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View Full Version : DROs ... last big ticket item on the shopping list guys.



Farndurk
07-12-2010, 07:27 PM
The DRO is the last large ticket item I was tinking of. I've pretty much nailed the rotary table issue (thanks tons to the folks here for that). The other heavy buck item I wanted to look into was a DRO system.

I've seen them from modded digital calipers all the way up to programmable beasties. How about the middle of road ones? Like these ...

http://www.grizzly.com/catalog/2010/Main/540

http://www.use-enco.com/CGI/INPDFF?PMPAGE=571&PARTPG=INLMK32

Or how about these other Chino Machino types here on ebay?......

http://cgi.ebay.com/XYZ-3-AXIS-DIGITAL-READOUT-DISPLAY-3-DIGITAL-SCALE-DRO-/260433807736?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item3ca3108978

http://cgi.ebay.com/XYZ-3-AXIS-DIGITAL-QUILL-READOUT-DISPLAY-SCALE-DRO-SET_W0QQitemZ300379046832QQcategoryZ12581QQcmdZVie wItemQQ_trksidZp4340.m8QQ_trkparmsZalgo%3DMW%26its %3DC%26itu%3DUCC%26otn%3D5%26ps%3D63%26clkid%3D716 5414954500998463

I kinda like the two Ebay items' type/style. As far as features ... kinda slim.

I am using a ZX45 and a 12x24 lathe. The ZX45 was going ot get the DRO first. I have roughly a *better than working knowlege* of the use of the end dials on a manual setup, but my wife does not. She'll be using the ZX for making faceted rings (rotary table or dividing head time!) and divided/faceted pendants, stainless steel divided lockets, etc .. so I figured the DRO would be a great way to help intro her into this stuff. And it could help me as well, I'm certain.

Any help?

Thanks!

SGW
07-12-2010, 08:37 PM
First off, how much precision do you need? Note that precision is not the same as "display resolution." A display can show resolution to an insane number of decimal places while the actual location, relative to where you think you are, can be way off if the scale isn't precise enough to actually measure that number of decimal places. Quality companies generally won't attempt to mislead you like that, but watch out for the cheap stuff.

If you want to be, for sure, within +/- 0.001" of where you think you are, that can be had for a given price. If you need to be precise to +/- 0.0001", that's going to cost more. When I bought mine I decided I wanted to be sure of where I was within half a thou, so I bought an Acu-Rite setup good to +/- 0.0002", or just under 1/2 thou total uncertainty. It's actually way more complicated than just that, but I figured that approximation was close enough for me.

The Anilam system you linked to looks good. You might check out www.candomachinery.com and see what they have. I got mine through them and was pleased by the price quote I got. In addition, Mike (the owner) was very good about responding to my numerous e-mail questions both before and after I bought mine.

Oh - when measuring for scale lengths, be sure you account for the TOTAL length of the scale, not just its travel length. I was considering a Newall system until I realized the overall length of their scales is 10" greater than the travel length, and they wouldn't fit on my mill.

Farndurk
07-12-2010, 09:02 PM
First off, how much precision do you need? Note that precision is not the same as "display resolution." A display can show resolution to an insane number of decimal places while the actual location, relative to where you think you are, can be way off if the scale isn't precise enough to actually measure that number of decimal places. Quality companies generally won't attempt to mislead you like that, but watch out for the cheap stuff.

If you want to be, for sure, within +/- 0.001" of where you think you are, that can be had for a given price. If you need to be precise to +/- 0.0001", that's going to cost more. When I bought mine I decided I wanted to be sure of where I was within half a thou, so I bought an Acu-Rite setup good to +/- 0.0002", or just under 1/2 thou total uncertainty. It's actually way more complicated than just that, but I figured that approximation was close enough for me.

The Anilam system you linked to looks good. You might check out www.candomachinery.com and see what they have. I got mine through them and was pleased by the price quote I got. In addition, Mike (the owner) was very good about responding to my numerous e-mail questions both before and after I bought mine.

