Looking for input/help on the Pro Tram System from Edge Technologies

[ScrapMetal]

While working on a project it came to my attention that my mill was in need of being trammed. I pulled out a new toy that I got a couple of weeks ago (didn't need it but wanted to try it) just for such an occasion. This new toy is the Edge Technologies "Pro Tram system", specifically, model 09-000 with indicator graduation of 0.0005" - http://www.edgetechnologyproducts.com/pr...stem1.html

So far I'm not happy with it but maybe I'm expecting too much.

I installed it on the mill using a 1/2" R8 collet. Since I already have a Kurt vise and my rotary table mounted I also decided to go ahead and use an EZ-Tram - http://www.eztram.com/product_results2.asp?ID=1 along with it. I've used the EZ-Tram before with an Indicol/DTI and have had good results but it was somewhat awkward and time consuming. I was hoping to see if the Pro Tram System was as accurate and less hassle.

I calibrated the Pro Tram using a small magnet/"standard" that comes with it and according the directions provided. Basically you place the magnet on the table, or in this case the EZ-Tram, and set one indicator to "zero" by moving the face to match the needle. You then turn the spindle until the second indicator is on the magnet and then set it's face to "zero" as well.

I trammed the mill on the Y-axis (but didn't double check it, this becomes important later) and then proceeded to do the X-axis. Upon getting the X-axis "set" it occurred to me to finally "double check" the results by turning the Pro Tram 180° to see if the readings on the two indicators were still "zeroed". What I found was that they were significantly (to me anyway) off. After going over my setup and not a small amount of cursing I went back and tried to calibrate the indicators again and taking more care in doing so.

When I tried to re-calibrate the first indicator, double and triple checking as I went, I found that the indicator itself would not repeat to zero. I would set the face then lift the indicator off of the magnet, set it back down on the magnet, and the indicator would no longer read zero. The readings were almost always different and varied by as much as 0.0015". As the indicators are roughly six inches apart (I didn't bother to measure) this means that the combined error of the two indicators could be off by as much as 0.003" over six inches.

Now, tell me guys, am I being too critical and that's actually okay? Am I doing something wrong? What the heck?

If I can't resolve this, tomorrow I'll go back to using the Indicol/DTI as my current project has to be done "yesterday".

Looking forward to hearing what you have to say.

Thanks,

-Ron

[TomG]

Ron,

I think indicating to that level of precision is pushing the limit of those low cost indicators and getting the two of them to agree is going to take more time than to just tram the head using the traditional method.

Tom

[ScrapMetal]

That's kind of what I thought I would hear. I may futz with it a bit more tomorrow but will probably go back to the Indicol/DTI setup just so I can complete this project. Christmas is coming up quickly, so I've heard, and I won't have much to wrap for my wife if this isn't done. - Wife's Christmas Gift

Thanks,

-Ron

[DaveH]

Well guys, I'm not sure I totally agree. If I 'zeroed' it then lifted and lowered the plunger I would expect it to read zero and certainly within +/- .00025"
of zero, maybe 1/2 a division max if each division was .001".
I see on the web site they say repeatability is .0002" - you are not even close to that Ron.
I would (if you can) certainly phone them.
Just my 2 cents

DaveH

[awemawson]

Do you have sufficient 'pre-load' on the indicator plunger? Have you scrupulously wiped clean the magnet top and the indicator ball? Is the magnet sitting on a perfectly clean wiped surface? Are there stray microscopic particles on the magnet?

I have a Pro-Tram and my indicators repeat well within spec. when all the above are taken into account.

Andrew

[stevec]

Ron, I'm just curious as to how you lift the indicator off of the magnet,
you wrote "I would set the face then lift the indicator off of the magnet, set it back down on the magnet, and the indicator would no longer read zero."
was it by pulling up the top of the indicator spindle between your fingers? or by raising the spindle of the mill?

Another curiosity, if one is supposed to rotate the device 180° to read the amount of "tram" why isn't one indicator face 180° to the other.

[b4dyc]

I have one of these and find it works great :)
To be honest, I think I left the magnet in the plastic container and measured off the top of that rather than off the magnet.
The results were noticeably better on the finish with both a milling cutter and flycutting.
The way it works Steve, is that you use the magnet as a reference point to set the dials to zero then set the tool down to the table and look for a difference in either dial both looking towards you :)

[Arbalest]

I'd use a pro tram if I had one but it does measure over only a relatively short distance. As others have said a single gauge on a longer arm is likely to be more accurate if time consuming. This is after all how it was done until the pro tram appeared, in fact a guy I used to work with just used a bent rod and cigarette papers!

[ScrapMetal]

(12-21-2013, 03:17 AM)DaveH Wrote: Well guys, I'm not sure I totally agree. If I 'zeroed' it then lifted and lowered the plunger I would expect it to read zero and certainly within +/- .00025"
of zero, maybe 1/2 a division max if each division was .001".
I see on the web site they say repeatability is .0002" - you are not even close to that Ron.
I would (if you can) certainly phone them.
Just my 2 cents

DaveH

I agree with you. What I was getting for "repeatability" was unacceptable. I did futz around with it before getting back to work today and what I found (or at least I think I found) was that using the included magnet was causing some of those repeatability problems. Cheap indicator, strong magnet, bad combination apparently.

(12-21-2013, 04:16 AM)awemawson Wrote: Do you have sufficient 'pre-load' on the indicator plunger? Have you scrupulously wiped clean the magnet top and the indicator ball? Is the magnet sitting on a perfectly clean wiped surface? Are there stray microscopic particles on the magnet?

I have a Pro-Tram and my indicators repeat well within spec. when all the above are taken into account.

Andrew

Yep, took all that in to account a number of times. That's where most of the swearing was produced. Once I tried it without the magnet by using the same spot on the EZ-Tram I got much better results.

(12-21-2013, 08:06 AM)stevec Wrote: Ron, I'm just curious as to how you lift the indicator off of the magnet,
you wrote "I would set the face then lift the indicator off of the magnet, set it back down on the magnet, and the indicator would no longer read zero."
was it by pulling up the top of the indicator spindle between your fingers? or by raising the spindle of the mill?

Another curiosity, if one is supposed to rotate the device 180° to read the amount of "tram" why isn't one indicator face 180° to the other.

As usual, my descriptions leave a bit to be desired. Your first supposition was correct. I did lift the indicator by pulling on the top of the indicator spindle.


As I mentioned before, it would seem that the magnet was part of the problem with the repeatability. Even after that I was still having some issues the source of which may take a bit of time to determine. As I am pressed for time I finished "tramming" the mill with a combination of "kind of using" the Pro Tram and just "by the seat of my pants" basically. It's not where I want it but it is close enough to finish up my current project. Once I have it completed I'll take the time to figure out just what is going on. Problem with the collet, spindle, Pro Tram, or just the user.

While purchasing the Pro Tram did save some time, at this point I think I would be ahead if I had just purchased two high quality indicators and made the thing myself. I will most likely be looking to replace the indicators in the Pro Tram if I survive the holidays. At least it would give me a little more peace of mind.

Thanks guys,

-Ron

[stevec]

Thanks Ron, I still don't understand why the indicators BOTH face the same way.

Andy, I'm sorry but I didn't understand much of your explanation, not a critique, I just didn't understand.