point grinding on tungsten for DC

[blackolive (Ste)]

Ive been grinding my tungsten point with a diamond wheel on the angle grinder, but having looked at the faq a bench grinder is the way to go. will a normal grey wheel do the job ?

 

[brightspark]

a green wheel ???

 

[Paul.]

An ordinary fine aluminium oxide wheel is fine, for high quality and specialised tig work there are alternative wheels, but not required for general work, green stones are intended for tool grinding and are wasted on tungstens, when I was taught to weld the recommended method of tungsten preparation was to use an emery band,

 

[brightspark]

An ordinary fine aluminium oxide wheel is fine, for high quality and specialised tig work there are alternative wheels, but not required for general work, green stones are intended for tool grinding and are wasted on tungstens,

lol that told me

 

[Shox Dr]

if you are already using, a grinder for the job, I wouldn't bother with a bench grinder until the disc on the hand grinder wears out. so long as you are grinding to the point, it will be fine




edited; to make sense

 

[blackolive (Ste)]

cheers, Ill try the bench grinder on the grey wheel ( my thought was would I need a green wheel ) .

how short can they go before binning them ??

 

[KennyC]

I'm guessing you're fairly new to tig welding.

I found this video fairy useful, hopefully you will too

http://www.youtube.com/watch?v=tNYmo2_DI6c

 

[Hitch]

Until they are too short for the collet to grip really. If the collet is in good condition it helps grip better.

 

[Garreth]

excuse me if this is a bit off topic......

on small (1.6) tungstens I always grind to a sharp point with length of taper 2.5 - 3 times the diameter.

I was reading somewhere the other day that recommended grinding a very small flat accross the point. The article said that a sharp tungsten eventually becomes blunt, and some of this lost tunsten finds its way into the weld causing contamination. The article said that grinding the flat helped to maintain the shape of the tungsten for longer causing less contamination but with no loss of arc performance.

Any thoughts ?

Cheers !

Garreth

 

[hotrodder]

Yeah, leaving a small flat at the tip can be benficial. Tungsten tip geometry is a compromise... arc stability, arc shape (and penetration) versus tip life/current handling ability being the biggy but more detail here http://www.pro-fusiononline.com/tungsten/geometry.htm Leaving a flat at the tip tends to improve tip life without having an impact on arc stability, kinda a best of both worlds

Personally i don't bother with tungstens smaller than a 1.6mm and just grind 'em very sharp with a fine finish when welding at low amperages, say 0.5mm stainless for example. At higher amperages i'll put a flat at the tip and use a shorter taper. Others might use a 1.0mm for low amp stuff and swap to a 2.4mm sooner and grind everything with a similar length taper, lots of ways to skin a cat.

If you really want to get into it then there's ... http://www.diamondground.com/TungstenGuidebook2011.pdf

 

[Garreth]

Yeah, leaving a small flat at the tip can be benficial. Tungsten tip geometry is a compromise... arc stability, arc shape (and penetration) versus tip life/current handling ability being the biggy but more detail here http://www.pro-fusiononline.com/tungsten/geometry.htm Leaving a flat at the tip tends to improve tip life without having an impact on arc stability, kinda a best of both worlds

Personally i don't bother with tungstens smaller than a 1.6mm and just grind 'em very sharp with a fine finish when welding at low amperages, say 0.5mm stainless for example. At higher amperages i'll put a flat at the tip and use a shorter taper. Others might use a 1.0mm for low amp stuff and swap to a 2.4mm sooner and grind everything with a similar length taper, lots of ways to skin a cat.

If you really want to get into it then there's ... http://www.diamondground.com/TungstenGuidebook2011.pdf

Thanks for that - makes very interesting reading !

I think I'll try using a flat and see how I get on.

Cheers for the heads up !

Garreth

 

[backpurge]

how short can they go before binning them ??

It's usually when you take the end of your finger off on the grind stone

 

[Shox Dr]

It's usually when you take the end of your finger off on the grind stone

I've just sat and reground, a drill case full, of small Tungsten's, I keep for use with a small end cap, varying in length from 60mm down to 25mm.

I used to put the short ones in a pin vice, but it takes far too long, messing about, so I just hold them now, quenching when required.