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DICKEYBIRD
02-13-2015, 11:43 AM
All of you grizzled vets please put on your thinking caps & post up your best DRO tricks & tips. None are too simple or obvious as far as I'm concerned. I'm getting close to finishing the 3-axis DRO install on my mill and am wanting to learn how to best utilize it.

I finished the Y-axis Monday night and already am already amazed at how great it is! I've read how much more productive one can be with a good DRO but didn't really understand until now. I've wanted one for a long time but didn't think I could afford one. Looking back, I should've put off buying a pile of other tooling and begged, borrowed or stolen the money to buy a DRO as soon as the mill arrived.

My advice to anyone getting started in this game is to put a DRO at the tippy-top of the list of things to get.

Toolguy
02-13-2015, 12:08 PM
I think the 2 greatest machine tool improvements in the last century (for manual) were the quick change toolpost for the lathe and the DRO for lathe and mill. The main benefit is to take a mill that could do .005 positioning with dials on the leadscrew and turn it into a mill that can do .0005 on positioning just by adding a DRO. Also on a long distance it's easy to be off by 1 turn of the dial. On a Bridgeport that is .200. With the DRO you don't have to keep track of turns, just go by the numbers.

You also need an edge finder (I have several) and a dial test indicator. These items help you start out in the right place. If you want to make quality parts, you can't be guessing or eyeballing the edge of a part or the center of a hole.

There are many different features on various models. The best general advice is to learn how to use every feature on yours. Some of them you may never use, but some will be gold nuggets that you will use a lot. If you don't know how to use something, it won't do you any good.

MrFluffy
02-13-2015, 01:32 PM
The one thing I did when I first got my dro going was drawing things out and dimensioning the key points to shoot for on the dro in advance.
I found it forced me to do my thinking in advance and its led to less whoops moments & even for pcd layouts or similar, having points with xy co-ordinates to the centre of each circle and a accurate backlash way to realistically achieve them meant I now spend a lot less time refixturing things on a rotary table to cut rotary details, but I still have the option if its a better process.

I also find when I have a lot of holes to make in something, if I haven't set the tool height up, at the end of the first hole I just hit zero on z, then every other hole feature needed I can just stop the feed when z approaches zero with less risk of going through into the table being absent minded.

The other thing you might want to do is when doing something with the table locked, is to keep a eye on the dro occasionally. Zero them if its not going to disturb what you are making, then you can very quickly see if the table shifts slightly before ruining the part you are making. I know mine does ever so rarely, and I never realized it until I fitted the dro, I had just chalked it down to poor operator error.

metalmagpie
02-13-2015, 03:42 PM
Here's a level zero tip. Let's say you want to mill a slot in a rectangular block. You put your edge finder in your mill spindle and spin it at about 1k rpm and touch off on the fixed jaw of your vise. Let's assume your edge finder's tip is 0.200" in diameter. Now what you want to do is to type in either 0.100 or -0.100 and zero your Y. My tip is this: FIGURE OUT WHICH AND MEMORIZE IT. I was always getting the sign wrong and having to fiddle to correct it. Same issue on the X axis, of course. Anyway, first tip is to truly learn how to pick up edges and zero your DRO to locate your part.

And then, of course, when designing, learn to put dimensions in absolute coordinates from the feature which you will locate using your edge finder. So if you have 3 things equally spaced 0.75" apart, the first being 1.5" from the left edge, you don't draw "1-1/2" and then "3/4" "3/4" "3/4", you draw "1.500" then "2.25" then "3.000" then "3.750" and so on. See the difference? You don't want to have to do the math when standing at the mill - that's how you make mistakes. Do it in the design phase.

