728VT really unhappy!

[55fairlane]

My lathe has a twist and since it is not bolted to the floor I could not pull it out so I used 150 pounds of lead in the aft tail stock corner of the cabinet and over a period of a couple months it settled down flat, cuts beautifully now. My mill settled down and I am now doing a final adjustment to it, it is a PM940V.

I hope your machines level,out and cut true for you!

 

[stupoty]

It's nice to see that Precision Matthews made good on your issues and got everything sorted out for you.

Stu

 

[Pevehouse]

That’s one thing I guess I need to do is level the base of my mill and see if I can get it to hold tram

 

[wrmiller]

The main reason I sold my 9x40 bed mill and bought the pm935 was so I can tram in the head in both X and Y. I have never owned a bench or bed mill that didn't have a forward tilt to the spindle (nod). The only bed mill that I have used (didn't own) that didn't have nod, was a 5000lb. monster that a friend owned. Impressive mill, but I couldn't afford one, nor had a place to put one.

 

[verbotenwhisky]

The main reason I sold my 9x40 bed mill and bought the pm935 was so I can tram in the head in both X and Y. I have never owned a bench or bed mill that didn't have a forward tilt to the spindle (nod). The only bed mill that I have used (didn't own) that didn't have nod, was a 5000lb. monster that a friend owned. Impressive mill, but I couldn't afford one, nor had a place to put one.

I will shim the head a bit to finalize my tram and eliminate the nod. The issue I had is keeping the Z gib adjusted.

 

[55fairlane]

That’s one thing I guess I need to do is level the base of my mill and see if I can get it to hold tram

I found a great tutorial by tormach , I can post a link to it if you want me to. Leveling the machine & having a solid base to sit apon will make a major difference

 

[55fairlane]

The main reason I sold my 9x40 bed mill and bought the pm935 was so I can tram in the head in both X and Y. I have never owned a bench or bed mill that didn't have a forward tilt to the spindle (nod). The only bed mill that I have used (didn't own) that didn't have nod, was a 5000lb. monster that a friend owned. Impressive mill, but I couldn't afford one, nor had a place to put one.

I can see that, while in happy with this machine, had I had it to do all over again I would have gone a different route.

 

[55fairlane]

I will shim the head a bit to finalize my tram and eliminate the nod. The issue I had is keeping the Z gib adjusted.

Is the gib mis-shaped? Need scraped in? Lacking lubrication? Something sounds a miss if you have to readjust the gib often...

 

[Dhal22]

Yep

I called it the first day. Being a business owner and with PM’s reputation here I knew it would be a return situation.

 

[MLab]

2 weeks ago we set a 728VT in my garage, spent this weekend installing the power feed, traming in the vise, ect.....
Got around to firing the machine up and making chips....went thru the square up the blocks routine, will not square up (in Y ) I tried everything (including getting my text book out from when I served my apprenticeship) finally bolt a 2-4-6 to the table & in the vise....using Z run an indicator up & down the blocks......0055 in 3 inches, the head in nodding at me, crap, call PM.....got thru the details with them, new Kurt vise, new Lyndex collets, used interapid indicator, and started my apprenticeship in 1986....been running machines since then.....3 hours on the phone, try this, they that, thy this.....short answer I get to pull the column loose & shim it....$5722.16 for new machine & I get the privilege of fixing it.....feeling very cheated

Even if nod is not an issue with your particular machine, it still makes sense to anchor the top of your column on a square column bench mill. I periodically tram nod out using the mechanism depicted in the attached photos. The mechanism relieves nod as well as preventing the opposite of nod (whatever that's called) when heavy drilling or milling. Tramming out nod takes very light pressure on the adjustment....little more than finger tightening on my machine makes a difference. It's hard to imagine that anything other than very light milling won't lift the head. I'm getting a light crosshatch patterns where fly cutter or shell mill passes overlap. My bench for the mill is attached to the same wall as the adjustment mechanism....and it's heavy. Periodic adjustments are minimal and positive. It seems column shimming would do little more than provide tram when the mill is not under load. Seismic restraint is an incidental benefit when you live in AK.