Author Topic: Dial Gauge Mill Tramming Tool  (Read 33186 times)

Bogstandard

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Dial Gauge Mill Tramming Tool
« on: August 01, 2012, 08:01:56 AM »
I remember seeing one of these that a long time machinist had made for himself, but it was about twice as long. The longer it can be made the easier to use and more accurate it will be. He did piece work, so anything that speeded up the tramming process meant more money in his pocket. :whoohoo:

A friend has asked me to make him one of these, and he has already given me the relevant dimensions required, I think for an X1 mill.

These are produced commercially, in a slightly different design. How they can have the audacity to patent it, I have no idea. :ThumbsDown:

It will be up to yourself as to whether you make one of these now, as when they were first commercially available they were rather expensive, around 150 UK pounds, but now they are available for half that figure.
If you have the materials hanging about, I reckon around 25 to 30 UK pounds to make, that would be the rough cost of a pair of dial gauges.

The one I will be making will be a short version, that will tram in both X and Y axis. But there is nothing stopping you making one much longer, just for use in the X axis. I should really have done that with mine, as I have no tramming adjustment in the Y axis on my mill, maybe I will just make another one but longer.

Now a few things that need to be said.

Please don't ask about tramming in this post, if you don't know what it is or how to do it, please raise a separate topic and all questions will be answered there. :Argue:

The other main issue is that this will end up as a precision instrument, and if your machinery or yourself are not up to working to tight tolerances, I would suggest you wait until you have the relevant experience or machinery.
Get it wrong, and you will be doing a non tramming exercise on your mill. :zap:

You will require a faceplate on your lathe with the same or larger diameter as the main bar is long, or if you can come up with something that will do the job I will be showing later, then good, but the accuracy of this tool depends on the final cutting on the lathe. If you can work to tolerances of 0.002" (0.05mm) or lower, you should be OK.

This is easily only a one day job. Its takes me much longer because I can only work a couple of hours at a time, and I make the post up out of what I have done in that time. :old:


So away we go, showing what I have been up to today in my little shop of horrors.


I will be turning this,




Into one of these.
It looks an easy exercise, but as I have said, all the work is keeping everything accurate, and being done in the correct sequence.




These are the rough materials I will be using for the job. I will be showing things in imperial for our US cousins, but actually I will be working in metric as that is the size of most of the bolts and bits used.
The length of the ali bar isn't shown yet, as that will be determined later, this one is about 8" long. You could just as easily make the bar out of steel, as long as you can get the surface finishes required. There is no handwork allowed except for deburring. By hand finishing surfaces, you will be introducing errors into the precision faces, unless you have a real nice lapping plate, and know how to use it correctly. The steel bar is 5/8" diameter.
You can work with larger or smaller dimensions, but it will be up to you to modify the design to your materials. These are the ideal sizes for the gauges I have.




This shows how deep the material should be for the gauges you are using, the sensing tips should be protruding out of the bottom of the finished tool by roughly the amount shown. You can use slightly shallower bar, but the gripping area for the top part of the gauge rod will not be supported as much. You don't want too much sticking out of the bottom as it makes the part vulnerable to being knocked.




If you are going to be making the dual axis version, you will need the dimension as roughly shown between the two points of the gauges. The easy way is to measure from centre to centre of the outside rails of the table. If just making the X axis version, just make it as long as you feel is right, 12" would be a good figure (if you have a faceplate that can take it).




So now we get to the machining bit, cleaning up the bits of rough material I have selected.

There is a bit of a catch 22 situation here, because of the high accuracy of machining and drilling, the mill needs to be trammed up as close to perfection as you can get it. I had no trouble, as I already have a tramming tool, you will just have to do it the hard way until you have made yours. A sure sign of having the tramming spot on, is when flycutting, you will get very fine pattern marks showing that it is cutting on both the forwards and backwards cut as it goes over the material.
Here it is just cleaning up the surfaces, with a 5 thou cut. I went thru the procedure as though I was squaring up a bar, and ended up with all faces parallel to less that 0.0005" (0.01mm).




Then using a countersink tool, a very small chamfer was put down each edge. This is to try to eliminate errors after the tool has been used for a time, no sharp edges to get 'dinged' and stop the precision faces sitting down correctly.




