# Homemade tram tool



## Leggman

I got the idea from a video on youtube by metal tips and tricks. 
The holes were a little out of plumb because I drilled them on a older drill press and it wasn't right.
I have a good chuck coming for my mill and when it comes in I will build another. 
Fun little project. 
Dave


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## Uglydog

I've never seen a three point tram tool.
But, I am wondering if the use of a disc or plate instead of a bar with three holes and three gages would allow for simultaneously tramming of nod and tilt.

Daryl
MN


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## RJSakowski

Uglydog said:


> I've never seen a three point tram tool.
> But, I am wondering if the use of a disc or plate instead of a bar with three holes and three gages would allow for simultaneously tramming of nod and tilt.
> 
> Daryl
> MN



I would think it would work but the prevailing design has the indicators diametrically opposite each other so an adjustment in one axis doesn't  affect the other axis.  Using a three point indication spaced 120º apart, the adjustments affect both axes.  I have a laser level that does just that.  With the level, it isn't too difficult to make an adjustment but it would be more annoying trying to adjust both trim and nod.

The third indicator could be mounted at right angles to the line between the first two but then the sensitivity would be halved as sensitivity is proportional to the distance between the indicators.


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## RandyWilson

Not to threadjack, but I've been wondering why people use 2 (or 3) indicators?  As I see it, a single indicator on a sturdy offset arm should be sufficient.


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## RJSakowski

RandyWilson said:


> Not to threadjack, but I've been wondering why people use 2 (or 3) indicators?  As I see it, a single indicator on a sturdy offset arm should be sufficient.



If you use a single indicator, you have to read, adjust, rotate, read, adjust, etc.  Not difficult and the original way to do it.  We do it all the time when we zero a four jaw chuck on the lathe. 
With a dual indicator tramming tool, we zero the indicators and rotate to the axis we are tramming and adjust until they read the same.  Done.


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## RandyWilson

Okay, that's the part I am missing. How do you zero the two indicators to be true normal to the spindle?  What is the initial plane of reference?


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## chips&more

RandyWilson said:


> Okay, that's the part I am missing. How do you zero the two indicators to be true normal to the spindle?  What is the initial plane of reference?


You are not missing anything! You have pointed out the BIG FLAW in that contraption! Why some people love that thing is beyond me! It needs to be calibrated every time you set it up! I’m very happy with using just one indicator. Marketing just loves to try and sell us new toys for our shop. A few are good ideas, but most are just a waste of money IMO.


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## Rustrp

chips&more said:


> You are not missing anything! You have pointed out the BIG FLAW in that contraption! Why some people love that thing is beyond me! It needs to be calibrated every time you set it up! I’m very happy with using just one indicator. Marketing just loves to try and sell us new toys for our shop. A few are good ideas, but most are just a waste of money IMO.



I'm a novice machinist, pre-apprentice, but I have been doing sheetmetal layout/fabrication and welding since high school (a long time). The same question still comes up when I see 2-3 devices checking for accuracy between the cutter and the product; Why? Now we're counting on all the devices in between, those that are suppose to be accurate to .0005" to provide accuracy.


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## chips&more

Rustrp said:


> I'm a novice machinist, pre-apprentice, but I have been doing sheetmetal layout/fabrication and welding since high school (a long time). The same question still comes up when I see 2-3 devices checking for accuracy between the cutter and the product; Why? Now we're counting on all the devices in between, those that are suppose to be accurate to .0005" to provide accuracy.


If I understand your question? Yes, the more contraptions you have in your set-up. The more uncertainties you will have. Just keep it simple!!! The simpler the better!!! With my projects, I usually sleep on it, toss ideas around and the next day will have a simple, fast and accurate way of making. And NOT with buying any new marking toys that I don’t need, good luck, Dave.


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## T Bredehoft

I use one .0005 indicator, with an 8" offset, gives me 16 inches of difference, far more accurate than 5". I guess that's 3.2 times the accuracy.


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## Rustrp

chips&more said:


> If I understand your question?


Yes you're correct but my question of "Why?" was more rhetorical. Tramming the mill or dialing in the centers between the chuck and tailstock only becomes difficult if a person doesn't understand the goal. I'm a **read the instructions first** kind of person which seems to make projects easier, IMO. Trammig the mill was one of my first mill projects, and knowing when it's accurate enough works well in many career fields. If I'm off a couple of thousandts and I'm milling a slot in a piece of flat stock that's good. If I'm milling a surface I want more accuracy. In both cases I begin with a square and place a light on the back side that gets me close, quickly.

With that said, and after all the keystrokes, I think making the tramming device causes one to think about the areas where we lose the accuracy we were trying to achieve or how to correct it.


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## Uglydog

My go to is a Starrett 650 back plunger. 
I've never used a "tram" tool.
Merely wondered if a three point made any sense.

Daryl
MN


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## tweinke

I made one and like it, set zero off a gauge block from one point and go quick and easy


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## RJSakowski

RandyWilson said:


> Okay, that's the part I am missing. How do you zero the two indicators to be true normal to the spindle?  What is the initial plane of reference?


