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When I started woodworking, I used to setup my tool, do a cut, stop my tool, re-position my piece (or take another one), start my tool, do another cut, stop, etc.

Today, I find myself leaving the tool run in-between cuts a lot more than I used too. It's more time efficient, but is it more dangerous? Is it better on the motor?

All it in all, is there a preferred method of working with stationary power tools such as table saws, jointers, router tables, drill presses, etc.

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    Do you also let the drill run when you finished one hole, on till the next one (I don't mean one after the other) ? – Nachmen Feb 8 '16 at 8:57
  • @Nachmen I'm not sure I understand your question to be honest. I obviously do not let the drill press run when I change my setup, but sometimes for repetitive cuts, I will let it spin if I have enough place to move the piece without danger. (I just loosen my hold down clamp, move, tighten and repeat...) – Maxime Morin Feb 9 '16 at 0:48
  • What I wanted to bring out is like a drill is dangerous keeping it running, the same all power tools are dangerous. A person could be tired, distracted etc. You need to weigh the positive against the negative. The little time that you win could be in one second a disaster that cant be rectified and the consequence will have to be held a whole life. It should never happen. – Nachmen Feb 9 '16 at 6:20
  • Better for the tool, better for your power bill, better for your work efficiency, better for your safety (including hearing), ...? Pick your priorities. – keshlam Feb 10 '16 at 15:50
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Generally, that is the right thing to do. Obviously you wouldn't let a power tool run all day when you don't need it, or even walk away and let it run unattended. But keeping it running in between making several cuts in a couple of work pieces or drilling several holes is absolutely fine (I am almost inclined to say "best practice").

For the tool as well for work efficiency, it is a huge deal better to keep the tool running for reasonable amounts of time. On/off cyles are what generally limits the lifetime of switches and electronics (although their count is typically in the 6-digit order), and both the force (and thus wear) acting on and the power consumed by the electro motor is highest when switched on. Please refer to the Wikipedia Inrush Current article for an explanation why switching a tool on is stressful to its electric components. While it is possible to somewhat mitigate the effect, there is no way to eliminate it alltogether, it's just the way physics work.
The prank described in the second half of Bastard Operator From Hell, episode 7, is based on that very effect: "...clicky..clicky...clicky... BOOM".

Many modern tools have a rapid stop functionality for operational safety, which is no more than a motor brake that brings the blade to a halt within a second or two (so basically switching off may be seen as switching "on" in some way as the tool is going from running at "idle" load into "full yield" reverse).

If you have dust collection or suction / vac on automatic (master/slave), each on/off cycle further counts twice (once on the tool and once on the suction). On the other hand, having dust collection run for longer than absolutely necessary is surely rather an advantage than a disadvantage. It'll pick up some extra dust which you're not going to inhale. Fine. No harm done.

There is of course the concern of having a power tool run being dangerous by definition. Running it longer means more exposure to danger.

Opinions will inevitably differ on this point, bit my stance is that if you cannot assure safe operation of a power tool for prolonged time, you should better not use it at all.
Power tools are dangerous, maiming and possibly lethal things, treating them with appropriate respect and safety measures as to exclude the possibility of an injury is a mandatory precondition. In that case, it doesn't matter if the saw is running for a minute longer. On the other hand, if you can't assert that, stay away from them.

  • I don't entirely agree about the safety - increasing the duration of the "danger" might lead to complacency. There might be a safety benefit in only keeping the tool running when needed, then the awareness for safety is "at the top of your mind", vs. leaving it running for another minute while you go grab the next piece of wood and align the fence of the saw, for example. – Eli Iser Feb 8 '16 at 9:10
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It's more time efficient, but is it more dangerous?

I think as long as any guards are in place and normal safety procedures are followed as mindfully as they should always be followed there's little increased danger. That's not to say there's none, and individual mileage as always will vary.

You list table saws, jointers, router tables and drill presses and I think this very much depends on each tool so it would be best to approach thinking about this on a tool-by-tool basis rather than looking for an overall idea of acceptable/preferable practice.

Is it better on the motor?

I think it can be, although it depends on the tool. And the key factor may be just how long it's left running. Industrial-level tools have very long 'duty cycles', where there may be an expectation that they have to have the motor running continually for an hour or longer at times. Consumer tools are not built as robustly and the potential for overheating when run for longer periods is higher, particularly in hot weather (temperature in the shop is definitely a factor).

Also the type of tool I'm sure must matter, table saws and especially jointers or thicknesses are obviously intended for working for longer periods compared to say a typical drilling operation.

But start-and-stop operation I presume is considered normal for drill presses so drilling, stopping and drilling again should be perfectly fine. And certainly you shouldn't be adjusting a workpiece underneath a spinning bit, that just strikes me as bad practice generally. Note: this is not to say that a drill is put at risk if run continually for long periods, many people use their drills for drum sanding, buffing, with wire wheels, even for turning operations, without apparent harm to the motors. But the quality of the tool probably matters a lot here.

With routers, they spin very fast and the motor and other internals are being stressed as a result so within reason I would want to stop the tool and let it cool periodically even if you might want to run piece after piece past the bit for extended periods, e.g. when doing long lengths of moulding. This may be unduly cautious but I would feel more comfortable doing it this way myself with a consumer-level router.

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    Also, continuous use of a router will heat the bit (assuming you're using it and not just letting it run). Heat will kill a bit fast. That's why you're supposed to take small bites. It generates less heat and is easier on the bit. – Charlie Kilian Feb 8 '16 at 20:23
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From a safety perspective, I turn off the band saw and table saw between cuts. Most other tools I am fine to leave running. Especially drill press, sanders, scroll saw, and other smaller tools.

I've seen others leave a table saw running while setting up cuts but this looks dangerous.

The motors don't matter. It's about safety.

  • The motors don't matter. It's about safety. +100. Buying a new tool because the motor burned out a bit early is annoying. Doing your woodworking or cuddling with a loved one when missing a finger or whole hand, is.. well beyond annoying. – FreeMan Feb 24 '16 at 21:01
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I purchased a Craftsman Radial Arm Saw in 1974. I turn it on to make a cut, turn it off, adjust for the next cut and turn the saw on. I just replaced a 290' fence in my back yard and had to cut 1-2 inches off the bottom of each 6" wide board. I cut them 3 at a time then turned off the saw stacked up three more and cut them. After over 41 years of using the saw like this it still works like new. Electric motors manufactured since the 90's are built to be turned on and off in this manner. The main reason your motor will fail is because of insulation and other parts breaking down over time. I say use the off switch and same the fingers.

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