This shows my setting tool from the bottom. It shows the layout of the slot and if you look very carefully, where the bolt sits. I will be showing how to do all this and dimensions a little later.




So now onto a bit of lathework.

The bar had a spigot machined on one end about 5/8" long (non critical but somewhere close), and 3/8" (10mm) diameter minus 0.001" (0.025mm). You could just about get away with being 0.002" (0.05mm) under size. This is to allow the use of high strength Loctite during assembly. The shoulder was also cleaned up as this will be a datum face.




The end of the spigot had a small chamfer filed on the end, and a hole drilled and threaded into the end of it. Mine was 6mm, for imperial, maybe 1/4"




So the bar was then turned around and the outside diameter reduced so that it was slightly smaller than the dimension between the chamfers on the ali bar. There will be slight length and diameter changes to this bar on the very final operation of making the tool.




The two main bits machined up and ready for the next stages.




Showing how they will be assembled, once the right holes are in place.



So there we have getting the bits prepared.

Lots more to follow.

John

Offline Jo

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Re: Dial Gauge Mill Tramming Tool
« Reply #1 on: August 01, 2012, 08:52:34 AM »
I want one....Looks like another job that needs to be added to my list. :facepalm:

Jo
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Offline Bearcar1

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Re: Dial Gauge Mill Tramming Tool
« Reply #2 on: August 01, 2012, 11:10:16 AM »
Yeah baby! This is the thread I have been wanting to see John. Thank you for showing it to us again. I really do like this one, one of the top ten tools I have seen made.

kind regards

BC1
Jim

Bogstandard

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Re: Dial Gauge Mill Tramming Tool
« Reply #3 on: August 01, 2012, 12:43:10 PM »
I hope another bit keeps you just as happy Jim.

################################################################

The dimensions given to me were in metric, at sometime during this post I have to use all metric measurements to get to where I want to be. I will be using 125mm between the dial gauge tips, plus 15mm at either end for the gauge clamp system. If you are working in Imperial, just use your own figure for the central measurement, plus a converted 15mm at either end. The end bits aren't too critical, but don't make them any smaller.




So after covering the side that was to slide on the bandsaw table, just to protect the surface finish, I hacked off the spare at the end.




After setting the bar onto parallels, both ends were cleaned up without removing too much metal.




The final length isn't critical, as long as it isn't under your length minimum limit. All I needed was a final length, so that I could find exact centre of the bar.
Unfortunately, my 6" digivern just wasn't quite long enough, so I had to revert to old mechanical tooling. This is most probably more accurate than the digivern anyway.




So now I had the OAL and width, I can easily find exact centre both ways.
The bar was tapped down gently onto a pair of thin paras.




The reason for the thin paras is that I need to drill right thru the bar, so I checked with the largest sized drill I will be using, just to make sure I won't be trying to drill steel as well as aluminium.




So I have a piece of ali all centred up in the vice, ready to start drilling.




First job, drill a hole right thru the bar. This is for the spindle holding bolt and I used a clearance hole for 6mm. This is a bit confusing here, dual measurements, but I told you I had to do some bits in metric.




I then followed it down with a 3/8" end mill. After a time using your machines, you get to know if it will cut accurately or not. I know that this will be an accurate cut. Maybe you could leave the spindle until you have cut your hole, and then trim it down to fit the hole minus 1 thou.
Not really the ideal, using a drill chuck to hold the cutter, but I know my chucks, and this one definitely cuts with no runout. My larger one would cut 0.002" oversize. Get to know your tooling, and you won't go far wrong.




This went to a depth of about 3/4". If you remember, the spigot was only 5/8" long. I don't want it to bottom in the hole, but to be pulled down tightly onto the formed shoulder where the shaft meets the spigot.




Next job, measure the diameter of the dial gauge holding shank. Near as dammit 8mm. You will have to measure yours for the size of drill you require.




Before drilling the gauge mounting holes, I did a quick check for fit of the spindle. By eyeball, it looks very close or even spot on, but as usual I am not trusting my eyes. Only when it is on the lathe will it show if it is out or not.

