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I am using a Festool router with a 1-1/2 Amana straight bit to create breadboard tenons on a table top. This appears to be generating a lot of static electricity -- evidenced by the jolts I receive if my fingers get too close to the metal parts of the body.

Any thoughts on how to combat this? Aside from wrapping copper wire around the router and connecting it to an electrical ground?

James
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  • Are you using a festool hose and dust extractor? This is essential to reduce/eliminate the static – Steven Sep 03 '17 at 15:37
  • Yes. CT26E and OF1400EQ. It has been better today. Humidity is a bit higher which might be helping. – James Sep 03 '17 at 16:23
  • Related, insofar as this answer has comments talking about Festool dust extraction and how it mitigates static build-up only for Festool tools: https://woodworking.stackexchange.com/a/4334/5572 –  Jul 12 '19 at 15:53
  • try spraying your work area with a solution of a fabric softener, such as Downy – jsotola Dec 13 '19 at 19:11
  • One remote possibility is voltage leakage, plug the tool into a GFCI outlet. – Monte Glover Dec 21 '19 at 17:19

2 Answers2

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It occurs to me that the primary reason for most static build-up in tooling like this is the use of a dust extractor. The small particles of wood swirling against hoses (which are good electrical insulators) builds up localized static charges. When some of those build up enough potential they can find each-other and eventually arc through to the nearest lower potential area. This is often a human standing on the ground touching metal parts of the tool.

As I mention in my comment, Festool has (AFAICT) built-in static dissipation built into their dust extraction systems. If you have modified that, or it is not quite connected properly, you can still get shocks. The issue here is that the entire ducting system needs to have a way for the localized charges to bleed off. I'm not sure how the Festool system manages this, but some people have had success by encircling the ducts through their system with lower gauge copper or aluminum wire, all leading in a continuous circuit to some lower potential area (which we can call earth or ground, but really is just lower potential than the large air-plastic capacitor hanging from the ceiling).

There is at least one well-known wood-working Youtube channel where this DIY static dissipation system is described.

Like I said, many dust extraction systems already have this built-in, though having more than one path for these high potential areas to bleed off to lower potential areas that are not the operators hands might be recommended in this case.

After all, being surprised by shocks while operating spinning edged tools could be considered a safety issue.

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Most equipment these days is double insulated. Some countries/states explicitly prohibit you earthing anything on them - it is illegal, and in some failure situations, dangerous.

Safest way would be to wear gloves, and put the router on a metal shelf in between cuts :-)

Nigel Pearson
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  • "Earthing" through a high resistance (like 1MΩ) will eliminate static, but is not an electrocution risk (because it can only conduct 240μA at 240V). – Martin Bonner supports Monica Jul 12 '19 at 12:14
  • @MartinBonner while true in principle, many double-insulated items will have a sticker that reads "NO EARTHING" and they will be strict about this for liability or warranty purposes. –  Jul 12 '19 at 13:55
  • @jdv : The reason I put "earthing" in quotes, is because connecting an anti-static device is not earthing. – Martin Bonner supports Monica Jul 12 '19 at 14:53
  • @MartinBonner I see what you are saying, which is why I, too, used specific language "in principle". But lawyers are unlikely to accept these subtleties. If warranty or liability is important, then a warranty sticker is a warranty sticker. This all being said, Festool integrates static dissipation into their dust removal systems that can be fitted to their tools. Again, this is where they might not accept any homemade anti-static system in a warranty or liability situation. –  Jul 12 '19 at 14:59