In this article we explore the process of what goes into turning a large piece on a lathe from my perspective and using my techniques. There are many different ways to achieve a wonderful outcome, and what I do will be different to many other turners. This is not a definitive process, and there are many turners who will have slightly different approaches to any particular step. As long as we all approach the task with safety in mind and a good idea of the process then there is a world of enjoyment in producing high quality centerpieces that people appreciate and treasure.
The list of things we cover.
- Lathe size
- Wood selection
- Tools required
- Safety considerations
- Faceplate or Chuck
- Turning speeds
- Sanding grits
- Finish techniques
What size lathe do I need?
Lathes have what is called a swing size. This is the measurement that the manufacturer has allowed for in the design that defines the physical size of a blank that can be turned safely over the bed of the lathe. Some lathes don’t have a bed so the swing is governed by the headstock-to-floor distance.
We have several lathes here at Pickers Ridge that will help illustrate the differences discussed in this article.
The first is a Vicmarc VL175SH that has a swing of 175mm.
This is the radius of the largest piece of wood that can be mounted over the bed and this swing varies greatly across all the different brands and models.
This particular lathe has a headstock that can be swivelled. Some manufacturers have tried to add features to expand the abilities of the turner and this lathe is a good example of it.
Some models allow for turning what is called outboard and the meaning of outboard in the turning world is to turn without a bed below the work-piece.
To achieve this some lathes allow the headstock to swivel while others allow for the headstock to slide along the bed after the tailstock has been removed to allow the work-piece to turn clear of the lathe bed end.
Turning outboard is not a straight forward thing though as tool rests have to be designed for each model of lathe and they need to be robust and effective. A cheap design may fail under pressure and introduce risk to the operator so bear that in mind.
Another issue that many wood turners will face is lathe stability. The lathe above has the ability to swivel the headstock 90 degrees so it can turn a much larger item than over the bed…..but…… the problem here is the lathe is relying on the base mass to counter the spinning object hanging off it’s side.
It is not a perfect solution, but comes in handy with thinner platters and plates. A deeper vase or centerpiece is a big ask for a lathe like this and is not recommended.
Some lathes have the ability to swivel the headstock 180 degrees and turn outboard off the end of the bed at the headstock and while this gives some mass to the lathe along the bed direction it actually narrows the sideways footprint of the lathe so an out-of-balance blank will have a tendency to rock the lathe unless the machine is secured to the floor somehow.
Our VL175SH has an outboard attachment for tool rests and it sits gathering dust because of the issues with balance. Yes, you could spend time with a saw removing excess weight in select spots to rough balance the blank and, to be sure, this should be done irrespective of the piece and the type of lathe you have.
We have just found the limitations of this particular lathe to be counterproductive to our intended goal, and that is to produce large timber centerpieces in a safe way. The final limiting factor regarding the lathe above is the size of the motor.
To turn large lumps of wood, you are going to need horses, a few of them.
The lathe here is our solution to the horse-power problems. It also takes care of the balance issue, and it also answers the question of swing capacity.
It is a VB36. It has no bed or tailstock.
It does have the ability to accept these as a manufacturers option, however we decided to forgo this and ordered just the main unit.
It is bolted to the floor at all four corners and has a thin rubber mat between the lathe and the concrete. This is not a product review but a brief description of the type of machine you might want to consider if you wish to start turning big stuff. They are expensive and take some time to arrive from Germany but I have no regrets.
The quick specs on this lathe.
- Swing 1150mm ( yes, you read that correctly)
- Weight capacity of blank….unknown.
- Motor 3HP (2,25 kW), 400 V 3 phase continuously rated motor with inverter, power supply 230 V AC
- Machine weight 265 Kg
Mass = stability.
Having owned and used this machine for several years now, it sets the standard for turning large wood in a safe manner and it would take a special lathe to unseat this for large faceplate turning.
What wood is best, wet or dry.
Lets talk about Dry wood first.
For every positive there is a negative. This goes for both wet and dry.
The plus for dry wood is that it far more stable than wet, as in there should be far less movement once the project is complete. Sometimes a piece will move a bit no matter how dry it is but generally speaking it is safe to say that dry wood is stable.
The benefit of this is that you can turn a piece to completion, sand it completely, then apply finish to it, all one process after another without any need to wait.
Dry wood is usually lighter in weight as well, so this comes into consideration when lathe size is limited. You should be able to safely turn a slightly larger piece when it is dry if the lathe capacity allows for it. The motor should not work as hard all things being equal.
A major downside for dry turning is dust. It gets everywhere so a good dust extraction system helps immensely. Another downside to dry turning is keeping tools sharp. It is my opinion that dry wood dulls tools far quicker than wet.
Wet, or green wood.
I prefer wet turning. The positive points for me are the lack of dust and tools keep an edge for longer. That means less round trips to the grinder and that means tools last longer. A decent bowl gouge is costly so I want to extract the maximum turns per tool.
The negatives for green turning are the juice, the weight, and the potential for splitting and warping. It can be disheartening to invest several hour in turning a large lump of wood into a rough shape then setting it aside to dry for a while only to see cracks and splits arrive potentially ruining a promising piece. It has happened more than once and is a cost that you must be prepared to pay.
To counter this splitting I will turn the piece to a rough shape and leave the thickness at around 20-35mm thick. I then place the piece on a drying shelf and depending on the season, will cover it with a towel or just leave it open to the air.
