How to select proper blank size for forging knife blade

[aprayinbear]

Please help with this Newbie question,

In the past I've just started with whatever size piece of steel I have, headed to the forge and see whatever comes out.  That's fine if I don't care about time to make or style of the finished product, but I'm trying to learn to work a bit more efficiently from drawings I create.  My question is, if I want to end up with a knife that is approximately 3/16" finished (on the back of knife) and about 1 1/2 inches wide, what size blank do I need to start with?  Is there a formula I can follow or some general guideline I can follow?

All The Best!

 

[jeremy k]

Figure out the volume of the size you want,  then start with your metal with the same volume plus some extra for scale loss. Your forging experience will determine how much you loose during forging....more heats = more loss.

[JHCC]

Here's an old-school trick: make a model of your finished piece in plasticine or other modelling clay, mush it into a cube, and measure the volume. Factor in scale loss per Jeremy K, and Bob's your uncle. Works for projects of all sizes.

Of course, the other option is to simply work off the end of a longer bar, so that you can forge the size you want and cut off the rest. The advantage of this method is that you have something long to hold onto, and won't have to rely on tongs.

[aprayinbear]

Fantastic!  That really helps.

Happy Hammering

[Rashelle]

Take notes. When I find a size of stock that makes my idealized knife size/style I write it down in a notebook. I then write it on a cut down ruler (cut to the right size), then I have a cut template and a notebook with my sizes. For unusual things, I usually do like jeremy k says and go off of weight if I have to. Such as for a sword. I take the finished weight I want to end up with, then figure out the size of material on hand and the amount needed for that weight when done forging and grinder clean up. With remembering handle, guard, pommel weight.

[ThomasPowers]

In your shop notebook, (I found one of the old school metal clipboards that had a metal cover too!).  when you get a design you really like make a tracing of it and write the info on starting size, time, special tooling, etc in it so you can duplicate it easily.  For popular designs, cut a metal version out and list the details on it with a permanent marker and punch a hole in it so you can hang it on the wall of the shop.  Customers like to see a range of "possibilities" and say---one of those with a smaller handle, or with a clip point, or made out of adamantium with an chequered diamond handle and for less than the cost of the fuel to forge it!