I've followed the K2CNC thread (for what seems like years...) Sometimes it seems like a love-hate relationship going on. (chair) 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

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

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

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

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

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.

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

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

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 (http://cuttingedgecnc.com/images/CNC%20Router/KG-3925/4-27-05/6.jpg) 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

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.

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. :)

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.

I guess it depends on how you view the machine, for example I based my axes on viewing the machine from the shortest axis and comparing that to drawing the axes on graph paper, then my X-axis would be the shortest moving left to right along with the Z-axis and my Y-axis would be moving backwards and forwards. Is there any particular reason that the Z-axis moves along the Y-axis and the Y-axis moves along the X-axis.

Jason

Just that X is usually the longest axis. You can call them whatever you want, it only gets confusing when two people have them named differently and are trying to understand what the other is talking about. :)

Ok, I am not crazy :) Jason, I have it like yours too. What confused me was I was looking at X axis as the longest movement (39") and the Y as the 25" (based on 3925 machine) but my Mach 3 setting where backwards. I left it because it worked but then I looked at my Sherline and it is the same way. The X move left and right the Y moves front and back.

I guess as long as it works who cares :)

taus

Well its settled, it works because it works. :)

Jason

Hey.....I care! You guys are confusing the Sh!t out of me! :withstupi LOL!

Alright, now you guys got me all dis-come-ba-be-u-la-ted. Wow thats a tough word to spell.

Here is a pic of the Sherline and K2 and how the axis are. If I look at my CAD program they are this way too. Are we talking about the same thing?

http://www.cnczone.com/gallery/data/500/medium/xyz1.jpg
In the Sherline case the X axis is the longest axis.

http://www.cnczone.com/gallery/data/500/medium/xyz.jpg
In the K2 case the Y axis is the longest axis.

Now this works in my CAD and on the machine. Is this not right?

Thanks
taus

In the K2 case the Y axis is the longest axis.

Now this works in my CAD and on the machine. Is this not right?

Thanks
taus

It'll work in your CAD either way. It's just a matter of which way you want to draw your parts. Longest way left to right, or up and down. If you stood on the side of your K2, and switched X and Y, it would still be the same, right? I've just read that the longest axis should be X. Ballendo posted a long explanation of why somewhere, but I don't recall the specifics. It goes back at least 50 years, though. :)

Like I said before, you can do it any way you like. It only gets confusing when you're talking to someone doing it the other (correct :) ) way.

Cool. I just want to make sure I am doing it right or the better/best way possible. I completely see how it really does not matter as long as it is setup the right way in your CAD and as long as it cuts. I have known "Ballendo" since the day I started machining and if he says it is this or that way, it IS this or that way. That guy knows so much.

taus

The reason it seems logical to us Tauseef is when drawing in CAD the coordinate 0,0 is at the bottom left hand corner, assuming positives, therefore, it then follows when viewing the machine from the end with the most access, ie where the gantry does not cut accross your view when cutting, we the deduce that the axis moving away from us is the Y-axis and the one moving to the right is the X-axis as we would plot a graph using the coordinate system.

Jason

Hey guys at www.Faztek.net they have 1020 aluminum extrusion for $32 dollars that is 97" long! Thats cheap. I put in my info and UPS ground is only like $4.50.

I am thinking of getting this and adding another rail to the long axis (Y in my case). I would put this to the inside and cut the crossbraces by 2 inches. Get some longer bolts and slap it back together (well a little more to it but you get the idea.)

What do you guys think? I bet it would take most flexing out of the frame.

taus

The idea sounds great but you need to spot on with your cutting. You do not want to even slightly pull the slide rail bar inwards or have it pushing outwards due to a cross brace being slightly too long or short.

Jason

Hey guys at www.Faztek.net they have 1020 aluminum extrusion for $32 dollars that is 97" long! Thats cheap. I put in my info and UPS ground is only like $4.50.

I am thinking of getting this and adding another rail to the long axis (Y in my case). I would put this to the inside and cut the crossbraces by 2 inches. Get some longer bolts and slap it back together (well a little more to it but you get the idea.)

What do you guys think? I bet it would take most flexing out of the frame.

taus


Thats a pretty cool site Taus, I love their AutoCad downloads section.

Hey Jason,
That is so true. I have been thinking of how I would go about cutting them. I have a table saw (cheaper version), a miter saw and also a 10" delta bandsaw. Then I could always cut them on the sherline or the K2 cutting one at time. I guess I figure with some of the parts I and others have gotten from K2, I couldn't do worse :drowning: But I am really excited abou it. It would make the Y axis so much stiffer. Heck if you can't think of something to make from the machine, make something for it :banana: (I love this banana guy).