So I then got back to drilling the holes in the required places. After centre drilling, I put a 6mm down thru the bar, followed by a 7mm, then the final 8mm. If you carry out this method, of coming up to size on a hole, the hole usually ends up spot on size. The reason being, only the first hole drilled relies on cutting the middle part of the hole out, so if the drill is ground slightly out, you can end up with holes of all shapes and sizes. The following sizes of drills are cutting a lot less material than if going straight in, and also no tip to throw it off line. My hole sizes ended up spot on, a nice snug fit.




So that was the top face finished with. The bar was turned the other way up, recentred and an end mill used to put a recess in for the spindle holding bolt head to fit into. If you remember, this bar is 1.5" deep, so I went to a depth of 1/2". This left an uncut middle to the hole that is 1/4" thick, top to bottom, plenty strong enough to take the strain of a real tight bolt.




So while it was this way up, I took the opportunity to cut a 3/16" deep recess into the bottom face. This is to allow the bar to sit better on the table when measuring without having to worry about dirt and damage under the whole length of the bar. The final faces of the datums ended up at around 1" long by 5/8" wide, with the gauge tips protruding in the middle of the face.




Now back on the bench, after all holes were given a nice clean chamfer and all edges deburred with a scraping tool. Plastic tape was then put over the datum faces, to protect them during the next machining operations.




The next job was a straight forwards slitting cut for making the gauge clamps, one at either end.




So what is the correct place for the clamping bolts?
Measure up your gauge like this, mine were 3/4" long, measured to where the lead in taper starts. Half that figure = 3/8"




Measure from the edge of the hole to the end of the bar, half of 1/2" = 1/4"




3/8" down, 1/4" in. I didn't blue up and mark out as I don't want scibe lines over the finished product.
The bar was remounted into the vice (with new tape on datum faces), and the hole positions found using my edge finder.
I used 5mm cap screws instead of the shown 6mm. The 6mm looked way too large.
So a tapping size drill was put right thru, followed by a clearance drill, but only until it reached the saw cut. The recess for the bolt head was then put in.




After tapping the rear side, and after another deburr, the block was finally finished.




Now the two main parts can be assembled together. Using hi strength Loctite (clone) on the spigot and holding bolt, everything was given a good tighten up. This is now ready for when I can get back onto the job tommorrow, and true it all up.





John


Offline ref1ection

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Re: Dial Gauge Mill Tramming Tool
« Reply #4 on: August 01, 2012, 05:59:24 PM »
I'm also very glad to see this re posted because like most things I put it off till it was to late to look it up. That will teach me.
Thanks again John :ThumbsUp:

Ray
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chuck foster

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Re: Dial Gauge Mill Tramming Tool
« Reply #5 on: August 01, 2012, 11:22:53 PM »
john thanks for posting this one  :ThumbsUp:

i made one about a year ago and i use it atleast once a month to check my mill.

it is so easy to make and easier to use, if you don't have one.............guys you should build one.

chuck

Bogstandard

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Re: Dial Gauge Mill Tramming Tool
« Reply #6 on: August 02, 2012, 06:02:09 AM »
Thanks for the good words gents, and here is the last installment.

#########################################################################

The loctite has set, so now I can get it onto the lathe to true it up.
First off, I checked the runout of my faceplate. 0.001", normally that would be acceptable, but I want it better for the precision I am about to try to achieve. BTW, this is a 0.0001" reading clock.




So I put on a 2 thou cut, and sent the tool on a 40 minute journey.




While the faceplate was being skimmed, I made a quickie set of clamps to hold the tramming tool to the plate.




So the plate was finished, and when checked, no runout.
This pic also shows a good example of the casting effects. Notice the shiny bits, that is because the casting was thicker in those areas, so that area cooled down a lot slower, and so ended up with a much finer chrystaline structure. You learn something new every day on MODEL ENGINE MAKER.

Just a note about what I just did, skim up the faceplate.
Faceplates should be classed as disposable tooling, and each time it is mounted up, it should then be checked for runout and skimmed up as necessary. Don't worry, the average use of a faceplate is usually fairly low, so it would take you many many years before you needed to buy a new one.



