[CodeMonkeyDan]

Bought the Grizzly mill about a year ago and its seen very light use mostly as a glorified drill press.

Last Thursday I received my probotix 3 axis kit and the cnc fusion x y and z kit.

I only intend to use this for hobby and I'm fine with the precision until it is not precise enough.

I had a blast pulling the mill apart, getting dirty, watching the Olympics and getting the mill setup as a cnc.

1. On the Z axis setup, the step were you insert the 12mm bolt from the mill column to the cncfusion block. I did not have a 12mm allen wrench and when I looked for one at the store I would have had to cut the wrench in order to get into the space. I completed the install just hand tightening it but I'm wondering if that is going to be an issue later on.

2. I bought the air spring from little machine shop but I did not install it. Is it even worth it at this point now that I have the cnc setup?

Spent several hours trying to cut a circle using Mach3...the hardest thing for me right now is figuring out coordinates. Also not having homing switch/limit switches...I worry about hurting the machine.

Bought the little machine shop vise/mill kit which came with a edge finder but none of the collets in the kit fit the edge finder...lame.

By the end of the day yesterday I got my perfect circle that matched a bearing...so I felt pretty good.

[hoss2006]

Welcome aboard Dan,
I've been watching the Olympics too but unlike you I haven't done anything else.
Don't worry about hurting the machine without limits, the steppers will just buzz if they run into something.
Look into soft limits, that could give you a little protection nevertheless.
ArtSoft USA - Video Tutorials
Hoss

[mhackney]

As a CNC Fusion user, i can say you are going to want to tighten that 12mm Z Axis bracket securely. Also consider doing the Z modification to allow reaching the gib screws. Check my X2 thread for a link to the source. Recently, I've had a problem with the Z motor mount moving. Even putting 3 extra bolts ini didn't stop it. I'm nursing it now but need to figure out a permanent fix.

Other than running an end mill into the table or a fixture or clamp, not having home and limit switches are not a problem. I just added home switches last month after several years of hard use. So, as the say, "just use it"!

Cheers,
Michael

[CodeMonkeyDan]

Michael...thank for the info.

It has been grinding me that the 12mm bolt is not tight and I even felt some flex in the Z when changing directions. I'm either going to break down and buy the tool or make one out of aluminum that will fit my socket..thats why I bought the machine might as well try to use it.

Was working in solidworks 2012 last night...headed to mastercam 8 tonight..so I'm hoping to get it done this weekend.

Will check out your x2 build...the Z gibs are annoying behind the fusion block..

[mhackney]

I just remembered, I got a 12mm Craftsman hex socket - it has a short 12mm hex in the socket. It comes out. I inserted that in the bolt and then used a 12mm wrench to turn it.

Cheers,
Michael

[chrisbryanolsen]

Guys,
I enlarged the hole on the oposite side where the quill handle passed through. Makes it easier to make sure that bold is tight even with the head down. Put the long end in and grab it with some pliers!.

Some gratuitas pics:





Full Size:
http://www.cboservices.net/vmc-x2/IM...810_095507.jpg
http://www.cboservices.net/vmc-x2/IM...810_095516.jpg

Chris Olsen
X2 Fusion CNC

[CodeMonkeyDan]

Not a bad idea Chris..

Are you not using the spring? Or did you just have it disconnected for the picture?

[chrisbryanolsen]

I think someone else mentioned taper pins, I just put in a few of these in another application on the tail wheel of my airplane. And boy does it work well. You need to get the correct tapered reamer to go with the pin you select. I am going to try and get some taper pins put in place. Will take some pictures when I get it done.

Chris Olsen
X2 CNC

As a CNC Fusion user, i can say you are going to want to tighten that 12mm Z Axis bracket securely. Also consider doing the Z modification to allow reaching the gib screws. Check my X2 thread for a link to the source. Recently, I've had a problem with the Z motor mount moving. Even putting 3 extra bolts ini didn't stop it. I'm nursing it now but need to figure out a permanent fix.

Other than running an end mill into the table or a fixture or clamp, not having home and limit switches are not a problem. I just added home switches last month after several years of hard use. So, as the say, "just use it"!

Cheers,
Michael

[chrisbryanolsen]

I leave it disconnected for now, the 381oz stepper does not seem to have a problem moving the head. I was seeing inconsistent backlash numbers with it connected, was not a linear as all. So left it off and have the backlash compensation turned on in LinuxCNC.

