Filling Holes and Re-Drilling

admin

I'm a total novice and learning as I go in the Garage,---It's certainly addictive and satisfying, when all comes out well.To start off, I just went ahead and bought a cheap Flux wire machine from H.F.( Despite all the good counsel not to !).  Frankly, so far, I'm impressed, ---but I'm a novice remember and probably don't know what I'm looking at.Changed out the supplied wire yesterday for .035" Lincoln Innershield NR-211MP.,---what a difference--, so much cleaner.  What I've tried to do, is probably beyond the capacity of the Welding Machine.I filled a couple of 1/4" holes, in a 3/4" wide, 1/2" thick piece of 1018 Steel.(I messed up measuring).  The drilled holes go the width of the steel(3/4"). Inserted a Brass Punch to about midway through the hole, clamped it and filled half the hole.  Turned the bar over an filled the other half.Looks pretty reasonable, but to Drill it, is something else !.Starts off ok, but as I go down the Weld fill, feels/is Harder.  I've blown away two HSS Dormer drill bits on one hole to the point where they're completly blunt.  Filing the Weld , prior to drilling, it feels soft enough and files ok.What might be happening (Physically) , inside the hole to make it so hard to drill through .There are no voids visible looking through the redrilled hole.Any good guidance appreciated. Thanks.
Reply:the welded area is now harder and stronger than the surrounding metal (from being welded) someone correct me if im wrong, but if the area was heated and cooled correctly with a torch it would make it easier to work with there might be some neat tricks in the minds of the experienced here but i dont know any other than the torch treatment
Reply:Bless your heart!  1/2" thick, Good Lord!! Anyway, weld metal is harder than base metal. Go slow with the drill and use a little oil to lubricate.City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:A 1018 steel is not hardenable by heattreatment. The only way it could be harder is if carbon is added or if it is work hardened. The filler must have added carbon to the base which made the steel harder. --Gol'
Reply:Ummmm, I generally like NR211-MP Innershield.  Within its limits and the welder's (machine) limits as well.And you are -so- over the limits on the machine and the wire!!!!Lincoln lists a material thickness limit of 5/16 inch thick for NR-211-MP Innershield wire up to and including 0.045 diameter.  For 0.068, 5/64, and 3/32" (1.7, 2.0, 2.4mm) diameter wires, maximum plate thickness is 1/2 inch.See http://www.mylincolnelectric.com/Cat...et.aspx?p=5853 for the spec limits on NR-211-MP wire right from Lincoln.Next, your machine (pretty much -any- machine) running 0.035 FCAW wire can not put out sufficient energy (heat and amps) to properly get the wire to melt and fuse into a 1/2 x 3/4 chunk of steel.  That's going to be a classic or textbook case of "cold lap" or "inadequate fusion" or a "cold weld".  Yes, the machine can melt the wire just fine, but that melted wire and the arc energy are not sufficient to melt into the workpiece properly.  And that's no matter how many passes you do (the MP in the wire name is for "multi-pass").As to why trying to drill through the weld is tough, it's because the weld -is- stronger than plain old 1018 steel.If your 'new' hole location overlaps the 'old' mis-drilled hole location and hence you are trying to drill (or mill or ream or whatever) through at least part of the filled-in 'old' hole, maybe you can take your original 1/4 dia hole and make it bigger so that the 'new' hole goes entirely through the hole and doesn't catch any edges.  Then plug the bigger hole with a solid rod (attach the rod to the main workpiece with a combination of a shrink-fit and some deep but not full depth welds.  Redrill the 1/4 inch dia hole so that it goes through the 'meat' of the plug and doesn't catch any edges of weld.Last edited by MoonRise; 12-06-2007 at 03:21 PM.