The tramming tool was mounted into my tailstock chuck and the main bar was gently pushed against the faceplate, with a piece of paper under the datum faces, to prevent damage. This is to get it somewhere near to central running.




While it was in position, I fitted the quickie clamps to hold it against the faceplate, again with pieces of paper to prevent damage. Once clamped up, the tailstock was backed well away, there is no further use for it on this job.




The DTI was now swung into use. I first trammed across the top face, to see if the paper was causing any problems. It was spot on. So I then concentrated on the spindle. By gently tapping with a lump of nylon bar on the tramming tool ali bar, I gradually moved the trammer to a zero runout position and then locked everything up tight.




So now was the time to see if my hard work was in vain. You guessed it, 0.0035" runout.

So it does go to show, if you think you are making it accurately, it just might not be so. I expected this and it was the reason I kept saying that it needed to be mounted on the lathe for final tuning. It only had to be a minute amount out of vertical, and by the time it reached the end of the long spindle, that error would be multiplied many times over.




The fix was dead easy, just gentle skimming up, and while I was at it, I reduced the spindle diameter to a very useable 12mm. Now it was truly spot on, and I was a happy bunny.
DO NOT USE YOUR TAILSTOCK CENTRE AT ALL DURING THE SKIMMING OPERATION.




So what do you do with it now?

Well the first thing was to fit the gauges, with a tiny bit of the gauge plungers sticking out of the bottom, and put the datum faces down onto a perfectly flat surface. You could just move the 0 dial to line up with each finger and that would be it. But I go a little further and and by moving the gauges up and down in their locating holes, I try to get the dials showing zero at the top. It just looks neater. But also make sure the tiny dial measures the same as well.




So how do you use it?

Just put it into your chuck (a collet chuck would most probably be a little more accurate, but I know this one is OK).

Bring the tips down until they are resting on the table and are moving the dials.

Then just adjust the mill head until the dials show the same figure, it need not be 0, it can be anything, 8 or 3, as long as they are the same (including the little dials).

Swing it thru 90 degrees and you can tram the Y axis as well using the same procedure. If you are unlucky, 5 minutes total time.

Once the needles are at the same setting, you have now trammed the head on your mill.

As you can see, and as I said, my head is perfectly in tram. I should know, I used my own little tramming tool to do it.

A lot easier than trying to use a clock on the end of a bar, and then attempting to swing it thru 180 degrees to take the next measurement ----- and so on until you eventually get it right.





Little and large trammers.

The little one can now go to it's new owner.





So this little tool looks a pig to make, but in fact it is very easy, as long as you can keep things under control with fairly tight tolerances. As I said, the final lathe work will true it up a treat.
 
Total cost -- However much a pair of gauges are and a few bits of raw materials.

Your gain -- tramming now becomes a joy, rather than a PITA.

I hope you have enjoyed the post, and it gives you the inspiration to make one for yourself. You would never regret it.



John
« Last Edit: August 02, 2012, 06:08:13 AM by Bogstandard »

Offline Jo

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Re: Dial Gauge Mill Tramming Tool
« Reply #7 on: August 02, 2012, 08:10:29 AM »
Oh no :facepalm: I've ordered the dial gauges: I have no excuses not to make one now.

Thanks John, great write up :cheers:.

Jo
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Offline ref1ection

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Re: Dial Gauge Mill Tramming Tool
« Reply #8 on: August 02, 2012, 02:08:31 PM »
I think there may be a run on dial gauges. This time I won't put it off.
Thanks again John.

Ray
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Bogstandard

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Re: Dial Gauge Mill Tramming Tool
« Reply #9 on: August 02, 2012, 03:00:21 PM »
I would just like to add, the dial gauges could be almost anything, mine were the cheapest available, just make the bar to suit.

All you are doing with this tool, once it is set up, is using the two gauges as a comparison, not for measuring anything.
I suppose you could use it, with a little maths, for measuring how much of an angle the head is out, but why bother, as long as you are in tram, then everything should be OK.

BTW, like other people have found, once you have used one of these, it is only a couple of minutes and you get instant confirmation that everything is OK. Because of that, I now check the tram almost every time I come to use the machine after a layoff or change of job, whereas before, I would only check when I thought the tram was giving me problems.

