Meister BC10M 3-Axis Glass Scale DRO Installed On Rong-Fu 45 Benchtop Mill - The Goods · Jan 11, 10:15

We’ve been itching to write-up something on these glass-scale DRO systems that are available from just about any and every vendor. We happened to buy ours from an eBay vendor. More on that later.

Here’s our story…

After receiving our Enco-branded RF-45 benchtop mill, we immediately started our search for the next step up in DRO systems – the ones using glass scales and a more feature-rich DRO unit. We didn’t really expect to make much use of 0.0002” resolution, but it would certainly be entertaining to watch the digits move about on the nice LED screen (no more LCDs here). What’s more, the DRO would have a built-in calculator. This is feature that’s nice to have on the unit itself. This sure beats trying to locate the calculator all the time..

We’ll post another article on the merits of each system we researched and post our Excel spreadsheet there.

We ended up purchasing the “Meister” brand DRO sold by some folks in Singapore. There was some hesitation to purchase from a non-US vendor mainly because of the ability to resolve warranty issues should there be any. Turns out, we would need some help..

What’s nice about most of these sellers is that they give you the option, for a fixed package price, to choose the lengths of scales needed. This indicates to us that the scales themselves aren’t where the cost lies – it’s in the DRO unit itself. That, or they attempt to decrease the number of sales inquiries by not having to answer such questions as “how much would it cost if I purchased an X, Y, and Z of lengths A, B, and C?”.

The only choice we had to make was the choice of housing – plastic or die-cast aluminum. For a minimal incremental cost, we opted for the cast aluminum. If we’re going to spend $600 on this system, why not spend a bit more for a more durable housing? We figure this is what most people opt for.

After sending a few emails to the seller, we placed the order via eBay. They also have a store on the internet, but by going through eBay, you would have some additional “buy protection” should this transaction be disastrous.

As it turns out, after we sent in specs for the scales, the seller replied back making sure that we were sure about the lengths. Since we mentioned that the mill would be an RF-45 but specified rather long scales, they had to make sure. We opted for longer scales in order to accomodate the transition from this mill to our larger Bridgeport-clone full-size knee mill.

In less than a week, a box arrived inside which contained the following:

Packaged neatly were two boxes. One for the display and the other for the scales. The piece of the metal on top is the guard for the long scale.

We’ll take a closer look at the contents. Here’s the boxed contents
containing the glass scales:

And the outside of the DRO display unit’s box:

Inside the box we find everything packed rather neatly:

At this point, we were just hoping that there wasn’t any physical damage that would be visible. Then we had to be somewhat concerned whether it worked! The contents of the display boxed are layed out here:

Now let’s take a close-up look at the scales (we’ll show you the inside of one later):

The scales have slotted mounting ends:

The cable is protected by a flexible housing like the flex conduit you find in electrical installations:

The sending unit on the scale is secured to protect it during transit (that’s the blue plastic end pieces:

That’s pretty much it for the quick overview of the system and what it contains. We’ll get into more detail in future posts regarding the actual installation, troubleshooting, etc. For now, here’s a sneak peak:

Installation as a unit. We decided to mount the scale onto a backing plate/bar onto which the guard is also mounted. This not only adds some rigidity to the setup, it allows the scale to be mounted as an assembly onto the mill as opposed to having the guard mounted onto the mill separately. In the following picture, we show the Y-axis setup as an assembly that now needs to be mounted to the carriage and mill base:

Even though the mounting was to be a prototype (upcoming plans/kits will be available), we still had to make it look good. This is a close-up view of the Z-axis mounting block. The scale is hidden behind the guard. Note that adjustments are made possible by the use of slots in all of our critical mounting pieces. The block is pretty hefty:

We like to be able to make adjustments as needed, so the DRO display is also mounted onto a backing plate with plenty of mounting holes. Since the mill column isn’t flat, we needed to use offset washers to space the plate accordingly. In addition, the Bondo/putty that coats the mill parts are somewhat gummy, so it takes a fair bit of adjustment to get the plate to seat properly. Here’s the end result:

As for troubleshooting and warranty issues, we needed help in both departments after our screen went bonkers:

After sending an email with a picture of the to the seller, he replied with the fix. As it turns out, this did the trick.

Some general thoughts:

The manual is very brief, though not as brief or poorly-written as the Harbor Freight “instructions”. When ordering scales, be sure to account for the additional length of the bracket ends (each scale has different dimensions for this). However, if using a mounting base for the scale, how and where the scale is mounted becomes more flexible. Newall is the brand name for this style of DRO systems. If you’re going to work in a flood-coolant environment, it may make sense to look at their ball-bearing style scales/linear encoders. They are are sealed and protected (IP67 rated). Most of these DRO units have the same feature-set such as an onboard calculator that transposes over to positioning and vice versa, bolt-hole and other positioning functions, and perhaps the most important… power-down memory. With the cheap DRO displays like the Positron, etc. that work with digital scales, the moment you have a power outage, or just plain power down, your position is lost.

All in all, this is a great next-step-up system from the digital scales versions. For larger machines such as this, we would recommend using this more feature-rich setup. What’s also nice about these DRO displays is that they work with various styles of scales:

Meister scale are compatible with Easson, Sino, Acu-Rite, Anilam and Fagor.

Here are some of the specs:s

Functions of Meister BC-10M Digital ReadOut:

* MM/Inch Interchange * 1/2 – Value is divided by 2. * Preset dimensions. * INC/ABS: Increment/Absolute co-ordinate interchange * Recall the last coordinate positions. * Mechanic Zero Position Memory -re-establish workpiece zero position after power failure * Bolt Hole Circle (Pitch Circle Diameter). * Holes equal distance on a straight line. * RTN: To pause and return to normal mode. * SRK: Shrinkage factor for working on moulds. * Linear error correction. * ARC/radius machining. * Power Down Memory. * Change linear scale direction (+/-). * Scientific Calculator.

DRO Display Specification:

o Response Speed: 60m/min (198.6feet/min) o Resolution: 0.005mm/0.0002” o Selectable 10um/5um/1um resolution setting. o Quantizing error: +/- 1 count o Power Source: AC 110 – 220V, 50 – 60 Hz. o Universal power supply. o Temperature range: Operating 0 ~ 40 deg C; o Display: 8-digits green color LED display o Dimension: 29 × 19 × 10 cm (11 × 7.0 × 4.0 inches)

LINEAR SCALE:

  1. SPECIFICATION: Etched glass.
  2. Resolution: 0.005 mm.
  3. Grating pitch: 0.02mm (50LP/min)
  4. Accuracy: ±0.005 mm or 0.0002” (at 20 deg C).
  5. Every scale has ABS reference marks.
  6. Response Speed: 60m/min or 40ins/sec.
  7. Output Signal: Two square wave signals, TTL.
  8. 3m long armoured cable.

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