Hey Rob,
Good to hear from ya bud. I did not check out that part on the website. Will do. Hows the cutting going?

taus
www.cuttingedgecnc.com

With a good blade, either the table saw or miter saw will cut them just fine. There are a few threads around here about cutting aluminum with woodworking tools. A triple chip blade is best, but anything with 60+ teeth will work fine.

Taus,
8020 has a downloadable calculator that computes flex. It didn't work for me otherwise I'd calculate deflection for you. It's going to reduce flex, the question is how much? I think it will be around 15/1000 if you double up the 1020 rails. You will get better flex reduction with a piece of plate that ties all the rails together (long axis and crossbracing) and the dimensions are not critical.
Carl

I cut aluminum with my miter saw with no problems. A little WD40 and all is well. I would ease up to the line a little at a time to make sure the fit is perfect. I also use a hand held circular saw for some of my rough cuts.

Just be prepared for the flying chips and NOISE!

Russ

Hey guys,

Hope you guys are cutting something with your machines! I had a great conversation with Ron today at K2. In effort to keep the post going, I must say things seem to be really changing. I talked to him about the upgraded ballscrews and we went over the price/accuracy...for my needs I nor Ron think it is worth it. What I did instead is get some felt pads that you put on the bottom of chairs so they don't mark your floor and cut a hole out of it. I then CA'ed that to the ballnut as a wiper. So far it seems like it is going to work well :banana: . I will post some pics of it soon.

I also asked about the rails and he said they should be able to hold something like 200 pounds! WOW! I have scrapped the idea of adding more rails and if needed I will get a top for it. As mentioned in other posts, I think that will be a better way to do things. I would still suggest new buyers to get 2 extra CROSS RAILS put in. Its great for clamping work etc.

My main thing I am going to do is get the servo motors from them with new mounts, etc. I can't wait to give them a try. I am gonna go from steppers to servos. Man I hope they really are better :)

Seems like they are coming out with new products too. Tables, duct collections stuff, etc. Looking good.

taus

Hey guys,
I talked to him about the upgraded ballscrews and we went over the price/accuracy...for my needs I nor Ron think it is worth it. What I did instead is get some felt pads that you put on the bottom of chairs so they don't mark your floor and cut a hole out of it. I then CA'ed that to the ballnut as a wiper. So far it seems like it is going to work well :banana: . I will post some pics of it soon.
taus

Hey Taus,

Do you need a wiper because of the debris from the cutting that gets into the ballscrew? Do you think a vacuum at the tool cleaning up the debris would solve the problem? I am thinking about buying a k2 3925 and am just researching its problems now. So far I haven't found anything that would stop me from buying one.

Thanks,
Brendin

Hey Brendin,

yeah, the sawdust, aluminum chips, plastic, etc gets all over the place and one place is on the ballscrews. Before you know it the ballnut is all gummed up and not running well. The X one for me (the 25" one) is not as much of a problem as it is easy to get to but the Y (39" one) is tough as it is under the table etc.

The upgraded ballscrews have wipers and a bit more accuracy but from talkting with Ron it depends on what your wanting to do with the machine. For me, I would of just spent more money to get wipers which I have already made. They also have really high end thompson ones if your going into some major production work now/too. A vaccume system at the router would help with much of the mess...I don't have one but should be getting one soon. I will keep you posted on what I figure out. I know K2 is working on this and some other products for the machines. I really like the tabletop and will probably get one someday also.

I am thinking about buying a k2 3925 and am just researching its problems now. So far I haven't found anything that would stop me from buying one.

While I had a rocky road in the beginning and looking back on it (I have read many of my posts over) I think, WOW. My goal was to give an honest review and hopefully I did...but thing are different now. Looking back on it , I would buy another 3925 as it just fits a good nitch in the market. The size of the machine is awesome and I have been happy with its cutting. Plus the parts that did not work they replaced without question and even sent me a new ballscrew for the long axis since mine was getting bent from me taking in and out. That I do think was my fault but they still took the hit.

I Just talked to Ron and have been really happy with our conversations. The customer service end really seems like its been stepped up and sounds like most of the machines coming off the production are doing well. You should get the machine with the updated parts and I don't think you should have a problem. I would suggest 2 extra crossbraces as they are great to help clamp down on parts if your not using a table. Hopefully the shipping companies will do their end and deliever the products. Ron said they have changed the way they pack the machines for shipping too. Sounds good to me.

I can't wait to get my servo motors. They are also sending me the mounts etc and wires. I just ordered 3 gecko 320 :)

Yipie!!!!!

taus

oop,

look below

Here is the felt I put in front and behind the ballnut.

