What Speed Do You Spin At?

[edbanger]

Hi All

I've been reading a post in the gallery posted by Sergio on his mirrors, he had a couple of faults which have been pointed out and he replied, he states that he normally turns at under 1000rpm and keeps a sharp tool and a steady hand.

I turn mostly larger items and in the main my lathe is spinning at 500rpm once the wood is roughly shaped and in balance, I think that I get a good finish with the gouge so not to much sanding is required, I have read post on here where people use different sanding methods because they think that there turned finished work needs it, do people spin their lathes to fast so they have not got full control of the tool in their hands?

This has prompted me to ask this question. What speed do you spin your work at and why?

Ed

[bodrighywood]

How long is a piece of string? Simple answer is the fastest speed that is safe. As you can imagine, some of the things I turn with cracks splits voids etc not to mention potentially loose bark are turned as low as 200 or 300 rpm at first but when I am say doing small spindles for drop spindles it can go up to as much as 3000 rpm. Sanding on the lathe I do at lower speeds as it generates less heat. As a sort of average I would guesstimate that I am turning at around 1000 rpm or less most of the time though on the variable speed lathe. the old Tyme Avon I use has belt change and is used for smaller stuff and is more or less permanently on 1000.

[The Bowler Hatted Turner]

Hi Ed,
          I turn at the correct speed for the piece I am turning, slower for large pieces and faster (but not always) for smaller pieces. The speeds range from just going round ie.about 5 rpm to 3000 rpm.

[Bryan Milham]

John & Pete have summed it all up,

As you get better the speed you turn at increases but it's still only at a 'Safe Speed' for the item you are turning.

[Turners cabin]

How long is a piece of string? Simple answer is the fastest speed that is safe. As you can imagine, some of the things I turn with cracks splits voids etc not to mention potentially loose bark are turned as low as 200 or 300 rpm at first but when I am say doing small spindles for drop spindles it can go up to as much as 3000 rpm. Sanding on the lathe I do at lower speeds as it generates less heat. As a sort of average I would guesstimate that I am turning at around 1000 rpm or less most of the time though on the variable speed lathe. the old Tyme Avon I use has belt change and is used for smaller stuff and is more or less permanently on 1000.

i total agree i personaly turn as fast as a piece will go and still be safe and that i feel safe doing so but its all personal just because turning a bowl at 1500rpm is ok for me dose not mean its the right speed for some one else

[bodrighywood]

Lowest speed I can go is 200 so there are times when I have decided not to turn something as even that is too fast. The speed that you use can also depend on the lathe. There are some lathes where the lowest speed is 700 rpm and to be honest that is far too fast IMHO for some off centre work. Remember that the faster you are going, the faster things happen and so if a piece breaks off or the work gets detached it stops being painful and becomes downright dangerous. With experience it is all too easy to become base and think it's OK to go faster. It isn't.

Pete

[edbanger]

Hi All

thanks for your answers, I agree that you should turn at a safe speed for the work you are turning, part the reason for asking was we purchased our son a Axminster lathe for his birthday as he quite like the idea of turning but the slowest speed his lathe runs at is 500rpm which seems a bit fast when your turning something to shape, this is designed to be a beginners lathe.

Ed

[Mark Hancock]

I'm so glad nobody has linked to some table showing lathe speed against dimension of timber. IMHO these are so dangerous as there are so many variables to consider when selecting the appropriate speed.

It's noticeable that everyone has referred to a speed suitable for the piece being turned but no-one has mentioned the lathe set up being used, though Ed has kind of hinted at it with the beginner lathe for his son. A bench lathe on a weighted bolted down bench would allow more use of the speeds available than one on a flimsy bench used for storage and not bolted to the floor.

[bodrighywood]

You're right mark. In fact some of the legs that come with lathes such as the one I was using at Yandles are IMHO not worth having.  have two old lathes on a a single big workbench. I have to dismantle everything to move it and yet there have been times when I can feel it vibrating if I have the speed up too much. One thing I learnt the hard way (not getting hurt fortunately) was to check the speed before putting the work on. Even with variable speed, turning it down after mounting isn't the best or safest way. Even small pieces that are off balance (and that can be for a number of reasons, not just the shape of the wood) can set up a surprising amount of vibration and potential hazard.

Pete

[seventhdevil]

it really depends on what each turner is comfortable with, i have recently turned some large walnut bowls and was down at the 4-5 hundreds but yesterday and today i've been turning 2 and 3" spindle work which was at 3000rpm.

when i make skittles i turn them at 2000rpm and they are usually 5" diameter. if it's balanced you can up the speed a bit if you want but if its too unbalanced then you need to keep it down.

[David Buskell]

Ed

Lots of good advice already given above. On a recent course, we were told to turn at the speed we felt safest with. Turning 8" bowls at circa 2100 rpm didn't feel safe at first but after  a few hours, felt OK.

Add a good sharp tool to the speed and you get a really good clean cut. We were using 180 down to 320 grit only as the finish off the tool was excellent.

The Axminster lathe does run fast for a beginner but with some careful supervision at first, should be OK for your son. It's amazing how quickly youngsters get the hang of things these days!

David

[Paul Hannaby]

A question for Mark - without some sort of speed guide or method for calculation, how do you explain to beginners what a safe speed is and what is a realistic maximum speed for a given diameter workpiece?

One observation possibly worth bearing in mind when considering turning speeds is that if you double the speed, the centrifrugal forces multiply by four because it's an exponential relationship. It's the centrifrugal force that will cause the workpiece to separate, particularly if there are flaws in it. Having a well balanced workpiece may not be enough to prevent an accident if it's running much faster than it should be.

[edbanger]

We all seem to have learnt that the safe speed is dictated by the piece of wood that your turning, but many people who start turning use pre-cut blanks could there not be a speed guide for this type of turning? It might make it a bit safer for those starting out who have little common scene.

Just an idea

[The Bowler Hatted Turner]

We all seem to have learnt that the safe speed is dictated by the piece of wood that your turning, but many people who start turning use pre-cut blanks could there not be a speed guide for this type of turning? It might make it a bit safer for those starting out who have little common scene.

Just an idea

Ed you have very nearly answered your own question here re:" those with common sense". It is not, as has been pointed out, the size of the wood that dictates the turning speed, there are many factors that can affect it. Some timbers have a marked weight difference from one side of the "plank" to the other. Weigh the light coloured wood from Laburnam and then weigh the darker wood and there will be a differential in weight between them. This will affect the lathe speed (or could affect it). If the wood you are using is damp the side nearest the floor when stacked will be heavier than the top. There are all sorts of variables that should be factored in. Those with common sense will realise this and work accordingly, those with little common sense will either hurt themselves or someone else and/or give up, I favour them giving up.

[Mark Hancock]

A question for Mark - without some sort of speed guide or method for calculation, how do you explain to beginners what a safe speed is and what is a realistic maximum speed for a given diameter workpiece?

One observation possibly worth bearing in mind when considering turning speeds is that if you double the speed, the centrifrugal forces multiply by four because it's an exponential relationship. It's the centrifrugal force that will cause the workpiece to separate, particularly if there are flaws in it. Having a well balanced workpiece may not be enough to prevent an accident if it's running much faster than it should be.

I asked for that Paul but a good question. I simply get my students to feel the lathe as they increase and decrease the speed along with explaining that consideration has to be made for both the timber blank and the tools that are being used i.e. faults/imperfections in the blank and it also has to be an appropriate speed to allow the tool to do it's job.