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Posted by on March 14, 2008, 11:30 pm
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I have a project,,, where I am welding a mild steel threaded tube to
a .106 thick mild steel tab that is about 1" long. The tubing is 3/8
OD, with .280 ID, threaded 5/16 x 24.
The weld goes lengthwise on the tube, and is the full 1" long.
I am having trouble not distorting the threads in the tube when
welding. I am tig welding with a 1/16 or 3/32 electrode (sorry, will
check in the morning for sure... it is the thinnest I have) and 1/16
(also the thinnest I have)mild steel filler. I am not a weldor, but
have had some tig and mig formal training.
Machine has a pedal that varies the welding amps, and I am not hitting
it really hard at all...
I tried putting a bolt inside the tubing while welding, but that just
fused the bolt to the tube, oops.
Anyone give me some constructive, positive help please?
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Posted by ED on March 15, 2008, 12:25 am
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On Fri, 14 Mar 2008 20:30:34 -0700 (PDT), rbce2003@hotmail.com wrote:
>I have a project,,, where I am welding a mild steel threaded tube to
>a .106 thick mild steel tab that is about 1" long. The tubing is 3/8
>OD, with .280 ID, threaded 5/16 x 24.
>
>The weld goes lengthwise on the tube, and is the full 1" long.
>
>I am having trouble not distorting the threads in the tube when
>welding. I am tig welding with a 1/16 or 3/32 electrode (sorry, will
>check in the morning for sure... it is the thinnest I have) and 1/16
>(also the thinnest I have)mild steel filler. I am not a weldor, but
>have had some tig and mig formal training.
>
>Machine has a pedal that varies the welding amps, and I am not hitting
>it really hard at all...
>
>I tried putting a bolt inside the tubing while welding, but that just
>fused the bolt to the tube, oops.
>
>Anyone give me some constructive, positive help please?
Possibly try a copper or brass bolt to insert into the tube.
I couldn't weld .047 wall tube without warpage, Silver
solder maybe but not weld. If it were me I'd weld the tab to
solid bar stock then machine the threaded hole.
ED
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Posted by Ned Simmons on March 15, 2008, 12:27 am
Please log in for more thread options On Fri, 14 Mar 2008 20:30:34 -0700 (PDT), rbce2003@hotmail.com wrote:
>I have a project,,, where I am welding a mild steel threaded tube to
>a .106 thick mild steel tab that is about 1" long. The tubing is 3/8
>OD, with .280 ID, threaded 5/16 x 24.
>
>The weld goes lengthwise on the tube, and is the full 1" long.
>
>I am having trouble not distorting the threads in the tube when
>welding. I am tig welding with a 1/16 or 3/32 electrode (sorry, will
>check in the morning for sure... it is the thinnest I have) and 1/16
>(also the thinnest I have)mild steel filler. I am not a weldor, but
>have had some tig and mig formal training.
>
>Machine has a pedal that varies the welding amps, and I am not hitting
>it really hard at all...
>
>I tried putting a bolt inside the tubing while welding, but that just
>fused the bolt to the tube, oops.
>
>Anyone give me some constructive, positive help please?
What, no opportunity for sarcasm or a redesign of your part? <g>
This isn't gonna be easy. If I was doing this (and I've TIGed a ton of
thin wall tubing) I'd try .035 or .040 filler. You want the smallest
bead possible. I like Inconel wire for this sort of thing. The 1/16
tungsten should be OK, but an .040 might work better. But I wouldn't
be too optimistic - as you've discovered, it won't take much
distortion to bugger your thread. How about silver brazing, or TIG
brazing with Everdur (silicon bronze) wire?
--
Ned Simmons
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Posted by on March 15, 2008, 1:07 am
Please log in for more thread options On Fri, 14 Mar 2008 20:30:34 -0700 (PDT), rbce2003@hotmail.com wrote:
>I have a project,,, where I am welding a mild steel threaded tube to
>a .106 thick mild steel tab that is about 1" long. The tubing is 3/8
>OD, with .280 ID, threaded 5/16 x 24.
>
>The weld goes lengthwise on the tube, and is the full 1" long.
>
>I am having trouble not distorting the threads in the tube when
>welding. I am tig welding with a 1/16 or 3/32 electrode (sorry, will
>check in the morning for sure... it is the thinnest I have) and 1/16
>(also the thinnest I have)mild steel filler. I am not a weldor, but
>have had some tig and mig formal training.
>
>Machine has a pedal that varies the welding amps, and I am not hitting
>it really hard at all...
>
>I tried putting a bolt inside the tubing while welding, but that just
>fused the bolt to the tube, oops.
>
>Anyone give me some constructive, positive help please?
Change your joint design possibly?
Drill a few holes in the tab on the center line that will be tangent
to the tube. Then "plug weld" it. To do this, you weld the hole edges
to the tube from the backside and fill in the remaining divot (if any)
with rod.
Probably your holes will be small enough so that you can just puddle
some of the tube and plate, and then give it one dab of rod to finish
the weld. May require a little hand grinding to smooth out the welds.
Other then that, your present problem indicates a difficulty
controling the puddle in the joint where the tube and the plate meet.
And welding a round to a flat with a TIG like that, that is not
totally unexpected. You may be able to get greater control by
extending the tungsten point further outside the gas cup so that the
tungten electrode reaches deeped into the weld area. In a tight weld
area like that, shielding gas loss shouldn't be a problem. I would try
this solution first.
Dave
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Posted by on March 15, 2008, 1:18 am
Please log in for more thread options On Sat, 15 Mar 2008 01:07:50 -0400, dav1936531@nowhere.com wrote:
>On Fri, 14 Mar 2008 20:30:34 -0700 (PDT), rbce2003@hotmail.com wrote:
>
>>I have a project,,, where I am welding a mild steel threaded tube to
>>a .106 thick mild steel tab that is about 1" long. The tubing is 3/8
>>OD, with .280 ID, threaded 5/16 x 24.
>>
>>The weld goes lengthwise on the tube, and is the full 1" long.
>>
>>I am having trouble not distorting the threads in the tube when
>>welding. I am tig welding with a 1/16 or 3/32 electrode (sorry, will
>>check in the morning for sure... it is the thinnest I have) and 1/16
>>(also the thinnest I have)mild steel filler. I am not a weldor, but
>>have had some tig and mig formal training.
>>
>>Machine has a pedal that varies the welding amps, and I am not hitting
>>it really hard at all...
>>
>>I tried putting a bolt inside the tubing while welding, but that just
>>fused the bolt to the tube, oops.
>>
>>Anyone give me some constructive, positive help please?
>
>Change your joint design possibly?
Or use a brass bolt as a backer when welding.
>
--
Posted via a free Usenet account from http://www.teranews.com
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>a .106 thick mild steel tab that is about 1" long. The tubing is 3/8
>OD, with .280 ID, threaded 5/16 x 24.
>
>The weld goes lengthwise on the tube, and is the full 1" long.
>
>I am having trouble not distorting the threads in the tube when
>welding. I am tig welding with a 1/16 or 3/32 electrode (sorry, will
>check in the morning for sure... it is the thinnest I have) and 1/16
>(also the thinnest I have)mild steel filler. I am not a weldor, but
>have had some tig and mig formal training.
>
>Machine has a pedal that varies the welding amps, and I am not hitting
>it really hard at all...
>
>I tried putting a bolt inside the tubing while welding, but that just
>fused the bolt to the tube, oops.
>
>Anyone give me some constructive, positive help please?