Grinding tungstens

[mudsplasher]

Does everyone grind their tungstens where the grind marks run with the tip or like sharpening a pencil.

The reason I ask, in another millenia, when I learned to weld, we sharpened like a pencil. Now reading about TIG welding, I am told not to do that because it causes the arc to wander. Today I was making an engine stand for a m/c engine and sharpened like I used to and my beads improved 100%.

[Sundown]

Convensional wisdom these days says to sharpen with the grind marks stright to the tip. I do it that way when I use my grinder, however my sharpie does kind of a slow sprial to the point and in all honesty I can't tell any difference. I guess if your welds are better one way than the other, then maybe thats the way for you to sharpen them. I probably didn't help you much :o ;)

[Quadlinear]

everything I have read and was taught in adult night welding class was to grind parallel to the tungston centerline. NOT LIKE A PENCIL. Reason stated was tendancy for arc to wander. I took it for face value and never tried the perpendicular grind route. Course with Aluminum the ball is needed on the end to promote dispersion of the heat.

Alan

[90blackcrx]

Just curious while we are on the subject

Does anyone use the side of the wheel to grind them ?

In my mind it seems like it would be the wrong way.

[JD in Socal]

There are types of wheels made to grind on the side. You are not supposed to grind on the side of a regular wheel. If you read the fine print regarding safety with the grinder, they tell you if you put pressure on the side of the wheel you can turn it into a grenade.

That would be bad.

JD

[Pile Buck]

I too was always taught to grind parallel with the tungsten. I have tried it in the past by grinding the tungsten like a pencil, man will that play tricks on your eyes :eek: . The resident Tig expert Engloid will be by sooner or later and give us the technical reasons for not grinding like a pencil ;)

[KB Fabrications]

I too was always taught to grind parallel with the tungsten. I have tried it in the past by grinding the tungsten like a pencil, man will that play tricks on your eyes :eek: . The resident Tig expert Engloid will be by sooner or later and give us the technical reasons for not grinding like a pencil ;)
Actually, I think it is more common sense than technical. If you grind the tungsten spherically, the arc will tend to follow those lines making for a wandering, more erratic arc. If you grind longitudinally, the arc tends to follow those lines and produces a more stable, focused arc. Just my .02.

[90blackcrx]

There are types of wheels made to grind on the side. You are not supposed to grind on the side of a regular wheel. If you read the fine print regarding safety with the grinder, they tell you if you put pressure on the side of the wheel you can turn it into a grenade.

That would be bad.

JD

The pressure you put on the side is basically none, I'm not worried about that at all.

But I would think it would be grinding the tungsten the wrong way.

[Pile Buck]

Actually, I think it is more common sense than technical.
Ok, I stand corrected :) . I was hoping for a technical answer. I came up where the only answer you got was “Because I told you to” :eek: :D

[mudsplasher]

I had been told that the arc would wander if I ground them sperically, but I can't remember ever having it happen, except when the tungsten was contaminated. I just did some beads using both methods, and both were ok. The arc does look different, and the pencil arc is more what I remember from way back when.

As far as grinding on the side, I have always used the side and the face for my own use. I have done fabrication, mechanical, and engineering work (and play) since I was 14 and have never grenaded a grinding wheel. I did sever a tendon in my hand using a 4 1/2" grinder once though.

[KB Fabrications]

Ok, I stand corrected :) . I was hoping for a technical answer. I came up where the only answer you got was “Because I told you to” :eek: :D
Hey no need to stand corrected (you can just sit :D ). Seriously, I'm no techno head, I just remember reading that somewhere (I think in one of my Lincoln books :eek: ). Longitudinally does seem to make more sense though and I'm sure that someone will come along and enlighten us on the the fundamentals.

[HAWK]

http://www.diamondground.com/HowtoPrepareElectrodes.pdf

[Sundown]

Interesting subject, all the litrature I can find says the the grinding lines should go in a stright line to the tip. Having said that, those small dedicated tungsten grinders (of which the sharpie is one) cannot grind stright longitudinal lines due to the way they work. There must be a smaller difference between a tungsten that is ground longitudinally & one that is ground in a slow sprial then there is between longitudinally & spherically. I better stop there as I am on the verge of confusing myself. :D

[KB Fabrications]

Interesting subject, all the litrature I can find says the the grinding lines should go in a stright line to the tip. Having said that those small, dedicated tungsten grinders (of which the sharpie is one) cannot grind stright longitudinal lines due to the way they work. There must be a smaller difference between a tungsten that is ground longitudinally & one that is ground in a slow sprial then there is between longitudinally & spherically. I better stop there as I am on the verge of confusing myself. :D
Your right George. I think they strike a balance somewhere between the two. My PIII from DG give a great longitudinal finish, albeit at a cost.

