Bill Grumbine Video

[Rob Holcomb]

It had been suggested to me to get the Bill Grumbine video when asking questions about problems I had while turning my first rough bowl. I got the video and have to say that most of what I was doing was wrong and I thank all of you that made the suggestion to get the video. The one thing he didn't cover in the video is at what speed do you rough out the bowl and then when doing the final turning after drying, what speed to use. Can some of you share the speed process you use from the time you put the blank on the lathe right on through to the finished bowl? Thank you in advance, Rob

[Allen Neighbors]

Rob, I believe that speed is our friend. I go slow as necessary until it is in balance. Then crank up the speed until it scares me, then back off a little, 'til I'm not scared.
That's it in a nutshell. A little dramatic, but that's what I do. Your experience may vary. :D

[Jeff Rich]

I usually start between 200-300 rpm when doing most bowls, sometimes a bit lower if it is a bit out of balance.
I then speed up to maybe 600-700 depending on the size of the blank.
There is a formula stated that Diameter x RPM=6000-9000.
I am not sure where this comes from, but, I have seen Del Stubbs, Dale Nish, Mike Mahoney and others use it.

[Sean Hughto]

The speed varies with eh size and shape of the blank. Bigger needs slower. And the less round and evenly balanced the blank is, the slower as well. If you try to spin a large or poorly balanced blank too fast, your lathe will start to vibrate and wobble like an out of balance washing machine on spin. Also, beginners tend to need slower until they get comfortable. With experience, faster is nice because it makes cutting seem smoother and just removes material quicker.

Your wood type and many other variable will all come into play in terms of speed. You need to develop judgement about it.

Specific example might help:

For roughing a medium sized blank in something like maple or cherry, I would say that you need not go over 400 or so to start, and there is nothing wrong with slower, it just means that the process will take a few minutes longer. If the lathe starts to wobble or vibrate, you are obviously going too fast and need to dial it back.

[John Keeton]

I am still finding my way on this, but I do agree with the concept stated by Allen - speed is our friend. On the smaller pieces I have been doing, I have found that increasing the speed into the mid teens - 1200 - 1500 really helps with certain woods. Of course, the surface speed isn't all that much different than turning a 9-10" bowl at 6-700.

Roughing out is mostly by feel. Sometimes there is a sweet spot where the out of balance blank will run a little smoother faster or slower - but generally around 2-300 to start and feel it out from there.

[Ken Fitzgerald]

Rob,

Here's a reference that I use

http://www.woodturnerscatalog.com/woodturners/Images/safe_lathe_speeds.pdf

[Rob Holcomb]

Thank you everyone. This information is very helpful! Of course I knew enough not to let things go thump thump thump but I didn't know if there was a starting speed, when to really crank things up etc. When I was doing my first try at a bowl, I was at about 200 and never did get above 450 during the rough out. It just never felt safe, but then again, the technique was wrong, the bowl never did get truly into round and my lathe bench was banging against the wall if I went any higher in speed. Hopefully now that I've learned how to do things a little more, I'll have a better feel for things.

[Steve Schlumpf]

Rob - glad you got the video - it is great!

You didn't mention if you have a variable speed lathe or not. If have a variable - basically turn the speed up until the lathe starts to vibrate - then back it off until it smooths out. As you rough out the blank - you will be able to increase the speed in steps as the blank becomes more balanced.

When I rough out a blank - I usually start around 400 rpm more or less - depending on how out of balance it is. When I turn the speed up - I never go faster than 1000 rpm even when balanced - but that is just my personal preference.

[John Tomasello jr]

I adjust my speed control up until I get some vibration then back it down until the vibration stops. Then as I'm turning I keep bumping up the speed mainly it's a comfort thing. I find that I get better cut at higher speed

[David E Keller]

Rob, I believe that speed is our friend. I go slow as necessary until it is in balance. Then crank up the speed until it scares me, then back off a little, 'til I'm not scared.
That's it in a nutshell. A little dramatic, but that's what I do. Your experience may vary. :D


Ditto!!!!!

[Curt Fuller]

Rob, I believe that speed is our friend.

I agree somewhat with Allen. But like all friends, it takes a while to become friends. With bowls and other off balance blanks start slow, <500 or slowest speed your lathe has. You can turn slow til the cows come home and it won't hurt anything. As you get more comfortable with the whole turning thing you'll find times when speed helps, times when it works better to just keep going slow. But anything you do wrong will usually be amplified by speed.

[Michael Armstrong]

Rob:
I'm pretty much with everyone else here. Start slow and speed up as it balances. I also do what others suggest and pick a speed that doesn't make the lathe vibrate. Bill is a very approachable man. I had a question and sent him an email. He promptly replied so give that a shot also.

Michael

[Jack Mincey]

One thing about speed. At 700 rpm's one has a chance to duck, zig or zig. When something goes bad at the lathe at 1500 rpm's one dosn't have time and bad things can get a lot worse. Being a high school shop teacher I turn slower than most so not to teach my students to turn at high speed. One of them ducks, zig or zag's most weeks and it helps having them at lower speeds.
Jack

[Richard Madison]

Must disagree with the "turn it up until it shakes and then turn it down" approach. Obviously if it shakes, turn it down. But start slow, at a speed that feels comfortable and safe to you. Work your way up gradually as the piece becomes round and balanced, but only to a speed that feels comfortable and safe to you. Your "comfortable" speed will increase with experience. Certainly many turners are comfortable with high speeds (and some awfully proud of it), but like Steve I never shift the belt to "high" range (above 1250 rpm), even for toothpicks.

[Cody Colston]

The speed at which I turn is a function of the lathe I use. 550 rpm is the slowest it will go so that's what I start out at, regardless of size or balance.

As soon as possible, however, I go up to the next speed increment, which is 900 RPM. That's where I stay for larger pieces...over 9 inches or so. For smaller vessels, I'll often go up to the next stop which is 1250 RPM.

In most cases, faster is better as long as there is no vibration. The more balanced the piece and the smaller the piece, the faster it can be turned.

When turning pens, duck calls, etc, I usually run the lathe near the 3000 rpm range.

[John Keeton]

...like Steve I never shift the belt to "high" range (above 1250 rpm), even for toothpicks.I will let my inexperience show here - in doing finials and small stemwork in the African Blackwood, I have found that 4000 rpm produces a much superior cut, and permits finer detail. I take very, very light cuts, and on the small stem cuts, I support the piece with my fingers. Of course, any disaster at that speed will be exponentially magnified!!

[Reed Gray]

Your comfort level, and the piece of wood will tell you what it the proper speed. Some pieces of wood will never balance out, no matter how perfectly round it is. The more you turn, the more comfortable you will become with speeds. I start pieces and ramp up the speed till things start to vibrate, which can be anywhere from 100 to 2000 rpm. Depends on the piece. If you aren't comfortable turning above 500 or 1000 rpm, don't worry about it. Like others I have found that higher speeds do contribute to smoother and finer cuts for me, and for production purposes, higher rpms means less time spent. Get comfortable with your turning skills before you bump up the speed.

robo hippy

[John Abt]

It's been a long time since I've posted.

Having taken Bill's class, I follow his mantra: "If the lathe ain't shakin' and you're not shakin'..."

John

[Lance kanaby]

Roy and Others: This is an excellent source of information regarding turning speeds.
http://www.woodturnerscatalog.com/woodturners/Images/safe_lathe_speeds.pdf