G4003G Conversion

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Marty_Escarcega
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Re: G4003G Conversion

Post by Marty_Escarcega » Tue Sep 09, 2014 1:51 pm

Dave,
Looks like things are coming along nicely and you are closing in on the project. Thank you for continuing to share your build with us!
I look forward to see it cutting metal soon.
Marty
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Re: G4003G Conversion

Post by Dave_C » Wed Sep 10, 2014 8:17 pm

A little more progress! Both axis are working now and one of the guards is almost complete. I made another 4 minute video to show more details. You'll note the Grizzly emblem is moved from down below to a better position below the switches.

Enjoy,

http://youtu.be/Ymh3awNps_A



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Re: G4003G Conversion

Post by Dave_C » Sat Sep 13, 2014 7:24 pm

Fellow CNC Enthusiast,

I decided to check my ball screws for accuracy. I did not spend much on my ball screws as I bought Roton 3/4" and 5/8" screws.

Well I fired up the electronics, turned on my glass scale DRO's and started making 1.000" moves. My first response was yuck! I was seeing errors of over .0008" per move.

Then it hit me... Maybe my steps per inch needed adjustment even though the math came out to 10,000 steps per inch.

So I made a spread sheet in Excel to do the math. I made a 1.000" jog and recorded the actual distance moved. I made this move 12 time and I could see I was off .0006" to .0008" with each move. (DRO won't read .0007 as they are 10 micron scales and not 5 micron).

So I entered the actual move in my software and got a new steps per inch number. I put in the new number to 10 decimal places and tried again.

WOW! This time I went 12" in Z before I saw .0002" of error. OK, I'll stop bad mouthing Roton Ball Screws now.

Then I checked the X axis and it went 1.000" for 1.000" with no backlash. I do have .0012" of backlash in the Z and I think I can fix that with more pre load. (Apron is pretty massive)

I'll share the spread sheet here and anyone who wants it can download it and do the same as I did. Make note of how to make the change if your moves are long or short. The math is just different but is done in the sheet.

I'm real pleased with the results and I haven't even done any Ball Screw mapping!

Enjoy,

Dave C.
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Re: G4003G Conversion

Post by ctwo » Mon Sep 15, 2014 5:04 am

I'm really curious as to why the math did not work out, only because I recall my setup required the same fudge factor. These screws are precision ground and we are sending discrete pulses, so I can't figure out how a little tweak makes it work out.
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Re: G4003G Conversion

Post by Dave_C » Mon Sep 15, 2014 9:07 am

CTWO,

Good question. In my case the 3/4" rolled screw could have a slight lead error but it turns out to be very consistent as it tracked perfectly out to 12" and then I have an error of .0002". The X axis is 5/8" rolled crew and the calculations worked with no tweeks and no error for the first 5" of movement.

So on a precision ground ball screw, that is puzzling!

Dave C.
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Re: G4003G Conversion

Post by Dave_C » Wed Sep 24, 2014 6:24 pm

Greetings all,

I finished (sort of) the Grizzly G4003G lathe conversion today. All limits are now hooked up and tested, all cables are done, tool post finished, backsplash on, spindle calibrated and software backed up.

I have some unfinished items like the drag chain (cable carriers) the flood tank, the front X axis belt guard, and some minor stuff like that but it works as it sits for now. I'll also have to make the spindle guard when I start running coolant.

The machined homed out just fine when commanded and everything checks out for now.

I made my first test run by just doing a simple face on some 1045 stock. Worked like a charm! I'll try to make a video later this week of a test part.

Anyone have any thoughts on what to use for cable carriers as the commercial stuff is like $40.00 a foot?

Later,

Dave C.
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Re: G4003G Conversion

Post by Dave_C » Fri Sep 26, 2014 12:39 pm

Ok, Last video and post for this thread. The machine is all wired up, checked out and tool table set up.

Here is a short video of a threading program for demonstration. The machine works very well!

So let's call it done as far as the thread goes and I'll get the flood coolant and spindle cover made later when I have time. I still need to come up with a cover for the front belt on the X axis.

http://youtu.be/jKDRkgTf2xo

It was a fun project!

Dave C.
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Re: G4003G Conversion

Post by Dave_C » Tue Nov 04, 2014 9:59 am

Just a couple of follow up pics since I made the belt guard and also installed the energy chain (Cable carriers).

Speaking of Energy Chains: Most I found were too expensive for home use! I ran across a company called IGUS and they have some good German made Chain that cost about $15.00 a foot and the two ends were less than $5.00 for the set. Most of the competition was in the $48.00 a foot range with $45.00 each for connectors. You can see what I bought in the pic below. Works great!
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In cutting position
MVC00050.JPG
Home Position
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Re: G4003G Conversion

Post by Dave_C » Thu Nov 13, 2014 4:30 pm

Everything has worked out pretty well on the conversion. I've been paying with making some parts! I sure like how easy it is to make a radius on an inside corner.

This part is to make a tension/compression tap holder on an MT3 shank that has a JT4 end. I turned the JT4 female taper by looking up the dimensions in MH-edition 27. I'd like to say I got it right the first time but I forgot to divide the Angle by half! Duh..

No big deal since the steeper angle cut left enough material to make the proper angle cut.

Dave C.
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Re: G4003G Conversion

Post by DICKEYBIRD » Thu Nov 13, 2014 9:17 pm

That's what I'd call a real success! Must be a rigid machine that's dialed in accurately to produce an accurate taper in steel on the 1st attempt. Kudos Dave! :D
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Re: G4003G Conversion

Post by GabeP » Sun Dec 21, 2014 9:28 pm

Awesome!
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Re: G4003G Conversion

Post by Marty_Escarcega » Sat Dec 27, 2014 6:35 am

I must say. You did a marvelous job on the conversion!
Was this your first conversion? Have you thoughts on doing the mill you have or a mill?
If you had to do it all over again, would you do anything differently?
Did you hit the mark on your conversion budget?

Marty
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