PICTURE 1 (http://cuttingedgecnc.com/images/CNC%20Router/KG-3925/ballscrews/ballnutfelt.jpg)

PICTURE 2 (http://cuttingedgecnc.com/images/CNC%20Router/KG-3925/ballscrews/ballnutfel1t.jpg)

Here is what I did to the front of the machine. I cut a slot using a standard woodcraft 3/8" (I think) key hole cutter. I used the router in the base and worked its way though. Little by little untill the nuts fit in. Now I can slide my top on in front without having to move the machine. I have suggested this mod to Ron.

PICTURE 3 (http://cuttingedgecnc.com/images/CNC%20Router/KG-3925/ballscrews/keyhole.jpg)

I got my geckos and should get my motors soon!

taus

I love that ideal you had about slotting the front so the top will slide into place taus. It sure beats taking it off or taking the motor in the back off to get the top on and off, I may do that to my machine also.

YIPPIE!!! :wee:

I got my servo motors from K2 today!!!

A+ for packing...awesome job!!
The servos look great and beefy. Man these things should really make the router zing :) I also got my Gecko 320s the other day. Man I wonder what I will be doing tonight ??

Ron also sent me the motor mounts for free as I upgraded to the servo setup (not sure if this is a normal practice or a one time deal...) but the mounts look great! They also sent me the wire and I got 2 new larger aluminum pullies. Man I can't wait to try this out. I am so excited!

I talked with him again today and I am really happy with them. They have really seemed to turn things around. I talked to him about "secret" projects they are working on :o which sound great! Ok, Ok, stuff like different tops, other machine setups, etc.

I did ask Ron about making a Sherline spindle mount so I can take my Sherline head off and put it on the router and he said, no prob just send the dimentions. So I will probably look into that too.

Good stuff K2! I am happy.

taus

Good to hear that Taus. Don't forget to sleep tonight!


Carlo

Thats great news about your new servos Taus!

Great news Taus. :cheers: When you get the whole setup complete post a video of your machine zipping along, let see how fast it can go. :D

Jason

Have you had a chance to try out the new servos yet Taus. If so how do you like them. I ordered 2 taller post for my gantry a couple weeks ago from K2, I should be getting them any day now. Im working on an Idea for a vacuum table for my machine and need a bit of extra room between the gantry and table.

Hey Robbie,

I have a little. I am a little confused on the power supply and have looked at K2's site for the setup they sell. From what I can tell there is no capacitor and they say the power is around 30V (which sounds right)...that means they put in some type of a regulator, etc. But there must be a capacitor??

If I use my 24vac transformer it will give off almost 34 volts DC in the end. In the gecko manual he mentions not to put more then 5 volts from the rated voltage on the motor. The rated volts are 24DC so that would be a bit over. Not sure if it matters but I just don't want to permaturely burn anything out. If you get a chance can you tell me how many volts your geckos are getting from K2s box?

The mounts they sent me are really well made. Very nice machining. They also sent me a bunch of screws. The Z mount they sent me was a drop in fit and I thinned out the Y axis mount a little (personal preference). The X axis mount does not fit but Ron already told me this may happen. When I bought my machine they had to make some custom mounts since I was running NEMA 23 steppers (seems I might of been the only one too), so they had to make some new smaller mounts. The NEMA 34 does not fit on one part of my machine. I have already contacted Ron but I think I will just modify the one I have. No biggie. Ron's and K2 has been great. I am really happy with the customer support.

The motors look awesome. I can't believe how quite they are. I am still blown away how you can make a DC motor such a contolled motor by putting an encoder on the back.

Here is the page with pics, I just put some up CLICK HERE (http://cuttingedgecnc.com/cncrouter.htm) Go to the bottom.

I also need to get my mach 2 setup right.

So I guess the short answer is yes but mostly no :)

tauseef

Well I played with it some more tonight. Not overly impressed with the speed compared to the stepper setup I had.. granded I am sure it is more the computer and that I am using a 1:2 ratio on the motor/pully instead of the 2:1 I did with the stepper. It seems they run as fast as the steppers but it they don't lose steps or "fault" then thats what I was looking for.

When I disconnet the encoder and plug the system in you can really hear the motors top end. My computer is a 900 mhz and I just don't think it can pump out the steps fast enough. Then again I also don't know if my setting are right. My brother has an occillscope (sp?) and the next time he comes over I will have him bring it. Then I can set the Geckos to the motors...not just guess. I also went to the 24 vac side of the transformer. What I don't get is the geckos fault if I turn the pot on the limiter all the way up..in the manual it says to put it there unless for some reason you don't want them to have that much torque.

