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12-10-2009, 10:29 AM #1
How can you clean a DRO optical Scale?
I have a AcuRite DRO with optical scales. I found some chips clinging to the rubber wipers and somehow some crud found itself inside the Y axis linear scale. I was able to disassemble the scale and clean off the crud on all the non critical parts.
My question is, what do you use to clean off the optical glass encoder and the encoder reader ? There seems to be a film of oil on both the glass and encoder reader. I was thinking of wrapping some lens cleaning tissue around a Q-tip and wiping it down with either Isopropyl Alcohol or Windex. Are these glass encoders so delicate that you need a special cleaning agent ?
Thanks for any advice.
12-10-2009, 11:05 AM #2
My day job is as a spectroscopist. We clean all optics with dry methanol or acetone if there is a really stubborn spot. Don't use windex!
12-10-2009, 11:09 AM #3
Contact AcuRite. Your method appears to be delicate enough but just check
with them, they probably have dealt with this issue many times.
12-10-2009, 09:08 PM #4
When I took the scale apart, I noticed that the casting that the glass reader is mounted on is broken. It looks like it is made of pot metal. I can't weld it, so I contacted a local AcuRite dealer and they told me that they nor Acurite will repair the scales and they can't sell me the replacement parts. I would have to replace the whole scale. Bummer, I told them. When I had this problem in the past with my Sargon DRO, I was able to have them repair the scale while I took my lunch break and it was finished in a couple hours. They told me Sargon went out of business in 2005. Double bummer !!
BTW, I mickey moused the scale back together and luckily I got it to work. I used a kimwipe wrapped up around a Q-tip and used lens cleaning liquid to clean the glass and reader. Not a 100% fix, but it works like a charm.
12-10-2009, 10:02 PM #5
12-10-2009, 10:58 PM #6
I have an old Dynamics Research optical on my Lagun that I cleaned with alcohol and an lint free wipe.
You want to test the end first, I understand some opticals are not etched, just printed and could be dissolved with acetone or alcohol.
12-11-2009, 09:57 AM #7
12-11-2009, 11:56 AM #8
12-11-2009, 12:17 PM #9
If the casting is pot metal, you might have success with using a brazing rod known as "3-in-1", made by Aladdin Products.
I've used it on aluminum castings, and it works very well.
12-11-2009, 01:38 PM #10
I thought that Accurite used an extrusion, not a casting?
12-12-2009, 05:08 PM #11
A_Pmech: Regarding Windex for cleaning -- there is a detergent component that can remain behind as a deposit (the smearing and streaking you see on that window when you are through cleaning it is the dirt, though, mostly...). You can generally get rid of the stuff with enough pressure and wiping, but for delicate optical surfaces, it's not best practice. Clean high-grade solvents are the preferred approach.
12-12-2009, 06:16 PM #12
While we're on the subject of cleaning scales, does anybody have a source for the rubber seals which go around the Accu-Rite scale to keep dirt and chips from flying up into the scale? It appears to be some kind of a stock per-foot product in several different sizes. I could use some as the stuff on my scales is hard, brittle, and cracking off in chunks.
Ahh, I figured it was some kind a deposit.
12-12-2009, 07:20 PM #13
While out on a service call for Ingersoll years ago, I had a heidenhain glass scale get smeared with something. I called Heidenhain in Elk Grove, Il for help.
They recomended windex and just cautioned me to not leave a film of it to dry on the scale.
Accurites have a plastic coating with the grid lines on them, i have been warned by accurite to not use any solvents that might make that film come loose.
Accurite should be able to supply replacement lip seals.
12-13-2009, 01:15 AM #14
Hi Minder, yes you are correct, the glass scale is glued to an aluminum extrusion with some sort of white epoxy. What I was referring to was the part that slides along the glass scale that holds the little circuit board that reads the glass. It is powder coated potmetal and the delicate tiny part was broken due to over-travel of the Y-axis. Whoever installed the scale on the mill for the previous owner did not do a good job and it was broken when I bought it.
