Cut Most of the Way

I’ve mentioned before that I did woodworking in one form or another for some 40 years before getting into blacksmithing.

I had not been into blacksmithing very long when I began noting the similarities and differences in the techniques of the two crafts.  I learned that to do blacksmithing I must become familiar with a new skill set and break some old habits.  One of the first things which struck me as different occurred in cutting stock.

In my wood working experience I cut a measured piece off of the parent stock completely and that was that.  In my blacksmithing I often found it more efficient to cut a piece only part way off.

Examples:

Using the hardy hot cut - I learned not to cut off a piece all the way and let it fly.  Now I cut it most of the way and break it off by hand with tongs and put the hot drop in a safe place.

Cutting a piece of stock for incorporation into a weldment - cut it 90% of the way, put in a convenience bend to position the piece using the parent stock as a handle.  Weld the piece in place and break off the parent stock handle.

Using the bandsaw or a cutoff disc I stop just a but shy of complete severance.  That way I can break off the piece and store the remainder without dropping either on the floor.

When an exact length is not important I use a severing die in the hydraulic press to sever stock cold.  The blade has a slight relief so complete severance is avoided and the bridge is so thin I can snap it with an easy bend.

It seems like I’ve switched from the notion of, by default, cutting for severance to cutting most of the way but leave a thread of attachment.

Notch, bend, use parent stock for handle.

Weld in place and snap off handle.

Convenience Bends

I read an article a few days ago in which the author detailes a list of things he wished he had learned earlier.  It started me thinking about how I might have benefitted from more instruction.

Probably the first thing I could have done quicker is to lear to work at high heat.  This is in spite of hearing the “get it hot and hit it hard” phrase time after time.  The flip side is learning to stop forging when it ltill looks pretty hot and get it back into the fire for mor heat.  I tended to keep on working and let the heat fall too far.

Another thing I could have given more attention was ending a forging segment with an intentional convenience bend so the area to be worked next would be easy to position to catch the next heat.  Putting in convenience bends to avoid obstruction when forging seemed more obvious to me.

Those two things probably could have helped me a lot.  Today convenience bends to fit the fire seem second nature.  But now I have another reason for using them - my tumbler.  While Ken and I were recently forging a piece which was about 60” long I realized it would not fit into the tumbler which only accepts pieces up to about 56” long.  The solution, forge a convenience bend, or two, which would reduced the overall length to 56” and which could easily be straightened later.

Twenty years ago the possibility of these bends wouldn’t have occurred to me as my mind was so cluttered with other things I was trying to learn.  In any new endeavor it takes a while to develop a minimal competence which allows moving from the awkward self conscious mode to a Zen-like state of relaxed confidence.  That’s when it becomes fun.

Creased Hot Collars

This illustrates another version of forming hot collars.  If the project calls for a number of nearly identical collars, test collars can be made and when the precise measurements are known, a “witness” collar can be formed.

From that template, many copies can be made.  To facilitate identical bending the bend points are creased with a fuller die.  This can be done by hand with hammer on anvil, treadle hammer, fly press, etc.  Presumably, a jig could be set up to make the process even more precise.

Metal bends where it is thinnest or hottest.  This is an example of exploiting both tendencies through selective torch heating at the crease.

I first saw an example of these collars lying on a platen table at Flicker Forge alongside the die which made the crease.

Fuller creases at bend points.

Forging Hot Collars

I did a web search for the Francis Whitaker hot collar formula.  It is illustrated in his “Blacksmith’s Cookbook” and I’me heard many people recite it.  It wasn’t so easy to find on the web so I decided to do some SketchUp illustrations and post them the the 3D Warehouse.  When I tried this morning I got the message that “The service is not available.  Try again later.”  So, I plan to do that.

In the meantime I’ll post images of some illustrations I drew.  The show the Whitaker formula and the sequence of steps in the forming process.

Bill Fugate published the formula in the Pittsburgh Area Artist-Blacksmith Association newsletter in July 2010.

http://paaba.net/Projects/BFCollar.pdf 

Carl Davidson published a nice article in the Northeast Blacksmith’s Association Spring 2012 newsletter showing how to modify and Engineer’s wrench into a neat adjustable collar making tool.  I couldn’t find a link to it just now.

Next time I’ll illustrate another way to make collars which I learned on a visit to Flicker Forge.

The Francis Whitaker Collar Formula 

Starting the collar forming after calculating the collar length and beveling the ends.  Francis suggested finding the CL then moving over one half the width of the waterfall to be collared to start the first bend.  This should get the lap pretty well centered.

A mockup of the workpiece can serve as a mandrel to be used with the vise. 

The collar can be finished on the mandrel and opened to fit or the final two bends closed over on the workpiece.

Sometimes is most efficient to form a batch of collars on a mandrel and open them up so they can later be fitted and closed on the workpiece with torch heat.

Two Hammer Straightening

This topic came to mind while making some long shank shoe spoons.  After fullering the blade some of the pieces had a slight offset of the blade-shank junction.  The shoulder was asymmetrical.  If the offset is not too extreme it is easily fixed by clamping the shank in the vise right at the shoulder leaving the blade extending beyond the vise jaws.  The neck-shaft junction is heated and the blade tip cooled...A heavy hammer is placed against the tip of the blade and a light hammer is used to tap the long-side shoulder until it is centered.

I first thought of this as a second class lever technique but now I’m not sure how is is properly described in mechanical engineering terms.  I do like the way it works.