Back on 12/14/13 I showed one type of rivet buck helper. http://persimmonforge.blogspot.com/2013/12/the-rivet-buck-helper.html This is just another version with a cross bar for supporting the reins of tongs while the rivet is being peened.
I have a project coming up which will use some short curved chisels. I had one holding tong for sizes up to about 5/8” but no larger. I made this pair which holds up to about 1” and another for holding up to 1.5” shafts. I’ll show how they worked out in the project which is making a die set for stamping tree ring lines on the face of a stump cut or branch collar cut.
I only use the helper until I get the rivet peened enough to not fall out. From that point I take the tongs in my left hand and use the torch in my right hand alternating with a ball peen until the job is done.