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Tramming a mill without moving the head ?

sasanifab

New member
So I have a rambaudi v3, the head can be moved left to right but not forward to back. In a situation like this do you then have to shim the part your working on? The table is off 4 thousands on that axis?
 

CarbideBob

Active member
Four thou over what distance?
That seems big. To the table top, result of part being cut or indicating something clamped in a vise?
 

sasanifab

New member
So I have a tramming tool that is 6-7 inches apart , so the back of the table is about 4 thousands lower than the front. I guess my question is .... there must be a way to make small adjustments in the table? Maybe with the gib . The head rotates side to side but not front to back. url=https://postimg.cc/sB6ZdYs8]
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sasanifab

New member
So if I use this tool north south in the middle of the table the back of the table is about 4 thousands lower than the front
 

CalG

Active member
So your machine head tilts, but does not knod.

The high table may be overcompensation for expected setteling, wear or sag.

Loosen the knee gibs just a little, and you will be astounded how much that table will fall out front.

As the machine is a ram type, but not a Turret type (If I see correctly from the pics) My first effort would be to looseen the ram gib and slide the head out and back a few times. Also, If the machine is new to you, Loosen up the knee gibs a bit and exercise the knee a couple dozen times full travel, lots of lube.

Get the machine to settle, whether "New and tight" or "old and clogged" You want the mating parts to be truly mating.

Then double check your tramming set up. I don't have anything good to say about those double travel dial set ups.

An indi-col and a couple of feeler gauge strips oiled to the table is all I ever use.

But for vise work, I only tram the vise. it's the only part that matters '=)
 

sasanifab

New member
I will take a picture of the saddle , there is several large bolts going down one size , i assume that's for adjustment? I
 

maybe try this--

figure out whether your knee/table is not perpendicular to the machine, or whether the spindle/quill is not perpendicular to the table.

If you have a decent precision square, use that and feeler gages between the column and knee top, and column and table top. Try that with the knee locked and unlocked.

Note: make sure you are clear what those bolts are on the knee clamping area. Not sure on your machine, but on a machine like a K&T those aren't for adjusting the gib, they're bolting on the piece which holds the tapered gib against the back of the dovetail on the column face. Best to get a manual to confirm, and/or look for a screw at top and bottom of the knee dovetail which would pull/push the gib.
 

EPAIII

New member
If the knee were sagging, I would expect that the front edge of the table would be lower. But you say the back edge seems to be lower.

That could be due to the ram sagging due to the weight of the head. I would clean and then LOCK DOWN the ways that the ram rides in. Then check with your two headed gauge again.

Of course, the knee should also be tight on it's dovetails while doing so.

A general rule is all adjustments on the dovetails that are not required to move for a given cut should be locked down if you want the best performance from any machine tool. And milling machines, with large weights hanging out, extended from their support dovetails, are a particularly severe example of this tendency to sag due to gravity.
 

John Garner

Active member
I share Limy Sami's concern. Did you set the dial gages' "zero" by 1) setting the indicator tool on a flat surface and adjusting the gages, or 2) installing the tool into the machine spindle and swinging the tool so that both gages are set with their contact points on the same spot?

Method 1 is, in my opinion, FUNDAMENTALLY wrong. Even if it's what the tool instructions might direct.

I regard this type of tool as a "nice to have" gizmo, BUT ONLY IF BOTH GAGES ARE "ZEROd" BY ROTATING THE TOOL.
 

eKretz

Active member
Figure out if the top surface of the table is out of square to the knee travel first. It might well be .004" out due to wear or sag, as noted by the others. You need to begin at the beginning and understand the geometry involved before you go making any changes to anything.
 

thermite

New member
I share Limy Sami's concern. Did you set the dial gages' "zero" by 1) setting the indicator tool on a flat surface and adjusting the gages, or 2) installing the tool into the machine spindle and swinging the tool so that both gages are set with their contact points on the same spot?

Method 1 is, in my opinion, FUNDAMENTALLY wrong. Even if it's what the tool instructions might direct.

I regard this type of tool as a "nice to have" gizmo, BUT ONLY IF BOTH GAGES ARE "ZEROd" BY ROTATING THE TOOL.

Not only "share the concern"..

I'm curious as to just WTF it is ....as even makes it "nice to have"?
 

sasanifab

New member
I generally just bring the table up until the ends of the dial indicator touch , zero them out and lower the table. Check for differences
 

thermite

New member
I generally just bring the table up until the ends of the dial indicator touch , zero them out and lower the table. Check for differences

I'm FAR too LAZY to rebuild a whole dam' knee when traversing in Z is not on the dance-card when in the cut, anyway.

Get you - or fab - a gadget akin to a "Big Box" telescoping "demolition" column.

Tilt the entire freakin knee a skosh. Run yer cuts.
Aside the adjustable jack until next critical need.

Correct wear-error in the knee's ways some other time.

Too great the hours worn mills must make good parts for money.
Too little the good time and money available to rebuild worn parts of mills.

Run what you got!


Not what you can only WISH you had.
 

Limy Sami

Active member
I generally just bring the table up until the ends of the dial indicator touch , zero them out and lower the table. Check for differences

Try doing a sweep with a single indicator - if you haven't a flat disc etc a sheet of glass will suffice ..........or at least get you very close - you can always rotate the sheet of glass to see if any anomaly is the machine or glass itself.
 








 
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