You don't have to be normal to the spindle axis.  All that has to happen is the indicators are zeroed at the same height. If you think about it, it's no different than  tramming the traditional way with a single indicator except you now have two indicators set 180º apart on the spindle axis.

If  you are out of perpendicular to the spindle axis with the tramming tool, you won't hit the same reference spot exactly but it would have to be a serious misalignment to cause a measurable error.


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## woodchucker

chips&more said:


> You are not missing anything! You have pointed out the BIG FLAW in that contraption! Why some people love that thing is beyond me! It needs to be calibrated every time you set it up! I’m very happy with using just one indicator. Marketing just loves to try and sell us new toys for our shop. A few are good ideas, but most are just a waste of money IMO.



So that might be true for a regular BP type of unit. One with a screw to adjust both tram and nod.
At least I might agree.

But I just rebuilt a Clausing 8520. It's a round support, no screw. So to tram you tap it with your hammer back and forth. When tightening the bolts it often changes.
With 2 indicators it would be easier, you would know if you went too far or not enough. And while tightening, you would get an idea of how much your are moving it and be able to tap it back as you tighten in stages.


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## RandyWilson

That is exactly the question I am asking; HOW do you get the indicators exactly even to the plane 90 degrees to the spindle? If your zero point on the two indicators are not exactly on the 90 degree plane, then you will not be normal to the spindle.

 As I read the other reply, you keep spinning the spindle and adjusting until you get both indicators reading the same at a single test point. Then it's a matter of trusting the rig to hold calibration.  Guess it depends on how often you tram the head.


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## woodchucker

So zero one, flip it around 180, then set the other to zero at the same spot.
Now they are both good to read.

You don't spin it again, you position in front of you and your good to read.
When you move your indicator back and forth (single indicator) you are trusting the rig to hold right?
Now you have zerod both on the same point when you have 2.


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## Rustrp

woochucker said:


> So zero one, flip it around 180, then set the other to zero at the same spot.
> Now they are both good to read.
> 
> You don't spin it again, you position in front of you and your good to read.
> When you move your indicator back and forth (single indicator) you are trusting the rig to hold right?
> Now you have zerod both on the same point when you have 2.



True, but with the tramming tool (rig), I must trust that the rod through the cross bar is accurate, plus both indicators are accurate. With the single indicator swung from left to right and arriving at "0" on both sides, (after splitting the difference) I will be accurate without question. Even if the indicator reads accurate to .oo5", when it's .000" Lt. and .000" Rt. the questionable reading is eliminated. Of course I would do this with an indicator that rotates only one direction.


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## woodchucker

If the bar were 30 degrees off, and you zerod it , it would still be accurate.  Because they were both reading zero at the same spot. Spin it around to face you and they should still be reading zero if in tram.
Now  if it leaned, but then both would lean.
Probably more true than swinging back and forth. So I probably think this for some would be better. In my case for the 8520, yes. If I had  a BP, it would be a luxury.  Wish I had a worm gear to tram I would not want or need that luxury.  without the worm gear you can tap too far in a heart beat. There's no way to control where you are, and how far you tap. Light taps often don't move it, then bammmmm it moves..
This looks better than trying to cobble a collar for a gear and add a screw...


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## T Bredehoft

Some of us have installed (on our PM25 type mills) a pair of captive screws, one on either side of the head. When snug they hold it in position, when one is loosened the other can be tightened and adjust the tram of the head.


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## Rustrp

woochucker said:


> If the bar were 30 degrees off, and you zerod it , it would still be accurate. Because they were both reading zero at the same spot. Spin it around to face you and they should still be reading zero if in tram.



Maybe I need another set of eyes on this, because I thought the purpose of the bar with two indicators was there is no need to spin. The process is to have both indicators read the same when the head is trammed in. i.e. both indicators read the same, whether it be 0, 10, 12.5 etc. To make sure the indicators and bar are accurate you would need to tram the tram bar setup prior to tramming the head. If we go with the bar being accurate then all is well, but if the bar is off a half degree, the head will be off as well. People who design things make it seem difficult so they can sell their product.


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## tweinke

Ok I think I see the confusion here. You put the unit in the spindle, then you put a 123 block or such under one of the indicators and zero the indicator, with out moving the 123 block you need to rotate the spindle 180 degrees and zero the second indicator and remove the 123 block, you can now turn the spindle back so that both indicators are lined up on the axis in question and tram till both indicators read the same reading. By setting zero at the same point for both indicators any out of square on the unit is compensated for. I in my newby state of mind I  had a heck of a time grasping the whole thing but think the theory is sound. Hope this all made sense.