John

Offline grayone

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Re: Dial Gauge Mill Tramming Tool
« Reply #10 on: August 02, 2012, 04:35:32 PM »
Thanks for the post John, I bought a pair of cheap Chineese gauges a while back after seeing your post on another site.  I did think about buying one but a) they were very expensive, b) too big for my Proxxon mill and c) imperial so thanks again as this post will serve ars the refereance for the build.

Regards

Graham

PS why is it called tramming?
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Offline KB

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Re: Dial Gauge Mill Tramming Tool
« Reply #11 on: August 02, 2012, 04:39:57 PM »

Thanks for the instructional post John,

Is my thinking flawed by assuming one could not care about accuracy and calibration of the tool, but instead face the dials away from you, zero them, swing them 180 and then split the difference?

Bogstandard

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Re: Dial Gauge Mill Tramming Tool
« Reply #12 on: August 02, 2012, 08:27:11 PM »
Kevin,

I think you have the wrong end of the stick.

You are not trying to get a measurement that you can split.

It is of paramount importance that the initial calibration is carried out by laying the tool on a flat surface, and having the two dials 'zeroed' up by moving the gauges up or down in their respective holes. Then locked up when they both read exactly the same.

When the tool is then mounted into the spindle and brought down into contact with the table, you then adjust the head swing to bring both needles showing the same, it does not mean that you have to use zero as the setting point, but any number on the dial face, as long as they both show the same number (including the small dial).

Once both gauges show exactly the same reading, your tram for the machine should be spot on.

If you then turn the tool through 180 degrees, and the gauges then don't match, it means that the centre spindle holding bar is not exactly square to the main clock holding beam, and you need to get it back onto the lathe and give it a good dose of fine tuning.

That is about the easiest way I could explain it, and I hope it clears things up for you.

John

Offline KB

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Re: Dial Gauge Mill Tramming Tool
« Reply #13 on: August 02, 2012, 09:54:12 PM »

Thanks John,

You made it perfectly clear, in your initial post, how to calibrate and use the tool. I am just wondering if it were not to be calibrated, could one use it in the traditional way.

After thinking about it. I see there is no benefit in using the two dial method unless it is carefully machined and calibrated. If a guy wants to swing it and split the difference, he may as well stick to the single dial.

Next time I'll think a little more before spouting off on the keyboard.

Thanks again.

Kevin

Bogstandard

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Re: Dial Gauge Mill Tramming Tool
« Reply #14 on: August 02, 2012, 10:00:14 PM »
Don't worry about it Kevin,

We all have our own 'special days' when it is just better to be quiet rather than trying to engage brain, and getting it all wrong.

I do it all the time.

John

Offline AussieJimG

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Re: Dial Gauge Mill Tramming Tool
« Reply #15 on: August 02, 2012, 10:16:15 PM »
I built one and went crazy trying to get the calibration correct. After several attempts including boring the hole for the main bar on the faceplate, and substituting an aluminium bar for the steel one so the final skim would not cause deflection, I still had 0.02 error.

Then I realised: follow Bogs' directions and then simply lower the tool onto the table until one of the dial gauges reads zero, rotate the tool until the  other gauge is over the same spot and tweak it to read zero as well.

That got rid of the last 0.02 and the tool is ready for really accurate use.

In retrospect, I could have done that to remove the error prior to using the faceplate. But I am glad I tried Bogs' method even though I failed. I am sure it will come in handy in the future.

Thanks John

Jim

Offline AussieJimG

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Re: Dial Gauge Mill Tramming Tool
« Reply #16 on: August 02, 2012, 10:22:09 PM »
Oh yes, I forgot to ask:

Is there a better way to tram the mill than by tapping the head with a lump of wood and a 4lb hammer while gradually tightening the three bolts holding the head?

Perhaps is does only take 5 minutes but it seems longer  :hammerbash:

Jim

Offline Bearcar1

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Re: Dial Gauge Mill Tramming Tool
« Reply #17 on: August 03, 2012, 05:46:34 AM »
Jim, a large rubber mallet is a good 'attitude adjuster' for tramming the mill. The one I have is about 3-1/2" in diameter and is made up of some sort of a hard-ish grey rubber/vinyl material that has just a touch of resiliency to it. I bought it at Sears a long time ago and it is the perfect tool for the job. It has enough -weight to it that it will nudge the mill head or the vise,l for hat matter, a few thousandths at a time with just a light tap without fear of damaging the machine's surface.

