On Tuesday 14 July 2015 10:49:08 Kirk Wallace wrote: > On 07/14/2015 04:02 AM, Gene Heskett wrote: > > ... snip > > > Interesting Kirk. Does that roller actually roll? > > On the good units the roller rolls well. The pins and the center > section are round and smooth. The bad roller has gone from round to a > gear thoothed shape all the way around. The "tooth" pitch mismatch > causes a double detent which allows the MPG wheel to stop in an > unstable, signal wise, position between marks so can be a bit > annoying. When adjusted, the good units seek and center the marks > well. All the MPGs had a generous application of a messy black grease. > I'm guessing it's some type of molybdenum grease.
I am in concurrence on that, and I would probably dip into a small jar of barrel treatment grease for its replacement. Do you need some? > > If all that wear is on just the side we can see, it apparently > > wasn't rolling. Critical lubricant needed on the axle pins? I > > don't see any plain evidence of wear either on the pins or the > > socket where it lives. IMO there should be at least a polished > > mark/area on the axle & holder. > > > > OTOH, if its worn like a 3 or 4 tooth gear, I'd wonder if the > > passing teeth on the detent disk were a perfect mathematical fit, > > meaning 1 full turn of the roller, for either 3 or 4 teeth passing > > on the detent wheel. When making a new roller, I'd try to have its > > diameter 3.5 linear teeth or 4.5, so the wear would be more evenly > > distributed in the future. Having an even fit, it would not take a > > lot of wear to assure it remained sync locked. > > > > In any event, thats a huge amount of wear. Not a normal looking wear > > pattern at all. > > Two MPGs are dated 1982 and the bad one 1985 so I suppose they have a > right to be worn. The plan is to use some drill rod to reproduce some > new pins and leave them unhardened. That way the cheap part, the > roller, will wear out, and not the detent disk or roller carrier. The > center section is 3mm dia. and the pins 1.8mm. If it doesn't work out, > I know a guy that can make more ( :) ). Oh, who might that be except for yourself? Does he work cheap enough? <VBSEG> Can you get drill rod that size? And how wide is the roller section? I'd almost be tempted to see about making it out of soft A2 tool steel too but brass might be less wear on the disk. If A2. OD polished to a mirror so it would not chew up the disk too fast. A stick of "DICO Stainless" on the buffing wheel should do that. That could be fun making another of those. Quite similar to the encoder wheel I have under construction & should be done or close to it when I next get to the shop. Right now I'm inside where its air conditioned because its 86F and at least 98% humidity under the umbrella on the shops front deck. No precip yet, but heavy stuff forecast after 17:00 local. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Don't Limit Your Business. Reach for the Cloud. GigeNET's Cloud Solutions provide you with the tools and support that you need to offload your IT needs and focus on growing your business. Configured For All Businesses. Start Your Cloud Today. https://www.gigenetcloud.com/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
