FAQ: Wood loosening in my chuck.
The piece of wood I'm turning keeps coming loose in my chuck jaws. Why would
that be? What would cause this?
A. There are various and many reasons for this to happen. Here are a few reasons
why this may be happening.
- Poor turning practice causing vibration when scraping, or catches when
the tool is not presented to the wood with the bevel rubbing or cutting
against the grain.
Remedy: Improve your turning technique.
- The wood being on the chuck so long (overnight for instance)
that shrinkage occurs causing the chuck to loose its grip.
Remedy: Occasionally check for tightness and re-tighten.
- Dull tools used with excessive pressure may cause loosening.
Remedy: Sharpen your tools more often.
Do you know that a turning tool in some woods can loose its edge in
- Chuck jaws do not hold the wood properly because of improper design
for the type of turning being performed.
Remedy: For light finishing cuts on small bowls, smooth
jaws may work. For heavy cuts on large bowls, serrated jaws of adequate
size are a must.
- I have none of the above problems, yet my chuck keeps loosening off,
I even insert my tail stock for extra support. Would a chuck with action
adjustment or a set screw on the scroll help me? I am desperate and
will try anything.
Cause: The standard scroll chuck design has been used
in machine shops for over a 100 years, it will not loosen under normal
Your problem is most likely misalignment between your head
stock and tail stock spindle.
Any misalignment beyond the elasticity in your wood will guarantee
that your project part comes loose from your chuck.
Remedy: If you must use your tail stock because of weight
or safety concern, then correction of alignment is the only solution.
- My serrated and even my smooth jaws are leaving marks on my finished
work. How can I avoid this damage?
You can’t. Let's be realistic; holding
wood in a chuck, no matter how careful you are, will cause damage.
Remedy: Find a way to finish the foot of your bowls, by holding with
a system that causes no damage.
a) For lowest cost, make a jam chuck from scrap wood.
b) Use wooden jaws mounted on your scroll chuck and turned to exact
c) Flat jaws with rubber mounting buttons will work on many projects.
d) A vacuum chuck could solve your problems.
e) If you insist on using the jaws of your chuck as they are, then
you must turn your object chucking area to exact profile shape and
design dia., and if you do, then most often you will sacrifice proper object
to foot relation. Your object foot may be too short, too tall, too small
or too large to look just right.