the gods smiled on me

[Cedge]

As the sometimes happy owner of a Chinese mini mill, accuracy is often dependent on how one holds one's mouth. I'm usually happy if the little beggar will keep me within a minor few thousandths of my goals. Imagine my delight when after having flycut a piece of brass to square it and putting the Micrometer on it, only to find that the faces were within .00030" of being parallel across the 5 inch length of the work piece. Triple checked all edges of the piece and either I got very lucky or the Micrometer is a bloody liar....LOL

I bought one of those simple tramming tools offered at LMS ,a while back, and have been using it to keep a check on the little mill. It makes tramming a breeze, so I try to do it much more often than I once did. I tram it to the top of my machinist vise and it works like a top.

I knew my cuts were looking better, but I also know I'm not quite that good. I'm convinced the gods of shiny yellow metals smiled on my efforts this evening. Nice feeling, that.

Steve

 

[Powder keg]

Great job!!!
Wes

 

[Tin Falcon]

Steve it is funny how God gives the skills to those who diligently pursue them. And stay humble .
I reminds me of a blacksmith conference years ago the demonstrator was talking out forge welding he said something to the effect of You practice and practice and struggle with it . Then one day God looks down and say OK you practiced enough now you can do it.
I also seems like if you brag too much even to your self the next part you make ends in the scrap heap and you are again climbing the learning curve.
Good job BTW anything under a thou in parallelism on the mill is fantastic. It would make me very happy as well.
Tin

 

[zeeprogrammer]

Hi Steve,

You mentioned a tramming tool from LMS. What is it?
And while you're at it...if you could spare a 'god' or two...

Sorry...all I've got for trade are some dust devils and maybe a sore goblin.

Thanks.

 

[zeeprogrammer]

Found it...Nano-Tram Top.

But...not clear how to use it. Do you know if it comes with clearer instructions than what I see on LMS? Or can you tell me?

I could throw in a poltergeist...but really...all I've got is bad luck...you don't want any of it.

 

[shred]

I have a Nano-tram top for my Taig. All it is is a flat plate that attaches at right angles to the spindle (on the Taig it screws onto the spindle nose, no idea how the others attach)-- what you do is put it on the spindle and then run the Z axis down until the tram plate touches the table (or vise top or whatever). if it contacts all the way around, it's good (usually I stick a couple strips of paper on the table at either side-- if they both 'pull' with the same force, it's in tram..) if not, adjust.

You can also do a quick-n-dirty tram on the Taig by loosening the column bolt a little and running the tram carefully into contact with the table and then have it push the column into roughly square, then retighten the bolt.

With a lathe and a little work, a simple version could easily be cobbled up-- make a thing that looks like a plate on a stick, chuck up the stick and face the plate.

 

[zeeprogrammer]

Thanks Shred. I'm curious to try this. In part to see how out of tram my mill is...but also to have more than one method that I compare.

 

[Cedge]

Carl
The Nano-Tram is a neat little tool and works pretty darned well for such a simple thing. Chuck it in the spindle, loosen up the column of the mill and run the tool down on the table. Use a .001 feeler gauge around the edges and if it won't slide under the plate, the mill is in the right spot to tighten everything back up. You'll probably have to shim the column on the Y axis, to get it vertical, the first time you use the tool but from then on that axis is pretty much right on every time.

I've now gone completely over to the Dual Dial Indicator tram tool and couldn't be happier with the results.

Steve

 

[mklotz]

I've now gone completely over to the Dual Dial Indicator tram tool and couldn't be happier with the results.

Perhaps you can explain something for me, Steve...

How do you align that tool before using it on your mill? It seems to me that your tramming accuracy is totally dependent on your ability to get both dial indicators reading the same when the plane they are on is truly perpendicular to the spigot that supports the tool in the mill. I don't see how that is accomplished with the accuracy needed to tram the mill to, say, a thousandth of an inch.

 

[kustomkb]

I've never used one, but do you turn it 180 and split the difference?

 

[Cedge]

Marv
The dial indicators are calibrated by setting them against a flat surface, before it is mounted in the mill. When I built it, I turned mine on the lathe when I made it so that all surfaces were sure to be parallel.

Yes... I do check the table at 90° postions. When the dials match, you're in tram. All I can say is the 5 inch fly cut test doesn't lie. When I can cross hatch a surface with less than a .001 DOC pass, things are pretty darned close to where they need to be.

