[TheForge] Welding cast iron

[Tod Estes]

Comments below

> As long as we are talking about welding cast iron, I have a question.
> Recently I bought an Acme post drill that looks exactly like one in the
> 1915 Sears catalog; the one for $7.10 at
> http://www.anvilfire.com/21centbs/drilling/postdril.htm.  After cleaning
> off 90 years of ossified grease and dirt and oiling it up, the drill
> worked great!  I was able to drill a 3/4" hole in 1/8" plate in a couple
> of minutes.  I was so happy I began gleefully drilling holes in everything
> I could find.  Then came the problem; I broke my new toy.
>
> The small wheel at the top advances the down-feed of the spindle by means
> of a pivot arm that works against the eccentric hub of the flywheel.  I
> broke the pivot arm by continuing to crank after the spindle reached its
> maximum extension. In my feeble defense, it broke at or near a previous
> repair.
>
> Now here are my questions.  Is this arm likely to be cast iron?  It looks
> like it might be because the angular shape of it looks like it was
> designed to release from a mold.  The interior of the break looks grey and
> grainy.  From this thread I take it the repair could be done by arc
> welding with nickel rod, brazing, or gas welding with iron.  Bernie points
> out that expansion is often a big problem in welding cast.  But that
> should not be much of an issue with this part since it is small and there
> is no restriction on expansion in the length of the arm.  It would also be
> easy to pre and post heat.  BTW, if I decide to weld it, I will find
> someone else to do it since I'm a lousy welder.
>
> Is any repair likely to be strong enough for the strain put on this part?
> Would I be better off just forging a new arm out of mild or medium carbon
> steel?
>
> Aubrey Washington
> Saltfork Craftsmen ABA, ABANA
> Rock Creek Forge
> Norman, OK
Hi Aubrey, think we will get snow today?

Since it is such a small part and you think that you can forge one to
replace it then you are not at a loss. Give welding it a try. With a small
part you can easily preheat then insulate to very slow cooling. If that
fails then forge a new one. Or mebe forge the new one first then try
welding the old one so you have a spare for the next time it breaks. I
have an old post drill too lots of fun to play with but I get too
impatinent and end up binding it too often.

Tod Estes
Oologah Smithy
Oologah,Oklahoma. (Home of Will Rogers.)
Saltfork Craftsmen ABA, ABANA
Time enough for sleep in the grave.

"Prometheus: I took from man expectancy of death.
Chorus: What medicine found'st thou for this
        malady?
Prometheus: I planted blind hope in the heart of
           him.
Chorus: A mighty boon thou gavest there to man.
Prometheus: Moreover, I conferred the gift of fire
Chorus: And have frail mortals now the flame-
        bright fire.
Prometheus: yes, and shall master many arts
            thereby."