Need help with adjusting Lathe

[Mkroe]

Hello all,
I have a Patriot VFD purchased in May. Have made many of the mods to eliminate vibration as well as upgrades I have made from ballscrews, new brackets and mounts for steppers and so forth.

I have converted it to total cnc, with 16" travel in Y as well. still don't have 4" travel in Z as advertised only 3.5" ? "scratching head"

My problem is this. How the heck do you adjust the lathe spindle to make it parallel to the X ways? It is off by 0.011 and this is causing a tapering of approx 0.001 for every inch of travel along the axis. It makes for useless shafts if you know what I mean

I know there are two mounting screws on each side of the base to head mount. What I'm not sure of is the center pins? They are threaded internally?

I know that most mating surfaces on this have location pins which I have had to remove in order to get things indicated in. Now I must tackle this as the last hurdle.

Anyone know the procedure for this machine?

Thanks in advance.
MK

[instructor37]

Originally Posted by Mkroe Hello all, I have a Patriot VFD purchased in May. Have made many of the mods to eliminate vibration as well as upgrades I have made from ballscrews, new brackets and mounts for steppers and so forth. I have converted it to total cnc, with 16" travel in Y as well. still don't have 4" travel in Z as advertised only 3.5" ? "scratching head" I would like to see the conversion for 16" travel- as far as the quill travel, its actually sort of unlimited- without the front set screw that rides in the machined groove , the quill will continue to travel until it comes out of the casting. Maybe the groove was not milled enough and is restricting your travel. My problem is this. How the heck do you adjust the lathe spindle to make it parallel to the X ways? It is off by 0.011 and this is causing a tapering of approx 0.001 for every inch of travel along the axis. It makes for useless shafts if you know what I mean The lathe column is held in place with 4 big bolts and on each side of the column between the bolts is a taper pin. The taper pin is threaded so you can screw in a bolt and pry it out. You can pull out the taper pins and loosen the bolts and move the lathe spindle into alignment by tapping it with a rubber mallet. Once aligned, you can re-tighten the four big bolts. However, putting the taper pins back in could return it to its original position, so you would need to ream the holes first. I know there are two mounting screws on each side of the base to head mount. What I'm not sure of is the center pins? They are threaded internally? I know that most mating surfaces on this have location pins which I have had to remove in order to get things indicated in. Now I must tackle this as the last hurdle. Anyone know the procedure for this machine? Thanks in advance. MK

.

[Mkroe]

Originally Posted by instructor37 .

Thanks I37,

I suspected it might be something like that as far as the tapered pins just didn't want to try until I was sure of the design.

I'll try and get some PICs up of the Y table.

Basically, I used a21" ball screw. Moved the bearing points out 2" at each end. Made a new Stepper mount.

I had to move the ballnut mount approx 1.5" towards the front of the machine.

This still allows 2/3rds of the table in the ways. Gib adjustment becomes a little more critical though. So far it is doing well. I have had my trials and tribulations though with this project. More so on the vibration issues.

As you may know, steppers and vibration do not work well together. Midband resonance becomes a problem and lost steps as a result. I have found using polyurethane rubber.

http://www.mcmaster.com note that this is the HARD in there durometer. part#8716K42

As a spacer between steppers and mount points as well as neoprene clad washers for the screws that holding them, eliminates most resonance problems.

Also good connectors using a Buna N style for direct connects or Pulleys with belts make a large difference. Even still, sometimes dampers to the rear output shafts are also required.

Again thanks for your reply.
MK