Oh - when measuring for scale lengths, be sure you account for the TOTAL length of the scale, not just its travel length. I was considering a Newall system until I realized the overall length of their scales is 10" greater than the travel length, and they wouldn't fit on my mill.
Super advice! Thanks for sharing your experience with me. Thanks for the dope on reading the specs too. VERY helpful advice. :) The scale length vs OAL was great too. :)

I figure .001 "actual position" is fine. I mean what's the point of having .0002 actual position (or even display rez) on a machine that is trying like hell to give you .001 anyway? Bragging rights maybe .. making your beer buddies go all "Oooo Ahhh" when they come over. All them big shiney numbers make me look so dang smart! HAA!

A big consideration is eyesight issues. I'm still not too bad .... I wear 1.25 diopter "readers" to do nearly everything inside of 24 inches. But I figure a half inch (or whatever) tall character is easier to see than a 1/16th character. Easy zeroing is attractive as well. And metric/SAE scales or divisions on the verneers are no longer an issue, so math conversions are reduced by an order of ... Especially handy with machines that use a bastard scale on the Z.

And besides, doesn't the DRO read part position instead of dial position? Granted I'm a n00b but it seems to me that if you're using your own dims for a part you designed with your own drawings, then it just seems like the wiser thing to do would be to record the part's position rather than the dial's. Sortof takes out any *maybes* doesn't it?

I've often wondered if anyone will ever do CNC of the part position rather than dial position. I mean I understand why it is done that way ("observable resolution" being the main thing I would think) but still, you'd think someone would find a way to get that tight of a resolution out of a linear device to facilitate reading part position. Just thinking out loud ... very ignorant opinions I might add.

Black_Moons
07-12-2010, 09:13 PM
People do use CNC's with linear feedback, the problem is backlash is still a problem (Climb cutting for example) reguardless how you compensate for it, You gotta have low backlash to start with.

Highpower
07-12-2010, 09:44 PM
The Anilam system you linked to looks good. You might check out www.candomachinery.com (http://www.candomachinery.com) and see what they have. I got mine through them and was pleased by the price quote I got. In addition, Mike (the owner) was very good about responding to my numerous e-mail questions both before and after I bought mine.
+1 on buying from candomachinery.....
Best price and especially helpful service I had found anywhere when I was looking for my DRO. :D

http://img.photobucket.com/albums/v82/Highpwr/Projects2/th_P2170002.jpg (http://smg.photobucket.com/albums/v82/Highpwr/Projects2/?action=view&current=P2170002.jpg)

Davo J
07-12-2010, 10:40 PM
Hi,
I would not look at anything without at least glass scale's. The caliper style are not worth buying for the little savings over a glass scale one.
I have 3 DRO's, 2 Miesters and a Sino that came with my mill.
The Miesters are a little easier to use but it's what you get used to, and they are a lot dearer.
The Sino's have been getting good feedback on a few forums and I have not had any problems with mine in 2 years. For $525US you can have a 3 axis DRO sent to you, and in this case cheap is not nasty.
One thing to remember most DRO's are made in the same factory.

http://cgi.ebay.com/Meister-Bc10M-3-Mill-Bore-DRO-digital-readout-3-scales-/130303511519?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item1e56b1cbdf

http://cgi.ebay.com/SINO-3-axis-digital-readout-/220496216879?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item335699432f

Dave

Farndurk
07-12-2010, 11:37 PM
..... One thing to remember most DRO's are made in the same factory.....

Dave
My guess is you could replace the word "DRO" with just about anything in the industry and that statement would still ring true.

Comes down to support in the end, doesn't it.

Thanks .... TONS!!! ..... for the help folks. I'll have the rotary table and the DRO figured out by tonight!