BC1
Jim

Online sco

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Re: Dial Gauge Mill Tramming Tool
« Reply #18 on: October 24, 2012, 03:23:49 PM »
I have a plan forming in my head to make one of these tools using an MT3 blank arbor fitted to a cross bar carrying the dti's.  The lathe headstock taper is MT3 same as the mill, so I'm thinking of fitting the arbor directly in the headstock, turning a suitable boss on the end of the arbor and then mounting the cross bar on this boss. 

Staying in the lathe I'm then thinking of facing the pads of the cross bar to get accurate reference surfaces relative to the MT3 taper - I know this will be an interrupted cut but any good reason why this method isn't as good as Bog's original method of mounting the cross bar on the faceplate and skimming the mandrel?
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Bogstandard

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Re: Dial Gauge Mill Tramming Tool
« Reply #19 on: October 24, 2012, 04:53:40 PM »
That should work just fine.

John

Online sco

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Re: Dial Gauge Mill Tramming Tool
« Reply #20 on: October 24, 2012, 05:28:24 PM »
That should work just fine.

John

The Gold Seal of Approval - thanks very much  ;)

Simon.
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Bogstandard

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Re: Dial Gauge Mill Tramming Tool
« Reply #21 on: October 24, 2012, 07:05:30 PM »
No problems Simon, there are always more than one way to skin a feline.

John

Offline ScroungerLee

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Re: Dial Gauge Mill Tramming Tool
« Reply #22 on: October 26, 2012, 01:24:03 PM »
Is it correct that the accuracy of the bottom pads really only comes in to play when installing the dial indicators and getting them to match readings?

If one were to set one indicator, swing the entire thing 180 degrees, and set the other indicator at the same place on the mill table wouldn't that ensure accurate setup?

Seeing an easier way almost surely means I am wrong, but I don't see why this wouldn't work.

Lee

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Offline zeeprogrammer

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Re: Dial Gauge Mill Tramming Tool
« Reply #23 on: October 26, 2012, 06:04:51 PM »
I'm not that experienced myself...

I used to do it that way. Very time consuming for me and prone to error.
Any flex in the arm holding the indicator will add error and you have to push the indicator up out of way to clear the table which can add error to the arm.

I've since gone the route describe below with the dual indicator.
(Except I cheated and bought one rather than make one.)

I like it and it's also easier to check in Y too.
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Offline ScroungerLee

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Re: Dial Gauge Mill Tramming Tool
« Reply #24 on: October 26, 2012, 09:40:42 PM »
To clarify, I meant initially mounting up the two indicators in the arm by referencing each to a single spot on the mill table, then using the two gauges as expected.

Not sure if that explained my question well.  It's not too important anyway, just me being curious .

Lee
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Offline Don1966

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Re: Dial Gauge Mill Tramming Tool
« Reply #25 on: October 26, 2012, 09:47:16 PM »
Lee I understand what you mean and don't see why it should not work. Seeing as you are just setting the dail indicator to the same as the other. The only thing I see is you have to have some accuracy in mounting the shaft and drilling the holes. should the holes be drilled at any angle other then 90 degrees to the shank the indicator would have a tilt and an error would surface.

Don

Bogstandard

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Re: Dial Gauge Mill Tramming Tool
« Reply #26 on: October 27, 2012, 11:51:55 AM »
Lee,

To put it as simply as possible for this unit to work.

There is only ONE critical item, the spindle MUST be perfectly square to the two datum faces, whether you do it my way or your way.

The setting up of the gauges can be almost anywhere, as long as when the datum faces are set onto a flat surface, without the tool being mounted into the spindle, both gauges are in fully operational mode and the zero setting finger is pointing to the gauge finger on each dial, to indicate a zero setting.

When the unit is then mounted into the spindle, and both gauges in operational mode, to get the quill perfectly square to the table, just swing the head until both needles are pointing to the two previously set outside zero pointers, but care must be taken that the tiny scales are working at the same sort of settings as when initially setting the two outside pointers.