Chris Olsen
X2 Fusion CNC

Not a bad idea Chris..

Are you not using the spring? Or did you just have it disconnected for the picture?

[CodeMonkeyDan]

Ok so I created my first part last sunday...very cool to have this machine in my garage.

I decided I would tighten the 12mm bolt as well as try and perform a z axis gib mod. I bought some 6mm x 20 1.00 bolts to replace the gib screws. I figure I would try that before going with the cncfusion block mod.

Question in tool changing. Right now I use collets to hold the endmills. But when I need to change cutting tools I loosen the draw bar and tap/hit the top of the draw bar with a rubber hammer. The entire machine shakes when I do this...am I doing this right?

[hndswthtshdws]

Use a brass hammer. A small sharp tap will knock the collet loose without damaging the drawbar hex and without shaking the machine.

[CodeMonkeyDan]

Fixed up the Z-axis last night. Fixed the bolt not being tight from column to cncfusion block and added the 6m x 20 bolts for the gibs..

My next issue is dealing with precision...things are not what I expect.

My motor tuning in Mach3 is:

steps = 314.96062 (200 x 1/8steps = 1600 x 5tpi = 8000 steps per inch / 25.4)
Velocity = 1100
Acl = 171

The video shows the x-axis ball screw..I believe it should work this way but I wasn't sure.

Picture shows the hole I'm trying to cut, the goal is a 22.25mm diameter.

Two things. I have not trammed the head and during the y-axis installation I lost one bearing out of the ball screw..

A full mm off is unacceptable.

[manton]

If what you are pushing on is the ballnut, I don't think it should be loose.

[CodeMonkeyDan]

If you see step #15

http://makeprojects.com/Project/CNC-...rdware-/1295/2

I see no way to secure the ball nut...it just drops in.....Did I miss something?

[manton]

Isn't the piece that is fastened to the mill threaded for the ballnut? AFAIK the ballnut should not rotate, as this would cause additional backlash and accuracy problems.

[manton]

I think I see what is happening now. The aluminum piece is turning as well. There are two setscrews on the saddle that need to be tightened so that this is held securely, otherwise, it can move back and forth, or rotate a bit. It looks like this is done at the end of step 19, even though it has nothing to do with the Y axis.

[CodeMonkeyDan]

Michael..that worked..getting better results now.

I switched back to half steps and adjusted the motor tuning steps in Mach 3 from the calculated 78.75 to 80 and things seem better but not perfect.

Just trying to cut a 22.25mm pocket for a bearing. I adjusted the cutting diameter to 22.3 and it would fit very tightly. Only noticed a small out of round area in one quadrant (approximately .25mm out). So I think I should be happy with this.

Could be column flex at this point

Not sure why but I was having all kinds of issues with 1/8 and 1/4 steps..even after turning up the Khz to 35 and 45..drivertest.exe was showing excellent....will dig into that if I have surfacing issues on 3D shapes

[CodeMonkeyDan]

Worked on back lash and getting Mach 3 dialed in last night for around 3 hours.

I'm not sure if I have a problem or Im chasing the impossible...but If trying to cut a circular pocket for a bearing and the bearing is 22.25mm, I tell Mach 3 it is 22.4 (gives me a bit of wiggle room)

I still cannot just drop the bearing into the hole. basically its 22.5 in one diameter and 21.8 in another...which is very close to a round hole but not good enough.

Cutting aluminum with a step depth of 1.5mm and total depth of 3.

Only things I can think of is to turn off the wireless card in the computer incase its causing pulse problems and to decrease acceleration on the motors.

Or tell Mach 3 the hole is 22.9 and deal with the out of round in a few quadrants. (Or buy a reamer)

[manton]

Are you performing a finish pass at the end? What diameter cutter are you using? Have you measured the backlash in X and Y? If so, what is it?

[CodeMonkeyDan]

Hey Michael

I'm using the circular pocket wizard out of Mach 3 for these test. I see no finish pass option but I've seen that in meshcam.

Endmill is 11.1125mm

I was trying to measure backlash with the edge finder and a marker..basically put a mark..try and move x amount and see if it happens.

My calculated steps for my setup was 78.74 but after using the setup tool in Mach3, I asked the x-asix to move 25.4mm and it only moved 25.3..y was about the same. Mach 3 then adjusted my steps accordingly.