Once again, it’s Woodworkers Safety Week for 2010. Because there is a lot of content about safety with other power tools and hand tools, I thought I’d cover safety with another tool in the shop that can sometimes be underestimated with respect to its potential dangers. So, in this post I’ll discuss the safety at the lathe and I’ll offer several helpful tips for safely turning wood in the workshop.
Turning wood is a great way to spend time in the workshop. Projects can be done quickly and for very little investment in wood – especially if you turn found green wood! Because of the nature of this work and the wood being somewhat “captive” on the lathe the dangers of turning can often be overlooked.
What follows are some points to help everyone turn more safely in their shops:
- Capture that wood dust – Just as in any other woodworking operation, turning and/or sanding at the lathe produces wood dust that is harmful to breathe. What’s more, the dust produced is shot right back at the woodworker due to the rotation of the work. Wood that is turned can often also be spalted and/or moldy from sitting in the elements before turning. Turning or sanding this wood can release harmful spores into the air that if ingested can be very harmful to an even greater degree than normal wood dust. As a result you should be extra-vigilant to wear personal respiratory protection while turning and sanding at the lathe at all times – especially when turning spalted wood.
- Speed is dangerous – Blanks that are turned on the lathe can often be heavy, large and out of balance. Spinning a large out of balance load on the lathe at high speed can be deadly – even if you are wearing protective head gear (and it goes without saying that you should be wearing a face shield every time you spin something on the lathe). The key things to remember when turning are: that you should always start at the lowest speed that your lathe allows and that you should stand out of the line of fire when you start up the lathe. On my variable speed lathe, I turn the speed dial down to zero RPM before starting and gradually increase the speed until the piece is turned into balance – if you don’t have variable speed then just start at your lowest speed. If your lathe is still unstable when spinning a blank, then you should get the piece more in balance by trimming it while off of the lathe before turning it. There are lots of rules of thumb out there for how fast you can safely spin a piece on the lathe in relation to its diameter. However, I really never use them. I find that for bowl/vessel turning I almost never have the need to turn higher than 600-800 RPM. Sanding is never done above 300 RPM (often much lower) and for out of balance blanks I usually start turning below 200 RPM until true. Of course, for spindle turning between centers lathe speeds are usually increased, but even then I rarely go above 1500-1800 RPM.
- The tailstock is your friend – Speaking of out of balance loads on the lathe, just because you have secured a piece onto a faceplate with screws or into a chuck with a tenon, that does not mean that your tailstock should be collecting dust in the corner of the shop! When I turn, even after the piece is trued up and balanced, I will always use the tailstock for support until the last moment where I have to turn away the support point. For turning the inside of bowls or vessels, I will follow this rule only on beginning hollowing operations of large pieces. After that the speed rule takes care of me because I turn at very moderate speeds.
- Dull tools are dangerous – We have all probably heard the adage that a dull tool is more dangerous than a sharp one. This is because if the tool is dull then you will naturally try to compensate for that lack of cutting effectiveness by applying more power to use the tool. This same adage rings true for the lathe. It’s true that we usually only sharpen our turning tools on a 100 grit grinding wheel and not on 8000 grit water stones but, that doesn’t mean that they aren’t sharp. More importantly, a freshly ground lathe tool with cut wood effortlessly, reduce tearout and allow for better control when turning. You should always be mindful of any extra effort that is required to cut wood at the lathe and when it becomes even a little more difficult, it’s time to sharpen. Sharpening a lathe tool only takes seconds and then you are back to work. Remember, as David Ellsworth is known to say: don’t grind the tool, dress the bevel – a quick, light touch at the grinder is all that it takes to get back to fantastic results at the lathe.
- Don’t bottom out – We often use holding devices when turning blanks on the lathe. The most prevalent of these holding devices is the lathe scroll-chuck. These chucks have 4 jaws that offer exceptional holding power for turning blanks (even without tailstock support – though we know you should always use the tailstock for support if you can!) I almost always use my scroll-chuck to grip the outside of a round tenon that I first turn on the piece while between centers. The biggest (and most dangerous) mistake that turners make with chucks is that they cut this tenon too deep so that the tenon bottoms out on the inside face of the chuck jaws. This actually offers less support for the piece. The correct way to use a chuck is the cut the tenon so that the top edges of the jaws rest flush against a flat on the piece at the base of the tenon, but with clearance between the bottom of the tenon and the inside faces of the chuck jaws. This scenario offers tremendously better resistance against the rotational forces which try to knock to piece off of the lathe and into orbit around the shop!
Hopefully these tips are of some help to you as you turn wood on your lathe in the workshop. I find that turning is occupying more and more of my time in the shop and I always follow these rules when I’m at work on my lathe.