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Tramming the mill head, what the heck

winklershop

Plastic
Joined
Aug 31, 2017
I bought a nice dual dial indicator tramming device and calibrated it. I got the head zeroed out left to right and front to back. In theory I should be able to slowly rotate the tramming indicator on the table and it should read zero as I rotate it correct? This is not the case for me, I don't understand. Any ideas whats going on here. Also any ideas on how I can use a r8 boring head on a mill that has a quick change qc30em system? Or do I need to buy a different boring head? Trying to get some production improvments here.
 

atomarc

Diamond
Joined
Mar 16, 2009
Location
Eureka, CA
Seems like the alignment of the spindle to the dual dial indicator gizmo must be dead nuts or you get a false reading. You're tramming the head to a device that's not in perfect alignment with the axis of the spindle so when you rotate the alignment gizmo your indicators start to move...wouldn't that give you the poor results you're seeing.

I use a Blake Coax and a 12" Blanchard ground ring to tram my mill, and it seems to work fine, as the spindle is actually turning during the procedure which would overcome the problem you're seeing.

I've always thought those two dial indicator deals were a poor way to tram.

Stuart
 

FredC

Titanium
Joined
Oct 29, 2010
Location
Dewees Texas
I guess it had instructions on calibration, but it seems to me the check for calibration would be to index it 180 and get the same reading. Probably looking at it with a mirror when the indicators are facing back? You are taking the reverse image into consideration? When I am using an indicator with a mirror for centering work I make a note of what side of zero the needle is on the "M" side or the "O" with a Mitutoya or B&E with the Brown and Sharpe.
 

GregSY

Diamond
Joined
Jan 1, 2005
Location
Houston
You don't say how much it's out so it's hard to form an opinion.

But, I'd toss that dual head POS in the garbage and use a single indicator on a parallel ground ring of steel. That way, you eliminate the hopping over the ways which is not a great way to look for a reading.

Last, I'd do it without the quill extended.
 

DDoug

Diamond
Joined
Oct 18, 2005
Location
NW Pa
I bought a nice dual dial indicator tramming device and calibrated it. I got the head zeroed out left to right and front to back. In theory I should be able to slowly rotate the tramming indicator on the table and it should read zero as I rotate it correct? This is not the case for me, I don't understand. Any ideas whats going on here. Also any ideas on how I can use a r8 boring head on a mill that has a quick change qc30em system? Or do I need to buy a different boring head? Trying to get some production improvments here.

You mean that stoopid thing they have on the front page of George Bullis's homeshop forum ?

With the irrate junior apprentice face all screwed up ?

Looks to be made of billet.....:ack2:
 

e-fishin-c

Cast Iron
Joined
Jan 1, 2008
Location
Hooksett, NH
You don't say how much it's out so it's hard to form an opinion.

But, I'd toss that dual head POS in the garbage and use a single indicator on a parallel ground ring of steel. That way, you eliminate the hopping over the ways which is not a great way to look for a reading.

Last, I'd do it without the quill extended.

I do this with a new large surplus bearing cup, 7-8” approx.
 

michiganbuck

Diamond
Joined
Jun 28, 2012
Location
Mt Clemens, Michigan 48035
Might be better off to save one indicator for the lathe and just use one for the mill.
You can get right and left zero and in and out will/ may be off, so you have to figure want a feature controls the head tilt to tram that way.

You might run the cross way in (or out) and find some different tram numbers.
You might travel the table far to right or left and find different numbers.

The machine errors don't matter if you remember that the part is king on a mill.

You can fab-up a simple offset indicator holder that fits your boring bar and with having a boring job check the tram then. Likely the holding of the part will induce some error so you don't want to trust only the machine.

The quill feed may travel a little differently than the knee feed so that should be checked also when boring.
 

John Garner

Titanium
Joined
Sep 1, 2004
Location
south SF Bay area, California
Those two-dial-gage things work, provided that they are 1) zeroed correctly, which is with respect to the spindle rotational axis, 2) all machine motions PERPENDICULAR to the table surface are locked, and 3) the table surface is parallel to both the machine along-X and along-Y motions.

