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AiR_GuNNeR
07-03-2011, 11:20 AM
The workshop was great as well as the people I met!
After building my mill at the workshop, taking it home, then taking it all apart again to lock-tite everything, scrape the ways and tune in Mach3, I made my first part today. This is a sidewheel focus comma for a Tasco Custom Shop scope. It's 5.75" from one end to the other.
I had to do a bit of fine filing to smooth out the curves. The Mach3 backlash control appears to be broken, (if I jog in the opposite direction, it takes one more step in the previous direction and then compensates on the next jog.)
http://www.compufoil.com/images/Tasco 8 inch comma.jpg

John Stevenson
07-03-2011, 04:42 PM
Eric,
That's really impressive and you have cause to be proud of this, more so with it being your first part.

Can't help with the Mach backlash as I never use it, trying instead to get all play out. However I do recall posts about it being broken in later versions and it working in earlier versions ?

To be honest we have stuck at R3.042 as we have found this quite stable on the mills and have stuck with this version. I know for a fact that the later versions won't work with out customised screens.

AiR_GuNNeR
07-03-2011, 05:57 PM
Thanks for the hint on Mach3 John. I'll see if I can find rev 042 and see if it acts differently.

Weston Bye
07-03-2011, 06:23 PM
I was bitten very badly at the CNC workshop.:eek: I now have VCarve Pro and Mach3.:D Came home and promptly ordered a Geckodrive G540. Wired it up and should be making machinery move tomorrow. I'm sure there will be questions...

John Stevenson
07-03-2011, 06:30 PM
Weston,
VCarve Pro has one of the shortest learning curves i have come across on a CAM package.
The forum over on the Vectric site is awesome when it comes to any help.

Off to bedey byes now, gotta go down to Oxford University tomorrow to install a KX3

AiR_GuNNeR
07-03-2011, 06:49 PM
Any idea where I can download version 042? It doesn't look like they have links for the older versions.

John Stevenson
07-03-2011, 06:56 PM
ftp://machsupport.com/Mach/

Get 042.040

Weston Bye
07-03-2011, 10:19 PM
Weston,
VCarve Pro has one of the shortest learning curves i have come across on a CAM package.
The forum over on the Vectric site is awesome when it comes to any help.

Off to bedey byes now, gotta go down to Oxford University tomorrow to install a KX3

I will have no problem with VCarve Pro. I learned Cut2D - was easy, no tutorials needed. Sat in the seminar on VCarve Pro at the CNC Workshop. Same basic interface, but I was impressed with the features available over and above Cut2D.

DFMiller
07-04-2011, 12:55 AM
Eric,
That a really nice first part.
So how much back lash are you seeing?
Wes, I like my G540, it sure works nice on my router. I assume you are hooking up your little table to it.
Vcarve is rather sweet. The learning curve is very short. I was hoping to cut this weekend but found a bad pin on Z axis and was unable to fix pin, waiting on a Digikey shipment.
John, have fun at Oxford.
Dave

AiR_GuNNeR
07-04-2011, 08:36 AM
DFMiller,
Thanks.
I am getting around .005 backlash. My X axis was sounding terrible so I pulled the table last night, (lots of ball noises from the start compared to the Y and Z axis). I found that the coupling rubber had compressed already; enough that the screw was able to drop .050 off center at the stepper and run acentric. I put a wrap of mylar tape around the rubber to get rid of the slop. I also pulled all the balls out of the nut and flushed everything. It sounds much smoother now. I'll be buying zero backlash couplers off of eBay once I figure out which sizes I need. I see both aluminum and steel couplers available. Any reason not to use the Al ones?

AiR_GuNNeR
07-04-2011, 08:43 AM
ftp://machsupport.com/Mach/

Get 042.040
John,
Yep, that version works better, but still not quite as expected. At least this version doesn't continue with the former direction on the first reverse jog.
What I am expecting is when I reverse directions with .001 jog, the stepper should turn enough to take up the backlash, plus the .001" with that first reverse jog. I don't get full backlash comp. until the second jog.

