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View Full Version : An Inexpensive DRO for my IH Mill...



BobWarfield
07-30-2006, 12:58 AM
After reading various threads on inexpensive DRO's, particularly for the quill (where calipers can be adapted), I perused eBay for a bit and quickly came to the conclusion that one could be had almost too cheaply to be missed. A few quick bids and I had 3 scales winging their way to me for a combined price of under $200. These are the type that have a head on them like a digital calipers. While it would be nicer to build a DRO (like a Shumatech) with a nice box to show all the axis positions, I intend to convert this mill to CNC in the not too distant future and so viewed the DRO as expendable. That meant the cheapest possible solution.

Getting the cheap scales left a little bit of work with the scrap bin to fabricate brackets and voila! I had a cheap DRO, at least for the X and Z (Quill) axes, which are the first I have completed so far. The Z-Axis uses a pushrod arrangement in virtually the same position as the old depth indicator:

http://www.thewarfields.com/img/Toys/MachineTools/MillStuff/CheezyDRO/P7243551.JPG

The X-Axis makes use of the T-Slot along the front edge of the table that's used for a travel limit system:

http://www.thewarfields.com/img/Toys/MachineTools/MillStuff/CheezyDRO/P7293563.JPG

There is a little more data on this on my web site:

http://www.thewarfields.com/MTMillDRO.htm

Honestly, the project was dead simple and very cheap given how useful a DRO can be. It's not the most durable arrangement, but I think it will serve me fine until I CNC unless I manage to drop the Rotab or Kurt vise on it!

I'll work out the Y-Axis in a few weeks, but thought I would pass along this progress as I'll be out of the shop for a couple weeks before I can get back after it.

Best,

BW

Norman Atkinson
07-31-2006, 06:27 AM
Bob,
So far no one has said " Well Done".
Might I say that whilst I have a very basic chinky mill drill with a round column but with a home made power feed, I have copied your photos?
I also have a pair of chinese scales

Let's have the other axis as time permits.

Many thanks in the meantime

Norman

japcas
07-31-2006, 07:19 AM
Hey Bob. I see your point about not wanting to sink a lot of money into the dro since you are going to cnc it. I have a mill similar to yours and am very interested in your cnc conversion. I would like to try it some day but I am electrically and computer challenged. Do you plan on buying the small display box that you hook the scales like you have into? It would make life a lot easier especially on the y axis. Good luck with the cnc and keep us posted.

BobWarfield
07-31-2006, 10:22 AM
Thank you for the kind words, Norman. The project was again, dead simple, and I highly recommend a similar undertaking to anyone who would like an inexpensive DRO. I was amazed at how cheap the scales had gotten on eBay that I could do this for under $200. I will add a picture of the Y-Axis when I've finished it.

Japcas, the good news is that these scales are set up to be connected to a central display, so it is possible to do that. They have a standard connector on each. In my case, I am not going to take the time to do so. For those who might be interested in going that route, and making a more permanent version of what I've done, I have a couple of thoughts.

First, the Shumatech DRO is a great display box you can build yourself if you can run a soldering iron at all. I actually do have one of their boards as well as the panel overlays, and was at one time (before deciding to CNC) planning to go that route. You can find out more about that DRO here:

http://groups.yahoo.com/group/ShumaTech/

I first heard about it while perusing this talented HSM's web site:

http://www.finelinehair.com/home/DRO_Mill.htm

Note that for lathes, you can use the third scale as a spindle tachometer (see the lathe DRO on the same finelinehair site), which I thought was pretty slick.

The finelinehair site brings me to my second point. If you intend to keep the DRO in operation for long, and especially if you'll be using it with coolant, you will want to arrange a little better protection for it. Note how finelinehair has some "L" stock being used as a DRO shield. Something along those lines would be very helpful I should think.

Best,

BW

lazlo
07-31-2006, 11:51 AM
First, the Shumatech DRO is a great display box you can build yourself if you can run a soldering iron at all.

The problem with the Shumatech is that Scott has pretty much stopped supporting them. He's not making anymore overlays, and the 7 segment displays he used have been discontinued.

The other problem, if you were planning to use the Jenix scales (which I what I did), is that the JBox guy (Travis) also lost interest in the project, so you don't have a clean way to attache 3 QCC adapters to the 3 Jenix scales.

I have another assembled Shumatech that I was going to use on my lathe, but the Jenix head unit is looking very attractive right now...

BobWarfield
07-31-2006, 02:29 PM
True, there are some small bumps in the Shumatech road, but Everlight still makes a MAN6940 and it looks like Mouser now stocks them, plus there are compatible substitutes known to work with Shumatech. The overlays are easy to make with help from Kinko's or the folks on the board, and the QCC converters are also straightforward.

With all that said, the Shumatech is a major DIY project more electronic than mechanical in nature. You need to be happy running a soldering iron, by which I mean you like to futz with electronics, enjoy troubleshooting, and won't get to frustrated by it all. Unfortunately, a lot of that gang is probably also just as happy to go CNC and won't need the DRO, which is my excuse!