Handy tool.....

Steve

 

[mklotz]

Steve,

I guess I'm still confused. Maybe I'm just having a geometrical senior moment.

Setting the DIs to read the same on a known planar surface guarantees that, when they read the same against some other surface, said surface is planar - at least at those two points.

However, that does not guarantee that said plane is perpendicular to the spigot used to grasp the device in the mill spindle.

If the spigot isn't perpendicular to the plane then, after tramming, the spindle will be tilted relative to the plane of the mill table. Imagine what would happen if, unknown to you, that spigot was bent over by a degree or so. You would end up tramming the mill head out by an angle equal to the bend angle.

I'm sure the maker makes every effort to keep the spigot perpendicular but we're talking very miniscule misalignments here and it's just not clear how the tool error is separated from the mill error.

Your fly cutter experience does indeed indicate that it works but I don't understand how one has confidence in the tool without the fly cutter confirmation.

 

[georgeseal]

Marv,

When the device is built base is 90* to the spigot Both DTI are 90 to base but mounted less than full depth of base

You put base on a flat solid surface and adjust each to read zero

if tram is out DTI's will not be the same and it shows you which way to go


http://www.use-enco.com/CGI/INSRIT?PMAKA=319-3127

 

[Cedge]

Marv
I've never been one to ask how the centipede learned to dance. I just marvel he can dance at all....(grin)

The tool is calibrated before each use by setting it on a flat surface and the dial indicators are moved until they match. I use a parallel bar myself. The body of the tool was turned parallel on the lathe and then the spigot hole was drilled in the same operation to assure it was square to the body. Once the tool is mounted in the mill and lowered to touch the table or the vise, any error in tram is indicated by the dial indicators reading differently. Adjust the tram until the dials are matching and you have the same effect as if the tool was still on the flat surface.

You don't shoot for any specific number on the dials.... just a perfect match, where ever they happen to register. Once you've used one, the tool not only makes sense, but simplifies an often otherwise tedious job. It's not a tool you want to toss in a drawer to get banged about, Mine is safely hung on the peg board near the mill for easy access and zero chance of being dropped or even bumped heavily.

I notice George chimed in. It also had him confused when I first made it but he finally grasped the concept and it all clicked. Last I heard he was going to make one. George?

Steve

 

[Blogwitch]

Marv,

If you go down to the bottom of this page, where it starts to use the faceplate on the lathe, it explains how the holding spigot is aligned at 90 degrees to the face of the tool. This should answer your question and confirm that your question above was a very valid one, purely by the comments I made in that part of the post. Without the last lathe operation, what you suspected would have a great outcome on the viability of the tool to do a good job.

You can ignore the rest of the article, that just shows how the tramming tool was made.

http://madmodder.net/index.php?topic=822.15

No need to join or hang about, just have a look at that bit of the article.

Blogs

 

[georgeseal]

Steve,

Done

 

[mklotz]

Marv,

If you go down to the bottom of this page, where it starts to use the faceplate on the lathe, it explains how the holding spigot is aligned at 90 degrees to the face of the tool. This should answer your question and confirm that your question above was a very valid one, purely by the comments I made in that part of the post. Without the last lathe operation, what you suspected would have a great outcome on the viability of the tool to do a good job.

You can ignore the rest of the article, that just shows how the tramming tool was made.

http://madmodder.net/index.php?topic=822.15

No need to join or hang about, just have a look at that bit of the article.

Blogs

Blogs,

Thanks for your reply and your confirmation that my concern was not the product of a age-addled mind. [My mind may still be addled but I do understand geometric interactions.]

It was just as I expected. You did your (considerable) damndest to mount the spigot perfectly and still had 3.5 thou of runout when you set it up on the faceplate. Had you not had the foresight to recognize the possibility of that error source and the experience to know how to correct it (including skimming the faceplate), that runout would have translated into a considerable tramming error on the final product. [John, I know I'm writing stuff here that you already know but I want future readers of this thread to understand the subtleties of this tool.]

Folks who intend to make their own version of this tool have to realize that the orthogonality of that spigot to the reference plane of the tool is extremely important. Just whacking a hole in the bar and jamming a pin into that hole is not going to cut it. Even if the mill on which that hole is made is perfectly trammed (chicken-egg?), small errors can creep in and they can kill the final accuracy of the tool. If you do decide to build your own, be sure to read John's reference closely and ensure that you understand why he's doing what he's doing.

