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View Full Version : Loosening stiff Thompson Slides? Source for rail?



BadDog
05-06-2010, 10:23 PM
For one of my projects, I recently picked up a couple of Thompson Slides profile ball slides (CG25AAAN-D236). They are supposed to be used, but appear (near?) new. They seem to work fine, but they are surprisingly stiff. They have what appears to be a very thick and sticky grease. I thought perhaps they are new and this is a cosmoline type stuff. It's not really as waxy as cosmoline, but perhaps just a different brand. Or, do these use a heavy/thick/tacky grease?

Regardless of what it is, the resulting movement, while nice and smooth, is a bit too stiff for my intended application. So how are these best cleaned and re-lubed, perhaps with some NLGI-2 Synthetic I've got on hand? I removed one truck, and it appears that reassembly without the heavy grease to hold the balls may be problematic. Maybe that's the intent, and I should wash out the (perhaps?) assembly grease with some sort of solvent while assembled? I've used petroleum jelly in similar cases in the past, but not when switching to synthetic.

Sorry if this is newbie ignorance, but I know a lot of you have experience with these things, so thought I would see what you have to say. Depending on what turns up here, I may call Thompson Tech Supt tomorrow (didn't see anything addressing this on their site).

I also made a miscalculation on rail length (I need longer - 24"+). Any suggested sources to buy rail by the inch/foot/whatever?

wierdscience
05-06-2010, 10:26 PM
This any help?

http://www.automation-overstock.com/categories.asp?cat=14

Ken_Shea
05-06-2010, 11:15 PM
Russ,
Some noticeable resistance is normal with those when un-loaded, try pressing on then while moving and see if that makes the difference.

Ken

macona
05-07-2010, 01:46 AM
Never take the trucks off unless they are self retaining or you have a keeper. You are going to have to take one of the ends off and repack the balls. No fun there...

Stiff is good as long as it move smooth. There are specific greases for linear guides.

BadDog
05-07-2010, 02:10 AM
Thanks guys.

weirdscience:
Looks like mostly priced well beyond my interests, and seems to be all as "sets". But given the add-on price for the rail of the length I need (even if I eat the truck), looks like I may be haunting ebay.

Ken:
I'll give the pressure a try next time I get out there, hopefully tomorrow.

macona:
Well, I guess I got lucky. I had it off and back on twice. But the "lubricant"(?) is so thick and sticky, the balls stayed in place. This stuff is somewhat like tar, really sticky and thick, so while 2 tried to pop out on the first reinstall, the balls generally stayed put just fine.

Anyway, sounds like maybe nothing is wrong, and (yet again) I simply don't know what I'm doing... :D

BadDog
05-07-2010, 04:01 PM
Just an update in case someone finds this in years to come...

I called Thompson Tech. Their routing software informed me that they are now owned by Danaheir(sp?). <sigh> But I asked the tech about outsourcing and country of origin/production. I was informed that for the moment they are manufactured in Germany, though we all know that this could change, particularly with the current economy.

Anyway, turns out these are likely NOS and probably have the OEM grease in them. It was a heavy/sticky grease, and based on age, likely further dried out over time. It also has both the "permanent lube block" and "scraper" options. He sent me an old catalog with relevant (though limited) information. That catalog indicates that the optional lube blocks double the sliding resistance. Couple that with dried out over-tacky grease and you have my "too stiff" problem.

He suggested flushing it with mineral spirits and replacing with modern light grease. I also suggested, and he agreed, that it might work fine with just adding some very light oil to act as a solvent/softener for the dry grease, which would then leave the grease in place as a sort of reservoir. This application won't have fast cycle speeds or frequency, so as long as it's not overly stiff, it should work fine and pretty much last "forever", particularly with the lube blocks (which are apparently like a plastic oil-lite type stuff).

Also, he had no dire warnings about disassembly other than being ham fisted and trying to force it in a bind, or loosing balls and difficulty of keeping the balls in place on reassembly.

macona
05-07-2010, 04:34 PM
Yep, Danaher is buying up companies everywhere. They bought Tektronix down the road and production is being moved to china.

clutch
05-07-2010, 07:38 PM
Thompson rail, brings back old memories. I bought a couple of their linear rail systems two decades ago. I mounted them crossed and drove them with some motors controlled by a Galil 720 motion control.

Learned what critical speed on a ball screw meant. Learned that right after production demanded that I try to improve cycle time over what I designed around. Think steel jump rope. If you want to run a screw fast, spin the nut.

Things I have learned.

Clutch