Tuesday, October 18, 2011

Choosing A Wood Lathe: What To Look For When Sturdy Counts

While it is obvious that wood lathes spin wood around, it is not always obvious to the first time buyer that spinning wood, if out of balance, vibrates tremendously. In addition, wood lathes may be asked to spin very heavy sections of wood and need to be able to withstand considerable force. There are a couple of simple things to look for to ensure that a lathe is sturdy enough for the work at hand.
If you have a small shop and intend to turn small objects, it may seem as if sturdiness will not be a factor, but this is simply not so. Most small lathes turn at high speeds and have a very high minimum speed. Just as on a car, an unbalanced wheel does not seem a problem at low speeds but vibrates at high ones, the same thing happens on a lathe with unbalanced wood or with unbalanced lathe parts. While a small piece on a small lathe may not try to walk across the floor, vibration encourages poor cuts and difficulty in a good finish.
Larger lathes tend to have lower minimum speeds and thus allow for less vibration in unbalanced pieces. However they also are generally bought with the purpose of handling larger pieces of wood and thus more weight. A bowl blank of forty pounds is not unusual on a lathe with a twelve to sixteen inch swing and can literally walk a light lathe across the floor of the shop.
The solution to the problem is to have a lathe sturdy enough to handle the work. It starts with a good foundation such as a stand that is well made and heavy enough to not move under the forces of turning. Sand is a good vibration absorber and many turners design their lathe stands to hold hundred of pounds of sand.
The lathe itself should have lots of cast iron and steel in its construction. Stamped metal parts tend to give little support. Good welds should be looked for. Check with your woodturning friends and find out what lathes they use for the type of turning you intend to do and then find out if they are satisfied. Good bearings are a must and even more important are the bearing housings. Bearings are easily replaced but not where they live in the lathe.
One of the best tests of sturdiness is common sense when looking at the lathe. If it looks solid it likely is. This would not be just a catalogue look but rather a chance to stand at it and see if the steel is substantial and the iron castings are solid and well finished. The mechanisms to hold the headstock, tailstock and tool rest should be strong and lock firmly. Speed controls should move easily and switches readily accessible.
The final test of the lathe will happen as you turn on it. Many turners will push the envelope of size and speed and safety is each individual's responsibility but much of it can be ensured with good planning and a little foresight.

No comments: