# Lathe owners with DRO’s



## COMachinist (Oct 17, 2020)

I have decided to put a DRO on my lathe. I have done a lot research on DROs it seems that the biggest majority are .5um resolution for both the x and z axis. I under stand the cross slide dilemma on .5 or .1um resolution. Having never used a lathe with a DRO, I was wondering what end users think of the .5 compared to .1 that have used both.
I will be using the magnetic encoders, most likely DRO Pros kits. The major problem I have now is my eyes can no longer read the dials as well as the used to, yeah I know bifocal safety glasses, I hate them. Seems they just don’t do as good a job. Any input is greatly appreciate.
Thanks for looking.
CH


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## addertooth (Oct 17, 2020)

You may have a decimal point transcription error.  Most that I have seen are 1 micrometer and 5 micrometer, not 0.5 micrometer. If you are working with the 5 micrometer scales, that translates to roughly 0.0002 inch resolution (0.00019685") per "step".  For most hobby machinists, that is close enough.  Keep in mind the display has to translate the metric scales to English Inch values, and you get some minor "rounding errors" in the math too. 

With the 1 micrometer scales, you get 1/1,000,000 of 39.37 inches of resolution per step, or 0.00003937 inch per "step". Assuming the scale is accurate, that pushes it down to 4/100ths of 1/1000th of an inch.  This is likely more resolution than most home users actually need. The slightest vibration of your cutting tool will make a much bigger difference than your trailing digit on your display.  

I am currently using a different sort of DRO on my lathe, which simply encodes the rotation of the dials. As such, it does not know what slap/slop exists in the mechanism. However, as most of my cuts are towards the workpiece, once they are zeroed to a reference point, then all cuts relative to that point are accurate.  My eyes are old as well, and having a DRO has made things much easier (and less error prone).  Hitting and holding sub 1/1000 cuts seems to be a bit easier.


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## Janderso (Oct 17, 2020)

Seems like an interesting start to a subject that I have been pondering myself.
In my experience, bifocals are great as long as you are in the zone. Most of the time I’m not.


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## Boswell (Oct 17, 2020)

My DroPros setup is 5um on the Z (carriage) and 1um on the X (Cross Slide).  This gives me 0.0002" on the carriage and 0.00005" on the cross slide. In practical terms you can use these to 0.0005" on the Z and 0.0001" on the X.   More than my skills and equipment can be expected to hit. 
I have been VERY happy with my DrosPros magnetic scales.


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## Winegrower (Oct 17, 2020)

There are other factors that degrade accuracy beyond the stated resolution of the scale/reader.   The error will at best be plus or minus a half count for perfect scales, and my experience with mag scales is that they are indeed not perfect.  Most if not all all the imported DROs are natively metric, so there is a conversion to inches internally that in my opinion is not done with great mathematical care.  So there is some error introduced there.  Then even linear compensation is an approximation.  And when in diameter mode, which i believe is most useful, the total error is doubled automatically.
i was unhappy with 5 micron resolution, went to 1 micron.  It’s better, but it also unmasks the other error sources.   So overall, for just trying to hit a diameter to less than 0.001, 1 micron is ok, not wonderful.


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## Janderso (Oct 17, 2020)

Boswell said:


> My DroPros setup is 5um on the Z (carriage) and 1um on the X (Cross Slide).  This gives me 0.0002" on the carriage and 0.00005" on the cross slide. In practical terms you can use these to 0.0005" on the Z and 0.0001" on the X.   More than my skills and equipment can be expected to hit.
> I have been VERY happy with my DrosPros magnetic scales.


I will second the Dropros magnetic scales, they work great. I had to replace one that was damaged before I bought the mill. The customer service was good. Prices are competitive


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## COMachinist (Oct 17, 2020)

Oh my mistake on . Just looking for input.
Thanks
CH


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## jbobb1 (Oct 17, 2020)

I installed the EL400 DROPros on my lathe last year. Works perfect and wasn't too big of a deal to install. There's plenty of videos on their website to watch.


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## Cheeseking (Oct 17, 2020)

Highly recommend dro pro also. Put an EL-400 on my lathe 5-6 yrs ago and its been a wonderful addition. No problems other than once in awhile the buttons fail to register when pressed. They are the mechanical type vs a membrane pad type which I prefer. At first I wasn’t sure it was worth the cost and effort to instal but now I would not want be without it. 
Installing it was a project in itself but enjoyable for a hobby shop.
The key for me going with the dropro mag scales was the small size of the scales and read heads vs others I looked at.


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## COMachinist (Oct 17, 2020)

jbobb1 said:


> I installed the EL400 DROPros on my lathe last year. Works perfect and wasn't too big of a deal to install. There's plenty of videos on their website to watch.


Did you go with the 1 or 5um cross slide encoder? The El400 is the lathe specific read out right?
CH


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## randyjaco (Oct 17, 2020)

Big fan of DROPros products


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## jbobb1 (Oct 17, 2020)

COMachinist said:


> Did you go with the 1 or 5um cross slide encoder? The El400 is the lathe specific read out right?
> CH


I did get the 1 micron scale for the cross slide. The kit comes with instructions on how to set the proper display resolution.
And the EL400 is machine specific.


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## ACHiPo (Oct 17, 2020)

Also interested in this topic.  Have also heard good things about DROPros--excellent documentation and customer service at a price a couple hundred dollars more than the AliExpress DROs (where you're on your own, but have also heard good things?)  Has anyone seen application of a DRO on the compound?  Can DROs be programmed/calibrate with trig if the compound is at 30°?


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## jbobb1 (Oct 17, 2020)

Never seen digitals on a lathe compound before. As far as your other question, my guess would you'll be breaking out the calculator.


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## addertooth (Oct 17, 2020)

jbobb1 said:


> Never seen digitals on a lathe compound before. As far as your other question, my guess would you'll be breaking out the calculator.


Only madmen have DROs on their compound.  Only the truly disturbed have them on their 7 X 16 lathes.


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## RJSakowski (Oct 17, 2020)

ACHiPo said:


> Also interested in this topic.  Have also heard good things about DROPros--excellent documentation and customer service at a price a couple hundred dollars more than the AliExpress DROs (where you're on your own, but have also heard good things?)  Has anyone seen application of a DRO on the compound?  Can DROs be programmed/calibrate with trig if the compound is at 30°?


The DRO's that I have used have a scale calibration factor.   I'm not sure why I would want a DRO for linear movement on the compound.  I expect that it would be more of a bother than useful.  There was a post a while back about reading compound angle with a DRO.  That might be of more use.


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## hwelecrepair (Oct 18, 2020)

I have only installed a handful of DRO's with stuff on the compounds.  The higher end Acu-Rite boxes can compensate for X/Z movement if you input the angle of the compound and its movement.  Again, I have ony put like 3 of those on.  To me it seems a bit pointless.

Jon


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## addertooth (Oct 18, 2020)

I work restoring antique fountain pens.  The threads that hold on the caps are "three lead threads".  With the compound set parallel with the ways, and a DRO on the Compound, it is easy to dial in the offset for the second and third lead of threads.  

You might ask "What is a three lead thread?".  As an example, you set your lead screw for 8 threads per inch, but cut to the depth for 24 threads per inch.  Then you offset your single point tool towards the chuck 1/3rd of the distance of your thread spacing.  Cut your new groove (which is offset from your first groove/thread.  Then you offset another 1/3rd towards the chuck and cut you final groove/thread.  To the naked eye, the threads look like 24 threads per inch, but in terms of rotation, it only takes 8 turns to traverse and inch. Because of the steeper angle of 8 threads per inch, most caps are secured in place with a single rotation (which is why this type of thread was so popular for the old Fountain pens).  It goes without saying that you are cutting threads without the 30 degree angle which us Americans are so fond of using, but in soft pen materials (brass, gold, ebonite, celluloid), chatter is not an issue.


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## BGHansen (Oct 18, 2020)

I have a TPACTools.com 2-axis on my Grizzly G0709.  The kit came with 5 micron scales, my install string is below.  The 5 micron scale on the cross feed only gives me resolution of 0.00039", 1 micron would be a fifth of that.  I've had no issues with my DRO after 4 years of use.  For my use, the 5 micron has been fine.  I've found when turning that the diameter of my work doesn't match the DRO after a pass anyhow.  Something a spring in the tooling and work.  I'll make a spring pass at the same setting or a shade deeper and get closer to the target.  If I'm trying to turn to better than 0.0005", I take the final readings with a micrometer.

