Will it be a problem to weld 1/4 or 3/8 inch steel plate to 1/8 inch steel tubing as in the attached closeup?I am using the plate as a mounting surface for a bearing.
Should not be a problem at all, what kind of plate are you using? What sort of tube?
Probably 1.5 inch hot rolled steel square tubing with 1/8 inch walls and 1/4 inch mild steel plate.
Yep, should be just fine
You likely won’t have full penetration in the plate, but it won’t matter. Put more dwell time on the plate than the tube, and you can help keep the greater thermal mass there from causing even less penetration on the plate than the tube.
So what you will do is set the machine up for 1/8 steel, you set it for your thinnest material & you shouldn’t have to worry.