12 Volt Drill Power supply query

[#1]

I have a "project" in mind... which involves some ingenious design work, and some diy engineering. But... before I start on the "constructional" part I need some help regarding whether I could power this 12v drill

Using my Regulated DC Power Supply...

In theory, I expect it would "run" the drill.... but I am considering whether the 2A continuous Output Current, would be sufficient to give the drill the necessary torque power.

A rough idea of what I want to do, is to make a "mini" circular saw table/bench... for cutting small pieces of timber, max thickness 3 inches. and probably no longer in length than 12 to 18 inches...

I made one of these many years ago, for cutting logs. using an old heavy duty sewing machine motor,  direct from the mains... which worked well,.... so I have  fair idea of how to do the design and construction side of it.

The drill has been used on a 12v car battery for various drilling jobs, including through steel, when we lived on a Narrowboat,  so I know it does have a decent torque on it...

[#2]

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@shutter wrote:

The drill has been used on a 12v car battery for various drilling jobs, including through steel, when we lived on a Narrowboat,  so I know it does have a decent torque on it...

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Which probably drew way more than 2A.

Bottom line is that you need to measure the current it draws under load before even thinking of hooking it up to that power supply or you may well kill the PSU and then regret it!

[#3]

@7up  Yeah... I do not want to blow the psu... hence my query on here...

Multi-meter "in-line" on the positive lead ? ? ?   to measure the current drawn on "free run"  ? ? ?

[#4]

@shutter wrote: Multi-meter "in-line" on the positive lead ? ? ?   to measure the current drawn on "free run"  ? ? ?

You could do that but make sure your multi-meter can handle the load. Nothing worse than blowing it or any internal fuses. Don't forget quite often the leads (if they are decent), will come with their own inline fuses.

But if it is a decent power supply, if you overload it or short circuit, it should just shut down. Cheap ones don't though.

But the PSU is suppose to be 20watts output? 80% duty cycle will be very close to that. At least you'll know if it goes over the top. Love the smell of overheated coils.

Wood can be quite fickle. Slight bit of damp and whatever is being used to cut it will work far harder. I doubt if 20watts of power is going to be enough - by a long way.

Me, I do similar things but went the whole hog and bought something like one of these when they had it on special offer. - i.e. very cheap. It does what it says on the box. Cuts wood rapid! Much safer too. Spinning blades aren't things to mess around with.

[#5]

@idonno  OK... thanks for the input.... and info... will give it a try, and see what the current is on "no load".. and probably that will scare me enough to think of some other way... even if it means getting a scrap battery, and charge it up for the odd job.

The cost of that one in the linky will not be justified in the little use it would get !  hence my "DIY" option... !

cheers

[#6]

@shutter 

I can see two potential problems:

1. The psu is capable of supplying a surge current of 5A. If the drill is loaded it could potentially run continuously over 2A and overheat the regulator.

2. If the drill is old it could be a wound armature type. These can spark and transmit high voltage spikes back into the regulator, potentially causing damage.

Personally I would not use it.

[#7]

@Baldrick1   ok  Thanks for that... much appreciate it....

will scrap that idea !... however, I do have quite a good 12v car battery charger.  I would say it`s middle of the range...can`t remember the output of it... because haven`t used it for a few years....  It has been kept in the boot of the car .... just in case.. so it`s not been in a damp shed loafing about gaining earwigs, and spiders and woodlice !.

Too late now... but will try and dig it out tomorrow, and see what it`s output is...

The drill, age ?  must be at least 10 years old... not a great deal of use.. and , again, kept in reasonable places.... just seems a shame that I have it, doing nothing... and this idea came to mind.... so a potential "cheap" circular saw..

( My father was a cabinetmaker, and I was brought up "in the shed"... and used his tools under supervision,... so do know the potential dangers and skill required to operate them ).

[#8]

@Baldrick1   Here is the Battery Charger... !  its 11 amp...

I will only be intending to use the home made circular saw for a couple of minutes at a time... to cut small pieces of wood... approx 6 inches to 12 inches long...

[#9]

It's certainly got more than enough output. Maybe I'm a pessimist but this also looks to be an intellegent device which makes me wonder if it's clever enough to detect that there's a battery detected before it switches on. 

Is it worth it I would ask myself? https://www.argos.co.uk/product/7106062?&cmpid=GS001&_$ja=tsid:59156%7Cacid:444-797-0832%7Ccid:16807...

[#10]

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@shutter wrote:

The drill has been used on a 12v car battery for various drilling jobs, including through steel, when we lived on a Narrowboat,  so I know it does have a decent torque on it...

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@shutter 

Without even trying what you're proposing, I'd say the torque required for a circular saw blade to cut through 3" timber would be quite a bit higher than required for a much smaller diameter drill bit.

Your blade would need to be in excess of 6" for a start, and to me that drill doesn't look sturdy enough to be able to be mounted in any contraption you're envisaging.

I'd say "Don't do it!"

[#11]

It may not look very strong.... drilling steel plate with 6mm drill bit, did not seem to be any real problem..( drilled a 2mm pilot first )..  also have used it for drilling walls to fix shelving, and other stuff. ( it does have a very high torque, considering how it looks ! )

As mentioned... I have worked "in the shed" on various equipment... including a home made treadle powered lathe, ( used the treadle from a singer sewing machine).. and a mighty MYFORD ML8 five speed wood turning lathe, powered on the same motor as the home made circular saw bench..

so I think, if I can get the power supply sorted, that the drill works as a circular saw, right,.... then the rest will be more about care and common sense in using it. 

[#12]

Have you considered that the chuck jaws may not be powerful enough to grip whatever spindle you're envisaging to mount the saw blade on?

I'd still say don't do it.

[#13]

@shutter even at 11amps you might find that more than that is still drawn under load - heavy duty work.

Your best bet is literally to use a car battery for the drill / jigsaw and then recharge it after use from your charger. Car batteries are designed to provide large currents (eg 80amps) so will easily power your tools however a charger could be easily killed by one.

I know the batteries can be heavy but trust me it's a better option than what you're proposing. There are some small car batteries out there too. Our old renault had a tiny varta battery that never gave us a moments hassle. Most vehicle dismantlers sell them cheaply enough.

[#14]

@7up  & @RobPN  Thanks for your input.... from the "general gist" of it, it seems you are assuming that I am going to be using this "contraption". for some really heavy serious wood working.however that is not the case... if it were, I would not be considering it,  (the work ) nor the construction of this project.

I understand your concerns, regarding the practicality of it, and appreciate the technical content of the input from all, and from that I have gained enormously... I shall probably construct the framework, and the adjustable table underneath, ( to adjust the height of the blade on the cutting deck) . then give it a trial on some small items of wood...probably deal/pine  of about half inch thickness, using the battery charger, as the power supply... From that position, I should be able to see if it is worth considering @7up  suggestion of going down the scrap yard and buying a half decent battery.  Of course, having the battery, will also make the saw table more "portable" and usable where there is no mains power outlet !

The work envisaged is only of a "modelling" type,,  not building a sofa or a four poster bed ! ! ..

[#15]

Why not use a mains powered drill - although there must be a good reason why a proper saw motor costs in excess of a £100. I don't think your average Black & Decker can hack it.