Would I go back to TPAC tools for another?  Maybe. . .  Going to a shop like DRO Pros is like going to your local hardware store with a knowledgeable salesperson.  Very helpful if you have any questions on the installation and/or function.  That help does come at a cost.  If you are self-sufficient, you can save yourself some money by buying directly from Aliexpress or one of the other importers.

I originally bought a 4-axis DRO from TPACTools for a Jet JVM-830 mill based on a recommendation from a co-worker who bought a 2-axis unit for his Rong Fu clone from Tom at TPAC.  I bought the 2-axis for the lathe a year later based on having no issues with the one on the mill.  However, I probably paid an extra $100 or so than what I could have if it was purchased from overseas.

Bruce










						Grizzly G0709 Lathe Dro Install
					

Absolutely LOVE the 4-axis DRO on my Mill, figured it was time to put one on my Grizzly G0709 14” x 40” lathe.  Many options out there for DRO’s, I chose TPACTools.com.  I paid a little more than I could have from some of the eBay overseas vendors ($375 delivered), but went with Tom for a few...




					www.hobby-machinist.com


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## mksj (Oct 18, 2020)

Definitely want to go 1 micron on the cross slide, otherwise in diameter mode the scale jumps in 0.0004" increments and you can get more calculation errors because of rounding. I prefer the graphical color displays if you have vision problems, I need readers all the time. You can get the Easson 12B/C from the UK with 3 magnetic scales for around $800 shipped with 3 magnetic scales. You need to contact them to specify the length of the scales and also the resolution of each scale. Since the ES-12B/C has 3 inputs, many individuals use the 3rd axis on the tailstock. Yet to see anybody put a scale on the compound. Some of the higher end DRO's will calculate the X and Z travel based on the compound angle.





						Universal Lathe Digital Readouts DRO Kits - Easy Fitting - Machine DRO UK
					

Wide Range of lathe Digital Readouts DRO Packages with Magnetic Encoders




					www.machine-dro.co.uk
				






My Easson 12B, mine was shipped from QMT with the incorrect glass cross slide scale (5um instead of 1um) and the Xo diameter mode had quite a bit of accuracy issues, when switched to 1 um scale the calculation errors went away. Diameter mode the Xo terns yellow, but there are different color options. Z1 axis is the tailstock. I added the magnetic scale to the tailstock when I found they were available for the ES12B/C.


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## addertooth (Oct 18, 2020)

(Humor)
Based upon some of the responses here:
 I had no clue there were so many hobby machinists who were making bearing race assemblies for high performance jet engines. 

Have I needed 1/10th of 1000th inch accuracy on occasions when I worked in a fabrication shop on bearing assemblies?  Yes.
Small factors like carbide wear caused significant drift, so the I.D./O.D. needed to be measured by a micrometer before the final
pass when that kind of accuracy was required.  Even dimensional growth from the part being HOT from machining caused 
variances as well which had to be considered.  The part would be flooded with coolant to get it to an "operating temperature range"
before the final pass.     

Have I ever needed 5/100th of 1000th inch accuracy on any home hobby part produced? No. Not once, Not ever.  I might chase that kind
of accuracy if a Tramming Jig is made for a mill.  Then I will get to sweat the fact the collet is only good to 1/10th of 1000th of one inch.


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## JimDawson (Oct 18, 2020)

addertooth said:


> (Humor)
> Based upon some of the responses here:
> I had no clue there were so many hobby machinists who were making bearing race assemblies for high performance jet engines.
> 
> ...




I thought we all worked to +/- 1um.


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## 38super (Oct 19, 2020)

Get what ever is cheaper, you guys are arguing over gnat's assholes


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## COMachinist (Oct 24, 2020)

Hi All.
Just to let every one know so you know the out come of my OP. I decided on the DROPro’s El-400 readout and the 10” 1um mag cross slide encoder and the 40” 5 um Z axis encoder. I don’t know if anyone is interested about the install, if so I’ll pst some pix and info in the PM forum. I want to thank everyone for the help, it is appreciated.
Have fun safe Hollloween.
CH


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## kb58 (Oct 24, 2020)

To the OP, don't confuse resolution with accuracy. Resolution is the smallest quantity that can be resolved, but just adding digits doesn't mean the part being cut reflects that. Accuracy means how close to truth the display is. As others have pointed out, adding digits can give a false sense of _accuracy _where it doesn't exist. Past maybe 0.2 mil, there are other inaccuracies that render the extra _resolution _as pointless.