From that point, it's a matter of 1) putting a parallel spacer on the machine table so that one of the dial gage plungers is resting in the center of the spacer, but won't extend far enough to contact the table. Lock the knee, lock the quill, and be sure the machine head's nod and tilt adjustments are locked 2) Zero the dial gage contacting the parallel spacer. 3) Rotate the spindle to place the second dial gage plunger in the center of the parallel spacer, and if necessary adjust the dial gage in its holder so that the plunger can contact the surface of the parallel spacer but not the surface of the table. 4) Zero the second dial gage. 5. Rotate the spindle through a full revolution, and verify that both dial gages are zeroed when contacting the parallel spacer.

From this point, I'd recommend removing the parallel spacer, raising the knee until both dial gage plungers are slightly depressed, lock the knee, and then have yourself a ball making head nod and heal tilt adjustments.

The same setup process works if you want to set the head to an angle, except that you'll almost certainly need to lower the knee to sweep your sine bar or sine plate.
 
Joined
Nov 19, 2007
Location
marysville ohio
Shit can the double clock toy. Extend your quill all the way, this maximizes any error. First set a 6x6x6 angle on the table against the quill, put a light behind the quill-angle, any light? Fix it so you see no light, do this on x and y axis. Now you are close, lay an 8" or so diameter tapered roller race on the table, this is the track for 1 high quality .0005 indicator. Do this with the quill fully extended to maximize the error. Tweek it till you have no movement on your indicator. It will take a long time the first few times but soon you will be good at it.
 

CarbideBob

Diamond
Joined
Jan 14, 2007
Location
Flushing/Flint, Michigan
If the readings at 0 and 180 rotation are not zero (good luck) or more important mirrors of each other the indicators are not zeroed correctly.
This part of the calibration and setup.
Make sure this checks out before trying to tilt/nod the head.
This aligns you to table top and not necessary the axis ways which is another confusing situation.
I would not measure directly on any B-port table top but instead on a .100 gauge block slid under each indicator point. (local imperfections)
Quill extended vs retracted is a interesting question since there will be a difference in most machines with hours.
Bob
 

atomarc

Diamond
Joined
Mar 16, 2009
Location
Eureka, CA
Extending the quill fully and locking it will...in my small brain, toss any reliable reading out the 'winder'...especially on a machine with more than a few hours on it. The quill does move around in the bore of the head as it has to move up and down freely.

When I move the head on my machine, I want to be able to re-tram it quickly and accurately, so that precludes using the device shown in the OP, along with magic mirrors and gauge blocks.

I know all this ranting doesn't answer the OP's original question as to why he's getting the readings he's getting, but using it the way he is has so many variables it's hard to answer that question.

Stuart
 

John Garner

Titanium
Joined
Sep 1, 2004
Location
south SF Bay area, California
Extending the quill (and locking it in place) is advantageous only if the surface of the extended quill is used as a reference surface. Extending the quill does not make any difference when using a spindle-mounted indicator to sweep a table-mounted reference surface.
 

car2

Stainless
Joined
Sep 19, 2009
Location
Apex, NC
I use a home-made version of those with two old Federal indicators. Seems to work well when calibrated, zeroed. If the table is all knackered up, use some sort of parallel laid across the table. I make parts on the mill that required a lot of movement of the knee height, and even have drilled DEEP holes from both ends on parts hung over the edge of the table on an angle-plate, and the tram is fine. While you might squeeze another .001 with much more tinkering, no need to throw it away, and it does save time.
 

atomarc

Diamond
Joined
Mar 16, 2009
Location
Eureka, CA
Extending the quill (and locking it in place) is advantageous only if the surface of the extended quill is used as a reference surface. Extending the quill does not make any difference when using a spindle-mounted indicator to sweep a table-mounted reference surface.

I don't understand this statement. If the quill is fully extended and locked in place, it will certainly move in the bore as it's tightened, won't it? The tram will read this as a tilt or nod of the head and the result won't be accurate. At least that's how I see it.

Stuart
 

dian

Titanium
Joined
Feb 22, 2010
Location
ch
these contraptions are useless:

- very small radius
- need "calibration" (introducing unneccessary errors)*
- they will never be true to rotating axis (deviations in taper, holder, collet)

to rotate them defies their (only feasible) purpose. its so easy to stick a test indicator on some horizontal extention in the quill and sweep the whole table. no mirrors needed.

*i wonder how thats to be properly done anyway.
 








 
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