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Machining aspect of reaming mig contact tips up to bigger size

JasonPAtkins

Hot Rolled
Joined
Sep 30, 2010
Location
Guinea-Bissau, West Africa
Hey all, I realize this would be a waste of time in the US, so please don't waste time commenting to that effect. My location, supplier availability, and local labor rates are different than the States and change the equation about what's worth doing in-house. Of course I know reclaiming a $1 contact tip isn't worth the thought in the US.

Given the above, I'm considering the feasibility of reusing worn out .030" mig contact tips by reaming them up to .045". Presuming equal consumption rates of the two sizes, I'd switch to just buying .030 tips and then when they were worn (since it's only ever the bore that wears on them anyway) reaming them with a .045 reamer and using those as the .045 tips we need. Since they're copper, would you expect to want to over or undersize the reamer for such an application, or should I just order right on .045"?
 
Jason,

I do it all the time. I find the nearest drill and drill them out.

If you run out of .45 contact tips on Friday afternoon and the welding shop doesn't open until Monday, it can be a huge time saver.

Can't hurt to try if your in a bind.

Chuck
 
Jason,

I do it all the time. I find the nearest drill and drill them out.

If you run out of .45 contact tips on Friday afternoon and the welding shop doesn't open until Monday, it can be a huge time saver.

Can't hurt to try if your in a bind.

Chuck
Thanks! You're not even bothering to ream, just run a twist drill through them? Do you notice they don't last as long as the factory ones, or not much different?
 
Been drilling em for decades. Getting rid of splatter and for upsizing. Easy to do but am doing just home shop level mig. No structural or pressure welding, and have nothing objective for quality of welds.
 
Never done it but I was told a D bit made of piano wire drills and reams ( or polishes) at the same time.
Seems like an idea, you’d want a smooth bore for good current transfer I suppose , though I butcher them with oxy nozzle reamers, works.
I do have a few carbide drills matching the tip for 0 and 1 DA / oxy for melty clogs.
Mark
 
Just drill em out and use them. I’ve done it to accommodate lightly rusted MIG wire. It isn’t rocket science.
 
I have never worn a contact tip's bore out. It's always the end which gets encrusted with spatter eventually (where's that dang can of nozzle dip?) and torn off when the spatter is removed that does for my tip. After awhile the wire sticks to the tip and then pops loose. Then it sticks to the tip and doesn't pop loose and the tip is done. I have tried sanding the tip smooth and square again on a fine grit sanding belt, but it always seems to smear over the bore. So I just replace the tip.
 
I have never worn a contact tip's bore out. It's always the end which gets encrusted with spatter eventually (where's that dang can of nozzle dip?) and torn off when the spatter is removed that does for my tip. After awhile the wire sticks to the tip and then pops loose. Then it sticks to the tip and doesn't pop loose and the tip is done. I have tried sanding the tip smooth and square again on a fine grit sanding belt, but it always seems to smear over the bore. So I just replace the tip.
Interesting. I always assume that the wire sticks to the tip because the bore is worn/pitted and not making good contact anymore, leaving the only contact point at the tip (which isn't enough surface area for the amperage) making it weld together. Unless you're touching the contact tip to the work, I think it's sticking there because there's not enough of the smooth bore left making contact to transfer the current.
 








 
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