This post is about dust extractor maintenance. It’s very easy to buy a dust extractor and forget about it. They are simple machines, but problems can grow slowly, so suction declines without you noticing.
Not long ago, I made some wheels out of a commercial cutting board, one of the thick ones used in restaurants or on deli counters. I cut some squares from it with the bandsaw with no problems at all. I put each one in my self-centring engineering chuck and turned it to size and shape. A flat bit in the drill press made the holes in the middle. Back on the lathe mounted on a wooden mandrel to complete the turning. Job done. The plastic material, that I think may be polypropylene, turned very easily with a negative rake scraper, leaving a smooth, shiny surface off the tool. The only problem was the shavings. Long ribbons of plastic wound round the chuck, the mandrel and everything else, with the loose ends flailing as the lathe went round. So although there was no dust, I put the dust extractor on.
Later, it seemed to me that suction at the extractor inlet was not as good as it once was, so I cleaned the filter cartridge. This was a job I had meant to do for some time. There was lots of fine dust in it, blocking the pleated filter. I took it outdoors and used a brush and compressed air to get as much dust as possible out. I put it all back together and switched on. Much better!
Dust extractor fan guard
But was the suction yet good enough? Perhaps there was a blockage somewhere. My extractor is a cyclone unit, and at the outlet of the fan housing there is a grid to stop people putting their hand in and touching the spinning fan. I dismantled the ducting close to the housing to check it. Sure enough, plastic ribbon had blocked the grid. It was surprising that air could get through it at all. The long ribbons had passed through the cyclone.
I knew what to look for, because once before when re-configuring the ductwork, I found the remains of a plastic carrier bag blocking the grid. Like the bag, the bird’s nest of ribbon was easy enough to remove. But this time I did my risk assessment and decided that although the grid removed one risk, it created another. The first risk was negligible to anyone with any sense, while the second was significant. So the grid had to go. I removed it, put the ducting back together and switched on. Now the suction is back to what it ought to be.
These are not the only times I’ve come across this problem. It’s possible for long splinters or other objects to get stuck at a bend so shavings build up, or for debris to accumulate at a low spot. And filters clog up from time to time. But often the drop in suction goes unnoticed, even if there is a vacuum gauge to check it.
So my recommendation is to make a point of scheduling maintenance, and to check suction at your dust extractor often. Whether you remove the safety grid is up to you. An objective way to measure suction would be useful. I shall have to consider a vacuum gauge.