Thanks Gregg for the info on the brazing rod. I got to try this sometimes. I often have cast aluminum parts break. I got another project to fill in the bottom of an outdrive on a boat that got scraped the concrete. I think I'll try it on this project. I consider myself a good micky mouser with JB weld and Devcon Aluminum putty. I have fixed many things this way. I glue the parts together and then shape the putty before it hardens with a wet finger.
About the windex. The Greeks taught me that it could be used for almost anything. I use it on insect bites, slight burns and I was even surprised how well it works for cleaning glass. However, it does a mediocre job as a degreaser, and the oil on the scale was most likely vactra way oil, so I used the lens cleaning liquid instead.
Thanks to all for the valuable information. It was very helpful.
12-13-2009, 08:55 AM #15
Acu-Rite sells replacement lip seal gaskets. Just give them a call, tell them what scales you have, and they'll sell you a roll of the lip seal gasket to fit. It doesn't cost much and you'll get enough to redo a couple of scales.
If you need parts, start your quest for them by checking with the manufacturer.
12-13-2009, 08:58 AM #16
09-06-2011, 03:35 PM #17
Anybody know of anything like say silicon for example that can be rubbed on teh wipers to keep them from cracking from the heat?
10-01-2011, 11:41 AM #18
Madmachinst asked, does "Anybody know of anything like say silicon for example that can be rubbed on the wipers to keep them from cracking . . ."?
I believe I do. But it is NOT at all like silicone. The product name is "Re-Seal" which is sold by a product supplier that mainly sells their products to transmission rebuilding shops. Search for ATP205 or ATP 205 Re-Seal or Reseal, or ATP207 or ATP 207. Sometimes vendors include the hyphen and a space, sometimes they list it all run together. It is available in containers all the way from 5-gallon plastic bucket down to an 8-ounce bottle and even in an aerosol spray can. Figure on about $1 per ounce in smaller containers, but a little will last you for a long time if used prudently on hardening synthetic rubber parts. It seems to work MUCH better than all competing "transmission stop leak" type products. I've added some to old floor jacks for which replacement seals were not available and had more than 50% of them restored to functionality! Windshield wiper blades, before they become brittle and crack have been restored to good soft sealing performance. Apply with a Q-tip or generic equivalent, leave it to soften the part for a day, then gently try to deform that part to determine if it has become elastic again. I started out being skeptical about this stuff. But when I saw repeated good results, I finally broke down and bought a 5-gallon bucket delivered from an on-line vendor for about $300 which has more than paid for itself, yet that bucket is still mostly full. Lexus engine with quarter million miles developed a main seal leak but other than that, still runs about like new. Diesel truck main seal was leaving black spots, same story. Tractor hydraulic seals leaking no more. Six-foot cutting diesel mower hydraulics were leaving spots where it was parked, but no more. Crazy stuff. Clear. Does not make parts gummy as some "Stop Leak" products absolutely do. I don't smell it but I like what it does. If my mill's DRO synthetic rubber seals have lost their elasticity, there is no doubt that I will apply it and expect 90% probable favorable results. I have no affiliation with the product maker. I wish I'd known about it years earlier.
10-06-2011, 11:22 PM #19
Man... I'm going to have to try this re-seal stuff.. I have an older surface grinder with crunchy aprons that were pliable once. I tried soaking them with WD-40 with no results so I have just learned to deal with them. I'll make a few calls to transmission shops in the morning. The rubber covered cloth pieces are not falling apart but have taken the shape of the area they lay on so when the table goes in or out the impression is still there. It's very annoying ..
10-07-2011, 01:43 PM #20
To clean the scale you want de-natured alchohol and a lint free wipe (like a kimwipe). Use something wood (toothpick / popsicle stick...) so as not to scratch the glass. Make sure you wipe the reticle (little glass window) on the readerhead as well. Don't use Windex (it will leave a film)
If the scale is really contaminated you can remove the sealing lips and end caps and take a high pressure water spray to it (I have seen guys clean heidenhain scales at a car wash with a pressure washer). Finish with the alchohol and wipes.
You can buy replacement readerheads from Acurite or their dealer. You should not have to replace the scale (depending on vintage)
The lubricant you want to use is called molycote 111. It is actually a food grade lubricant made by Dow