[HELP] Welding Disc To Threaded Rod

[EdK]

A friend wants me to weld threaded rods to a steel discs, despite telling him I suck at welding. These will be feet for some device, I'm not sure what. So in order to have a chance in hell at accomplishing this task I need some help in setting up the welder for this situation. The threaded rod is 10-24 mild steel and the disk is about 3/4" in diameter by about 1/4" thick made of CRS. I've got a piece of aluminum held up against the underside of the disc to keep the disc at a right angle to the threaded rod. I countersunk the disk so I can fill it in with weld. There's not going to be a lot of pressure on these so if I can get a reasonable amount of weld to hold them together, it should be fine for his application. The weld will be faced off on the lathe after welding.

I don't want to blow through the disc and/or rod so any tips would be appreciated.

Do you think I need to use .025 wire instead of .030?

Ed

   

[Mayhem]

Nice simple job there Ed and you certainly will not blow a hole in that disc. The important part when doing this is keeping the disc perpendicular to the shaft.

Start the weld in the centre of the shaft and then work the weld pool in a circle so it fills the hole. This one is pretty difficult to mess up.

[EdK]

(06-26-2015, 09:01 AM)Mayhem Wrote: ... This one is pretty difficult to mess up.

You forget who you're dealing with. I'm sure I could blow that thought out of the water pretty easily.  

I read a lot about button welds, which this seems to be, and most say to start on the inside and move in circles to the outside. Miller says the opposite.  
I'm not sure that it matters though.

Ed

[f350ca]

This would be a great excuse to buy a TIG machine Ed.
Not sure about the aluminum behind the disk, it might melt, but probably not with this small a weld.
When plug welding I start on the outside and fill the remaining hole in the middle but on that small a part make a small circle in the middle.
Would be easiest if you can get the rod vertical.

[zmotorsports]

(06-26-2015, 09:01 AM)Mayhem Wrote: Nice simple job there Ed and you certainly will not blow a hole in that disc.  The important part when doing this is keeping the disc perpendicular to the shaft.

Start the weld in the centre of the shaft and then work the weld pool in a circle so it fills the hole.  This one is pretty difficult to mess up.

Agreed. I would have no issues using .030" wire on this job. Use a practice piece and treat it like a normal Rosette weld, sometimes called a plug weld. Snip the wire at an angle prior to starting a new puddle to give the current a chance to start the process quicker and will better penetration. Also keep your stickout short, like less than 3/8". Once the puddle starts move in a small circular motion staying on the leading edge of the puddle and moving the puddle to fuse the disc to the rod. It will be pretty easy to get good fusion and penetration on a small item like that so just get in and get out.

(06-26-2015, 09:35 AM)f350ca Wrote: This would be a great excuse to buy a TIG machine Ed.
Not sure about the aluminum behind the disk, it might melt, but probably not with this small a weld.
When plug welding I start on the outside and fill the remaining hole in the middle but on that small a part make a small circle in the middle.
Would be easiest if you can get the rod vertical.

Agreed. If I had access to a TIG welder this would be a great job for that. If this was to come into my shop I would use the TIG process over the MIG. But if MIG is all you have at your disposal then it will work just fine.

Mike.

[Roadracer_Al]

If you had TIG, you could TIG Braze that.

You don't mention if the disk is threaded - that would be a great aide in keeping it perpendicular to the rod.

Also, silver brazing would be a very good process for this part.

[EdK]

Sorry guys, I only have MIG right now. Maybe someday a TIG will show up for my birthday or Christmas.

Ed

[zmotorsports]

(06-26-2015, 12:18 PM)EdK Wrote: Sorry guys, I only have MIG right now. Maybe someday a TIG will show up for my birthday or Christmas.

Ed

Better make sure your not on the naughty list then.

Mike.

[stevec]

(06-26-2015, 10:45 AM)zmotorsports Wrote:   Snip the wire at an angle prior to starting a new puddle to give the current a chance to start the process quicker and will better penetration.

Mike.

Mike, I don't understand the "snip the wire at an angle" part at all.
Could you explain what an angled point on a .025 or .030 wire would accomplish ?

Steve

[zmotorsports]

(06-26-2015, 03:21 PM)stevec Wrote:

(06-26-2015, 10:45 AM)zmotorsports Wrote:   Snip the wire at an angle prior to starting a new puddle to give the current a chance to start the process quicker and will better penetration.

Mike.

Mike,  I don't understand the "snip the wire at an angle" part at all.
Could you explain what an angled point on a .025 or .030 wire would accomplish ?

Steve

By snipping the wire at an angle it creates a smaller "point" at the end of the wire.  Even for a .030" wire creating a smaller point at the end it will require less current to establish a puddle at the start of the weld.

Many times when welding and releasing the trigger, a small ball or radius will form on the end of the wire.  I have seen these balls on the end of a .030" wire being over .050".  Also as the trigger is released as the end of the wire cools it attracks contaminents from the atmosphere which when restarting the weld will be re-introduced right into the molten puddle.

For small work it makes quite a difference, but for larger weldments using higher voltage and wire speeds the benefits are diminished.  I keep an inexpensive pair of diagonal cutters on my MIG welder for this purpose.

Also when welding 4130 or 4140 chromoly using the TIG process, I do the same thing even though on TIG I have my post flow timer set to flow gas for a few seconds to protect the weld as it cools and solidified but I have a tendency to pull the wire out of the gas stream and the contaminents can collect on the TIG wire.  Many people don't go to quite that extent but on chassis used for racing the smallest details can be of benefit.  You don't have to snip an inch at a time, just a 1/8" is all that is needed, just above the end of the wire.

Mike.