Tramming a PM25 - making the tool

[WobblyHand]

Spent a little bit of time cruising HM and the www looking at various means to tram a mill. As I have started to make more things, I'm seeing the small errors and imperfections that I'd like to minimize. So I'd like to tram my PM25 to make it better than it currently is. Not interested in buying a gizmo at this time. But, I would like to make a single indicator tool. It's relatively simple, which I like, and I only have a single indicator. Besides, I've blown the tooling budget for a while, so I need to make something from the stock at hand.

Have a couple of questions. Is it better to use a dial indicator or a DTI? (For indicators, I have a Federal DI 0.0001", or an Enco DTI 0.0005".) How does one account for the differing lengths of the X (23") & Y (7") axes?

On one HM thread, I saw a tramming tool that had rod in the spindle. On the rod there was a block. A second rod that was perpendicular to the first was attached to the block. Finally, there was a second block which attached to the horizontal rod. The dial indicator was attached to the second block. This tool had a way to adjust it's length. What I don't understand was how the rods were captured. I understand milling out a hole and making a slit and clamping across the slit to captivate the rod. What I don't understand is how the dark block below works. Can someone explain it? I've been pondering this a while and it's not coming to me.

Thanks for any tips and ideas.

 

[bill stupak]

It's hard to tell from the photo, but it might be something to allow the rod to slide in for a shorter span. It shouldn't matter how you hold the indicator as long as it is somewhat rigid. I prefer a .001" back button dial indicator, just easier to use, and the dial is always visible. I haven't tried a ten reading indicator, but I suspect it would be a little too fiddly. Unless you're working for NASA tramming to tenths could get frustrating very quickly and.

 

[Joe F]

Spent a little bit of time cruising HM and the www looking at various means to tram a mill. As I have started to make more things, I'm seeing the small errors and imperfections that I'd like to minimize. So I'd like to tram my PM25 to make it better than it currently is. Not interested in buying a gizmo at this time. But, I would like to make a single indicator tool. It's relatively simple, which I like, and I only have a single indicator. Besides, I've blown the tooling budget for a while, so I need to make something from the stock at hand.

Have a couple of questions. Is it better to use a dial indicator or a DTI? (For indicators, I have a Federal DI 0.0001", or an Enco DTI 0.0005".) How does one account for the differing lengths of the X (23") & Y (7") axes?

On one HM thread, I saw a tramming tool that had rod in the spindle. On the rod there was a block. A second rod that was perpendicular to the first was attached to the block. Finally, there was a second block which attached to the horizontal rod. The dial indicator was attached to the second block. This tool had a way to adjust it's length. What I don't understand was how the rods were captured. I understand milling out a hole and making a slit and clamping across the slit to captivate the rod. What I don't understand is how the dark block below works. Can someone explain it? I've been pondering this a while and it's not coming to me.
View attachment 354927
Thanks for any tips and ideas.

For X and Y tramming most of the time you would only sweep a 7" circle. Looking at he photo, I would think the jig is for a tilting head machine, and designed specifically to reset the X axis without removing the vise.
Joe

 

[WobblyHand]

My PM25 can tilt the head (X). (But there is nothing for nod.) Obviously the easy button is to tram in a 7" circle.
Was wondering if it was worth using a longer arm for the X axis. In the thread the OP said the part with the indicator could slide along the bar. I just can't quite fathom the attachment method for the "black bar". Guess I've never seen one up close to understand it. Was hoping for an explanation of the mechanism.