BTW, the real savings you're going to get by building a Shumatech DRO is not that great, probably on the order of $100 based on what they're saying on the board versus buying a finished system such as the Jenix that Lazlo mentions. I have heard many great things about those scales, BTW.

I think you have to consider where your interests lie (would you enjoy getting out that soldering iron, or rather get making the chips sooner?), what your budget is (how much does that $100 savings really count for you?), and what you're trying to accomplish (I wanted a real short term solution) to see what route works best for you.

Best,

BW

Norman Atkinson
07-31-2006, 02:46 PM
Bob,
Again, my appreciation for your comments extending to lathes.
It would be nice to see further photos on this. I feel that many of us like the simpler things.

Lazlo,
Again, thanks! I actually got around to the Shumatech idea and gave up because of difficulties-real or imagined- of suppiles.

Earlier, I had spent a great deal of time trying to set up a proprietory DIY CNC set up- at considerable time, money and 'being pissed off' with it.
Again, the same firm got a connection with suppliers of chinese scales and the latter got a set up in its cat. and it subsequently stopped the advertising of both set ups.Again, I have a Myford- well, two and there was digital set up and then there wasn't. I started to get infuriated and the scales lay unused. Bob, to his credit, has quietly brought in concepts which can weary old brain can appreciate as not being all the bells and whistles but more than 100% reliable. I do blow my crust from time to time. Of course, you won't know this- said he waving his wooden leg aloft.

Currently, I have been getting rather frustrated with a new Myford lathe.
I'd done write up yonks ago in Model Engineers Workshop. It was, unashamedly, simple. Bob like? For a friend, like all the guys do here. Help a mate. Then I actually got a ML7 to lark with for myself. Had the bed "blancharded" for little more than washers and started with a batttered old T&C grinder to take the wrinkles out. Then, out of the blue, the phone rang and I was offered a Super 7 with a gearbox- for the E-Bay price of a gearbox or little more. There were one or two snags which I hadn't foreseen.
The guy had been using it for turning mahogany, the motor was clogged and dead, the gear box was dry etc. Britain had invented a new series of swearwords.
So there is progress and I am doing magic things with wooden jigs on an ancient Clarkson grinder. It would be cheating to be a highbrow and dig the Quorn out- and make life easy.

So, good folks, I am keeping faith with an old friend- sadly gone to the Great Lodge above who said " Keep telling people how to do jobs with little or no equipment"

Thanks for the use of microphone and loudsqueaker.
And if my spelling is rough- well, bollocks- write it yourselves.

Norm

lazlo
07-31-2006, 03:50 PM
Then, out of the blue, the phone rang and I was offered a Super 7 with a gearbox- for the E-Bay price of a gearbox or little more. There were one or two snags which I hadn't foreseen.
The guy had been using it for turning mahogany, the motor was clogged and dead, the gear box was dry etc.

But that's all easily fixable Norman -- especially considering the spectacular deal on the Myford!

Bob: the Jenix scales a great. Built like a tank, and extremely repeatable. In fact, I was looking at the Jenix scales next to a set of Accu-Rite scales, and it's not immediately apparent where the vast difference in price is coming from.

Tim Barnard (Linear Measuring Systems) is also a great guy.

I've got a three-axis Jenix/Shumatech setup on my knee mill, and I'm about to buy the Jenix scales for a 2-axis setup for my lathe. The Jenix scales also have a resolution of 0.0002", which is about 3x the resolution of the caliper scales. With the Shumatech head you only have 3 digits of accuracy with a LED dot to represent 5 tenths, but the Jenix heads have a full 4 digit decimal point, so you can "see" the full resolution of the scales.

Standard disclaimer: there was a brief flame war a couple months back when someone posted a glowing review of the Jenix head and scales. I'm not in any way affiliated with Tim or LMSC -- just a very satisfied customer.

Norman Atkinson
07-31-2006, 04:13 PM
I think that I have enough spectacular deal on my tool and cutter grinder and enough mahogany dust to make my wife think that I have started to smoke again.
The post has really brought out practical advice for ordinary workers like myself and specialists with real application- so I can mutter words of Jealousy and envy and that.

Thanks folks!

Norm

BobWarfield
07-31-2006, 07:32 PM
Here's one more crazy thought on the issue of cheap DRO's. I mention it hesitantly, because it involves a PC nearby and that would just not be acceptable to many. However, I did just come across this new link today:

http://home.lsces.co.uk/ModelEngineersDigitalWorkshop/YADRO/index.html

I am intrigued. It is yet another electronics project however, so those not so inclined would be well advised to look into a completed set like the Jenix unit. I agree that their scales look really well made!

Norman, I can appreciate your sentiment. The DRO is unfortunately one of the few times when I did not get carried away and radically over engineer my project!

