I grabbed a bowl blank tonight from my stack and decided to rough turn it.....let it dry then finish turn in a few weeks or months. Anyhow, I did what I always do, and the weird thing is that the darn lathe shook the entire time. Don't mean this to be a thread about sandbags and weighing down my lathe, rather, I turned the top and bottom, as well as the side, and it still shook. I have never had this happen before. It almost seemed like the blank sat on it's side (which it didn't) and the weight of the moisture went to one side which caused the wobble or shake. Anyone have this happen and have an explanation? I posted this in the newbie forum to protect me just in case this happens a lot. LOL
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Very Odd thing happened tonight
- Thread starter Scott Brandstetter
- Start date
Dont know how common it îs, but I swear it happens to me too. Everything looks and feels right but I still get some vibrations. I am a noob so hopefully some others will chime in as well.
It is possible that the moisture did go to the down side of the round/log or etc. depending on how long it sat. Some say roll your logs so this won't happen but I find that is way to much of a pain to attempt, course I have about fifty logs in the field. It could also be that on a previous turning session you knocked your lathe out of level or your lathe slid to a new spot on the concrete which left one foot not touching the concrete. I know there is a lot of talk to not bolt your lathe to the floor and for some who don't turn bigger stuff that is fine. If you are turning bigger stuff or out of balance stuff I would highly recommend bolting the lathe to the floor. The only thing worse than bolting your lathe to the floor is not bolting it and having it bounce (some call it dancing) and twisting around your shop which is constantly knocking it out of level, this is very hard on equipment. If you bolt your lathe to the floor find some hard rubber (only needs to be 1/8" to 1/4" thick) to put under each foot.
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This can happen if the weight is unequally distributed in the wood.
If the bowl is Punky on one side or the grain is way off center and a wide sap ring dominates one side of the bowl Or if a log has been on the ground a long time the top half may be dry while the ground contact side I has high moisture content. some large limbs have different density on the top and bottom.
These are usually more evident in natural edge work where the differences are magnified.
Also if the chuck is not fully seated it can cause vibration or the lathe is not leveled.
If you have a variable speed lathe there is usually a speed where the vibration is minimal. Often you might get vibration a lot of at 500 RPM and a minimal vibration at 650 I don't have any speed readout on my lathe I just work with the vibration and the cut feed rate to adjust speed.
If the bowl is Punky on one side or the grain is way off center and a wide sap ring dominates one side of the bowl Or if a log has been on the ground a long time the top half may be dry while the ground contact side I has high moisture content. some large limbs have different density on the top and bottom.
These are usually more evident in natural edge work where the differences are magnified.
Also if the chuck is not fully seated it can cause vibration or the lathe is not leveled.
If you have a variable speed lathe there is usually a speed where the vibration is minimal. Often you might get vibration a lot of at 500 RPM and a minimal vibration at 650 I don't have any speed readout on my lathe I just work with the vibration and the cut feed rate to adjust speed.
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I experience this occasionally on store-bought blanks. On wood that I harvest myself, I generally don't go to the trouble of making it nice and neatly round or square -- just chainsawed into manageable size. Then I balance it on the lathe between centers.
I think that Al gave most of the reasons that cause the mass center and the geometric centers to not be close to the same point. Just keep in mind that wood, unlike metal, is not homogeneous. If the blank has been drying for a while and has both sapwood and heartwood, the sapwood generally dries faster.
I think that Al gave most of the reasons that cause the mass center and the geometric centers to not be close to the same point. Just keep in mind that wood, unlike metal, is not homogeneous. If the blank has been drying for a while and has both sapwood and heartwood, the sapwood generally dries faster.
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