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## RJSakowski

Rustrp said:


> Maybe I need another set of eyes on this, because I thought the purpose of the bar with two indicators was there is no need to spin. The process is to have both indicators read the same when the head is trammed in. i.e. both indicators read the same, whether it be 0, 10, 12.5 etc. To make sure the indicators and bar are accurate you would need to tram the tram bar setup prior to tramming the head. If we go with the bar being accurate then all is well, but if the bar is off a half degree, the head will be off as well. People who design things make it seem difficult so they can sell their product.


You spin the tool because you set the zero on the same spot.  It doesn't matter where you pick the spot.  It just has to be stable.  I actually pick a spot at the front of the table because it's easier to read without rubbernecking
edit:  tweinke, you beat me by a minute.  Nice explanation.


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## rdean

Before I made my dual indicator tram tool I had the same questions and could not find exactly how to set the unit.  I will try to go one step at a time.
With the tram tool in the arbor and the gauges facing you place a spacer of good quality under one of the indicators stem.  The spacer does not need to be any particular height but should have parallel sides.  I use a piece of 1" bar that has been faced in the lathe about 1/2" long.
Move the spindle down until the stem contacts the spacer and then down a little more (maybe 0.050) to there is some wiggle room for out of tram.  Lock the spindle at this position and then turn the dial case to indicate 0.000.  
With the spindle still locked turn the spindle 180 degrees so that that the other indicator's stem is resting on the spacer in the same location. ( The face is now read from the back side of the gauge)  Now set the dial on this indicator to 0.000.

You have just calibrated the tool and am free to unlock the spindle and remove the spacer.  
To use  turn the spindle around so you see the dials and lower the spindle until you see both dials move and continue down until one of the dials reads 0.000.  Lock the spindle and now read the other dial which indicates how far out of tram your head is.  Now you can adjust your head so both indicators read the same amount and it may not show 0.000 but just the same on both dials.
If you now hold the indicator stems up you can just turn the spindle 90 degree and immediately read the nod of the head.  Calibrating the tool in this way takes all the variables out of the setup and the tools shaft can even be bent.

Hope this helps

Ray


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## brino

tweinke said:


> Ok I think I see the confusion here. You put the unit in the spindle, then you put a 123 block or such under one of the indicators and zero the indicator, with out moving the 123 block you need to rotate the spindle 180 degrees and zero the second indicator and remove the 123 block, you can now turn the spindle back so that both indicators are lined up on the axis in question and tram till both indicators read the same reading. By setting zero at the same point for both indicators any out of square on the unit is compensated for. I in my newby state of mind I had a heck of a time grasping the whole thing but think the theory is sound. Hope this all made sense.



Now I finally get it!
Zeroing the two indicators to the same spot calibrates the tool and cancels out any "out of square" imperfections in the t-shaped holder. Thank You!

-brino


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## Rustrp

RJSakowski said:


> You spin the tool because you set the zero on the same spot.  It doesn't matter where you pick the spot.  It just has to be stable.  I actually pick a spot at the front of the table because it's easier to read without rubbernecking
> edit:  tweinke, you beat me by a minute.  Nice explanation.



With the two indicators on the tramming bar what's the purpose of zeroing the indicators? If the bar is accurate then I begin with both indicators zeroed. I can bring the indicators down and touch the table and adjust the head until both indicators read the same. What they read isn't important as long as they are the same and we accept the bar as accurate and true. If the bar isn't accurate then we may as well use the tried and true one indicator setup.

To check the bar I would place a parallel on the table and bring the indicator down to touch the parallel and lock the spindle. Spin the bar and the second indicator should read the same on the same spot. 

If I make my own bar then I need a surface plate with all the pertinent measuring devices to insure the bar is square to the round that's perpindicular. If the hole is drilled crooked through the bar I have defeated my purpose. You can't IMO, zero out two separate indicators on a bar that's inaccurate.


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## RJSakowski

Rustrp said:


> With the two indicators on the tramming bar what's the purpose of zeroing the indicators? If the bar is accurate then I begin with both indicators zeroed. I can bring the indicators down and touch the table and adjust the head until both indicators read the same. What they read isn't important as long as they are the same and we accept the bar as accurate and true. If the bar isn't accurate then we may as well use the tried and true one indicator setup.
> 
> To check the bar I would place a parallel on the table and bring the indicator down to touch the parallel and lock the spindle. Spin the bar and the second indicator should read the same on the same spot.
> 
> If I make my own bar then I need a surface plate with all the pertinent measuring devices to insure the bar is square to the round that's perpindicular.


They don't have to be zeroed, its just convenient.  They just  have to read the same when resting on the same reference point.  It is not necessary that the bar be dead nuts perpendicular to the shaft mounted in the spindle or that the spindle not have any angular runout because the zeroing process accounts for that.  The way I made mine, I can move the indicators up or down and clamp them at any vertical position.  

If there is excessive non-perpendicularity, the indicator that is down will be slightly closer to the spindle than the other and they won't track on the same circle.  However, if the reference surface is reasonably flat as in a 1-2-3 block, the error will be so small the it won't matter.  You are looking for variations on the order of a thou over six inches.  If you are off by 1/4 inch on the position of the reference calibration, the error in the calibration would be a fraction of a tenth of a thousandth.


