AcuRite DRO Digital Readout Mill Lathe, $600, Calgary, AB

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[Susquatch]

That's more than brand new prices today.....

Edit - brand new competing brands like Aikron or Ditron that is.

 

[trevj]

That's more than brand new prices today.....

You have not priced out an AcuRite then...

If you can buy me Acurite scales for lower prices than this outfit costs, I want to know where! I have a couple read heads of different vintages, as well as a couple mismatched scales.

 

[Susquatch]

You have not priced out an AcuRite then...

If you can buy me Acurite scales for lower prices than this outfit costs, I want to know where! I have a couple read heads of different vintages, as well as a couple mismatched scales.

Sorry, I guess I wasn't real clear. I wasn't comparing the price to a new Acu-Rite. I was comparing to the likes of a new Aikron or Ditron on Ali.

If the old AcuRite is better than say the new Ditrons (just to pick one), then I need to change my post.

I'll happily do that if you can convince me that it is.

Edit - actually, I just fixed my old post now to make it clearer what I meant.

 

[trevj]

Sorry, I guess I wasn't real clear. I wasn't comparing the price to a new Acu-Rite. I was comparing to the likes of a new Aikron or Ditron on Ali.

If the old AcuRite is better than say the new Ditrons (just to pick one), then I need to change my post.

I'll happily do that if you can convince me that it is.

Edit - actually, I just fixed my old post now to make it clearer what I meant.

For the likes of us in a home shop, I have no problem with the available offshore new stuff. But I have 30 year old (plus some!) AcuRite units that are still working, and I'd expect them to be still doing so long time after the offshore stuff went to the landfill. Built to a different standard, and in use, the difference is pretty easy to feel and see.

 

[Susquatch]

AcuRite units that are still working, and I'd expect them to be still doing so long time after the offshore stuff went to the landfill. Built to a different standard, and in use, the difference is pretty easy to feel and see.

I dunno TrevJ, you didn't really tell me what is better about them. I can at least tell you what I like about the Ditron cuz I have one and I love it.

It is accurate to 1 micron. There is some debate about this, but in my testing, that claim has born out. I do plan more testing. Certainly a 10th is easy peasy. We will see about the micron in due time. What does the accurit claim?

The Ditron will also do all sorts of fancy math like bolt circles, arrays, and angles. These can all be specified in multiple ways (eg 3 points on a circle, 1 point and a radius, a diameter, etc etc lots of choices).

It will store a library of tool offsets.

It is easy to add increments from where ever you are. Just go someplace, set a temporary zero or even a coordinate, then add or subtract constants.

It presents a graphical display of where you are and where you want to be PLUS the x/y/z coordinates. In other words, a picture of the bolt circle itself as well as where the tool is as well as how much to move to get to exactly where you want to be.

It will add two axis together - eg Z plus quill. That way you can move the knee or the quill and still get a total Z for the part and tool.

It uses highly compact magnetic scales that only take up about 1/16" of space. So it can be installed INSIDE the cross-slide!

It can be zeroed anywhere, and then zeroed again in multiple locations all while maintaining the original zero.

It can survive a power outage and pick right back up where ever you left off. No need to reset the reference.

That's just a peek under the covers.

The design is based on a modern microcontroller. It is easy to update and I really don't think it is less robust than any other electronic system. About the only item that might wear is the buttons. They are easily replaced with common off-the-shelf parts.

And...... Drum roll please..... If it does fail, I can just go buy another Readout box for a few hundred dollars. The new box will work with my scales AND will likely include dozens of improvements. I have heard more than a few guys say it's time to drop their dro on the floor and then go get a new one!

I get your nostalgia. I LOVE my HP Calculator. Nothing will ever replace it. That doesn't mean I don't like my Android smart phone and all the modern features it has. To be honest with you, if I had to choose between my HP and my phone, the HP would go. I can always run an HP Emulator on my phone. Ya, not the same as those tactile buttons on the HP, BUT... damn close enough. The phone can substitute for the HP, but the HP can't substitute for my smart phone.

Note, I didn't mention the Touch DRO. It's even more amazing!

In the absence of concrete reasons why the Accurit is better than a modern Ditron, I'm sticking with my original post. In my opinion, that used Accurit is way too expensive for what you get!

Of course, we can probably both agree to disagree on that!

And after reading your endorsement, I confess that I do look forward to trying an Accurit some day.

 

[trevj]

Meh. all pretty normal functions. Last shop I was in had all AcuRite except for one Newall (which i was not impressed with, though I think we had a dud), and one high end Japanese unit on the Tool and Cutter grinder (Sony, IIRC). The Acurite's ranged from a brutally simple two axis unit that had only two toggle switches (one to switch between inches and MM, the other to zero each of the two axiis), and an on/off switch, and two LED displays for the measurements, on a surface grinder, ranging up to a four axis capable Milling DRO with a touch Probe option.

