I'm not an engineering person, but I know that the common recommendation for the nylon gears in motorcycle instrument assemblies is either white lithium grease, silicon grease (plumbers grease from home depot) and graphite (those little tubes you use for lubing locks). Been using them for years and none have ever harmed the nylon/plastic.
FWIW, and not so applicable here, but loctite will turn plastic as brittle as a potato chip. Steve From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Guy Giacopuzzi Sent: Saturday, July 26, 2008 12:10 PM To: [email protected] Subject: [drakelist] Re: Lubricants and plastics... I wish we had a engineering materials person who could comment on this....but I do have one experience I think should be shared....in addition to restoring Heathkits, Collins and Drake radios, I occasionally work on my 1976 911S Porsche....one of the bugaboos is the pedal assembly....it has nylon bushings...and ...it's right on top of the master brake cylinder....and...if the master cylinder leaks just a little bit, brake fluid gets into the bushings and guess what happens...they swell, making your brake and clutch pedals drag...the solution is to remove the bushings and replace them with bronze ones...so that begs the question....which plastics react with which lubricants? I don't know that answer. I've heard, from my auto parts friends, that white lithium grease is quite inert, and has a big enough molecule, that it doesn't react with any known plastic....but what about oils, heavy and light? Any materials specialists out there? Regarding the comment about nylon being "self lubricating", it really isn't...it just has a low friction coefficient...as does teflon. But these pieces do wear, and they are, for all intents and purposes, NLA....so we should be doing everything in our power to make them last longer, without hurting them. Guy, WA6OQQ Don wrote: "Don" <mailto:[EMAIL PROTECTED]> <[EMAIL PROTECTED]> made an utterance to the drakelist gang ---------------------------------------------------------------------- http://www.eurekafluidfilm.com/globals/faq.html It's been around for sometime, and really does work as well as their website claims. doesn't breakdown plastics, doesn't gum -up, doesn't dry out, repels moisture, ect,ect. I can vouch for it. It does however have a bit of an odor when first applied. just a happy customer. Don ad7ll ----- Original Message ----- From: "Darrell Bellerive" <mailto:[EMAIL PROTECTED]> <[EMAIL PROTECTED]> To: <mailto:[email protected]> <[email protected]> Cc: <mailto:[EMAIL PROTECTED]> <[EMAIL PROTECTED]> Sent: Friday, July 25, 2008 10:46 PM Subject: [drakelist] Re: VA7TO 2-B: Lubricants? Darrell Bellerive <mailto:[EMAIL PROTECTED]> <[EMAIL PROTECTED]> made an utterance to the drakelist gang ---------------------------------------------------------------------- There have been some interesting responses to my question about lubrication. Thanks to all who have replied. Here's what I've learned so far. 1) Be cautious about lubricating plastic or nylon parts as petroleum based lubricants can damage the plastic or nylon. Some forms of Nylon are self lubricating and do not need lubricant. 2) Don't mix lubricants unless you know they are compatible. If you can't remove all the old lubricant, use what was already there. And not all white lithium greases have the same base. Some use a petroleum base, while others use a silicone base. 3) Choose a lubricant that corresponds to the load. For example, grease for automobile wheel bearings is not suitable for use in capacitor ball bearings as it is too coarse. So this has got me rethinking the lube job. I see no evidence of any previous lube on the two plastic or nylon wheels in the dial pointer mechanism. I'm not sure what the wheels are actually made of. So probably best not to lube them. The ball bearings in the variable caps look fairly clean. Question now is what did the capacitor manufacturer(s) originally use to lube them? I do not wish to even think about removing the variable capacitors or the passband tuning unit. While these controls do move fairly well, they are not smooth through their entire rotation, exhibiting stiffer and easier rotation at places. While I should be able to lube the ball bearings in the variable capacitors with grease and a toothpick, the shaft sleeves are more difficult. Perhaps rather than do more damage with some lube spray I should just live with them as they are. I don't see any other way to lube the shafts of the preselector capacitor and the passband tuning unit other than spraying into the knob end of the sleeves. Perhaps a bit of new grease in the preselector capacitor ball bearings will be enough without worrying about lubing the shaft. The main tuning knob shaft is easy to clean and relube. Probably a good candidate for white lithium grease. Also I don't see any evidence of grease along the metal where the dial pointer slides. In cleaning up this panel, I am removing what I suspect is residue from cigarette or tobacco smoke. Perhaps just getting rid of that gummy substance will be enough for the dial pointer without any lube. And that combined with a bit of new grease on the capacitor ball bearings and the main tuning knob shaft may be good enough. Not sure if the bandswitch bearing and detent at the rear of the 2-B was lubed at the factory or not. I will open it and see. The bandswitch actually moves quite well. Also the pots that are only set during alignment will be left alone, except if they indicate a problem during the realignment. Only then will they get a shot of Deoxit. I have new pots for the AF and RF gain controls. The bandswitch contacts will still be cleaned up with deoxit and a foam swap. Please keep those emails coming as I am learning a great deal. 73, Darrell VA7TO On Thursday 24 July 2008 20:12, Darrell Bellerive wrote: What lubricants do you use for the ball bearings, sleeve bearings, and other moving parts. I see in the archives that lithium grease is popular and Tri-Flow teflon Superior Lubricant has been used. I would like to lube the following parts: 1) Preselector shaft and ball bearings. I am a bit scared of this one as it incorporates a reduction drive and I am afraid that changing the friction may affect the reduction drive. 2) Main tuning capacitor ball bearings. 3) The two plastic wheels at the top of the dial string pointer mechanism. 4) The dial pointer. 5) The main tuning shaft. I will also experiment with slightly thicker washers to see if I can eliminate the fore and aft play. Perhaps a felt washer may do the trick. 6) The detent at the rear of the bandswitch. 7) The passband tuning control shafts. This one looks difficult. I will clean the bandswitch contacts with a foam swab and deoxit, and spray the pots and slide switches with deoxit. I will make note of the position of the pots before spraying them and return them to their original position. I do plan on doing an alignment and fine tuning them then. Anyone successful at cleaning the bandwidth rotary switch contacts? They appear to be completely hidden. Any tips, tricks, suggestions, or cautions on the above? For those of you getting tired of my many posts, this is the end of my weekend as I get Wednesday and Thursday off, so there won't be as many posts for the next 5 days. :-) Thanks to everyone who has offered advice and encouragement. It is much appreciated. 73, Darrell VA7TO No virus found in this incoming message. Checked by AVG - http://www.avg.com Version: 8.0.138 / Virus Database: 270.5.6/1574 - Release Date: 7/25/2008 4:27 PM