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## RandyWilson

woochucker said:


> So zero one, flip it around 180, then set the other to zero at the same spot.
> Now they are both good to read.
> 
> You don't spin it again, you position in front of you and your good to read.
> When you move your indicator back and forth (single indicator) you are trusting the rig to hold right?
> Now you have zerod both on the same point when you have 2.




I was referring to using the rig multiple usages.  If it's really not that hard to set up... and I find myself in possession of a few spare indicators...


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## Rustrp

RJSakowski said:


> The way I made mine, I can move the indicators up or down and clamp them at any vertical position.


This video makes absolutely no sense to me. The device is zeroed on a surface that you have no way of knowing it's flat or accurate. The magnetic calibrating gimmic follows in the same order.





This is the tool that makes sense (it's the same as the Starrett 649) because I want my spindle to be perpindicular to the vice/table, not to a measuring device that's inaccurate. The spindle square is zeroed on the surface plate then inserted in the spindle. Tramming could then begin any time after both indicators move, but he took one to zero, split the difference by adjusting the head and zeroed them both.





Maybe I like a challenge but I don't see tramming with one indicator as being difficult or difficult to follow. OR,,,,maybe I'm just not as addicted.


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## woodchucker

Rustrp said:


> Maybe I need another set of eyes on this, because I thought the purpose of the bar with two indicators was there is no need to spin. The process is to have both indicators read the same when the head is trammed in. i.e. both indicators read the same, whether it be 0, 10, 12.5 etc. To make sure the indicators and bar are accurate you would need to tram the tram bar setup prior to tramming the head. If we go with the bar being accurate then all is well, but if the bar is off a half degree, the head will be off as well. People who design things make it seem difficult so they can sell their product.


To set it up you must spin it so both read zero on the same spot.
After that you have them face you and work them both to the same reading.


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## RJSakowski

At 1:12 - 1:16 in the 1st video, he shows the calibration procedure. First one indicator is zeroed on the magnet and then the second.  When the indicators both read the same, they   At this point you are not saying anything about the table and its relationship to the spindle angle; only that when the indicators read the same, the indicator tips lie in a line perpendicular to the spindle axis.  The head could be tilted by 10º and the calibration would still be valid as long as the indicator points reference the same point.

The one concern that I have with Tubalcain's calibration is that it doesn't take into consideration any angular runout in his collet, chuck, or however he mounts the spindle square. Edge Technology's method does compensate for any runout.  
Also, when he splits the difference in his tramming procedure, he is actually adjusting so both indicators read the same just as done in Edge Technology's video.


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## ronboult

RJ you are absolutely right that using a two indicator traming tool is both more accurate and quicker than using a single indicator. The error using a two indicator tool is confined to the accuracy of the indicators used. Run out in the spindle/collet is eliminated. When a single indicator is used and rotated run out in the collet/spindle is also added to the error of the indicator. If uncertain after tramming to zero with the two indicator tool rotate the tool 180 deg again and check that as expected both again read zero.
Ron


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## RJSakowski

Ron, I don't believe that it is more accurate than mounting an offset indicator in the spindle as has been done for many decades before and here is why.

The error that you have in your tramming adjustment is caused by a stack up of errors. One source of error is the error in reading the indicator.  In zeroing the tramming tool you might read the first indicator as .000 but it may actually be .0002.  The second indicator might be adjusted to .000 but it may actually be -.0003.  Now you move on the the tramming process where you could experience similar errors and they may go in opposite directions.  The total error will be the algebraic sum of the individual errors. (for those of you too long out of school, that means consider the direction of the error when adding).  In addition, every mechanical device has inherent internal errors (nonlinearity, backlash, etc.) which all factor in.  Finally, there is your ability to read the instruments.

So the bottom line is double the number of readings, double the potential error.  However, the question is, are the errors associated with reading the tramming tool significant enough to result in an significant error n tramming.  IMO, the answer is no.  I am confident enough in my ability to set and verify the tram to +/-.001 over a distance of 6" which is good enough for my needs.

The other factor is ease of use.  When tramming in the traditional fashion, you determine an offset and make an adjustment to reduce the offset by half.  Then you swing the indicator 180º and if your lucky, they now read the same.  If not, you repeat the process until they are.   The geometry of the mill head is such that rotation of the head through an angle does not produce equal and opposite offsets.   With the tramming tool, you're reading both at the same time  so you should be able to accomplish the tramming with a single adjustment.

The tramming tool was a simple enough tool to make and the investment was under $30.   It has uses other than tramming.  You can quickly set up work at an angle to the horizontal in a vise.  My tool can work with an offset of 5" and the total differential height can be as much as 2" so I can quickly set angles as large as 20º although not as accurately as using a sine bar.


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## Iceberg86300

Eh, all that crap is too difficult. Just get it close, torque everything to ludicrous levels, insert a shell mill, then cut the table. If you didn't cheap out on the shell mill and make excessively small cuts you'll be perfect. You should probably square the table/saddle first though.  

