Hello first post so please be gentle.
I will start I have very rudimentary knowledge of electronics , I have created a pwm vaping box mod before , that's about the extent of my skill .

I need some advice regarding controlling the speed of a main power drill 240v ac , application is to run a slitting saw arbour in the drill mounted so it will not move , it is to cut aluminium jump rings.
Building the device is not an issue but it's getting the speed of the drill down to sensible cutting speeds
Around 400 rpm ish .
I have done alot of research but have managed to confuse myself more than help , hence I thought it would be sensible to ask for advice from people who understand electronics .
Hoping someone can point me in the right direction .
Did look at using a cordless drill with a 18v 20a 340w led driver , from the " experts" on Google that seems to be the way to go , but I'd rather use mains drill as the mounting etc is easier.

 

Welcome to AAC.

To answer your question, we need more information about the drill. Particularly the current requirements of the motor. Is this not a variable speed drill already?

 

In all probability the mains drill is a Universal motor, if so the traditional way is by using a Triac circuit, if the motor has very little reduction, you may have a problem getting it to run at low RPM with the triac method.
The DC cordless drill may be the better option using PWM.
Max.

 

As max says , you need a triac "dimmer"

These can be used to dim lights or control mains motors ... this one is 2 Kw ... always good to by a high power device , then no chance of blowing it ... many types on ebay around 5 to 10 pounds

 

This is the mains drill I'm thinking of acquiring for the project , it states variable speed but am dubious as to how variable it will be https://www.screwfix.com/p/erbauer-ehd650-650w-impact-drill-220-240v/336fv

And if going cordless it would be a 18v something along the lines of this , https://www.screwfix.com/p/mac-allister-msdd18-li-2-18v-1-5ah-li-ion-cordle already have a good cordless drill so dont want to sacrifice that

Appreciate your responses so far

 

this one is only 2 pounds ,,, 2 Kw

https://www.ebay.co.uk/itm/High-Pow...981069?hash=item3d7b8f1a8d:g:108AAOSwdLhcAOAL

 

So, I would start by getting the drill and using a clamp to hold the trigger on and the speed setting know on the trigger to see if you can get the speed you want. I suspect that if the trigger doesn't do it, adding an external control won't either—but at least you will know you need to try it.

This looked promising IF you need it: https://www.amazon.co.uk/Regulator-Stabilizer-Transformer-Temperature-Controller/dp/B075QGDW6J/

 

Also this 4kw one in a case, ebay 401089441241 for 3 quid..
The hammer drill shown probably comes with Triac already.
Max.

 

Ok ty for advice , I will get bits for project in next week and I'll let you know how it turned out
Much obliged gents

 

Mrs has given me the go ahead to get a better drill ( bribery of a nice dinner ) has 2 speed + variable so hopefully were good , if not I will be back to pick your brains further , much obliged peeps

 

MaxHeadRoom: For case of drills there are in stores of drill parts the specialized construction containing a switch, regulator know and thyristors inside. It is interchangeable with ordinary switcher in most of cases. However it is dedicated for use in Europe, so the 240 Volts are bit too much, but 10% of tolerance reserve I am sure it genuinely has, just may dare it. But about that construction You find at ebay, I have very sharp negative experience in dozen of cases, where 3 kW claimed regulator was burned just by 2,2 kW drill. I think it has no tolerance at all about pulse currents - its not designed for collector motor feed.

 

Martin, about cordless: 1,5 Ah 18V=24 W*hr compare with 650W. Your battery pack will allow so tiny as 2 minutes before empty. And no any thyristors may solve a DC/DC conversion. Thus there the thick igbt based convert-down topology will be most suited.