Reply:there are ways to temper/normaize the metal that would allow you to work it easier, but the weld would have to be the same composition as the base i believe... even if it were able to happen, it takes a couple hours usually and a LOT of heat... you are pretty much re-heat-treating the metal, but cooling it slowly over a period of time... a bunch of carbon molecule movement mubo-jumbo... long story short, you probably don;t have the time, nor the equipment to do it right. you are better off just going as slow as possible with your bit(s) and lubricating... use pilot bits as much as possible... split-points work great... make sure they are SHARP too... it's only the sharpened edge that SHOULD be doing the cutting... get some good Cobalt Bits if you plan on doing any real drilling into metal in the future... one or two jobs won;t jsutify the cost, but in the long run, they will save you money...even the tip angle helps... this is an excerpt of an e-mail i got from my old boss... he's a manufacturing engineer/machinist... been doing it since the early 70's..."the more cobalt in a drill bit the tougher it is. Carbide would be over kill in cast or aluminum plus too expensive also you need to look at the drill tip cast iron needs to have a 35deg split point to cut well, most newer drills have this point already. For aluminum you need a drill with some TiN coating so the metals will not stick (cobalt would still work here also) and a 118 deg or greater point. I would not spend too much cash getting the top of the line drill for something your only going to use once in a while. A good HSS (High Speed Steel) will do a good job with the right point on it."hope that helps.Later,Andy
Reply:If the welded area can be annealed, it has to be heated red and cooled slowly.  I can't give you exact temps, but low cherry red should be enough.   Bury it in sand,or Speedi Dry $7.00for 40 lb bag, or something to keep the heat in including wrapping it with insulation.  Let it cool and try to drill again.  Maybe 150 Rpm with some kind of coolant or cutting oil. I use penetrating oil from a spray can.I really would like to see a pic of this.  I have to agree, 110 mig is not in the 1/2" plate league.  I would be amazed if there are no slag pockets.DavidLast edited by David R; 12-06-2007 at 05:17 PM.Real world weldin.  When I grow up I want to be a tig weldor.
Reply:Thanks for all the replies and expertise: I have a LOT to learn.  Just blew another drill away !.Best thing would be to get another bar of Steel, which is "order online", as I can't find the stuff locally.Working within limits of Machine and capability is obviously the key to success.Thanks again folks, time for new steel.  Good lesson though, I'll know better next time.Last edited by David R; 12-06-2007 at 05:44 PM.Reason: Fix pics
Reply:I attached the pics to show how deep I can go through the 3/4" width before the "hardness" appears.  Finally managed to get through the other end.Need new piece of steel though.
Reply:You could heat that red on a gas kitchen stove.Thanks for the pic.  It doesn't look as big as it sounds.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:I'm going to slice through with a cutting disc to look at the inside. I'll post a pic.What doesn't look as big as it sounds ?--Don't understand.
Reply:Cross section of piece, Pics attached.Last edited by David R; 12-06-2007 at 06:29 PM.Reason: Fix pics.
Reply:Decent post-mortem pics of your weld-filled holes.Notice that you can pretty easily see a demarcation line between the weld metal and the old hole wall?  That weld never melted into the steel bar!  It's pretty much just sitting as a slug of hard metal in a hole.If the weld doesn't melt into the workpiece, all you have is "cold lap" AKA "a cold weld" AKA "lack of fusion".Depending on the service needs of your workpiece, for mild service needs you might have been better off taking a rod of steel and plugging the misdrilled holes via a shrink fit.  For critical or severe service needs, scrap the oops piece and redo with a new bar.Remember that just because the welding wire melted doesn't mean that the workpiece melted so that the two sides became one with one another.
Reply:Thanks Moonrise, makes perfect sense.  Now I know what a "cold Weld is".Never occurred to me. Blissful ignorance !!.Thanks again everyone
Reply:Ok, I'm back.   That's not to bad of first effort though, is it, for a 90 amp H.F. Unit and about 4 hours of Welding experience .   Even though the "Patient" died something was learned.
Reply:I don't see any real chips around that hole if that fine dust is what I think it is  .  My guess, and let me know, is you're drilling with a hand drill and fairly high speed. You're work hardening that filler material as you drill. With something like T-11 filler, if you spin much at all without cutting and making forward progress---------you're done. Stainless is triple worse yet. Another note would be for future reference, if this needs to be done for some reason, go ahead and open the hole up some more so you can get a good puddle going and work it up.
Reply:The attempted drilling was done fairly slowly on a Mini mill. The fine dust was all that was coming off. Normally , I see lots of nice curly spirals of cut steel. It's abandoned and need to get more steel.
Reply:Originally Posted by RetiredoneThanks Moonrise, makes perfect sense.  Now I know what a "cold Weld is".Never occurred to me. Blissful ignorance !!.Thanks again everyone
Reply:Originally Posted by RetiredoneThe attempted drilling was done fairly slowly on a Mini mill. The fine dust was all that was coming off. Normally , I see lots of nice curly spirals of cut steel. It's abandoned and need to get more steel.
Reply:How true.  Whilst I look for a good source of Steel I'll cut a little a more off the end and attempt a Double Butt join Weld ? (been reading !), just for the practice. If it comes off ok , I might still be able to use that piece and have virgin 1018 to drill into. It is really soft steel though.