In all seriousness, at least during my tenure at Haas, they actually had a table cut program for each machine. IIRC, this program was sent to customers on request. Can't remember if a service tech was involved or not though. From my position as a design engineer this seemed exceedingly rare (we would do "specials" from time to time as well). But it may have been more prevalent in the service dept. 

---------------------------
IIRC (again: design engineer, not manufacturing or assembly), all squaring was done with an indicator in the spindle (error?) sweeping granite angle slabs or T slots (error?) and then a precision bar (error?) was placed in the spindle (error?) which was then moved up and down while in contact with an indicator affixed somewhere (error?).

^^^^^^^ that's A LOT of potential error going into adjusting a machine that has ±.0005" accuracy and ±.0001" repeatability. 

However, these were brand new machines and all the metrology above was calibrated quite often. Plus a ball bar test to confirm everything.


Bottom line, for an old Bridgeport every method discussed so far has it's merits and is perfectly acceptable.

*The key point to takeaway here is don't skimp on your metrology gear, have it calibrated at an interval based on use/abuse, and use an accuracy level based on your needs.*

Sent from my SM-G900V using Tapatalk


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## ronboult

RJ
Thanks for the reply. You are correct regarding the summing of errors leading to greater uncertainty. However a general rule for accuracy is to use a measuring instrument an order of magnitude greater than the accuracy required i.e. need to tram to +/- 0.001" then use a tenths indicator. Then the significant error is less than the other errors in the system like Collet /Spindle run out and flex in the column. The dual indicator tool removes the collet runout from the measurement and as you say anyone who has actually used one to tram a mill will know how they really work and make the process much easier. You don't even have to go round the back to read the indicator.
Ron


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## woodchucker

ronboult said:


> RJ
> Thanks for the reply. You are correct regarding the summing of errors leading to greater uncertainty. However a general rule for accuracy is to use a measuring instrument an order of magnitude greater than the accuracy required i.e. need to tram to +/- 0.001" then use a tenths indicator. Then the significant error is less than the other errors in the system like Collet /Spindle run out and flex in the column. The dual indicator tool removes the collet runout from the measurement and as you say anyone who has actually used one to tram a mill will know how they really work and make the process much easier. You don't even have to go round the back to read the indicator.
> Ron


Yep, I watched someone on U tube build an ER collet on his lathe. He used a .001 indicator and was hoping for less than .001 runnout. Aside from some astute comments on why he failed (like failing to insert a rod in the collet when bluing) , I felt he should have used a .0001 indicator, as when looking to make a tool, you want more accuracy than the part you are looking to create. So many guys shot me down. But when you are looking for .001 or less, using a .001 indicator leads you to +-.0005 error. so a .001 can be .0015, but in his case he was .003 if I remember off.   Anyway, when making tooling, I always think finer precision, to  help get better accuracy, but the tool must be accurate to begin with.


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## woodchucker

T Bredehoft said:


> Some of us have installed (on our PM25 type mills) a pair of captive screws, one on either side of the head. When snug they hold it in position, when one is loosened the other can be tightened and adjust the tram of the head.


Any chance on seeing what you did? 
I realize they are two different style mills, but it would be interesting seeing what you did.
I envision it like a tailstock with screws to align


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## kd4gij

This is the tramming adjust screw Tom is talking about.


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## T Bredehoft

The problem I see with a commercial two-dial tram gadget, is that you place it on a surface plate and zero both indicators. This is OK if it's commercial and you trust it. If it's shop made, (if I made it) I wouldn't trust that the spindle that goes in the quill is square with the base which was on the surface plate. Not square and there's no point in starting. 
Use one indicator, swing it, and you're good to go.


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## woodchucker

kd4gij said:


> This is the tramming adjust screw RJ is talking about.
> 
> 
> View attachment 232256


That's a lot easier than what I would need to do, but you guys have me thinking that maybe I am overthinking this.  The square column helps you a bit more than my round overarm.
But that's helpful.


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## kd4gij

woochucker said:


> That's a lot easier than what I would need to do, but you guys have me thinking that maybe I am overthinking this.  The square column helps you a bit more than my round overarm.
> But that's helpful.




I would love to get my hands on an 8520.  I would be more than happy to design something for it and share it with you.


hint:  My birthday is coming up soon.


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## woodchucker

kd4gij said:


> I would love to get my hands on an 8520.  I would be more than happy to design something for it and share it with you.
> 
> 
> hint:  My birthday is coming up soon.


Don't tell anyone it's a surprise.


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## Rustrp

RJSakowski said:


> The one concern that I have with Tubalcain's calibration is that it doesn't take into consideration any angular runout in his collet, chuck, or however he mounts the spindle square. Edge Technology's method does compensate for any runout.



