Checking mill is vertical (tram)

[DickDastardly40]

Gents

I hit upon this idea to check the tram of my mill without removing the vice and sweeping with a DTI. I don't know if it is my own thinking or I read about it elsewhere; anyway I'd appreciate you views on its accuracy. My mill head doesn't nod so I think it's a valid test.

I put the angle rod for my DTI into a collet at just past 90 degrees and measured the height to the highest point.
on the left and right. As it turned out, mine was spot on, but I guessed thet you could measure the high and low sides, then split the difference to adjust to correct it.

Sorry for the crap camera phone pics.

Al

 

[te_gui]

One suggestion I might make is to put a finger indicator in the height gage rather then the scribing point. You would know exactly where the high point is on your tram rod. I like the idea though, hate having to always pull the vice.

Brian

 

[kvom]

You are tramming the spindle to the table that way, but not to the vise. Unless you are sure that the vise is parallel to the table it is probably better to tram to a parallel clamped in the vise. I know the for model size parts I almost never clamp to the table.

 

[BobWarfield]

I do something "kinda sorta" like this:

The indicol is just used as a "feeler" and I use my quill DRO to measure how much one side is high versus the other. A plunger indicator on a decent rigid tramming arm would do same, but I haven't bothered making one yet.

KVOM is right on what you're tramming to. I've seen that argument go on in a lot of places of which is better. I like the longer baseline when tramming of tramming to the table, but you do want to make sure your vise is trammed too when you put it on the table.

Best,

BW

 

[te_gui]

I alway tram to the table, try and swing the biggest radius I can, so its easy to adjust. When tramming my BP in the X (long) direction if I get it within .001 over 20" thats plenty good for me. The Y takes a little more fiddling since table is only 9" deep. If you tram to the vice, you dont know that the bed of your vice is parallel to the table ways which could give you taper. I alway check that the vice bed is flat, then indicate the fixed jaw for square. You get pretty quick at it. I remember first qtr of Machine Shop when we learned how to tram a mill, seemed like they were always out for the first week or so, after that they got lots better, took me a bit to realize the teacher was tweaking them out prior to class.

 

[DickDastardly40]

I know the vice was parallel to the bed as it was fitted then checked with a DTI.

Thinking on it I suppose the term tram refers to tram lines and parallelism. What I was particulary wanting to do was check the spindle was vertical and and square to the table easily so that any holes drilled with the quill aren't cock eyed.

My table is 6" wide so sweeping with a DTI is awkward I find. I have my eye out for a large bearing race I can use to make life easier still. I like Bob's method, however I have no quill DRO so would have to do trial and error to find the best way.

 

[modelbuff]

A tramming tool you may not have thought of is a disk brake rotor. A few years ago I was in the vehicle shop at work and the mechanic had just resurfaced a rotor. When he measured the thickness he found it was tinner than the minimum required so it was to be discarded. I took it home and cut the center out on the lathe. the rotor remaining made a great tool to lay on the table of my mill to measureto in a complete circle.