Convert Light Switch to Light Switch + Outlet Combination
The Regulated and safest answers is No.
The DIY answer is absolutely not.

Why?

Running carpenter machinery of even the smallest type will use a good 300Watts? Then to the large saw tables or routers that can be anything between 800Watt and 2000Watts..
It can cause an electrical fire and will void any insurance of any kind in any country.

Light Outlet

By building regulation these should be about 1200Watts maximum.. That is 12 100Watt lights bulbs that is easily achieved in 3 rooms with 4 fittings... Also these wires are usually 1.25mm core which is way to small for heavy loads!

Solution

You will have to pull a SEPARATE, or find a separate socket that is handled by 1 breaker for this heavy machinery.

It might take a bit of work but this will be the best and safest way to do it. Pulling power from your DB(Distribution Board) you can put a new 15Amp breaker(220Volt) on the supply phase giving you extra 3300Watts just for your heavy tools. You also want to make sure to have earth leakage connected as this is a life saver in many cases!And that is no joke.

You would pull that using a 5mm2 Solid copper core cable. You can run it along the outside of the wall or in tubing but it MUST be in a shielded coating. If you run it within pipes within the walls unshielded wire is fine.

TIPS

When working on the DB, turn off the Main incoming power, usually a big switch before the DB in newer installations of somewhere outside your house. This can seriously hurt you if you don't.

A DB box should be neatly wired, like this.



Earth leakage, a life saver! It is easy to install however it can be costly, but its worth it!



Cables, this flex cable is commonly used



Cables, a shielded copper core flex cable, for extra safety!



Alternatives

If you really really cannot do it the proper way for whatever reason then you must seriously think about some safety precautions when connecting to your light switch. At least put a breaker 5amp(@220v = 1000Watts) after the light switch stop overload if any and then wire a plug in. Sometimes you can buy Isolated plugs with build in fuses. Try not to exceed 5AMP. This is highly unrecommended though.