So as for the motors they are awesome. VERY silent and seem to run very well. I can now totally understand how a servo system needs to be fine tuned compared to the plug and play stepper system.

If my encoder is 250 CRP (I think) and its quad then thats
250*4=1000 and since my ballscrews is 5 tpi or (.2) then would I put in 1000/.2=5000 steps in my Mach for the inch setup?

Always something new to learn :)
taus

Hey guys,

I just got off the phone with Kevin at K2 and the transformer they use is a 24 volt type so the DC coming off of it is around 36 ish volts. He said the volts drop due to the PWM (something like that) so it is fine..cool!

I also downloaded the mach 2 setup they have from the site. At first I totally did not understand it but after talking with Kevin it is a xml file and directly loads into mach 2.

Sweet. I should be able to make some progress tonight and give a better review now.

taus

Just a quick question Taus, will this XML file switch your X and Y Axis format? ;)

Jason

I have steppers on my other machine and much prefer the servos. The servos run much cooler, much quieter, much faster and if steps are missed shut down further movement.
You should be getting comfortable rapids around 100ipm, moderate cutting at 70ipm.
My xyz are at 10000/in I think with the same setup you have, gecko 320's US Digital E5S 250 250 (250 cpr)

You should be getting comfortable rapids around 100ipm, moderate cutting at 70ipm.

I thought he was getting faster than that with his steppers?

Hey Carlpa,

Your right, it is 10000 steps per in. If I did this right it is
250 CRP and since it is quad then its 1000 lines per rotation (??) and we have a 5tpi ballscrew so that is 5000 steps. Now we have a 2:1 pulley system so it bumps that to 10,000.

Hey ger1,
Your right. I was getting close to 300 ipm (if mach 2 is right) with the steppers but probably closer to 250 ish (with some stalling). This was however with a 1 to 2 ratio on the steppers. The servo setup I have is setup as 2 on the motor 1 on the ballscrew. Safely I would say I was getting around 100 ipm fast jog without the steppers stalling.

I think overall the steppers and the servos turn about the same speed (computer pending) but the servos do run a lot cooler, are silent (not that it matters as my Y ballscrew 39" axis is very loud)...and if they lose steps will shut down. Are they better...I still can't say.

I will try to get it together tonight and see.

From a speed stand point with the 2:1 ratio it is not faster then the steppers...I thought it would be the same, thinking the servos would turn faster...but I think it's then a computer thing...I think.

Ooooo. so much more to learn :)

taus

Those of you that have made your own table top for your KG-3925 machines, I was wondering how many bolts did you use to hold the top down to the frame? The one I have now I only have 3 on each side. It seems to be working fine, but Im in the process of designing a new top and don't know if I should change it or not. Thanks- Robbie

Taus, with 10,000 steps/ inch, the most youc an get from Mach2 at 25Khz is 2.5 inches per second, or 150 ipm. That should be at 1500rpm for the servo? What speed are the servos rated at, and what voltage are you running them at? RPM is proprtional to voltage with servos, but you can't exceed the rating. If the motors are at there max speed, you may want to go to a 1:1 gearing to get more speed. If Mach2 is limiting you, get a 2Ghz PC and run in 35Khz or 45Khz mode.

Hey Robbie,
For my MDF top I use 6 bolts on both sides. I would like to also put 2 bolts on the crossbraces but that more work :) Someday. Not sure if I need 6 but that is what I came up with.

Hey ger21,

The motor are rated at 24v 2800 rpm. Once I see my bro today and get his oscilliscope and get the setup "perfect" I will give my inital views. So far I like the servos, they are quite and I can run them at max without them skipping or missing.
I am using 24V and when rectified its 33.93 V (my voltmeter says 37 ish). I talked with Kevin at K2 and he said that is what they also use and when you consider the PMW or PWM (something like that) from the motor it decreases the volts to a save amount. Sounds good to me :)

I tired the computer (900 mhz) at 25K and it was half the speed of the steppers setup. I tired the computer at 35K but never at 45K when I had the STEPERS and it would lock causing the steppers to go full out.

For kicks I tried the computer at 35K and it works fine with the SERVOS...so then I pumped it up to 45K and it still works fine. I have ran (dry) 4 five 5 files and all sees great. I am getting about the same speed at 45K as I did at 25K with the steppers and the switched around pully setup. However my resolution is twice that with the current servo setup. If I can keep this setup going I am quite happy. Its quick and does not stall.