Thanks again .. I know I've been a pain around here lately but I am on a short schedule on this new equipment issue. Thanks for helping me spend the monies! :)

Brian ..

danlb
07-13-2010, 12:10 AM
You will find the SINO does a nice job. It will calulate positions in a circle (bolt circle patterns). It will calculate positions along a line (straight and at an angle) It will find the center of your work piece if you touch both ends. It has a hundred memory positions, so you can go back to the same places time after time.

The glass scales are bulky, but accurate. You may lose a little bit of travel depending on how you mount them. They may get in your way, depending on where you put them.

One thing's for sure. You will like having the DRO.

Dan

Mcgyver
07-13-2010, 12:28 AM
The price difference between the chinese and high end DRO is so compelling....hmmmm. Farn, "last big purchase" haha hehe haha famous last words :D

let us know what you decide and why, I'm there;s lots of in the same boat that would like the benefit of your insight since you just went through it

Cobbler
07-13-2010, 01:47 AM
... probably going to get some flak for being so cheap on this one... (one time I squeezed a nickel so hard the buffalo pooped!)

Grizzly has these little cheapos, even on sale right now.
http://grizzly.com/products/0-6-Digital-Fractional-Horizontal-Vertical-Remote-Scale/T21577

It was soon discovered, although they are sold as 6" scales, there is actualy a bit over 10" of "accurate" readable magical black area. I cut a couple strips of aluminum down to the same thickness and width as the scales, and then cut both the extensions and the rear of the scales at both ends to create a lap joint.

http://i187.photobucket.com/albums/x308/kennyrolling/DRO1.jpg

I glued the pieces together with "panel bond", an adhesive used in the auto body industry.

The cleaned up joint looks like this...

http://i187.photobucket.com/albums/x308/kennyrolling/DRO4.jpg

Now I have a 10.625" scale for the price of a 6" scale.

http://i187.photobucket.com/albums/x308/kennyrolling/DRO5.jpg

I mounted an unmodified scale on the Y axis and my new longer scale on the X axis of my mongrel "AtPort" milling machine.

http://i187.photobucket.com/albums/x308/kennyrolling/Workshop3-1.jpg

I've been using this setup for about 6 months now and really like it. The only complaint is the time-out / auto-off feature of these units is only about 2 minutes. It turns back on right where you left off but it is a bit annoying.

loose nut
07-13-2010, 07:52 PM
One very important, not to be missed point. Make sure what ever kind you get, it has the ability to shut off the forth decimal place. If you are only interested in .001" accuracy which is good enough for 99% of things, the forth decimal can be a pain.

Davo J
07-13-2010, 09:55 PM
One very important, not to be missed point. Make sure what ever kind you get, it has the ability to shut off the forth decimal place. If you are only interested in .001" accuracy which is good enough for 99% of things, the forth decimal can be a pain.


The Sino SDS6-3V in the link is the same as mine and has that feature , some of the earlier Sino's dont.

Dave

v860rich
07-13-2010, 11:11 PM
I have the Sino and I've been using it for more than a couple years. No problems, fairly easy install and good support from Shars.
It does everything that danlb says, and more!!

THANX RICH

People say I'm getting crankier as I get older. That's not it. I just find I enjoy annoying people a lot more now. Especially younger people!!!

gearedloco
07-13-2010, 11:51 PM
I also bought a DRO Pros system and am pleased with it so far. I haven't had time to play with it much, but it generally seems to be high quality equipment.

Some of the mounting brackets are cast out of some type of mystery pot metal. I needed to cut a couple of of pieces and there are a noticeable number of air bubbles inside. HOWEVER - they seem plenty stout for the purpose intended so I'm more than likely being picky.

The other problem is the included assortment of mounting screws, which are metric. The assortment wasn't terribly useful in my case. I just about cleaned out our local Orchard Supply and seriously dented the assortment at our one remaining ACE Hardware. I'm reasonably sure that I put things together in a way the manufacturer never intended.

SO - bottom line - I think my minor complaints are "way down in the noise" and I believe I got an excellent deal. I would not hesitate to buy another system from this outfit.

-bill