Monday, December 9, 2013

My Power Hammer Depth Stop


Last week I made the elements for two console tables which required forging 1” square bar, breaking the corners and drawing a taper about a foot in length between the upper part of the leg down to a 1” foot.  To ensure that all eight were quite similar I used an adjustable depth stop on the spare tire power hammer.

The tool consists of a tang of 1” square tube which fits into the left-hand die socket on the power hammer; the 9/16” round slide shaft with with 1/8” x 2” x 8” flat bar stop arm; a 3” piece of pipe guide tube which closely fits the slide shaft and has a T-handle welded bolt/nut screw lock; and a 6” piece of 1/4” pipe which is a cheater pipe for tightening the T-handle screw onto the slide.  The tang also has a T-handle welded bolt/nut screw lock to hold the cheater bar securely when the jig is stored.

When forging the legs, I first broke the corners giving them a noticeable chamfer.  Then I set the depth stop as short as possible to isolate the foot and used a 5/8” thickness stop in the right-hand die socket.  After all eight feet were forged I set the depth stop to about 12” and worked from the foot up about 6” with a 3/4” thickness stop in place.  Finally, I removed the 3/4” depth stop and worked free-hand to smooth the taper transitions for a distance of about 12” from the foot.


If I was doing this an a pretty regular basis I probably could have done it all by eye and come out looking about the same but this assured it would go quickly and smoothly.  I didn’t want to mess one up because I was working with the last of my 1” square stock on hand.  I seldom stock more than 20’ of bar stock that large.  With short notice I can get it when I need it.

Cheater bar tightening the lock screw.
Depth stop set for the short work. 
Depth stop set for the long work.
The foot-leg taper.
Eight legs coming out of the tumbler.

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