The one and only problem we ever had was on a brand new lathe, which the supplier had cheaped out and used a 'not quite long enough' glass scale on, it tore the read head off the reader, at the end of the travel of the cross slide. Took exactly one phone call, and no money, AcuRite sent me a new, inch longer scale, as well as a shipping box for the damaged one to be returned in. Easy!

Like I said, the modern stuff is fine for a home gamer. Maybe even OK for some shops. But I have, as I said thirty to forty year old units that are still running just fine, and for which I can still get support.

We never needed tenths level accuracy in general, but at least we had machinery that was of a quality that it was plausible to expect that it was an option, which I suspect most of the folks that have home grade machine tools, are never going to achieve, let alone twice in a row, generally through a lack of rigidity, or simply that the machines were never actually as straight and aligned as they needed to be, to make working at that level possible. So Micron level measuring is only worth talking about, if the machine it is ON, can actually achieve it. Dan Gelbart covers some of this sort of stuff in a video where he makes a lathe that actually CAN do this every day... Worth watching!

I mean, great talking point and all, but when do you see needing to measure that accurately, and do you honestly believe that your machinery is worth the time and effort?

FWIW, I had, and sold on with a lathe that I sold, a Sino DRO with glass scales. Same basic bells and whistles as what you have. It's cheap enough to add to a software package. Harder to make the Hardware last as long as the useful life of the Machine Tool.

My problem with magnetic scales of any sort, no matter how thin, is that they are affected by any other sources of magnetism, that may be within range. After playing a bit at watch and clock repair, I gained a deep respect for the stuff, as well as the importance of demagnetizing anything that was even vaguely suspected of having picked up a magnetic charge... Your machine tools are full of ferrous metal parts. Ever magnetized a screwdriver, so that screws would stick to it? You stroke it across a magnet. Or expose it to a strong current flow. Do you really think that a magnetic Indicator base, does not leave some traces of magnetism behind when it is removed? Or Moved, esp., while the magnet is on? Very small forces, can have big effects! FWIW, I also have been qualified to do Magnetic Particle Inspections, at one time, long ago. Best advice ever... "Do your bolts in batches of ten, so that when your hands start moving and your mind is asleep, you have a pretty solid idea how far back you need to go to re-do the inspection and actually LOOK at them!"

Anyways, YMMV, but if I have a choice, I will buy a used "Industrial" quality tool at a reduced price, rather than a "New" one, built down to a price point, rather than up to a standard of quality, any time!

 

[Susquatch]

Meh..... (I love that sound).... LOL!

Ya, we are just agreeing to disagree.

Nonetheless, you make a few points that I want to address simply because others are reading this.

There is a big difference between what a machine can do and what metrology can do. One is a result, and the other is a reference.

It is my opinion that one should not throw the accuracy of metrology under the bus just because you and your machine are not up to the same standards. There is a nebulous limit to that of course, but it's my opinion that better metrology can be a goal of its own regardless of how good you or your machine are or can be.

Besides, without good metrology, how do you know how bad or how good you really are? Quite ironically, I have been experimenting with my DITRON DRO to understand its limits, (and help resolve the ongoing discussion I referred to earlier) and in the process I am beginning to understand how bad some of my other metrology equipment might be. It's really quite frustrating to say the least.

Another REALLY NICE DISCOVERY about the Ditron is that it makes a FANTASTIC LONG SCALE for measuring things. Traditional long scales are both expensive and difficult to store and maintain. There was a time when I despaired of ever being able to make reliable long measurements. Few of us can afford a 2 foot micrometer! But I have discovered that I can use MY DRO to do long measurements quite reliably. Of course all assuming careful control of temperature and setup.

Anyways, I discuss this primarily to point out that there is a big difference between talking about the accuracy or precision of metrological equipment and the precision or accuracy of a machine.

The other point you dwelled on was the unreliability of magnetic scales. I can appreciate your scepticism. In fact I initially shared that scepticism. I had originally planned to install shields on my scales and I also deliberately chose mounting locations that would reduce magnetic interference. The shield plan isn't dead yet, but it has drifted waaaaay down my priority list because it simply hasn't been a problem. A blast of compressed air is all it takes to clean my scales and they don't collect swarf they way I feared that they would. They do collect a little metallic dust that is easily wiped or blown off and doesn't affect the measurements.