Yesterday was a busy day so I didn't have time for comments. The distinct difference I see in the two videos is one is selling a product and the other is demonstrating the use of a tool. If we do comparisons there's lots of things to compare but I don't see anything in the ET video that indicates compensation has been made for spindle runout, and if spindle runout is a concern, this should be done with an indicator at the spindle. 

It becomes confusing when I step into this arena of H-M **Be Perfect** to get explanations that justify otherwise. I realize we are discussing a milling machine with tolerances that vary form machine to machine but pointing out spindle runout while ignoring the 5" long piece of 1018 we pressed into the crossbar/beam/device that holds the indicators escape logic. How true or straight is the piece of 1018 or stock that was used?

With that said, I will default to my position on accuracy. Using one indicator may not be the easiest method but it rules out all the possibilities for errors which are introduced by using multiple indicators. In one way the device demonstrated by tubalcain sets up an issue or question regarding the accuracy of the table, but in his behalf he did mention the importance of the table's flat surface. In the ET video we see the use of a magnet (very small surface) used to calibrate (zero the indicators) the device on one spot of the table, and are we then to assume the flatness of the table where it's indicated for the purpose of tramming is the same. This is a good segue into this video showing a single indicator. 

At about the 4+ minute mark in the video he sets up a pair of parallels across the table which is more than an arms reach towards accuracy when comparing the one spot anywhere on the table used to zero two indicators. When using one indicator .0000" is always .0000" given our limited abilities to set to zero, and the same can't be said when using two, because most of us don't have a way to check the indicators against the other. Now if I step a half dozen steps away and pick up a measuring tape the rule still applies. I was taught to use one tape when building a project or product to assure accuracy. The more obstructions we introduce the sloppier the job becomes.  I am aware and didn't forget we are making things for ourselves and this is all that's important to some.


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## owl

I made one of these tools, and it was an eye opener. It made the tramming process fairly easy, but it is sensitive enough that after the adjustment was as perfect as I could get on my little mill, I leaned on the head, and watched the gages move.  It makes me wonder just how much heavy cuts affect flatness.


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## tweinke

owl said:


> I made one of these tools, and it was an eye opener. It made the tramming process fairly easy, but it is sensitive enough that after the adjustment was as perfect as I could get on my little mill, I leaned on the head, and watched the gages move.  It makes me wonder just how much heavy cuts affect flatness.



Makes one think about chasing zeros doesn't it?


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## Leggman

I am so glad I could be of service in starting a s&%t storm on this forum. My only intention was to show a first project on the mill. 
It's a good thing I didn't ask for opinions on Donald Trump , or abortion, or immigration. 
I DO see the validity of one indicator vs two but I think we are all missing the point. Whether one or two or ten it should all be about what works best for you and makes the job quicker and easier. I personally would rather be making shavings than tramming a mill. 
Peace and Love
Dave


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## Rustrp

Leggman said:


> I am so glad I could be of service in starting a s&%t storm on this forum.



I'm not sure how you come to your conclusion about the storm, but from my perspective I look for answers that are more than opinion. Easier isn't always the most accurate but I've come to understand that accuracy isn't a priority and how we get there isn't important for some folks. I definitely wasn't critiquing your project but when I saw your comment I was wondering why you drilled the hole on your drill press and not your mill. I'm a novice at machining, but this doesn't mean I don't understand taking measurements or have the knowledge to use them. I'm here to learn and I prefer instruction based on a standard not an opinion. I know we have been improving on the mouse trap for centuries, and some improvements are better and some not so good.

You can't teach the apprentice to be a good machinist if you promote shortcuts supported by **that's good enough**. I'm aware that a lot of what's presented is opinion and many times I choose to pass. I've watched three of more videos where the promotion of making the spindle square touts how inexpensive it is to make ($30 or less), and the materials list includes two dial indicators from HF. Unless you have the indicators checked against something that's tested and calibrated you could be off by .010" before you start. That's the reality of +/- .005" in manufacturing and it results in a pretty sloppy transmission.

There's a saying that goes; There's enough mystery in the world without creating more. My question to a comment, any comment, isn't saying I think you're wrong, I'm asking you to support it. Now my question to you is; How would you go about making the most accurate spindle square with the tools and equipment you have to work with?

I'm a sheetmetal worker, welder fabricator and when a customer wants a product "exactly" to a specific dimension after I ask what are the tolerances, I tell them they need to find another shop, I don't do perfect. The differences in what I see as accurate or as intended would be something mikey posted that he turned with gravers, and it doesn't have specific dimensions, it's perfect as it is. Another example would be Justin's machinist jack project. I would be more inclined as the instructor to give him 100% on his grade if he wrote a description on how the part ended up .010" short, because I would know he still learned the lesson.


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## Joe P.

It is apparent that there is a division of opinions of the validity of this tramming gage. Personally, I made one of these gages and find it quick and accurate. But I would like to point out what ever your preferred method of tramming your mill and you are following this thread, then at the very least it made you think a little deeper into the process and physics of tramming. Which is a good thing. 