Best,

BW

Elninio
07-31-2006, 09:23 PM
very interesting!!! came just in time w/ my post of the indexpensive DRO :D tnx!

lazlo
08-01-2006, 10:22 AM
Here's one more crazy thought on the issue of cheap DRO's. I mention it hesitantly, because it involves a PC nearby and that would just not be acceptable to many. However, I did just come across this new link today:

http://home.lsces.co.uk/ModelEngineersDigitalWorkshop/YADRO/index.html

There was a discussion late last year about this project on either the Shumatech or CNC_EDO... Yahoo group, and someone had the brilliant idea of adding an Intel QX3 microscope interface with some simple software to make an optical center finder. You could move the table around with crosshairs from the microscope, and instantly pickup any point on the workpiece.

The author added it to the next release of the software.

A.K. Boomer
08-01-2006, 10:41 AM
But that's all easily fixable Norman -- especially considering the spectacular deal on the Myford!

Bob: the Jenix scales a great. Built like a tank, and extremely repeatable. In fact, I was looking at the Jenix scales next to a set of Accu-Rite scales, and it's not immediately apparent where the vast difference in price is coming from.

Tim Barnard (Linear Measuring Systems) is also a great guy.

I've got a three-axis Jenix/Shumatech setup on my knee mill, and I'm about to buy the Jenix scales for a 2-axis setup for my lathe. The Jenix scales also have a resolution of 0.0002", which is about 3x the resolution of the caliper scales. With the Shumatech head you only have 3 digits of accuracy with a LED dot to represent 5 tenths, but the Jenix heads have a full 4 digit decimal point, so you can "see" the full resolution of the scales.

Standard disclaimer: there was a brief flame war a couple months back when someone posted a glowing review of the Jenix head and scales. I'm not in any way affiliated with Tim or LMSC -- just a very satisfied customer.


I'll third or forth that, i have the two axis jenix system that I got from Tim, great guy to deal with and what a solid product, yes my scales res. is to 2/10ths and all the components are south korea, cant believe the price, very happy...

BobWarfield
08-01-2006, 12:41 PM
There was a discussion late last year about this project on either the Shumatech or CNC_EDO... Yahoo group, and someone had the brilliant idea of adding an Intel QX3 microscope interface with some simple software to make an optical center finder. You could move the table around with crosshairs from the microscope, and instantly pickup any point on the workpiece.

The author added it to the next release of the software.

Lazlo, I have always liked the idea of a centering scope, but have been too cheap to purchase one. Maybe I should. I understand Mach 3 also has similar support. It sure would be nifty for a lot of things. I understand their accuracy can be quite high if they are good ones.

Best,

BW

lazlo
08-01-2006, 01:35 PM
Lazlo, I have always liked the idea of a centering scope, but have been too cheap to purchase one. Maybe I should.
...
I understand their accuracy can be quite high if they are good ones.

I have one -- the same USA brand that used to ship with the K&T boring machines. Mike Henry has the same one, but I can't recall the name off the top of my head.

It's essentially a 45x targeting scope with a focal length of around an inch, so they're very accurate. In fact, I can't scribe a line as small as the crosshair on the centering scope :o


I understand Mach 3 also has similar support.

Oh wow, that's cool! :)

Norman Atkinson
08-01-2006, 02:33 PM
I recall two things( wow!) that were published recently in Model Engineers Workshop.
The first was a laser alignment using one of these cheap pointers- with a mask to reduce the 'spot'. There was a development using one of these cheap laser theodolite gadgets.
Now this is more or less what is used for an alignment jig for crashed vehicles which includes graticules.

Also there was the write up of the Hemingwaykit thing which was to all intents and purposes a bit out of a cheap monocular from a few dollar or £10 set of Chinese binos.
The write up continued with how to black aluminum for the body.

All of these seem eminently practical- but!

Normie still has a bit of a ??????? Well, in Model Engineer, a million years back give or take a week, a guy called Geometer wrote a series called Microscope on the Lathe which detailed how to optically align. Again, these are worth a second look. Has someone got out the series or know where it is stored?

Geometer, I suspect was none other than Ned Westbury or one of his chums.
For those who are younger than me ( and who isn't), Ned was supposed to be Nevil Shute's Trustee from the Tool Room.

Can I now go and snuggle my head in Matron's - well, can I?
Oh, never mind.

Norm

JPR
08-01-2006, 04:28 PM
Has someone got out the series or know where it is stored?
they are here (http://groups.yahoo.com/group/Geometer/) and here is an index (http://www.walteranderson.us/hobbies/metalworking/geometer.html), but you need to be a member of one of the user group to access the files.

Norman Atkinson
08-01-2006, 05:41 PM
Thanks for refreshing my memory. Presently, I have been trying to do the Martin Cleeve thing

Cheers

Norm

Evan
08-01-2006, 07:38 PM
Another cheap approach is here:

http://www.lindsayengraving.com/other_interests/dro.html

You need some quad encoders and a PC, an old laptop will work fine.

Laser Motion has 5 micron resolution linear quad encoders here for $99, 12.5" travel.

http://www.lasermotion.com/servo.html