High humidity allows me leave it open and low humidity pushes me cover it up. Your climate will dictate how you go about it. Trial and error is the best teacher. Once dry and sill a useful piece it then goes on the lathe and is turned to completion.
A few notes of caution are in order.
If turning wet (green) wood some acacias will rust your chucks and faceplates if left on overnight or longer. The juice can also play merry hell with the bed of your lathe. I suggest wiping down your lathe bed after turning green wood regardless of the species. I also suggest hanging spray curtains to protect the items and wall/ceiling near your lathe as the moisture exiting a spinning lump of wet wood can travel a surprising distance.
Wearing a rain jacket and a full face shield is also beneficial. I kid you not. I wear a carbon filter disposable mask when turning green as being on the lathe without a mask can still lead to health issues down the track. If you can smell the fresh wood, then there is an element of risk from those fumes/smells in my opinion.
Consider turning green when you get the chance, it can be fun.
Do you need special tools to turn large pieces?
Not really, but things like bowl gouges should have some length to them. I have tried turning with gouges that are short from use and sharpening and they are next to useless in many situations. Once you have replaced a short gouge with a new longer one you will understand exactly what I mean.
I do recommend using tools with longer than standard handles as the forces involved with large lumps of wood can be extreme so leverage is your friend.
I use HSS tools for generally although we also have a cnc lathe that takes carbide and I am very impressed with these cutters. I have adapted them from hand tools so the carbide option for hand turning is definitely worthy of consideration.
Having the tools is half of the equation. How to sharpen them is the other half.
I use a CBN wheel in 180grit. I cannot speak highly enough of this tool. It does everything I expect of it without issue and that is all I can ask. If you do not have one of these wheels, put it on your wish list as you will not regret it. I use a vicmarc jig on the grinder but sharpen by hand.
Whith angles at the tool tip I like the 40-40 grind as it suits my style of work. Youtube has a video by Stuart Batty called “how gouges cut”. I have nothing to add to what he teaches as he really knows his stuff. I do recommend you check it out.
I use both with the disclaimer of where appropriate. That is an important point. Using a chuck with a large blank is just asking for trouble and you could find yourself having a spinning lump of wood chasing you around your shed.
When I load the VB36 with a rough blank I use a faceplate. It is 320mm diameter and 10mm thick. It is a large lump of steel in its own right. The faceplate is connected to the wood by as many screws as I can use.
The VB36 employs a fantastic method of connecting the faceplate to the lathe that I trust implicitly. Once the blank is mounted I will turn the blank by hand to locate the points where material needs to come off to balance it. I use a chainsaw to take the majority off and then a power planer to fine tune if needed.
Another special tool I use is an endless chain to lift the blank onto the lathe. The faceplate alone is heavy and adding a large fork of a hardwood tree to the total is far too heavy for a hand lift.
Add more weight if the wood is still moist, as this lump was. This is just a section of a bigger piece of Lychee trunk that was donated to us.
Then I start the slow process of shaping the piece. It can take several hours depending on the wood species and the size of the blank. I will usually hog out the hollow section of a typical centerpiece and leave a spigot in the center that will allow me to reverse the piece and use a chuck.
That is the last use of the faceplate for these jobs.
Once the work-piece is now mounted on the chuck I will turn the base and foot. This is completed to sanding stage if the wood is dry enough, if not then the foot is left rough and the piece is stored until dry. Once dry, we repeat the above process until the foot is complete.
I like to turn an angle on the foot that will match the nylon lugs of a set of bowl jaws. This allows me to again reverse the whole piece and grab it by the base with the bowl jaws to complete the hollowing of the bowl section of the centerpiece. Once completed I sand and apply a pure Tung oil finish to the piece.
This is an important subject. Lathes can be very dangerous machines when respect is discounted or ignored. The forces involved with a 30 kg lump of hardwood spinning at 150 RPM while rough cutting are scary. The risk only increases with diameter.
A few numbers here will give an example of some of the forces involved. A piece of wood with a diameter of 300 mm or 12 inches roughly spinning at 150 RPM will, at the perimeter, travel 282 mtrs in a minute if it was a free rolling wheel.
Think about that for a second.
Now turn the speed up to 1000 RPM and you get a distance of 1880 (ish) mtrs per minute. Per Minute! Now stick a sharp bit of steel into it!
I cannot give enough weight to the safety aspect of this process as one simple error can be very harmful. The danger vectors are numerous so being well aware of yourself, your surroundings, and yours and your machines limitations is of utmost importance.
Having said that, if you pay attention to the risks and plan out the job before you start there is no reason you cannot undertake this pastime safely and productively.
- Keep the floor around you clean and clear.
- Wear safety glasses at a minimum, a full-face visor is far better.
- A mask should be worn, even with dust extraction.
- Use sharp tools.
- Spin the work-piece at an appropriate RPM.
Don’t let the work-piece shake the lathe violently. Slow the speed or stop the machine and take wood off with hand tools like a saw or similar to balance the blank better before spinning it again by motor.
Be confident in your work. Find your comfort zone and enjoy yourself. Expand your zone when you are ready. You will know if it feels ok or not.
I hope you have enjoyed exploring the process above as much as I have enjoyed describing it. Wood-turning is a wonderful process that captures many people of all ages. I hope it continues to do so.