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## addertooth (Oct 24, 2020)

COMachinist said:


> Hi All.
> Just to let every one know so you know the out come of my OP. I decided on the DROPro’s El-400 readout and the 10” 1um mag cross slide encoder and the 40” 5 um Z axis encoder. I don’t know if anyone is interested about the install, if so I’ll pst some pix and info in the PM forum. I want to thank everyone for the help, it is appreciated.
> Have fun safe Hollloween.
> CH



People here like How-To articles.  A lot of people struggle with the placement of the sensors on lathes (and the running of the cable for the cross-feed). We like to see how you try to install it, so that you lose the minimum of travel distance. I realize you are installing on a lathe, but on a Mill, minimizing Y axis travel (due to the sensor taking up space on the column side of the table in most cases), is always a challenge. The cross-feed sensor often is installed on the tailstock side of the saddle, which can then limit how close to the tailstock you can move the carriage.   I always like seeing how various people approach these challenges.


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## COMachinist (Oct 24, 2020)

kb58 said:


> To the OP, don't confuse resolution with accuracy. Resolution is the smallest quantity that can be resolved, but just adding digits doesn't mean the part being cut reflects that. Accuracy means how close to truth the display is. As others have pointed out, adding digits can give a false sense of _accuracy _where it doesn't exist. Past maybe 0.2 mil, there are other inaccuracies that render the extra _resolution _as pointless.


Ok, Like I said I’m a retired Engineer, which means it will be close enough, to do the job. I rad this some where. If line up 10 beautiful women on one side of the room, and 5 engineers and 5 machinist on the other side. Told them they can move only 1/2 the distance at a time., all the machinist would leave. They would say you could never get there, the engineers would stay, you can get close enough to get the job done.
CH


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## 38super (Oct 24, 2020)

Watch your cable routing, don't want tension on the read head.


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## Suzuki4evr (Oct 24, 2020)

I am so glad I work with metric. For this fact for me .5um would be perfect. Just one problem. ........don't have a DRO for my lathe........yet.


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## kb58 (Oct 24, 2020)

COMachinist said:


> Ok, Like I said I’m a retired Engineer, which means it will be close enough, to do the job. I rad this some where. If line up 10 beautiful women on one side of the room, and 5 engineers and 5 machinist on the other side. Told them they can move only 1/2 the distance at a time., all the machinist would leave. They would say you could never get there, the engineers would stay, you can get close enough to get the job done.
> CH


Since you're an engineer, you know that the above example is silly. Engineers repulse women, so the distance would never change.


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## addertooth (Oct 24, 2020)

Not all, but many women want a man who is just smart enough to fix things around the house, but not smart enough to win an argument.
A really sharp Engineer does have trouble finding women attracted to him sometimes.  The pool of women who really dig brainy men is not especially large.  Think of all the billionaire tech giants, whose first wife was exceptionally plain.  Their brains and potential did not get them runway models.


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## COMachinist (Oct 24, 2020)

L


kb58 said:


> Since you're an engineer, you know that the above example is silly. Engineers repulse women, so the distance would never change.


LOL, maybe so, maybe so


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## hman (Oct 25, 2020)

kb58 said:


> To the OP, don't confuse resolution with accuracy. Resolution is the smallest quantity that can be resolved, but just adding digits doesn't mean the part being cut reflects that. Accuracy means how close to truth the display is. As others have pointed out, adding digits can give a false sense of _accuracy _where it doesn't exist. Past maybe 0.2 mil, there are other inaccuracies that render the extra _resolution _as pointless.


I have a DRO with 5 micron (0.0002") resolution scales.  The last two digits seldom come out as even multiples of 0.0002", because the scales are basically metric, not inch.  Just to avoid confusion, I taped a piece of clear red-colored film over the last two digits.  I can still see the numbers, but the red film reminds me to take them with a grain of salt.  Haven't yet done anything to test accuracy ... but there's no way it can exceed the resolution, is there?


