Best bit for rosette weld holes

@Lizer you could do some test welds using pieces of the old floor, to see what welder setting gets you proper penetration with that 1/4" hole
 
It's always best practice to do a few practice welds with the same kind of setup that you'll be working with, but in the collision industry the practice welds often end up being on the vehicle because everyone's in a hurry. :confused:
 
With plug welds a flat to slight protrusion of the weld = a good hot setup. More than that it is either too cold or too much wire speed, Like Crash said practice on similar materials first in the position you are going to weld.
 
metlmunchr said:
I'm all for a bargain, but I wouldn't buy a used Whitney punch unless I could hold it in my hands prior to purchase. The list price of the kit with the full range of punches and dies is $95. If you buy used and unseen, and it happens to need new dies, those are $67 for the set, or 20 bucks each.

I spent a good portion of my adult life in a sheet metal shop, and the average person can't even imagine all the creative ways some guys can dream up to abuse a Whitney. Other men would have one they'd used for 20 years or more, and it would still work just like a new one.
Click to expand...
Caught a guy who borrowed mine, 'cause his were sloppy, using a 20 ton press to pop holes in 16 Guage stainless! He had the handle in the press and the material facing him. Fired him for the safety stupidity alone!
 
You can use a smaller bit than the recommended 5/16, but just turn up the heat a bit to ensure good weld penetration. We had an A-pillar repair that we did and our fabricated replacement part's flange was so small that 5/16 would have taken out the flange. (this did match the original piece) Here's our carnage:

The flange is quite small compared to what we normally plug weld, so we opted for a .169 drill bit to keep the heat away from the edge...


IMG_5769.jpg



In order to clean he primer out the inside of our plug weld holes, we flattened and backfaced our drill bit to mimic an end mill....


IMG_5770.jpg



Does a good job of giving us nice clean metal for a good weld..


IMG_5771.jpg



IMG_5772.jpg



much better....


Click to expand...


Typically I use a letter A for my plug welds as I've never seen a spot weld 5/16 in diameter on sheet metal, so I go with the smaller size and just bump up the heat.
 
Last edited:
You must log in or register to reply here.
Back
Top