Thursday, October 10, 2013

Making Bolted Spring Dies



Especially in the early phases of making dies the die face may need several refinements.  I made most of my early dies it the flat bar spring design usually from 3/16” x 2” or 1/4” x 2”.  Each time I needed to redress the die face I heated the hairpin of the spring and opened up the angle until I could access the face area.  Then I had to heat the spring again and close it up and get it back into register.

I started thinking about finding a way to disassemble the die to make those adjustments easier.  That would eleminate the torch work and allow even better access to both die faces and would avoid the problem of possible misalignment.

I thought that this type construction might be less flexible that the typical hairpin, D or oxbow type of spring loops so additional flat bar length might be needed.

Looking over my available scrap I selected a 2” square tube with 1/4” wall to use as the spacer/mounting box.  I elected to cut two holes in the top so I could weld two nuts flush with the surface or slightly recessed.  That way I could put the die back in the tumbler and clean it up if I wanted and not risk thread damage.   I decided to use substantial bolts, 7/16” minimum, grade 2.  I haven’t used them enough to determine if they need to be grade 8.

I’m just starting to use these dies so I don’t have a long run experience yet.  It looks promising and by spring I’ll have made the decision of whether this will be my standard spring die construction scheme.

The images show a generic die made for my main power hammer. There are end tangs which have a loose socket fit and a central saddle which wraps around the bottom die.  The bottoms of the tangs are welded shut so, when I put a die in the tumbler, small pieces of metal aggregate don’t get stuck inside.  During use the die is relatively constrained but not tightly constrained and I believe this saves a lot of wear and tear on the hammer itself.
Nuts tacked flush with top surface.  Complete the weld and grind flush.

Assembled die.

Disassembled die.

No comments:

Post a Comment

I don't often check for blog comments, so the best way to contact me is directly: at ottercreeksmith@gmail.com or djedwards@cableone.net