post before made no sense and why my mach 3 setup is right but it just never made sense. I was saying the X axis would be great with 2 stacked together aluminum rails when it should be the Y axis. I have had the X and Y mixed up in my head all of this time on this machine. Gezz. I tell ya sometimes. Its amazing I got anything cut

I think you had it right before. Typically, the Y axis is the one on the gantry. The Z moves along the Y, the Y moves along the X. The X axis is usually the longest axis on the machine. Many people here call there X axis Y and their Y axis X. But this is the **correct** way.

[CNCRob]

Originally Posted by ger21 I think you had it right before. Typically, the Y axis is the one on the gantry. The Z moves along the Y, the Y moves along the X. The X axis is usually the longest axis on the machine. Many people here call there X axis Y and their Y axis X. But this is the **correct** way.

I was thinking he had it right before also.