Greg Young Morris wrote:
> Why not try paraffin or bees' wax? Probably less likely to pick up dirt and
> dust, and it works well enough on the bottoms of wooden planes to reduce
> friction...

and Travis (Gye Greene)wrote: 

>> For handscrews (and wooden vices), what would you think about a
>> non-drying oil such as mineral oil?  (The author says "...or any other
>> type of oil."  Seems like a non-drying oil would be OK.  Unless the
>> concern is that it would soften the wood(??).


I somehow missed this developing thread. 

    On no account rub beeswax or paraffin wax on wooden threads. I've several
times had to repair bookbinders' presses where this was done in an attempt to
ease a slightly stiff screw. Instead, it froze things up completely, between the
extra bulk of the wax and the fact that beeswax is is sticky wax, not a slippery
wax. And if you don't have the original screw box its time consuming and boring
to correct the problem, with a danger of completely destroying the screw if you
aren't careful.

    If you have a surface that is already very smooth, like a plane bottom, a
very, very thin layer of wax can act as lubricant, but with a rough surface like
a wooden screw thread it will gum things up. And a soft wax will indeed pick up
dirt and dust, though maybe a hard one like carnauba wouldn't.

    I doubt whether a squirt of thin oil would do any good whatever as a
lubricant; I think it would just soak in. Possibly, if you absolutely must have
lubricant, a thick grease would work. I think a better bet would be graphite.
However, in general I don't approve of lubricant on wooden screws at all: if
there is enough play in the fit it shouldn't be necessary, and if there is not
enough play it shouldn't be necessary.


    I do soak new wooden screws in BLO, submerge them for a couple of hours for
good penetration, to strengthen and consolidate the threads. But that's for
strength, not lubrication, and I'm careful to blot off every bit of oil that I
can (I do this by wrapping the screw in a paper towel, then wrapping a piece of
string tightly around the paper towel in the low parts of the thread, pulling
the towel down into tight contact with the wood; leave that a few more hours,
maybe repeat). You have to be a bit careful for the first day or two after
soaking, because the wet oil leaves the threads even more fragile and tender
than they were before soaking. The tender stage passes pretty quickly, though,
and when it over the dried oil ***seems*** to leave the threads a bit tougher
and stronger. I've got no measurements or numbers or hard evidence that this
toughening actually occurs, just a touchy-feely observation that it seems to.
The linseed oil does nothing for
 lubrication, though, and if you leave any on the surface after soaking it will
definitely gum things up.

Tom Conroy
Berkeley


Tom Conroy