PK200 Table Saw Accident

[Little Ern]

I’m an avid reader but never feel confident enough to contribute very much so it’s a while since I posted on this forum but I thought I’d just share with you the accident I had this morning on my table saw. I was ripping some 25mm timber, guard in and riving knife in place, when the saw stopped dead. I switched off the saw and also at the plug. I thought, I wonder if the blade will rotate freely so, like an silly person I grasped it between thumb and forefinger to see if it would spin. It span alright! taking a chunk out of my thumb. I can only think that it was stored energy in the spindle.
I won’t be doing that again in a hurry. A trip to A&E and all’s OK except my saw won’t operate at all. I’ve checked the fuse in the plug which is OK and can here a slight clunk from the NVR switch but nothing else. Does anyone know if there’s an internal fuse. The saw is PK200. Any other thoughts on what to look for to fix the saw would be appreciated.

Many Thanks.

 

[Lord Nibbo]

Sorry to hear about the injury. I expect if it is belt driven it still had tension on the belt after it was turned off. A bit like elastic pulled tight.

 

[Lark]

thanks for sharing as i did not know that could happen

 

[gidon]

This sounds very nasty and not something I quite understand to be honest. So thanks for the warning and hope it heals quickly.
Cheers
Gidon

 

[Gordon T]

Sorry to hear about your misfortune, they need treating with respect don't they!

I am not familiar with that saw but it would be worth ringing a dealer and to pick the experts brains, they may have come across this before.
( just remember ex is an unknown factor, and a spert is a drip under pressure) :lol:

GT

 

[Woodmagnet]

Sorry to hear about your accident Ern, but thanks for reminding us to be vigilant. :wink:

 

[Digit]

If it's belt driven Gidon, and the blade jambs, for example, the motor will still be pulling the blade round till the fuses blow, cut out operates, etc.
This means that one side of the belt is under tension, and as soon as the jamb is removed the blade will turn, pulling the motor round with it till friction, (thumb etc) stops it.
Belt driven means smooth power, and they can be quieter, but this habit should be remembered and applies to all belt driven machines.

Roy.

 

[Little Ern]

Thanks for your your comments.
I'll contact the local Tool Shop to check on the repair options as suggested.
I still can't explain anymore how it happened other than to confirm there was no electrical power to the saw and the timber being cut had been removed and laid aside long before I reached for the blade???

Thanks again.

 

[Digit]

That's certainly odd!

Roy.

 

[Racers]

Hi,

When the motor stops its not applying any force to the belt, it can't store any energy unless the bearings are sticking causing drag, any tension in the belt would just turn the motor equalising the tension on both sides of the belt. The only thing I can think is the motor must have been spinning maybe running down not quite stopped.


Pete

 

[newt]

The PK200 is not belt driven

 

[CHJ]

Is it a series (commutator) motor? could it be that there are suppressor capacitors in the circuit and moving the commutator caused them to discharge through the com. segments. If this is so I would check the length of the brushes.

 

[kafkaian]

I think it certainly needs reporting to the manufacturers so they can include a warning in their manual if they haven't done so already.

Bad form! Get well soon!

 

[oddsocks]

I've got a PK200 and the motor hesitates occasionally (i.e once or twice a month) - I mailed matebo (they own elektra beckum now) some months ago but never got a response. its not the brushes as I bought replacements.

Little Ern - the brushes are easy enough to take out once you realise that you don't need to completely remove the motor if you just tilt it!!! I of course realised this the hard way.

If you find the brushes are worn down you can buy new from metabo dealer - but bizarrely they sell them in single packs so you will need two! Alternately PM me and i'll see if i can find my old ones and I'll post them- they were hardly worn at all

 

[steve tighe]

Little Ern

Have a look in the electrics box on the machine,there may be some kind of reset button there mate,an overload safety device to stop the motor burning out if the blade jams ?

 

[Digit]

Read the instruction book! :wink:

Roy.

 

[Little Ern]

Thanks once again for the replies/comments and thanks for the offer Oddsocks.
Confidence slightly dented at the moment so I think I'm going to take it along to the local DIPT dealer who service Metabo stuff. I'll talk to them and get them to fix it. I don't have an instruction book as the machine was second hand.

Reasons to be cheerful! A friendly TNT driver delivered a Metabo KGS255 Plus SCMS yesterday afternoon.

Thanks again.

 

[newt]

When you spun the blade are you sure there was some stored energy or did it just spin due to your input. It is difficult to understand how there could be stored energy as I do not think there is a starting capacitor as it is a brushed motor. If it did have stored energy sufficient to cut you before it stopped this is a very serious issue. I have tried to simulate this on my PK200 using a stick but there is nothing, of course my motor is servicable so clearly not the same conditions as yours. Please keep us posted.

 

[Little Ern]

Hi Newt,

I didn't actually spin the blade but just went to try and see if it would move. It zoomed around for a few revs and the rest is history. It was almost as if the timber being cut had nothing to do with the blade stopping dead. I think just the slight movement I made on the blade released whatever was holding it back. Just to confirm, I'd switched it off prior to this. I have to confess not to thinking too clearly from that point onwards!
It makes little sense I know, but that's how I'm sure it happened. The fact that there has been no power to the blade since then sort of confirms that the saw was off at the time.

The only thory I can offer is this (but it's only an idea):
The saw blade stopped dead mid cut.
The power was turned off.
The wood was retracted and the blade remained stationary.
If the motor was trying to turn the blade but couldn't then there would be some torsion in the shaft which was released when the blade eventually freed.
Probably daft but I can't think what else could have caused it.

I'll let you know the outcome when I take it to the repairers.

 

[newt]

Little Ern, I just wonder if there was a fault with the switch and there was still power at the motor, but went off when it started to turn. From my engineering back ground I cannot see there was any energy in the shaft that would cause the blade to spin up and do several revolutions. Very interesting and worrying.