As far as the smaller units like the Sharpie go, I have often wondered whether they leave a "hollow" section on the taper like what a smaller wheel on a grinder can do to a chisel. Have you noticed this at all? It may not be an issue with the small surface area. Just a thought.

[Sundown]

Your right George. I think they strike a balance somewhere between the two. My PIII from DG give a great longitudinal finish, albeit at a cost.

As far as the smaller units like the Sharpie go, I have often wondered whether they leave a "hollow" section on the taper like what a smaller wheel on a grinder can do to a chisel. Have you noticed this at all? It may not be an issue with the small surface area. Just a thought.

Kevin,

I put them under a microscope and the grind is flat without a hollow, the sprial is caused by the small diameter of the wheel. I really like the PIII but until I win the lottery it is on the list of wish's.

[precisionworks]

Does anyone use the side of the wheel to grind them ? Most diamond wheels have the abrasive layer on the side and are designed to work that way:

http://i12.photobucket.com/albums/a206/barrymilton/101_0517.jpg

"The flow of electrons along the electrode surface drives current transfer, but surface finish influences it. Scratches and grinding marks not parallel to the axis inhibit free flow of electrons. For this reason, it is important for grinding to be longitudinal and concentric.

A typical surface finish of 0.5 Ra is essential for optimum operation. Electrodes grounded normally to the axis or that have a surface finish coarser than 0.5 Ra will lead to instability in current flow. This results in:

* Arc initiation away from the tip
* Arc wander
* Thermal shock at the tip"

(Source: http://www.weldingdesign.com/323/GlobalSearch/Article/False/11347/)

[KB Fabrications]

Kevin,

I put them under a microscope and the grind is flat without a hollow, the sprial is caused by the small diameter of the wheel. I really like the PIII but until I win the lottery it is on the list of wish's.
I suspected they probably didn't, otherwise someone would have mentioned it. The fact that you, and most everyone else, have not had any arc problems from using them goes a long way to proving their effectiveness. As far as the PIII goes, If you ever want me to grind you up a bunch of custom tungstens, let me know and I'll email you my address.

[KB Fabrications]

Most diamond wheels have the abrasive layer on the side and are designed to work that way
The PIII's diamond wheel is made that way. Lasts a helluva long time too. :cool:

[HAWK]

Kevin,

For the money the PIII can't be beat.

[Sundown]

I suspected they probably didn't, otherwise someone would have mentioned it. The fact that you, and most everyone else, have not had any arc problems from using them goes a long way to proving their effectiveness. As far as the PIII goes, If you ever want me to grind you up a bunch of custom tungstens, let me know and I'll email you my address.

Thanks Kevin.....I will keep that in mind :)

[KB Fabrications]

Kevin,

For the money the PIII can't be beat.
.......... ;)

[90blackcrx]

See if you grind up top like that
http://i12.photobucket.com/albums/a206/barrymilton/101_0517.jpg

I would imagine it is the right way, but if you move down a little, I would think the grind would be sprial more which is the wrong way ( atleast when I picture it in my head it is ).

[lowlypawn]

I’m going to go against the grain and say it doesn’t matter. Ok maybe if you welding in a nuclear power plant it might matter but for the rest of us I don’t believe it maters.

What I do is stick the tungsten into a spare collet and then hold the collet so the tungsten can spin. Then I hold the tungsten on the side of my grinding wheel and it grinds a perfect point in seconds. When you stick your tungsten as often as I do you need a way to sharpen it quickly and I’m glad I didn’t spend hundreds of dollars on a tungsten sharpener when this method is nearly as fast and perfect.

Now this goes totally against what the experts say because the groves are all perpendicular to the point but I can tell NO difference form tungsten sharpened the correct way. In fact the person who taught me the trick is a professional certified welder at my work with over 20 years experience. I’m talking refineries, HIGH pressure pipeline and all kinds of other amazing welding jobs, Every time I talk to him I’m amazed by his knowledge.

Anyway I’m convinced all this “tungsten must be sharpened parallel to the point” is nonsense and would only matter in the most extreme setting IE welding parts for the space shuttle.

Someone posted this link.
http://www.weldingdesign.com/323/GlobalSearch/Article/False/11347

The only part I agree with is it will shorten the life of your tungsten but I stick mine way before that. It seems like I could weld for and hour before the tip gets really dull, but I always dip it in my puddle way before then. So shorting the tungsten’s life is really not an issue for me.

And this tungsten contamination phobia, don’t grind the metal off your tungsten because you will contaminate your wheel bal bal bal. I mean holy crap, what are people welding that it would ever matter! Rollcages for NASCAR?!? Aircraft? Even then I’m not sure it would matter.