And learn your DRO's advanced features like regular arrays or bolt circle holes. Or at least keep the manual in a known place somewhere close to the mill.

metalmagpie

Lew Hartswick
02-13-2015, 06:23 PM
And then, of course, when designing, learn to put dimensions in absolute coordinates from the feature which you will locate using your edge finder. So if you have 3 things equally spaced 0.75" apart, the first being 1.5" from the left edge, you don't draw "1-1/2" and then "3/4" "3/4" "3/4", you draw "1.500" then "2.25" then "3.000" then "3.750" and so on. See the difference? You don't want to have to do the math when standing at the mill - that's how you make mistakes. Do it in the design phase.



I think learning how to dimension is one of the very first things a beginning machinist should do. And doing all from two perpendicular axis is a good beginning . It fits right in
with use of a dro on a mill. :-) Sure there are always exceptions. :-)
...lew...

gundog
02-13-2015, 06:25 PM
I have a DRO on my lathe for X & Z it is great with a quick change tool post you can store up to 99 tools. I make an hour glass shapped roller from UHMW 50 to 100 in a batch. Using the dro and switching between tools is great. I have also used my cross slid to set up a stop for the tail stock. I needed to counter bore some rollers the other day to exactly .500" depth I set the bit just touching the stock to be drilled then ran my cariage over against the chuck in the tail stock and zeroed the z axis moved the cariage to .500" and drilled all the holes in 20 parts. The tail stock chuck hit the end of a boring bar I had held as a stop it worked great and was a very fast setup. I just called out a different tool number on the DRO for the setup and did not lose any of the other dimensions I had set.

Mike

sarge41
02-13-2015, 06:45 PM
DICKYBIRD: Don't forget to put in a permanent stop on the backside of the cross slide to protect your x-axis scale. If any questions about this, don't hesitate to ask.

Sarge

Rich Carlstedt
02-13-2015, 08:58 PM
You have two measuring systems ...Absolute, and Incremental...Use them both !
Generally the Absolute is used on the mill to locate your solid jaw and one edge (Left Usually) as was suggested by another poster
When you position work in the jaws, slide it left til flush and even to the edge and clamp, and you have your X,Y starting point

You can use your DRO to find center on anything, and without an edge-finder !
You will loose your preset Absolute position, but what the heck, this is fast.
Method one :
say you are milling a slot in a 1/2" rod. Put a 1/2" dowel pin in the collet and bring it down and "Watch the light !" as you move the pin against the solid jaw. When the light disappears, the spindle is centered . Zero out the scale and change to a cutting tool and you are ready. Some machinists use a endmill the same diameter as the work, but care is needed.
Method two:
Works for ID in a bore, or OD on a part or casting. Lets say you want a bore centered to make a larger hole
Drop the small dowel pin into the hole and move the Y axis away and when the dowel hits the edge and travel stops, Hit "0" on Y absolute
Now move the table towards you ( DO NOT MOVE X) and when you stop against the work -Hit "0" on the Y incremental scale .
Now move the spindle to the center and while doing so, keep switching Abs and Inc back and forth.
When the two numbers are the same , you have found the Y AXIS center point..Stop, and reset the Absolute scale for Y to "0"
Repeat left and right for the "X" axis setting and you have the bore center.
You could use a indicator as most do for very accurate work, but this method works and uses ....your digitals...as requested
rich

Breze
02-13-2015, 09:12 PM
The DRO can be used as an optical measuring device when you need to measure something and you don't have a hand held measuring device with enough capacity. I position the end of a part against the shank of a .500 end mill and zero the X axis. I then just add .500 to the dimension I want achieve and mill the other end until I reach that number on the X axis of the DRO. If the end mill is accurately .500 in diameter then the part should be milled to a very accurate length.

Ron

Blogwitch
02-17-2015, 06:59 AM
I hate giving out links to what I have done, but this is such a big post, it would take me hours to redo it.

It shows how and why I fitted a proper DRO to the tailstock of my lathe. I had already fitted the second head to the topslide (compound) so in fact I have four read heads on my lathe, and it makes life a lot easier for me.