Sometimes I wonder if thinking is becoming an  obsolete skill. 


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## RandyWilson

Joe P. said:


> But I would like to point out what ever your preferred method of tramming your mill and you are following this thread, then at the very least it made you think a little deeper into the process and physics of tramming. Which is a good thing.




This. In spades. I'm a root cause of the ****storm.  But at least I now have a clearer grasp on the mechanics involved, what is really important, and what is smoke-n-mirrors.


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## Rustrp

Joe P. said:


> It is apparent that there is a division of opinions of the validity of this tramming gage. Personally, I made one of these gages and find it quick and accurate.



I agree on the division or opposing views and understanding but when we mix words and definitions it can be confusing, especially if the word doesn't fit the definition. I'm a novice, a neophyte to machining, especially the physical application. I think the process is easier to see if we begin with the head trammed in and work backwards by recording the steps. One of the hiccups in the process leans heavy on accuracy, whereas what is probably more appropriate would be to define the calibration process of the two indicators as precise.


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## Joe P.

Rustrp said:


> One of the hiccups in the process leans heavy on accuracy, whereas what is probably more appropriate would be to define the calibration process of the two indicators as precise.



Exactly! When I was  contemplating whether or not I was going to make it, I just couldn't wrap my head around the calibration process and was concerned on how super accurate the spindle had to be in relation to the bar. After watching the videos a few times, it clicked. Hard to put into words, but the best way I can explain it would be that you are eliminating the differential of 2 indicators that were referenced at the same spot. 


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## Leggman

I drilled the first one on the drill press because I had not yet received my r8 integral shank drill chuck. I have one now so I have entered a new more accurate world


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## 38Bill

I built one out of scrap material and I already had the two indicators so it cost me nothing. I'm a novice machinist so I like the fact that you see both indicators and just split the difference. That way I don't have  to remember any numbers.


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## bobl

RandyWilson said:


> Not to threadjack, but I've been wondering why people use 2 (or 3) indicators?  As I see it, a single indicator on a sturdy offset arm should be sufficient.



That's all I use 


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## Rustrp

Leggman said:


> I drilled the first one on the drill press because I had not yet received my r8 integral shank drill chuck. I have one now so I have entered a new more accurate world



I read your OP and my question was based on putting the drill bit into the collet, the same one you have the spindle level mounted in.


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## RJSakowski

There seems to be a basic misunderstanding with some members as to how the tramming tool works and how to properly calibrate it.

Part of this stems from SPI and Starrett making the instrument convenient  by providing the base of the square as reference surface.  That surface is "pre-calibrated" to be perpendicular to the shank of the square and the indicators are "calibrated: when they read zero when the tips are in the same plane as the base.  Well and good..... as long as you don't disturb the alignment by bumping or dropping and as long as there is no angular runout in in the spindle mounting scheme.  If either or both of these conditions exist, the calibration is useless.

Enter the Edge Technology spindle square and others like it.  It is actually calibrated in the machine prior to use.  The square is calibrated by zeroing the indicator  on a fixed vertical reference surface. 

In the following illustration, the square is mounted in the spindle and the first indicator is zeroed when its tip contacts the reference point "B" on the table.  the square can be rotated and the circle the zeroed indicator tip describes is concentric with the true spindle axis and is contained in a plane which  perpendicular to the spindle axis.  Now rotate the second indicator to reference point "B" and zero it.  If the square is rotated, it also sweeps a circle which is concentric with the true spindle axis and in a plane which is perpendicular to the spindle axis.

Since both planes are perpendicular to the spindle axis and both planes pass through the calibration reference point "B". The planes have to be coincident.  To put it another way, if point "A" is on the true spindle axis,  distances AC and AD have to be equal  and the only way that can occur is if the line CD is perpendicular to the spindle axis.

Note that there are no assumptions made about the indicator mounting bar or the shank of the square being straight or there being zero angular runout.  The bar and shank of the square simply are a means to rigidly position the indicators.

But what if there is runout due to a bent shank or angular runout in the mounting system?   All the happens is the swept circles of the two indicators have slightly different  diameters.  As long as their contact point with the reference "B" is at the same z height relative to the spindle, the calibration is still good.  If reference "B" is actually a small cylinder, the calibration will be good.  Say that the spindle is out of square by .010" in 5" or .002"/".  If the reference surface "B" is .25" in diameter, the error will be at most .0005".  With any reasonable care in manufacturing the square, this error should be much less.

As to the issues with possible errors arising with using a cheap indicator, as long as the indicator will repeatedly return to a reading, there should be no problem.  Whether a division is reading .001 or .0015 makes no difference. You really don't even need a scale on the indicator to use it.  You can just adjust until both indicators read the same as your calibration point.


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## Downunder Bob

Uglydog said:


> I've never seen a three point tram tool.
> But, I am wondering if the use of a disc or plate instead of a bar with three holes and three gages would allow for simultaneously tramming of nod and tilt.
> 
> Daryl
> MN


Might work, but why be shy, go for a 4 way tool.

