Roughing green bowls - advice please...

[Chris Colman]

I am just beginning to work with green wood, roughing bigger bowls and filling racks in my garage with roughed out blanks.

My largest bowls so far have been 12 inch diameter, because that is the maximum I can turn over the bed. The head does swivel, so I can turn bigger stuff, but I have not done so yet.

My problem is that the lowest speed my lathe will turn is about 600 rpm. (Grizzly with a reeves drive) At that speed, with a 12 inch blank that is even slightly out of balance, the lathe really wants to bounce around until I can get the blank rounded out. :eek: Surface speed on the outside diameter is kinda scary too, when the gouge is biting only intermittently at first.

You veteran turners let me know what you think. Am I just a chicken, or are we getting into the danger zone here, over 12 inch diameter at 600 rpm on rough hewn blanks. Unfortunately I have no plans or finances to get a nice variable speed lathe in the near future, so that option is out. Do I need to stay with the smaller stuff, or is there a way to slow a reeves drive down?

Your advice is greatly appreciated.

[David DeCristoforo]

I'm with you...

http://www.daviddecristoforo.com/Misc/chicken.gif

When that puppy starts bucking around like that, it makes me think that maybe this was not such a great idea after all... It's probably a hilarious sight... me chasing my lathe around with a sharp chisel in my hand1

[Art Kelly]

Use a short power cord so the lathe can't leave the property...:D

Oh yeah, and keep the work between centers at all costs. Check the integrity of the drive and tail centers often. Wear PPE.

$0.02
Still shakin'
Art

[David E Keller]

Sounds like things are a little sketchy... The best advice is probably to avoid anything that seems unsafe.

With that said, I have found memories of trying to rough out blanks on my little Rikon midi using the 'Keller hip check maneuver'(patent pending) to keep the lathe on the bench top long enough to get things round. Definitely not one of my brighter ideas!:D

[Michael James]

I admit to a HF mini 10" strapped at the head stock, clamped to a porta bench on the end of the ways....and using 1 foot to hold the table down.:eek:
I've done 3 rodeos so far and will probably retire while Im top. I like David's words..if it seems unsafe you should prolly pass.
mj

[Scott Hackler]

600 rpm is pretty fast with a 12" out of balance blank, IMO. I will slow my lathe down to 300ish if I have something big and out of balance. I will only attach the fresh half log with a faceplate and the tail stock is also wedged up real tight. Then I turn a tenon and flip it around into the chuck. I then and only then speed the lathe up to at least 1000 and with the tailstock in place again, I hog out all I can. Speed it up to 1400 and finish the rough out.

[Jon McElwain]

My best advice would be to use the band saw to round your blanks as carefully as you can. Get a circle template, transfer a circle to the piece you wish to turn and cut it round. Mark the center carefully after cutting out the circle. Place it on the lathe as others have said - between centers or with a faceplate and tail stock, then turn by hand with the tool rest close so that you can see if the piece is turning true by watching the gap between the wood and the tool rest. Adjust the piece in the centers until you have it running pretty close. I would also highly recommend adding some sand bag ballast to the machine to help absorb some of the vibration. Sand is cheap! Keep the tools super sharp so they cut it down to round quick. Good luck and start saving your lunch money for a VS drive lathe!

[Bob Wolfe]

I don't know if this is even possible with your lathe, but if you can control the belt tension and allow it to slip this might work for you. I have been able to rough turn pretty large, out of balance logs on my Jet 1220 by doing the following: (I have done this with logs so for the sake of simplicity, I will refer to turning stock as a log but it could be a bowl blank or whatever)

With the lathe at it's lowest speed (550 for me), and the log held tightly between centers, adjust the belt tension so there is just enough contact to spin the log, but if you get a catch the belt slips easily. Now, with the lathe off create a catch on the highest spot with your turning tool to completely stop the log from moving and hold it there. When you are ready, turn on the motor and quickly retract your tool just enough to free it from the catch and start your cut immediately and knock down the high spot. Don't allow the log to spin up to full speed before you start your cuts and be ready to hit the power switch immediately if the speed starts getting high and vibrations start. You are going to regulate the speed by the depth of your cut. You will get a feel for how much slower the stock spins with how deep of a cut you are taking. Remember when the log is not turning the belt is slipping, so try to slow the log with your cuts without stopping it. If you stop it, turn off the motor or you might destroy your belt. You want to get it into balance as quickly as possible, so knock the heaviest or highest spots down first and move on to the next section instead of trying to make one area perfectly round. Again, Don't allow it to spin all the way up to speed if it is out of balance or your lathe might start jumping around on you or your stock could become a projectile. Keep checking to make sure the log is secure between centers during this process. Continue until all the high spots are removed and the log is into balance enough to increase the speed.

An EZ rougher type tool or a heavy oland tool are my tools of choice for this operation. After a few passes you should be able to tighten the belt and increase the speed. If you think this is dangerous or fear that it will damage your lathe then by all means please don't do it. I had to work with what I have and figured out that this method will work when I need it to. YMMV

Happy Turning,
Bob

[Jon Lanier]

Buck up, grit your teeth and man up. Go after... even if you have to chase it around the shop.

[John Keeton]

Chris, I assume you have the HF34706 lathe? If so, it is a clone of the Jet 1236, and it may be that you can reduce the speed somewhat with this modification (http://www.chrisbillman.com/Projects/LatheSpeed.htm). It won't work on every 34706, as some do not have enough 'play' or extra movement in the speed control function. But, it is worth testing yours to see.

[Tom Sherman]

Chris while you are roughing out make sure to check often that your tailstock is snug to your blank it adds a good bit of support for your safety!

[Dennis Ford]

You might try to balance the blank better after it is mounted on the lathe. An angle grinder with coarse sanding disk will remove wood quickly and it is not hard to take some off the heavy side.

If your lathe is moving around, it is no fun turning and not safe either!

[Kyle Iwamoto]

I feel your pain. My big lathe is a Shopsmith, and minimum is 700 or so. For me, anything over 8" is "exciting". I'm in the chicken group. If it don't feel safe, it's not. Mount the blank, and attempt trimming to balance it out. I sometimes use a draw knife to balance things out. The SS is also not very heavy, so it likes to jump about, even with smaller stuff.
One trick I learned is to hold the blank lightly between centers, so the blank can swing on the pins. Loosen the tailstock and move the blank about until the blank is as balanced as possible. After the initial roughing, can again relocate the blank etc etc. Keep that tailstock tight tight tight.
Good luck!

[Steve Schlumpf]

Chris - I started off with a Craftsman mono-tube lathe and the low end speed is 875 rpm. I learned to turn bowls on it and used it for 2 years before upgrading my lathe.

I found using 7 bags of quick-crete for ballast helped keep the lathe on the ground but it still shook violently at times. Also spent a lot of time with the blank between centers - before turning it - trimming it up with a bowsaw. I would cut some off - loosen the tailstock and allow the blank to rotate so the heavy end would always drop down. I would remove a little more wood off that heavy section - rotate it and see if it was close to balanced. Only needed it enough so that I could start the lathe without launching the blank! That happened a few times - so I highly recommend NOT standing in the line of fire when you first fire the lathe up!

As mentioned - it can be done but take the time to think things through before turning and remember - if it doesn't feel safe - STOP! Check things out - it's not worth getting hurt over!

Have fun - out of round blanks can be very entertaining! Looking forward to seeing some of your bowls real soon!