Your other point relates to magnetic influence. I worried about that too. But I've tried it and found that it didn't affect anything to any detectable level. On reflection that makes sense because magnetic scales don't depend on field strength. Instead they use what I'll simplify to call field boundaries. Nearby magnets don't affect that. At some point I suppose they could reach a destructive level, but I don't anticipate that ever happening any more than I'd expect an Acu-Rite scale to survive a sledge hammer blow.

Truth is that magnetic has simply not been the issue that I had thought it would be. You might find your own view would change if you gave them a chance too.

Best advice ever... "Do your bolts in batches of ten, so that when your hands start moving and your mind is asleep, you have a pretty solid idea how far back you need to go to re-do the inspection and actually LOOK at them!"

I managed vehicle safety and recall campaigns at a vehicle manufacturer for part of my career. I totally get the importance of what I call lot tracking and control. Doesn't negatively affect my view of the advantages of modern magnetic scale DROs though.

So ya, we are gunna have to just agree to disagree. I don't want that ancient used old school tech at that price. I'd much prefer a modern DRO at less cost.

 

[trevj]

Alright.

What are you using as a reference for your so called checking of accuracy, of this supposed micron capable scale?

I was taught that if you wanted to actually verify and calibrate the capability of your measuring tool, you had to have reliable reference gages, at 10 times the accuracy of the resolution you are testing at.

I have used and relied upon, Gage Block sets that were nowhere near that accurate (being qualified to be capable of reliably testing micron measurements), and I know what those Gage Blocks cost, too, and am glad to not have been paying.

Like i said, not really much more than a 'cool' talking point, if your machine is not capable of getting back to the same point (and producing a cut that makes the same dimension). Otherwise it is about the same value as claiming that your dad can beat up mine. It really doesn't matter, if you are not capable or required to, work at micron level accuracy!

Agree on the "long Scale" though. Have used a lathe bed for same, but we sure were not worrying about Microns, as, quite simply, our being in the same room as the machine we were using, and the temperatures we added to the parts in handling them, made more difference than that.

Before the DRO was common, there were calibrated sets of rods, and special racks to lay them out upon, that could be installed on lathes and mills for such work.

 

[Susquatch]

Alright.

What are you using as a reference for your so called checking of accuracy, of this supposed micron capable scale?

To be clear, that's another project. I have referred to it in this thread, but I have only done some initial work. I'm not exactly sure how to do it and that's why it isn't done yet.

My current plan is to use my Gauge Blocks. I think perhaps you have not looked at what is available today. My accusize set is certified to lengths well below a micron. It's easy to find other sets that are similarly accurate. Am I certain that the certification is good? No, I am not. Lots more work to do.

I was taught that if you wanted to actually verify and calibrate the capability of your measuring tool, you had to have reliable reference gages, at 10 times the accuracy of the resolution you are testing at.

I totally agree with that rule of thumb.

I also believe that your metrology equipment should be 10 times as good as what you are trying to machine to.

I have used and relied upon, Gage Block sets that were nowhere near that accurate (being qualified to be capable of reliably testing micron measurements), and I know what those Gage Blocks cost, too, and am glad to not have been paying.

I don't think they cost that much anymore. Mine are Grade B and actually came with a certification chart that lists the actual measurement of each block to 6 places - ie to the micro inch. For example, my 0.25 block is labelled .25 but they measured it to actually measure 0.250005. I was shocked when I bought them and I'm still shocked, but also a bit skeptical. Regardless, they are 3 orders of magnitude better than thousandths - certainly more than enough to validate a micron level measurement if I can satisfy myself that my measurement methods are valid.

Like i said, not really much more than a 'cool' talking point, if your machine is not capable of getting back to the same point (and producing a cut that makes the same dimension). Otherwise it is about the same value as claiming that your dad can beat up mine. It really doesn't matter, if you are not capable or required to, work at micron level accuracy!

Your beliefs and mine are similar. I believe your metrology should be 10x as good as you and your machine, and I extend that same logic to believing that that certifying your metrology equipment requires 10x that. You don't have to agree with that though. It's a point we can easily agree to disagree on and I think most readers would simply say "who cares!"

Agree on the "long Scale" though. Have used a lathe bed for same, but we sure were not worrying about Microns, as, quite simply, our being in the same room as the machine we were using, and the temperatures we added to the parts in handling them, made more difference than that.

Yup. I doubt most people understand that. But again, I don't care about machining to microns. I do care about measuring to microns from time to time though.

Before the DRO was common, there were calibrated sets of rods, and special racks to lay them out upon, that could be installed on lathes and mills for such work.

I'd really love to find a set of such rods at a price I could afford to pay. They are prolly out there somewhere, but I have not been lucky enough to find any.