I went to great lengths when setting my gauges and pointers up, setting them at the fully up position, with the same rotational setting on the two small clock faces. That way, even if I was half drunk, everything would be very easy to do.

I think people are looking at this tool and are expecting it to operate in a very complicated way, nothing could be further from the truth. Once the gauges, pointers and fingers have been set, they should never again need to be played about with at all. Just pop it in the spindle, and check or set the zero position of the head.
That should also work perfectly even if going from mill to mill, or lathe to mill or vice versa, as long as the spindle used is compatible with each fitting.

John


Offline ScroungerLee

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Re: Dial Gauge Mill Tramming Tool
« Reply #27 on: October 27, 2012, 02:10:35 PM »
Thanks Bogs,

I didn't mean to disrail your fine thread .


You wrote "That way, even if I was half drunk, everything would be very easy to do.". -  I had noticed your DRO readout says ALE, I assume that is used as a reminder :)

Lee
« Last Edit: October 27, 2012, 02:16:02 PM by ScroungerLee »
Mmmmm.... Shiny!

Bogstandard

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Re: Dial Gauge Mill Tramming Tool
« Reply #28 on: October 27, 2012, 02:56:59 PM »
No problems Lee, if someone doesn't understand what I have written, then it is up to me to make things, hopefully, a little easier to understand.

With regards to the mention of alcohol consumption, for the first time in a very long time, last night I got bladdered, not normally touching it, and my head today says I won't be doing that again anytime in the foreseeable future.

John

Offline MichaelP

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Re: Dial Gauge Mill Tramming Tool
« Reply #29 on: February 23, 2015, 04:39:45 PM »
I'd like to thank the OP for taking his time to take photos and write his posts. This is a nice project. It just doesn't need to be so complicated, IMHO.

I'm afraid that all the efforts to make everything square and precise were required only because of the suboptimal calibration routine.

The only critical element here is to make sure that the indicator mounting holes are are equidistant and parallel to the central shaft. The rest is non-critical at all. The aluminum body can be machined or not, be crooked and not perpendicular to the shaft, etc. It doesn't affect the performance of the device.

To calibrate the device, you zero both indicators at the same spot. Zero the first one, then rotate the device 180 degree so that the second indicator is at the same spot and zero it. That's all. Now proceed with tramming.
« Last Edit: February 23, 2015, 05:10:10 PM by MichaelP »

Offline Jo

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Re: Dial Gauge Mill Tramming Tool
« Reply #30 on: February 23, 2015, 05:38:27 PM »
You lost me a bit with there Michael  :headscratch:


The only critical element here is to make sure that the indicator mounting holes are are equidistant and parallel to the central shaft. The rest is non-critical at all.

To calibrate the device, you zero both indicators at the same spot. Zero the first one, then rotate the device 180 degree so that the second indicator is at the same spot and zero it. That's all. Now proceed with tramming.

That makes it so much easier for me to understand  ;).

Jo
Enjoyment is more important than achievement.

Offline BaronJ

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Re: Dial Gauge Mill Tramming Tool
« Reply #31 on: February 23, 2015, 09:23:55 PM »
Hi All,

I thought you might like to see mine.  Its one that I made based on Boggs thread.  At this point it is uncalibrated.  You will notice that, though the two dial gauges are 0.001, they are two different ones.  The supplier swapped one for me so that I had a pair that were the same.  When I made mine I bored the centre hole on the lathe and made the 12 mm shaft a press fit.  The 8 mm holes at the ends were drilled on the mill.
Best Regards:  Baron.

I don’t regret the things I’ve done, I regret the things I didn’t do when I had the chance.