The term tram for a mill is new to me, never heard it before joining this forum. maybe I was away that day we learned about it in trade school, but I don't think I've ever heard it used outside this forum. So what does it really mean and how did the term originate. I understand it is setting up a mill so that the table is square to head. and I realise the importance of that, just curious about the origin of the name.

Here in downunder a tram is an electric public transport vehicle running on rails, like a light rail. I think you call it a streetcar.


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## NortonDommi

Hello,
          If you own a verticle mill the best investment is a centering indicator, they speed things up in an order that is silly. I use mine on the lathe as well.
With a resolution of 0.01mm,(0.000394"), that is well within anything we will approuch manually. I am attaching an article  I downloaded from Gadgetbuilder.com and another from Model Engineers Workshop.
  Substitute a center finder for the DTI in the Homier article and once you've checked  X & Y axies via Paul Murry's system I would look at a vernier replacement for the zero mark. Fretts.com also has a great quick 'N' ready method of getting close.
  Invest in a center finder, one tool, only one dial and a bit of perspex makes life easy and encourages use of the tilting head if you have one.
    Cheers,
  - Barry.


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## NortonDommi

Hey bobshobby,
                           Those folks down there are a long way from Brisbane aye?
 Tram in these terms means to track true & level. Maybe something only understood this side of the ditch? 
And down there.


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## Dave Paine

NortonDommi said:


> Invest in a center finder, one tool, only one dial and a bit of perspex makes life easy and encourages use of the tilting head if you have one.



For US readers, perspex is equivalent to Plexiglas.


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## higgite

FWIW, the term “tram” comes from “trammel”, which has numerous definitions, one of which is:
“Any of various gauges used for aligning or adjusting machine parts.” Like the tool(s) that this thread is all about.
https://www.merriam-webster.com/dictionary/trammel

To tram something, such as a milling machine, is to align it using a trammel.

I guess it could be the age old situation of two countries separated by a common language, but that’s my story and I’m sticking to it.

We now return to our regular programming.

Tom


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## Rustrp

bobshobby said:


> The term tram for a mill is new to me, never heard it before joining this forum.


Demographics and geographics always play a part in the names we attach to inanimate objects. From the mechanical side of the house (especially machining) the word tram is a reference to alignment. In transportation it refers to moving people or product. Is "I was away" another way of saying you cut class?


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## Downunder Bob

higgite said:


> FWIW, the term “tram” comes from “trammel”, which has numerous definitions, one of which is:
> “Any of various gauges used for aligning or adjusting machine parts.” Like the tool(s) that this thread is all about.
> https://www.merriam-webster.com/dictionary/trammel
> 
> To tram something, such as a milling machine, is to align it using a trammel.
> 
> I guess it could be the age old situation of two countries separated by a common language, but that’s my story and I’m sticking to it.
> 
> We now return to our regular programming.
> 
> Tom


Thanks Tom, tram from trammel, now I get it. The long standing misunderstanding of our shared language is the stuff of legends. Here in downunder we generally can understand american, this is because we watch a large number of movies and tv shows made in Nth America, but are well aware that Americans have trouble with our versions. Movies and tv shows made in Australia have to have  a modified soundtrack so that it can be understood.


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## Downunder Bob

Rustrp said:


> Demographics and geographics always play a part in the names we attach to inanimate objects. From the mechanical side of the house (especially machining) the word tram is a reference to alignment. In transportation it refers to moving people or product. Is "I was away" another way of saying you cut class?



I didn't "cut class", as you so delicately put it, very often, it's more like I just wasn't paying attention, I was pretty good at that.

I think we just called it squaring the mill.


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## Leggman

I really wasn't happy with the two indicator tool I made so I made another using one arm and one indicator. I believe this to be the most accurate way to go since (at least on one axis) the indicator is much farther from the center which seems to make it all more accurate. Also you don't have to sync two indicators. 
It is adjustable so the radius can increase / decrease as needed.
I thought my mill was spot on but left to right I was 14 thou out. Easily adjusted to within a thou now.
The nod is four thou out and will be corrected as soon as I can get out there today.
The next thing is a DRO.


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## ddickey

Is your vise sitting flat on your table?


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## Leggman

yes, vise is flat


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## Rustrp

Leggman said:


> yes, vise is flat



I think the question regarding the vise is noteworty for a couple of reasons. From the photo on the right it looks as if you have quite a bit of surface rust and that would be an accuracy issue. When I watch the tramming videos from tubalcain he trams to the head to the table with plenty of comments regarding the flatness of the table. Most of us are doing milling tasks in the vice so while tramming the table is good, tramming to the vice is the most important if that's holding the workpiece. In your redesign you stated reaching out farther on the table to tram the head which seems to indicate you haven't trammed the head to the vice or seems so in my observation. If the vice trams to .000" after the table is trammed this is really good.


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## Leggman

I just checked the vise and it varies less than a tenth of a thou from side to side. Good enough for me.


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