I’ll close with this. The welder at my work, Dave, has been grinding his tungsten on an old dirty grinding wheel for his entire career with the lines going the WRONG way. He never failed an X-ray on any joint. I guess he could be lying to me but I believe the guy to be very honest and I can attest to his welds looking like a machine created em.

[HAWK]

Most diamond wheels have the abrasive layer on the side and are designed to work that way:

http://i12.photobucket.com/albums/a206/barrymilton/101_0517.jpg

"The flow of electrons along the electrode surface drives current transfer, but surface finish influences it. Scratches and grinding marks not parallel to the axis inhibit free flow of electrons. For this reason, it is important for grinding to be longitudinal and concentric.

A typical surface finish of 0.5 Ra is essential for optimum operation. Electrodes grounded normally to the axis or that have a surface finish coarser than 0.5 Ra will lead to instability in current flow. This results in:

* Arc initiation away from the tip
* Arc wander
* Thermal shock at the tip"

(Source: http://www.weldingdesign.com/323/GlobalSearch/Article/False/11347/)

Barry,

Good information. I want to share some information I learned the hard way. A 20 Ra finish seems to work fine on most machines. This can be achieved with a 300 grit diamond wheel.

Lower number Ra finishes appear very slick and smooth to the eye. This slick as glass polished and tapered tip works great with orbital welding machines and eliminates one more variable of error. However, some manual welding GTAW power sources will not strike an arc with less than a 20Ra finish. This seems to be prevalent in machines with weak HF generators. Also the larger the electrode size the coarser grind it can tolerate. I use a 300 grit wheel on 5/32" and 3/16" tungstens while I prefer a 600 grit wheel on 1/8"-.040" diameters. I used chem sharp on .020" and .010" tungstens.

Just for the record I have used highly polished and tapered tungstens ground on CNC machines for orbital welding that work just fine on the Dynasty 200 and 300 series machines.

[Pile Buck]

Not a very good picture, but best I could do :confused: . The tungsten on the left I’ve had since the late 1970’s. For a project requirement I had to pass a 6-G open root 316-L pipe test. Company sent me back to school. Around here the Navy has a huge presence. The local jr. college welding school was taught by one of the local Navy yards P-1 weldors. This guy worked on high pressure piping systems on the nuclear submarines. The last week or two of my class he would bring in 1-inch hydraulic tubing with consumable inserts. He would set them up 6-inches from the ceiling, and 6-inches from the wall, and have me weld with a mirror. At this time he would bring in these machined tungstens. He said anything to do with nuclear they were required to only use machined tungsten. The picture doesn’t do the quality of the finish justices. The one on the right is how I hand grind my self if I want little penetration.

[precisionworks]

A 20 Ra finish seems to work fine on most machines. This can be achieved with a 300 grit diamond wheel.

Hawk, good information! I wondered when reading the article about the .5Ra finish (mirror polish). My diamond wheel seems to produce around a 10 to a 15 finish.

Since going to the diamond wheel, I've noticed much easier arc-starts on low-amp aluminum with 75 Helium. The 'green wheel' used before, fine grit, produced a coarse grind. Low amp arc starts were always iffy, especially with Helium.

Also, arc starting in an undercut is much easier and arc placement is more precise. I always undercut (bevel grind or bevel turn) round stock that will be welded to flat stock. The diamond ground tung allows arc starting at the deepest part of the weldment - what pipeliner's would think of as a root pass. Before, the arc would want to start short of the deepest point.

[RadMan]

See if you grind up top like that
http://i12.photobucket.com/albums/a206/barrymilton/101_0517.jpg

I would imagine it is the right way, but if you move down a little, I would think the grind would be sprial more which is the wrong way ( atleast when I picture it in my head it is ).


Crx, If you keep grinding the color bands off your tungstens, you will most definatly get a visit from the electrode police . :D

[90blackcrx]

Thats not mine radman, someone else posted that pic.

[precisionworks]

I'm busted! Those belong to me :D

Not much of a problem, as there's nothing in the shop but 2% Ceriated. .040, .062, .093 & .125.

Nice tungstens for AC & DC both.

[halbritt]

I wonder if I'm the only one using a belt grinder to prep tungsten. I chuck it in a cordless drill and run it into the belt at whatever angle I like and get a nice longitudinally ground point every time. I use dedicated belts as they're cheap and I can get whatever surface finish I like (up to about 600 grit).

[HAWK]

If I'm working in my buddy's machine shop that the way I do it too. It's all they use other than the occasional dip in chem sharp.

[RadMan]

I'm busted! Those belong to me :D

Not much of a problem, as there's nothing in the shop but 2% Ceriated. .040, .062, .093 & .125.

Nice tungstens for AC & DC both.



Aha! the KISS principle....I like it. unfortunatly I need my colored bands, my tungsten drawer is a dogs breakfast.


Halbritt , belt grinder eh? interesting....