 

[trevj]

I'd really love to find a set of such rods at a price I could afford to pay. They are prolly out there somewhere, but I have not been lucky enough to find any.

I have seen machines with them, come up from time to time on the Practicalmachinist site. Typically found on the toolroom Monarch lathes, and their like, have seen sets of bars for Deckel mills too. Just long skinny Gage blocks, and at that, unless you have a temperature controlled room to keep them and your machine in, they are as subject to creating errors from expansion and contraction as any instrument.

FWIW, we had 10 micron scales on the length on our lathes, and 5 Micron scales on the cross slide, and they served us well. 2 Micron and 1 Micron scales were available. IIRC, if you went in to the setup menu on the DRO display (enter secret (not very!) code), and start scrolling through the options, and the displays could go to six or seven digits after the decimal place, but, since we had no real use for that kind of dimensions, we typically had them set to read tenths or half thousandths. This was all in aid of making aircraft parts, most of which were toleranced to 1-5 thou, plus or minus, though we did a lot of freeze fit bushings (liquid Nitrogen) that we regularly needed to hit withing a few tenths on, and did, as well as a LOT of stainless steel and Al-Bronze flat shim washers, that were expected to be bang on the requested thickness as we could get. We had VERY good equipment, and a very good Calibration tracking and control system as well, and money really was NOT an object, as long as there was a practical need for any special measuring gear that was requested.

So. What do you propose to measure that you think you need Microns for?

 

[Susquatch]

I have seen machines with them, come up from time to time on the Practicalmachinist site. Typically found on the toolroom Monarch lathes, and their like, have seen sets of bars for Deckel mills too. Just long skinny Gage blocks, and at that, unless you have a temperature controlled room to keep them and your machine in, they are as subject to creating errors from expansion and contraction as any instrument.

I'll have to keep my eyes open.

And yes, the environment matters.

FWIW, we had 10 micron scales on the length on our lathes, and 5 Micron scales on the cross slide, and they served us well. 2 Micron and 1 Micron scales were available. IIRC, if you went in to the setup menu on the DRO display (enter secret (not very!) code), and start scrolling through the options, and the displays could go to six or seven digits after the decimal place, but, since we had no real use for that kind of dimensions, we typically had them set to read tenths or half thousandths.

That's how mine works too. Typically, I set them to read tenths and usually work to thousands or even much courser for farm stuff.

This was all in aid of making aircraft parts, most of which were toleranced to 1-5 thou, plus or minus, though we did a lot of freeze fit bushings (liquid Nitrogen) that we regularly needed to hit withing a few tenths on, and did, as well as a LOT of stainless steel and Al-Bronze flat shim washers, that were expected to be bang on the requested thickness as we could get. We had VERY good equipment, and a very good Calibration tracking and control system as well, and money really was NOT an object, as long as there was a practical need for any special measuring gear that was requested.

Making farm stuff is not like making aircraft parts, but I also do precision gunsmithing which sometimes requires working to tenths.

So. What do you propose to measure that you think you need Microns for?

Ah Trev, you will have to pay dearly to look into my life that deeply. A first born son will not cut it! LOL!

I do all kinds of things that can vary from eyeballing a rough close anuf, to using calipers, to working to tenths with micrometers and indicators. .

My current task is to qualify the one micron scale itself. I alluded to that earlier in this thread. I would like to determine with some confidence what the magnetic hysteresis of the sensors boundaries are and what the practical limitations are. It's not a straight forward task without metrology that is at least an order of magnitude better still - which I don't have. All I have is a 1 micron millmess that has unknown hysteresis in its own mechanisms and a stem of unknown stiffness. So I am planning to use gauge blocks but I think I need to make a fixture to hold them in such a way that they can be stacked without introducing other errors first. I am currently noodling the issues that arise from this approach.

Don't get me wrong, I understand your point about not needing that kind of accuracy to make things. But not every task involves making something. Some things are done just to answer questions, or to scratch an itch, or even just because I want to.

But none of this discussion changes my first post. I'm not buying, or recommending, a used Acu-Rite that costs more than a brand new Ditron.

 

[trevj]

Making farm stuff is not like making aircraft parts, but I also do precision gunsmithing which sometimes requires working to tenths.

Man, ain't THAT the truth! The F-18's we made parts for, were pretty hot stuff in the mid-1970's but compared to Airplanes, tractors and implements, these days, are some pretty high tech stuff!

I'd be willing to make a small bet, that there are more lines of code running in almost any modern tractor, than there are running the whole of all the systems on an F-18!

Anyone who is impressed by the frequent use of terms like "Mil-Spec" or "Aircraft Grade", really ought to give their head a shake and learn just how little those terms are worth.