hello is their any type of ratio for size of bowl/spindle to rpms? such as an 8" bowl should be turned around 1000rpm after roughing?? from what i remember my lathe goes from 500 to 2850rpms. now i usually rough at the lowest speed. i bought some new sorbys and now i can get some pretty good shaving, on an 8" bowl i am working on now. now i can't exactally tell what speed i am at but i put it around 1/3 of full speed and seems ok. should i be faster or slower or is it kinda like an aquired skill? i am kinda new to turning but look to get into it a little more. also if anyone is intrested i bought some robert sorby tool on ebay that sears was getting rid of, some i got for more than half of retail. point #2 is i also just bought my first scroll chuck. i was going to go with the oneway talon but then i found a website in canada that sells the nova and supernova very cheap. i got the supernova, the #2 jaws that come with it 2 other sets of jaws(i can't remember which one) and the cole jaws for $224. from what i found on a lot of turning websites that is a good price.?
Dear woodturner regarding the speed setup.for that size bowl around 800rpm then when you have the final shape increase up to 1100 at the most ED
There's a quick formula... dia x rpm ...this should ideally be between 6 and 9 max. Your 8" bowl @ 1k rpm = 8 ...well within the safe range.
Lathe speed is a faq by people on my course... I always advise turning at a speed YOU are happy with ...within the limits of safety...if the lathe's leaping about it's probably a might too fast :wink:
me? I'm a speed freak... (it's not unknown fro miniaturists to turn at 15 to 20k
Update 29 Aug 03 :oops: I've amended the formula... should'nt have put the 'k' in figures other than the rpm!
You of course must keep the speed down to keep the lathe from rocking, but when the piece is round and balanced you can speed up. For me, there is a 'magic' speed where the tool will ride and cut with little effort. This is difficult to explain but the combination of tool weight, angle and sharpness, along with rotational speed will induce harmonics into the bowl. I look for the fastest and safest speed that minimizes this effect. This means that two 8" bowls may cut well at very different speeds. Good luck! 8)
I agree with Oldsoke: the right speed is the speed YOU are comfortable with. The less experienced a turner is, the slower you should go.(to a point...) Until you have good tool technique and have some ideas of how different wood will react to the tool, go slower. The size of the bowl and the speed of the lathe is just a rule of thumb.
Regarding the chuck: I had the same dilemma. I purchased it from the same place you did (I'm guessing) and I'm quite happy with my chuck. I think the Talon is a better chuck (better quality) but it was quite a bit more expensive and the difference in quality wasn't enough to warrant it.
One thing I have noticed: the jaws they include are a little limiting: I have wanted to turn a little more larger stuff and this jaw doesn't accomodate it. I am planning to buy the powergrip jaws set to give me the larger size. Good job with your purchase, though. I doubt you could have gotten it any cheaper.