Replies

1. 
   fingers | Jun 03, 2009 07:27pm | #1

   I would think any kind of grease would suffice.  Crisco?  Bacon fat?

2. 
   john7g | Jun 03, 2009 07:28pm | #2

   A tub of wheel bearing grease ought to work well.  It's thick enough to use as rust preventative in between uses as well. 

3. 
   junkhound | Jun 03, 2009 10:18pm | #3

   If you are never going to turn the jack under load (we all wish), anything will work.

   Under load, use a high pressure grease, or even better, 120 wt hypoid gear oil (car rear end oil)

1. 
   davidmeiland | Jun 03, 2009 10:44pm | #4

   They are definitely used under a lot of load. Currently using a bunch of them to deform a house that has settled. Probably need to exert more force doing that than if I just lifted the house entirely.

   Sounds like I oughta stop by Napa and see if they have 120wt hypoid gear oil.

   Next question, I guess, is there any smart way to clean the female threads on these things? Small wire brush and paint thinner?

1. 
   junkhound | Jun 04, 2009 12:38am | #6

    clean the female threads

   Since they are big (2"), I'd try a pressure washer with angle nozzle.

   Beleive it or not, I do not have any big screw jacks.  Pop had a bunch, too heavy to ship out here after he died, so brother has them.  Pop had some mil surplus EP grease (extra pressure) that the railroad called out for use on screw jacks.

   Kinda got spoiled with hydraulic jacks.

   Recall the MD80 (think it was) that crashed off LAX due to horiz stabilizer jack screw being improperly lubricated?  If you are turning your jacks under heavy load some type of high pressure lube is needed, and hypoid gear oil is about the highest pressure stuff there is IIRC.

    

1. 
   davidmeiland | Jun 04, 2009 01:17am | #7

   I have and sometimes use hydraulic jacks but in this case, where the jacks are in place for a long period, screws are easier. They can sit on the piers right next to the (now too short) posts and I can raise them a little each week. It would be awkward to lug a large hydraulic around under the house to each location. Noticed some big Simplex ratchet jacks on eBay, they look very cool but weigh so much that shipping is ridiculous.

1. 
   Piffin | Jun 04, 2009 01:23am | #8

   I have both hydraulic and screw jacks. The screws are better to leave a load on. Anytime we go home for the night or weekend, we block up next to any loaded hydraulics. They can blow of bleed down.Always used 90 weight for the screws,mostly because I have it handy and it is easy to use, but wheel bearing grease is probably the more right thing for them 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

2. 
   dovetail97128 | Jun 04, 2009 02:18am | #11

   Cleaning the female threads: For a solvent I use 10w-30 thinned with kero.
   Male end of a battery post brush for getting into the threads, or one of the wire brushes used to clean out drilled holes in concrete.

   Edited 6/3/2009 7:19 pm by dovetail97128

4. 
   spike999250 | Jun 03, 2009 11:25pm | #5

   Kerosene or heating oil. Thats what my grandpop told me to use on the ones i got off off him.  It lubes em and cleans em.  Grease tends to collect too much dirt for my taste, especially when dragging around under houses.

5. 
   WayneL5 | Jun 04, 2009 02:00am | #9

   A grease containing molybdenum disulfide.  The MoS₂ is an additive for very high pressure, low speed sliding surfaces, which is what you have with a jack screw.  "Regular" grease is better for bearings with rolling elements such as ball bearings or roller bearings.

   As far as the female threads, I presume you can dismantle the jack.  Yes, a small wire brush or even a toothbrush with a suitable solvent.  I like electrical contact cleaner myself, but thinner should work fine.

   
   

   ---

   Edited 6/3/2009 7:07 pm ET by WayneL5

6. 
   Dan612 | Jun 04, 2009 02:12am | #10

   I second the reply of using kero or diesel.  A little messy, but it makes them turn really easily.  I have found that heavier grease in cold weather makes the screws a bear to turn.  I have also used Wd-40, but you have to keep re-applying it during the job.

   As for cleaning the threads, I scrape as much junk off with a metal scraper, then I use any degreaser solvent that I can find.  I then add a light layer of grease and use the spraying of wd-40 to thin it out.  Basicly, a little of this and a little of that.

   I meditate, I burn candles, I drink green tea, and still I want to smack someone.

7. 
   mike4244 | Jun 04, 2009 02:24am | #12

   Any weight motor oil slopped on with a brush.

   mike