DRILL DOCTOR Grinds Tungsten Electrodes

Which way does it put the grinding marks? You have to keep the grinding marks axial, not radial.

Pete C.

It puts them axially. The drill doctor works like this: there is a vertical cylindrical diamond wheel, and drill bits are inserted from the side. I do the same thing with a tungsten, except that I do not use the special drill holder for precide drill grinding, and instead hold the electrode by hand.

Finally, somebody found a legitimate use for a "Drill Doctor"

Haha... Actually, it does a pretty decent job at sharpening drill bits too!

Why? Old welders tale or has anyone actually tried it?

GmcD

Ask Ernie on sci.engr.joining.welding

I believe radial grinding marks will negatively affect arc stability.

Pete C.

Absolutely all tig manuals say to grind electrodes axially. They say that doing otherwise will cause wandering arc.

Axial grinding is the only way that I can grind electrodes in my drill doctor, anyway. I am basically happy with it.

Are you grinding thoriated tungsten? Is the grinding dust hazardous?

Sigh..ya..Ive tried it. And yes..it makes the arc wander all over the place if you dont do it axially. I now rough radialy..then turn the electrode parallel to the wheel and fine point it.

It was driving me nuts and I finally looked it up. Self learning Tig has been a roller coaster ride.

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the s*it out of you for torturing the cat." Gunner

It is not considered hazardous, but it is mildly radioactive. I can always take this drill doctor outdoors.

Call me chicken, but I would not want to breath the dust.

I do not want to breathe any metal dust. I breathed some bronze dust recently and had bitter taste in mouth for a week, from any food that I would eat.

I am not emotionally attached to DD, but it works great for me. I sharpened both big and small bits. I am curious, what model did you buy. I have a model 750, IIRC. Perhaps you had a less advanced model?

"> Haha... Actually, it does a pretty decent job at sharpening drill bits

You have a low "Does a pretty decent job" threshold. IMHO, they are crap! Send me whatever you spent for the DD and I'll sharpen your drills for life!

Tom, I am not a drilling whiz. What I do know is that drill bits that I sharpen with DD, work pretty well for me after re-sharpening. That includes some 1/2" drill bits that I thought were fully ruined.

Not to be a dufus here, but just what is grinding "axially", I grind my tig electrodes and would hate to think that the trouble I am having welding Aluminum is because I am grinding my electrodes wrong.

Thanks

John

I'll have to second that... I have one of the older model 500 sharpeners, and it works remarkably well for what it is. I did find that it takes some getting used to the wrist motion required to get a nice finish on the bit, and it helps if you clean up the bit a tad with a stone after you grind it, but I have always found it more accurate than freehanding a drill bit. I'm not ham fisted with grinder work by any means (as an example, I can hand grind my tungstens well enough that my TIG instructor thought I was using an electrode grinder), but the Drill Doctor is just more reliable at getting the angles correct.

I don't doubt there are people who can do a better job by hand than what is done by a Drill Doctor, but I'm certainly not one of them. And I've never had a bit sharpened with the thing fail to put a clean, proper hole through the workpiece, which I'd think is about all could ask for a device of that sort in its price range.

The grinding marks need to run along the axis of the tungsten rod, a.k.a. along the length.

Aluminum is tricky for sure. According to most references you're supposed to ball the end of the tungsten when welding aluminum. You're also supposed to use pure tungsten or the newer Lanthenated for aluminum.

Various sources indicate you should grind it leaving a flat at the tip and then run it on DCRP (I think) on a scrap of copper to ball the end. Other sources say just point it like you would for steel and run it hot on a scrap for a few seconds to ball the end.

The aluminum alloy and it's cleanliness make a huge difference in the results. The AC balance control on the square wave TIG machines helps a lot in overcoming surface oxide issues. The other thing that is a bit counterintuitive is that you need more current on aluminum due to it's thermal conductivity. You have to basically hit it hard and get the weld done before too much heat spreads outside the weld area and turns the whole thing into a puddle.

I'm certainly no welding expert (Ernie on sci.engr.joining.welding is), but the things that I've welded (steel and aluminum, mostly TIG) have all held together.

Pete C.