DFMiller
07-04-2011, 09:32 AM
Eric,
When you had the nut apart did you measure the balls? I am having issues with my new router and the ballscrews. Mine has 0.0065" lash. I did find an eBay vendor who sells balls of various sizes for 12 bucks per hundred. Most of the nuts seem to take 68 to 72 balls so a hundred lets you drop a few. ;-)
Funny thing I I have bought some cheap screw assemblies from China off eBay and they seem to be almost zero lash. Go figure.
It good a cleaning helped. Do you have any wipers on the screws? I imagine that keeping them clean will be important.

Got any pictures of your coupler? Not following how it is running eccentric?
I would imagine the Aluminum ones might be good. Are you talking about the ones that are three piece with a compliant cross in the middle?
Glad to see you are using your machine.
Dave

AiR_GuNNeR
07-04-2011, 09:55 AM
Eric,
When you had the nut apart did you measure the balls? I am having issues with my new router and the ballscrews. Mine has 0.0065" lash. I did find an eBay vendor who sells balls of various sizes for 12 bucks per hundred. Most of the nuts seem to take 68 to 72 balls so a hundred lets you drop a few. ;-)
Funny thing I I have bought some cheap screw assemblies from China off eBay and they seem to be almost zero lash. Go figure.
It good a cleaning helped. Do you have any wipers on the screws? I imagine that keeping them clean will be important.

Got any pictures of your coupler? Not following how it is running eccentric?
I would imagine the Aluminum ones might be good. Are you talking about the ones that are three piece with a compliant cross in the middle?
Glad to see you are using your machine.
Dave

I didn't measure the balls and no wipers as of yet. I see some thick felt purchases in my future though.
I didn't take any pictures of the coupler. I am talking about the three piece type.
The rubber insert is like a four leaf clover shape. The stepper coupler side has two fingers and two more on the screw side. The fingers fit in between opposite sides between the clover petals if you will. If the fingers don't fit tight, the stepper and screws are not forced concentric to each other. I put the tape around the perimeter of the petals to take up the clearance.

John Stevenson
07-04-2011, 10:04 AM
Eric
Still on the road at the moment but look at Oldham couplings will post later

DFMiller
07-04-2011, 10:51 AM
Eric,
Those are the kind I was thinking about. They are like the ones I have ,but the compliant inserts are a press fit and not sloppy. The oldham couplers are similar. The oldham style seems to tolerate mis-alignment better since the insert seems to self align.
There is always some fine tuning it seems.
Dave

John Stevenson
07-04-2011, 12:19 PM
Just got back in.

Those jaw type couplings are useless, they will only allow, not correct, for misalignment in one plane only and they take power to do this.

The Oldham Coupling is the only non backlash coupling that will compensate for misalignment in two planes at the same time.

http://www.youtube.com/watch?v=utEKKox2WHA

hareng
07-05-2011, 07:10 AM
Slightly off topic John, wheres best place to get decent leadscrews from? To replace or mod conventional mill.

Incidently make by the hundred what OP posted, many in the US.
As regards actual control of the Tasco, it will hinder it better off with standard larger wheel, gaps mean nothing!

RonGinger
07-08-2011, 06:05 PM
I was not pleased with the Lovejoy couplings, but because they were part of the CNCfusion package I went with them. I would change to one of the spiral type if possible.

On the Mach version note you have a smoothstepper, and backlash comp is new to smoothstepper. If you go back to the old Mach version Im not sure you can run the latest SS plug-in. see the smoothstepper site for some explanation of backlash. Note the one case you are doing, single .001 steps is exactly what the SS does not yet handle.

AiR_GuNNeR
07-12-2011, 11:59 AM
I was not pleased with the Lovejoy couplings, but because they were part of the CNCfusion package I went with them. I would change to one of the spiral type if possible.


Hi Ron,
I checked out some of the spiral couplings available on eBay. The 1/4" end for the stepper is no problem, but the 5/16" screw end would need to be reamed. The biggest problem is the end to end height I am seeing is 25mm, while the lovejoys are 1-5/8" height. I need to look at it closer to see if it would cause any issues, but it appears that we would need to take off the .625" from the stepper mounting blocks.
Eric