Offline Courierdog

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Re: Dial Gauge Mill Tramming Tool
« Reply #32 on: January 28, 2021, 01:55:15 AM »
Michael:
I want to clarify your statement
"The only critical element here is to make sure that the indicator mounting holes are are equidistant and parallel to the central shaft. The rest is non-critical at all. The aluminum body can be machined or not, be crooked and not perpendicular to the shaft, etc. It doesn't affect the performance of the device."
IF I am to understand correctly, My take away is,
the Key is the three holes must be absolutely Parallel to the central shaft.
IF I am to read correctly the squareness nor the absolute dimension of the bar is non-critical.
BUT
The Absolute Equidistant and Absolute Parallel placement of the outside holes to hold the Dial indicators are the key elements.
The calibration of one dial indicator to the relative ZERO Must then be repeated or be copied on the exact same spot by the opposite Dial indicator.
The surface of the indicator pin side or the Dial Indicator Meter side is immaterial.
The original Bogstandard approach of having the respective face of the bar is not essential to the measurement nor its accuracy, The facing is only a convenience to setting up and calibration as outlined in Bogstandard's original proposal/concept
My first thought as I read the article and others like it, the face of the Didicator Meter Side and the actual Pin of the measurement probe of the Dial indicator had to be perfectly level.
How the initial setup was done and as others read it the bar was set on a surface Plate forsimplicity.
This would allow much more leeway for a prank set up.
I was initially thinking of using if possible an R8 Arbor like the FMB-22 while this may allow for simplistic storage of the Bar only it does not comply to the original Bogstandard article.
I assume you have other thoughts and I would appreciate hearing them.
Thanks
Dave C

Offline peakfour

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Re: Dial Gauge Mill Tramming Tool
« Reply #33 on: February 14, 2021, 04:17:16 PM »
I actually only joined this forum to see how John "Blogwitch" ex "Bogstandard" was getting on; I see he's not logged on since last October.

There seems to be a few folk who have missed the basic principal behind the way John designed the tool/gauge.
The most important aspect is that the arbor is perfectly parallel to the two separate feet at the ends.
That being the case, if you stand the gauge on a flat surface, the arbor is exactly perpendicular to that surface.
The idea is that you fit the two gauges, sufficiently high in their respective holes, that the plungers can fully retract when when the gauge is stood on its feet.
Next job is to set them at the same height, lock the allen screws, and zero the clocks.
That's all you need to do in order to calibrate the gauge.

Essentially, if the gauge is fitted to the arbor and the table is perpendicular, the two feet will be equidistant from the table; the clocks are only there to indicate the difference between the two ends.
You have previously zero'd the clocks with the feet on a flat surface, so they now show the two distances, one at each end.
This indicates which way, if any, that the table is out of square with the arbor/spindle.

The main difference between John's design and mine is that his used a parallel arbor, whereas I've used an MT2 taper, to suit both my milling machines; a Centec 2B and a Dore Westbury.
John went to great lengths to ensure perpendicularity; as did I, though I fitted the arbor into the spindle of my Myford (with a drawbar) and took the feintest skim off the two feet.

My tool/gauge in its box;
Mill Tramming Tool/Gauge by Bill Williams, on Flickr

Sitting on a flat surface to zero the clocks. Any flat surface will do; these appear to be slightly different, but that's parallax error from the central camera
Mill Tramming Tool/Gauge by Bill Williams, on Flickr

Now set up in the spindle and just touching the table with the two clock plungers.
As you can see, the left clock impacted first, by about 18 thou over 8"
Mill Tramming Tool/Gauge by Bill Williams, on Flickr

Centec head now trued up; again slight parallax error is a bit misleading
Mill Tramming Tool/Gauge by Bill Williams, on Flickr

Finally, if you don't want to wind the table all the way up, a couple of precision ground blocks will assist.
Mill Tramming Tool/Gauge by Bill Williams, on Flickr

If you want to spin the whole arrangement around to check the nod, either use a long enough precision parallel, or a brand new car brake disk.
The latter is likely precision ground out of the factory, and has the advantage that the clock plungers don't drop into the Tee slots as you rotate the spindle.

Also, once everything is set true, I then slackened off the arbor in the spindle, rotated the spindle 60°, nipped up the drawbar again and re-measured.
I did this for one full rotation of the Centec spindle, as that would show if there was anything bent, or bruised inside the taper, thus throwing the arbor out from the axis of rotation.

I'm hoping this clears up a few points in the absence of John being around to comment himself.
I did discuss my method of construction and use with him when I called in and bought some kit as part of his great workshop clearance.
All the best
Bill
« Last Edit: February 14, 2021, 04:21:16 PM by peakfour »

 

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