I am not sure it if is healthy for me to run the computer at 45K but it seems to work. I am sure if I was cutting a real piece it would stall :) I think with the encoder any blips etc., are handled. REALLY COOL.

The servos sound like silk. 1:1 ratio with 45K would be a killer speed :) but I can just see the Y axis (39") leadscrews whipping around.

thanks
taus

I am not sure it if is healthy for me to run the computer at 45K but it seems to work. I am sure if I was cutting a real piece it would stall :) I think with the encoder any blips etc., are handled. REALLY COOL. taus


Do you get the same speed at 35Khz as with 45Khz, or is 45Khz faster? If they are the same, use 35Khz. Neither will harm the computer, either they'll work or they won't. But you should always use the lowest speed setting possible, to give the computer a little breathing room. :)

Hey guys,

I finally cut a holder for my dremel tool. There are many times I find I don't need to run the porter cable router due to the material I am cutting and well...noise. The dremel tool is much quiter and I think might get me by for a lot of the things I like to make (engraved signs, foam airplanes, etc.).

I have to get a top mount still done and will post a dxf if anyone else wants to make one.

Here are some pics:

Dremel Mount 1 (http://cuttingedgecnc.com/images/Dremel%20mount/10.jpg)

Dremel Mount 2 (http://cuttingedgecnc.com/images/Dremel%20mount/11.jpg)

You can see the whole making HERE IF YOU LIKE (http://cuttingedgecnc.com/dremelmount.htm)

time for bed!

taus

Hey, where are you buying the upgraded ballscrew and ball nut?

Hey bradyfb,

I think at least here on the k2 stuff people are getting them from k2. You might want to call k2 and see if it fits your machine or if they can cut something for you to fit it.

taus

Hello,

The original Air Force standard for NC--and later CNC--machines says that the axis with the longest TRAVEL, OR the axis capable of handling the longest dimension of a workpiece is properly called the X axis...

The Z axis carries the tool, and the Y is what's left...

So you can have a gantry or bridge style machine with a short travel OF the gantry or table--y is actually longer in travel--and the shorter axis will still be properly called the X axis. Because it can handle a part of longer dimension, since it is not limited by the uprights of the bridge or Gantry, as is the case with the Y axis.

More than a few folks "prefer" to call the "across" movement, X and then call the "towards/away" movement,Y; regardless of travel length. Even some manufacturer's; especially those making plasma machines, IME, seem to do this.

If you take the time to consider all the possible names you can give to the axes AND the repercussions/results of each, IMO you discover that the original standard makes sense.

If you stand at the left side (looking from the front) of a "properly" named Gantry of bridge cnc machine; you'll look at your work being cut in the same orientation as the screen shows it... Perhaps more importantly, you'll BE off to the side. Out of the way of yourself... And the machine. Safer. And correct.<G>

Another point is what this does with the "home" position.

In a "properly" named and oriented machine, the home position--in it's typical minus end of the XY axes for this type of machine-- will be left rear when you stand in front (where you'll load and remove work). In other words, when th emachine goes to home, it CLEARS the way FOR you to add or remove material...

And when you're setting up, the home point is right in front of your keyboard/screen...

BTW, If you use the positive ends of the travels for home--as is done in most metalworking machinning centers-- you're still clear.

I've seen some guys say that it's more "comfortable" tohave the "across" be X and the toward/away, Y. I say that if you're learning anyways, why not take advantage of what 60 years of pretty smart folks have discovered???

It isn't always OBVIOUS to a beginner WHY some thigs make sense; they find that out later... And this is true of FAR more things than CNC... Any coach has had the task of explaining that hwat's "comfortable" NOW, will very likely lead to "problems" later.

Baseball grip in golf, anyone?<G>

Why set yourself up to have to mentally "rotate" when you wanna cut that larger part? You know, the one which will "fit" just fine no matter what, if you stand on the shoulders of the giants who've preceded you in this CNC endeavor...

There ARE reasons that in about 60 years of development, CNC folks have made some things "standards"...

Hope this helps,

Ballendo


Just that X is usually the longest axis. You can call them whatever you want, it only gets confusing when two people have them named differently and are trying to understand what the other is talking about. :)

ballendo,

Good to see you post again. Been a while. As usual you are full of good info, although I am probably one of those that didn't learn correctly from the beginning. I started out with a Digital Tool machine, still have it and it's still making parts. It was already set up with the y axis being the long axis, the x the gantry and home in the minus to my left facing the machine. You are 100% correct that in this configuration I had to move the gantry to load and unload the table. I wish when I had started this journey there had been sites like this and folks like you. Just wanted to say hi and thanks.

Mike