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View Full Version : Anybody have the grizzly dro for calipers?



snowman
08-22-2010, 12:44 AM
http://www.grizzly.com/products/24-Remote-Digital-Readout-Inch-Metric-Fraction/T23013

I just want to make sure it works before I drop the cash on it. I am sick of not having anything.

Cobbler
08-22-2010, 01:29 AM
I put those on the X and Y of my mongrel vertical mill last fall and have no complaints thus far. I probably wouldn't trust them plus or minus .001" or a bit more but for what I do, that's close enough. It sure is a lot nicer having those than nothing.

dewat
08-22-2010, 01:31 AM
I just bought some 6" models and a couple of longer ones from a different source on Amazon, I haven't had time to play with them yet but here are a couple of threads,

http://www.homemodelenginemachinist.com/index.php?topic=9163.0;topicseen

http://www.homemodelenginemachinist.com/index.php?topic=7767.0

Hope this helps.

http://www.amazon.com/iGaging-DigiMAG-Magnetic-Digital-Readout/dp/B003JUII2A/ref=sr_1_27?ie=UTF8&s=hi&qid=1272995945&sr=1-27

http://www.amazon.com/iGaging-DigiFENCE-Magnetic-Digital-Readout/dp/B003JURUJM/ref=pd_cp_hi_2

snowman
08-22-2010, 01:31 AM
Thanks Cobbler...at this time, a majority of what I do are weldaments...so even 5 thou would be good enough for me.

snowman
08-23-2010, 02:59 PM
Well, just ordered one. We'll see how well it works...once it arrives.

dp
08-24-2010, 02:51 AM
Pop back in and give a product review - you have me ready to write a check :)

doorknob
08-24-2010, 08:53 AM
The Grizzly scales are apparently the same as the iGaging DigiMag Remote Readout - http://www.igaging.com/page9.html#miniHeight

There's a useful discussion about them at: http://www.cnczone.com/forums/showthread.php?postid=812851

One thing to note that may impact your use of these scales is that apparently they automatically turn off after about 3 minutes of use, and so far reportedly nobody has figured out a way to either disable the auto-off or jury-rig a workaround.

wierdscience
08-24-2010, 09:06 AM
Is that just the remote display or the scale too?The ads aren't to clear on that point.

doorknob
08-24-2010, 09:24 AM
Based on what it says and shows on the igaging.com site, the unit includes both the scale and the remote display.

Cobbler
08-24-2010, 10:33 AM
One thing to note that may impact your use of these scales is that apparently they automatically turn off after about 3 minutes of use, and so far reportedly nobody has figured out a way to either disable the auto-off or jury-rig a workaround.

The auto-off feature is very annoying and I would like to find a way to disable/modify this feature but, thus far, it has not caused any problems. When you turn it back on after a time-out, it has always come back on at the same point where it shut off. If it turned back on to zero or something, I'd probably rip them off the machine.

doorknob
08-24-2010, 11:19 AM
I am having visions of a servomotor-controlled robotic arm/hand assembly that will push the 'On' button every three minutes...

WaveDude
08-24-2010, 12:03 PM
I am having visions of a servomotor-controlled robotic arm/hand assembly that will push the 'On' button every three minutes...

http://www.youtube.com/watch?v=Z86V_ICUCD4

doorknob
08-24-2010, 03:43 PM
http://www.youtube.com/watch?v=Z86V_ICUCD4


I want one.

whitis
08-24-2010, 04:51 PM
One thing to note that may impact your use of these scales is that apparently they automatically turn off after about 3 minutes of use, and so far reportedly nobody has figured out a way to either disable the auto-off or jury-rig a workaround.

The popular chinese scales and calipers are never off, only the display on the scale/caliper turns off. Since they are incremental devices, they have to constantly take measurements to detect motion or they would lose their position and you would have to reset them. And they continue to output data over the 4 pin connector when "off".

The display won't turn off if you push buttons or move the scale.

It turns out there is a way to simulate pushing buttons over the 4 pin connector. You can simulate pressing the zero and mode buttons (most calipers don't have the physical mode button) by connecting resistors between the positive battery lead and the clock/data. This is primarily used to switch the caliper between fast and slow reading mode.
http://www.yadro.de/digital-scale/protocol.html
By rigging up a small low power microcontroller to play with the buttons periodically, for example switch to fast mode and back to slow mode or switch to hold mode and back, you could probably reset the display auto-off timer.

