how to use a die grinder?

[balmerchris]

Got a Metabo die grinder a while back and it's a useful bit of kit but it scares the bejesus outta me. Sometimes it works a treat and then for no apparent reason it bounces or flicks up away from the piece. Sometimes I can't even keep it on a piece as it seems to just want to bounce or vibrate on the piece. Is there a special way to hold it can it be used horizontally and vertically?
By the way I'm using tungsten carbide burrs

 

[normspanners]

sounds like the burr is not central, the collets and some burrs are different sizes 6mm and 1/4 and if mixed are not happy with each other that can cause bounce.

 

[pedrobedro]

Direction of travel might be the problem, clockwise works for me with my air grinder and the electric ones we used to use for fettling were the same.

 

[p0689109]

I concur with pedrobedero. It depends in which direction you are moving the bit in. The grinder can react due to its motors rotation. You just have to be aware especially near an edge.

 

[balmerchris]

Ok thanks I'll try one direction.

 

[balmerchris]

sounds like the burr is not central, the collets and some burrs are different sizes 6mm and 1/4 and if mixed are not happy with each other that can cause bounce.

Ok thanks norm I will check that
that!

 

[mike 109444]

If you are familiar with the term "up cut" and "climb mill" then what you need to do is "up cut" Climb mill is where the cutter is trying to climb over the job and will grab and jerk. With a die grinder once it starts to do that it will jump around. Another thing to try is to (if you are right handed) hold towards the front of the die grinder body with your right hand and use your left hand to move the back end of the grinder to take a cut. Your right hand acts as the pivot point and if possible should be rested on something firm. I don't use die grinders but use small routers to do the same thing.
As a point of interest I did work at a place where they machined 3ft x 2ft x 3" cast iron tables for presses and would machine 3 at a time slots for the "T nuts" using climb mill. Interesting when the cutters found a hard spot in the cast iron

 

[balmerchris]

Thanks Mike, very interesting.

 

[AndyStobbs]

Also for best speed control sit your fore finger under the trigger plate and use your thumb to apply the pressure. Moving your finger back or forward will give you excellent control. Snap the stupid flap off the end of the plate if fitted. The thing that you have to pivot pefore the trigger plate will depress.

 

[balmerchris]

Also for best speed control sit your fore finger under the trigger plate and use your thumb to apply the pressure. Moving your finger back or forward will give you excellent control. Snap the stupid flap off the end of the plate if fitted. The thing that you have to pivot pefore the trigger plate will depress.

The one I have is 110 volt andy
http://www.metabo.co.uk/Product-catalogue-handheld-powertools.23958+M5a1f8da1b5d.0.html
Older version of one in link. Bit of a hand full compared to an air one.

 

[AndyStobbs]

Oh. {Shot down smiley}

 

[chunkolini]

Hold it securely. Make sure the cutting edge cant bounce of the edge of the workpiece. it can snag and and bounce horribly.
Dont try and ream out holes with one. Ahem. it can work but once it goes wrong it goes wrong horribly and bounces all over the place and snaps the bit.
Once you get used to it you can use it one handed, a lovely tool but one that can bite.
I guessed that yours would be a long handled model.
I can see how they would get out of control at that length.
Other thoughts, dont wear your best fleece jacket when using it. (picked this one up from here) the tiny bits of swarf stick in fleece like nobody's business and get everysodding where. Collars up as well. if you work in strong sunlight, sun low in the sky it is like standing in a rain of glitter. It looks lovely. Itchy scratchy glittter. In my workshop this time of year I get this effect at the end of the day.

More thoughts, spin direction? it is trying to drive itself as it spins against the workpiece, move against that. Then it cant catch and kick itself off (from personal experience) you are driving it, it is not trying to drive you.
I tend to use my right hand to drive it and left hand as a guide.
Buy decent bits for it, the good ones last ages. Gerryson? I think.
Never let anybody else use it, they will knacker the bit instantly and refuse to pay twenty quid for a new one.

Brilliant tools. But a bit scary.

 

[balmerchris]

Thanks chunkolini. I got a box of 10 Metabo cutters with the machine but only really use 2 of them. Do you think an air powered one would be easier to use?

 

[cecotto479]

Ok thanks I'll try one direction.

They're crap!

I always preferred Westlife myself.

 

[GrahamGKD]

The one I have is 110 volt andy
http://www.metabo.co.uk/Product-catalogue-handheld-powertools.23958 M5a1f8da1b5d.0.html
Older version of one in link. Bit of a hand full compared to an air one.

I think I probably have the 240v version your Metabo - it doesn't have the removable rubber sleeve that the one in your link has but it does have a long neck down to the spindle? Mine is variable speed. I mostly use it for surface finishing with the spindle mounted flap wheels that have been mentioned on this forum for surface finishing (brushing) stainless steel. I do a lot of that for one of the jobs I do periodically. I have used grinding tips in it but have not got around to trying burrs. I hold it with my left hand on the neck close up to where the spindle emerges - right hand on the motor body next to the switch.