So here is the link, I hope you can maybe pick up a few tips from it.

http://chestermachinetools.forumchitchat.com/post/fitting-a-dro-to-crusader-tailstock-7282746?pid=1286071543#post1286071543

John

MrFluffy
02-17-2015, 08:13 AM
Drop the small dowel pin into the hole and move the Y axis away and when the dowel hits the edge and travel stops, Hit "0" on Y absolute
Now move the table towards you ( DO NOT MOVE X) and when you stop against the work -Hit "0" on the Y incremental scale .
Now move the spindle to the center and while doing so, keep switching Abs and Inc back and forth.
When the two numbers are the same , you have found the Y AXIS center point..Stop, and reset the Absolute scale for Y to "0"
Repeat left and right for the "X" axis setting and you have the bore center.

My sinpo dro has a y/2 function button to do this, just sense the first edge as your post, then zero the readout on that axis position, then move to and sense the second edge, then hit y/2 for on centre point for that axis and move to 0.0 to repeat for X. Lazyier and easier way to do it if you have that functionality in the dro.

DICKEYBIRD
02-17-2015, 08:33 AM
Great link John & some good tips there as usual; cheers. I'm delighted to see you back to posting and happy to have you 'ere! I've learned a lot from your posts through the years on the various forums. (fori?)

I've got a hacked-up digital caliper fitted to the tailstock of my manual lathe and the retrofitted CNC ORAC lathe is (grudgingly) teaching me how to make decent parts on it.

After using the new DRO on the mill over the weekend, I've decided to look around for a good price on a short glass scale to temporarily install on the X & Y on the ORAC so I can map the ballscrews for even more accuracy. Mach3 allows you to do this & compensate for any ballscrew "quirks" just like the big boys do. The screws on the ORAC are pretty good but it'd be nice to dial them in even closer.

DICKEYBIRD
02-17-2015, 08:39 AM
My sinpo dro has a y/2 function button to do thisMy mTech DRO has this function as well as a bunch of others that I need to study up on. The Chinglish manual isn't too bad but I need to actually use all the functions & get familiar with them as Toolguy wisely advised earlier.

So far I'm delighted beyond words with it! Another one of those "How did I get along without it" things.:)

Rich Carlstedt
02-17-2015, 09:42 AM
My sinpo dro has a y/2 function button to do this, just sense the first edge as your post, then zero the readout on that axis position, then move to and sense the second edge, then hit y/2 for on centre point for that axis and move to 0.0 to repeat for X. Lazyier and easier way to do it if you have that functionality in the dro.

Great !
Was not aware of that function( Y/2)..thanks !

My Spaulding DRO is a 1985 unit and still kicking butt
It does have a 99 location memory storage positions , which was state of the art back then

Rich

Stepside
02-17-2015, 09:47 AM
Two Things: The first is to use ordinate dimensions if you CAD will do it. Or if pencil drawing do ordinate dimensions as well. Then use the 0,0 feature on the part to zero your DRO and all your "math" has been done.

The second is finding the center of features, holes or ends of shafts using an edge finder.
1) "Eyeball place the edge finder at the center of the "Y" and find the edge. Zero the edge and then find the opposite side of the feature. divide the reading in half and move to the resulting value. Set the new position as "0"
2) Do the same for the "X" axis.
3) Repeat for the "Y" axis as check.

I usually back up beyond the halfway toward the starting point and then approach the middle from the starting side. I do not have a clue if that makes a difference.

Blogwitch
02-17-2015, 11:31 AM
Thanks for the welcome Dickey. I have so much on at this time, I just don't have enough time to post like I used to, but once I have caught up, things should change. I am just about to convert a Seig Super X2 to CNC, but the hard way.

If I could make a suggestion to you, and one which I should have done. Have a look at the high reolution magnetic heads rather than a glass scale. I bought a 100mm glass for my compound, and had to cut it down a bit to get it to fit. If I had gone magnetic it would have been a doddle, and they are much smaller. But as I said, do take care with the resolution, there are usually two types, one not as good as a glass scale (they are the norm) and one that is better than, go for the better than if you can afford it.

John