But with a remote DRO readout, you don't need to.

doorknob
08-24-2010, 06:46 PM
The popular chinese scales and calipers are never off, only the display on the scale/caliper turns off. Since they are incremental devices, they have to constantly take measurements to detect motion or they would lose their position and you would have to reset them. And they continue to output data over the 4 pin connector when "off".

The display won't turn off if you push buttons or move the scale.

It turns out there is a way to simulate pushing buttons over the 4 pin connector. You can simulate pressing the zero and mode buttons (most calipers don't have the physical mode button) by connecting resistors between the positive battery lead and the clock/data. This is primarily used to switch the caliper between fast and slow reading mode.
http://www.yadro.de/digital-scale/protocol.html
By rigging up a small low power microcontroller to play with the buttons periodically, for example switch to fast mode and back to slow mode or switch to hold mode and back, you could probably reset the display auto-off timer.

But with a remote DRO readout, you don't need to.


Based on what I have seen elsewhere, a degree of caution is in order here.

There's a 6-page thread on a different forum about the Grizzly/iGaging scales with the remote display starting at http://www.homemodelenginemachinist.com/index.php?topic=9163.0


There's a discussion on page 3 of that thread where one poster claims that the data communication protocol between the scale and the remote display is not the same as the one commonly-seen on other Chinese import scales (and documented at YADRO and at Shumatech). So, while what you have described above applies to the common Chinese imports, it may not apply to this one.

For example, an excerpt from that thread (if that's OK to do here):

one guy says: I wonder if this display can be wired into the cheap chinese scales I already have? From the looks of it there is power, ground, data, and clock signal(ssy).

another guy replies: There was another thread about these scales some time back and the same question came up. So I opened up both types of scales and had a look at the signals on my O-scope and found that they are not the same format at all.


There's some other useful info over there, including pictures of various mounting methods on X2 mills and discussions about extending the length of the scales.

Cobbler
08-25-2010, 01:00 AM
I did a little bit of testing on this myself and found that the reader for the cheap Grizzly unit (I-Gaging) would not read any other digital scale I have in the shop. A couple friends of mine who were doing some experimenting with them at the same time reported the same results.

wierdscience
08-25-2010, 01:31 AM
Looking at the picture a little closer the display shows an ABS or absolute function.Wonder if it's a knock off of the Mitutoyo digimatic calipers which also had they're own unique output?

IIRC none of the Chinese scales I have or have ever seen had the ABS function on them.

Bob D.
09-28-2010, 06:11 PM
http://www.grizzly.com/products/24-Remote-Digital-Readout-Inch-Metric-Fraction/T23013

I just want to make sure it works before I drop the cash on it. I am sick of not having anything.
-------------
I just installed the 12 inch version on the X axis if my Linley jig bore. I played around with it on the workbench and it functioned fine. I took it apart to make measuring for installation easier; it went back together fine and the installation was a bit tricky, but it's done. However, the readings were erratic and the display was not steady. :eek: I installed another display with with the same result and both displays worked fine on a 6 inch scale, so the fault was clearly in the scale. On close inspection, it became obvious that I reinstalled the reader upside down on the scale. :(

It's all back together and working fine. I'll post some pics when the other axes are done.

randyjaco
09-28-2010, 10:16 PM
I am on my second 24" Grizzly for the knee on my mill. The first one was way off. This second one is off by 3 to 4 thou. It is supposed to be plus/minus .001" I have spent a day trying to improve my mounting, but I am still 3-4 out. I wish I could figure out what is wrong. This one is a damn site more touchy than the other DRO's I've done.

Randy

whitis
09-29-2010, 12:34 AM
I am on my second 24" Grizzly for the knee on my mill. The first one was way off. This second one is off by 3 to 4 thou. It is supposed to be plus/minus .001" I have spent a day trying to improve my mounting, but I am still 3-4 out. I wish I could figure out what is wrong. This one is a damn site more touchy than the other DRO's I've done.

Randy

If you look at the ubiquitous cheap 6" calipers, the spec there is something like 0.001" per 6" with the error being predominantly a scaling factor with length (i.e. the total length of the stripe pattern is slightly off). At 24", a scale made to the same relative accuracy would have about 4 mils of error, so look at the fine print of the accuracy spec. If you have the $45 unit (T23013) , it is questionable whether you paid for 0.001" accuracy over 24" whatever the seller may have lead you to believe.

If the scale is not perfectly parallel to the axis of travel, there can be some cosine error. 0.01 degrees or 63 mils of offset is enough to cause the error you report.