If instead you buy a commercial version of this tool, you really should test the orthogonality before trusting it. I'm not sure about the best way to do this but I suspect it would require a setup similar to that used to test a machinist's square. [Hmm, I wonder if the manufacturers supply a *meaningful* tolerance for their product's accuracy. Or do they just quote the division size on the DIs as their "accuracy"?]

Personally, I'll stick to my single DI tramming tool. As long as the cantilevered bar supporting the DI is rigid enough, I can ignore the nuances of spigot orthogonality.

Steve and George,

Thanks for your explanations but I understand how the tool is used. As you can see from the above, the real concern is how one verifies that the tool is accurate.

 

[Cedge]

Marv...
I think we were all aiming a the same target but shooting from different angles. The last step I made on the lathe was to make a cut on the newly press fitted spigot to true it up against the lower bar. When finished, the spigot had no choice but to be, both, concentric to the bar and perfectly perpendicular.

You are quite correct.... the newly installed spigot was not perfectly aligned after being forced into the hole I'd drilled in the bar. However, by turning it on the lathe and truing it, all the nasty deviation was removed. Having made the tool to my own specs and testing it all along the way, the confidence thing never became much of an issue, although that maiden test tramming was a little bit confusing at first. Once it dawned on me that any matching readings were what was desired, the tool quickly became an indispensable addition to my routine. Since its so easy to use, I tend to check the tram much more often than before.

I'm not that good of a machinist, but if I test things enough I can generally chase most of the gremlins off the property. I too would be less confident with a freshly bought commercial version, at least until it proved itself to be accurate. That lack of "try before you buy" is just another chicken/egg situation.

As much as you enjoy making handy gizmos, why not give it a test run? I think you'll be pleasantly surprised with the results. The worst that can happen is a shiny new addition to the scrap metal box and another pair of Horrible Fright dial indicators in the tool box....(grin)

Steve

 

[zeeprogrammer]

Don't nobody tell on me, but I bought one of those spindle squares shown in reply #12.

As the topic suggests, 'the gods smiled on me'...then they had some fun with me.

I set the tool on my surface block and trimmed both dials to zero. Moved it around. Lifted it up and down several times....stayed at 0. Was careful with parallax.

Set it in a collet and installed it in the mill (HF 44991 - so I held my breath during the following procedure lest it moved).

Lowered the head until both indicators started moving. (Do not allow the tool to sit on the table - only the indicators. Instructions suggest 1 rev of indicators.)

Not so bad (it would appear)! Just over 0.002 out of tram in X. I was expecting much more. Even better, near 0.000 out of tram in Y (used a parallel bar). No shimming for me! (A good thing as I still have no idea where they would go and what I would use.)

So...loosened up the column nut, took a rubber mallet, and tappy tapped the side of the column and tightening the nut. Occasionally going upstairs to breath. Got within 0.0005. Took another whack. Nut is pretty tight by now. Shouldn't be a problem. Now off by about 0.030.

What? ???

I said 0.030. :-\ Took the tool out and back to the surface block. Zero. Back to the mill. Less than 0.0005.

What? ???

I said 0.0005. Moved the tool around, checked both X and Y. Looking good. Then I noticed one leg of the tool was a little further away from the table. Hm. That doesn't seem right. Then I noticed the indicators don't go from 0 to '100'. They go from 0 to 50 back to 0. Hm. That might make a difference. Then I noticed that one indicator was showing 40 while the other was showing the 'other' 40. Hm. That might make a difference. Then I moved the tool up and down a little. The needles were going in opposite directions. Hm. Hm. Hm.

To make what is a long story shorter...I started over. The trick is to be near tram when you do this. .01 off and things go weird. Now when I move the tool up and down, the needles move in the same direction. No gap between a leg and the table. I'm within 0.0005. Good enough. Can't wait to see what a fly cut will do now.

I should recheck the Y but not now. I need to breath.

Costly tool but saved me oodles of frustration.

Steve...thanks for this thread. Very helpful.

 

[vlmarshall]

Congrats, Zeep. Another tool added to the ever-growing collection...one you'll probably find other uses for.