Unwanted twist in taper

[Eric W.]

Good afternoon.  I have been practicing the ABANA taper lesson and wanted to change it up a bit so I figured I could go to octagon after I had my 3 inch square.  When I start to forge the corners down, a twist is imparted.  I am sure I am doing something wrong, but can’t find anything online saying why the twist is happening I even use the “site:iforgeiron.com” search string.  I am heating up to a bright orange heat, using slot tongs to hold the 1/2 inch square bar.  I am using a proper anvil and a Hofi style hammer.  Any tips or ideas that you could give?

[Eric W.]

1 hour ago, Eric W. said:

3 inch square

3 inch taper...

[Goods]

Generally, the three reasons for twisting when going from a square cross section to octagon are:

1) the work piece is not perfect vertical on the corners.

2) not hitting the work piece with the hammer face parallel to to anvil.

3) not hitting with the face of your hammer centered on the stock. (Not as big of an issue as the two above.)

These errors will cause the stock to twist as you work the corners in. Just be aware of them and practice.

As soon as you notice a twist starting, put it in the vise a straighten it. Things go wrong and correcting issues early will save many forgings.

Keep it fun,

David

[swedefiddle]

Good Morning,

When you are drawing the taper or square, turn clockwise, back to center, turn counter-clockwise. Our natural reflex is to suck up on the Tongs when striking, going back and forth keeps the twist straight. Yes, it is just a little thing but is adds up.

Neil