Head Tram Square

Looking for a used set of these ; 01 Pro Tram Bridgeport Head Square Knee Mill Spindle CNC Router milling endmill | eBay

To square my spindle against my cutting table.

Just use one normal dial indicator. If you mount it on an arm, which can just be a bent piece of steel bar, you can take measurements at 4 points (i.e. 12:00, 3:00, 6:00 and 9:00 on the clock) and compare them to find how far out the spindle is in each axis. That tool is just a gimmick to make it slightly faster.

Thanks Johnathon. If you could post a pic for ref, it would help me. I am new to all this, so still a learning curve. Where do I get a dial indicator and which one ?.

Here:
Squaring a Drill Press Table

For the indicator you don't need anything special, just get a cheap one:
dial indicator | eBay

If you get one on a stand you'll find it useful for other things, like checking backlash and spindle runout.

Then this one ? Toolzone Metric Dial Test Indicator DTI & Magnetic Base | eBay

Just seen the post costs to France 24.99 LOL
Just an example

That would be fine.