Temperature induced error (coefficient of expansion) could be significant over 24". The coefficient of linear expansion for stainless is about 17.3ppm per celsius degree. Thus 1 degree change produces about 0.4 mil of error and 10 degrees the amount you report.

Whatever you are using to measure the error could be affected by temperature as well or the difference in thermal expansion, though it would probably take a rather large temperature change of 31 celsius degrees to get that much difference between steel and stainless. Baring some rather uncomfortable conditions, it probably isn't temperature alone. But what is the accuracy of what you are comparing it to, under the conditions you are comparing it?

Specs on some of the cheap import products can be inflated, which may be your issue. I can't even find accuracy specs for the ones I looked at on the grizzly site.

And, yeah, DROs and similar instruments can be touchy about alignment of the reader head to the scale as well.

And, regarding earlier comment, it looks like grizzly's cheap DRO isn't using the same hardware as the most common chinese calipers, unlike some others, though it may be based on a different caliper. Their more expensive ones look like they may be optical/glass scale.

dp
09-29-2010, 12:56 AM
I am on my second 24" Grizzly for the knee on my mill. The first one was way off. This second one is off by 3 to 4 thou. It is supposed to be plus/minus .001" I have spent a day trying to improve my mounting, but I am still 3-4 out. I wish I could figure out what is wrong. This one is a damn site more touchy than the other DRO's I've done.

Randy

I bought a couple for my lathe. Reading your experience makes me wonder if the .001" figure is accuracy or repeatability. It might just be reliably off 0.004" +- 0.001" :mad:

I haven't installed them yet.

winchman
09-29-2010, 03:01 AM
Totally confused, as usual.

I clicked on the link in post #1, and got this image

http://cdn6.grizzly.com/pics/jpeg288/t/t23013.jpg

with this description

Description
24" Remote Digital Readout, Inch/Metric/Fraction

All that stuff in the image for $45.00 seems ridiculous, but the image doesn't the description, so who knows.

I'm also confused about the title of this thread.

"Anybody have the grizzly dro for calipers?"

Why not just buy digital calipers?

randyjaco
09-30-2010, 10:09 AM
Yeah,
After 2 days of trying to get the error down to +/- .001" I have decided that this isn't the way to go. I think I will stick with the dial and use the DigiMatic as a range finder. It is probably safe to depend on it for the +/- 0.1" and then go back to the dial 8^(

Randy

Bob D.
09-30-2010, 10:50 AM
[QUOTE=winchman]Totally confused, as usual.

I clicked on the link in post #1, and got this image

http://cdn6.grizzly.com/pics/jpeg288/t/t23013.jpg

with this description

Description
24" Remote Digital Readout, Inch/Metric/Fraction

All that stuff in the image for $45.00 seems ridiculous, but the image doesn't the description, so who knows.

-----------------------

It's just a generic picture of the whole series of cheap DROs. For 45 bucks you get one 24" version, for $35 you get a 12" (that's the one I just installed), and a while ago they had the 6" for $22.

For the general, not-too-fussy hacking around I mostly do, it seems to fit my needs. I can't justify spending $500 or more on a "real" DRO:(

snowman
09-30-2010, 12:04 PM
I got mine in the mail but haven't had time to install them yet. Maybe this weekend.

wierdscience
09-30-2010, 09:36 PM
I bought a 12" three weeks ago and haven't installed mine yet either,I see a pattern forming here:D

The main reason I haven't installed mine yet,is it's bigger than the old scale,so all new brackets have got to be made.

Doozer
09-30-2010, 10:11 PM
I know different strokes for different folks, but...
I would rather spend about $1000 for a commercial DRO
than monkey around with finicky and cumbersome Chinese
calipers. I know this is a home shop environment but one's
time and aggravation is worth something.
Of course if you have more time than money, it may be
worth it, but always consider the big picture.

--Doozer

wierdscience
09-30-2010, 11:43 PM
If they made a $1,000 DRO or for that matter a $500 DRO that would fit on a Sieg X2 I would probably buy one,but they don't.

Rex
10-01-2010, 12:30 PM
If they made a $1,000 DRO or for that matter a $500 DRO that would fit on a Sieg X2 I would probably buy one,but they don't.

Get your credit card out:

http://www.littlemachineshop.com/products/product_view.php?ProductID=2665&category=-1536942993

wierdscience
10-02-2010, 09:31 AM
Get your credit card out:

http://www.littlemachineshop.com/products/product_view.php?ProductID=2665&category=-1536942993

Nah,looked at that one already,the scales would fit,but the reader heads won't.Nothing like losing half the axis travel to the DRO mount.