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## 38super (Oct 25, 2020)

Hey, I resemble that alligator


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## COMachinist (Dec 23, 2020)

Merry Christmas All.
Just got a shipping number delivery 12/30/20, for a DRO Pros EL 400 1um cross slide kit for the PM12x36T ultra lathe. It is the magnetic kit, nice Christmas gift from Mom Santa. I want thank everyones input on this thread. I hate leaving a thread hanging so here it is.
Happy New Year an a prosperous and better 21.
CH


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## KevinM (Dec 23, 2020)

Once you use DROs you will never look at your dials again.  I wear trifocals and have blind spots.  I can read the DROs fine, dials not so much.


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## KevinM (Dec 23, 2020)

hman said:


> I have a DRO with 5 micron (0.0002") resolution scales.  The last two digits seldom come out as even multiples of 0.0002", because the scales are basically metric, not inch.  Just to avoid confusion, I taped a piece of clear red-colored film over the last two digits.  I can still see the numbers, but the red film reminds me to take them with a grain of salt.  Haven't yet done anything to test accuracy ... but there's no way it can exceed the resolution, is there?
> View attachment 341727


Good idea on the red film. A few times I have read the numbers wrong due to too many digits and the last 2 digits are a fantasy.


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## COMachinist (Dec 23, 2020)

KevinM said:


> Once you use DROs you will never look at your dials again.  I wear trifocals and have blind spots.  I can read the DROs fine, dials not so much.


I have age related Macular Degeneration starting to interfere with my vision. Strait lines tend to look curved, so it is really a pain to get them lined up. I have had 2 surgery’s on my right eye and it is still not much better. I need readers to see up close and reading. It‘s really hard to see those little marks on the dials. I can see the mic numbers with magnifier but it is hard to get down close to the lathe dials on the lathe with the magnifier. I figure it will help sell the lathe when I have to let it go. I have a DRO Pro’s 3 axis on the ofmill, they make it easy to use. I’m hoping this will extend my shop time by some number of years. 
thanks for the input and Merry Christmas and a Happy better NewYear.
CH


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## kiwi_007 (Dec 24, 2020)

mksj said:


> Definitely want to go 1 micron on the cross slide, otherwise in diameter mode the scale jumps in 0.0004" increments and you can get more calculation errors because of rounding. I prefer the graphical color displays if you have vision problems, I need readers all the time. You can get the Easson 12B/C from the UK with 3 magnetic scales for around $800 shipped with 3 magnetic scales. You need to contact them to specify the length of the scales and also the resolution of each scale. Since the ES-12B/C has 3 inputs, many individuals use the 3rd axis on the tailstock. Yet to see anybody put a scale on the compound. Some of the higher end DRO's will calculate the X and Z travel based on the compound angle.
> 
> 
> 
> ...



Is that a Machtach below your DRO readout?  If it is I can't recall seeing one with a led for RPM, SFM, INPUT & EXP, what are the INPUT and EXP for?  Thanks


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## mksj (Dec 25, 2020)

Installed a MachTach on my fist lathe, on my second one they were no longer available so purchased a Tachulator. Installed it in my own housing and changed it to a magnetic input instead of optical. Works well, but the MachTach was more compact and versatile, it did have a SFM LED. Input is for a second input, EXP is an error indicator when the RPM is too low to be accurate.





						tachoptions
					






					www.mkctools.com


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## hman (Dec 25, 2020)

kiwi_007 said:


> Is that a Machtach below your DRO readout?  If it is I can't recall seeing one with a led for RPM, SFM, INPUT & EXP, what are the INPUT and EXP for?  Thanks


That's a Tachulator.





						tachoptions
					






					www.mkctools.com
				











						Tachulator Tachometer & SFM Meter 2658
					

Mini Lathe Accessories 2658 Digital tachometer for lathes and mills; Displays rpm and surface feet per minute; Range to 9999 rpm, 9999 SFM; Accuracy a...




					littlemachineshop.com


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## kiwi_007 (Dec 25, 2020)

hman said:


> That's a Tachulator.
> 
> 
> 
> ...



Thanks John, looks very similar to the MachTach


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## kiwi_007 (Dec 25, 2020)

mksj said:


> Installed a MachTach on my fist lathe, on my second one they were no longer available so purchased a Tachulator. Installed it in my own housing and changed it to a magnetic input instead of optical. Works well, but the MachTach was more compact and versatile, it did have a SFM LED. Input is for a second input, EXP is an error indicator when the RPM is too low to be accurate.
> 
> 
> 
> ...


Thanks for the reply, I'm looking at going down the MachTach route


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