Re: Help me design a new Grab Iron Bending Jig

Spen Kellogg <spninetynine@...>

On 3/1/2019 7:42 AM, Craig Bisgeier via Groups.Io wrote:
Hey folks - I'm thinking about designing a tool for bending grab irons
that can be 3D printed. I know that Micro-Mark has a tool for sale,
and I could use that as a starting point. But I thought I would open
this up to the braintrust and see if there are any thoughts on
designing such a tool that doesn't necessarily follow that model.
What I'm looking for is something adjustable and repeatable that
allows grabs to be sized to any length, or at least many lengths. It
should have a feature that alows the user to set a particular size
with a groove, stop or fence that the user can place the wire against
and bend many grabs to the same size without guess work.
I have some ideas on this of my own but I'd like to see what others
can come up with. If someone can help provide useful ideas that lead
to a workable tool I'll gladly provide them with a finished copy of
the tool when the project is completed.
Any ideas? Please share them with me!

A plastic or metal spiral with a hole in the center and a series of Vs
cut in around the edge at various redii (that's the plural of radius).
The center hole should be deep enough to produce a good right angle.
Although more complex, it could have a series of tubes (sleeves) with
the ID the correct size for various wire sizes. The outside diameter 
would be the same for each sleeve. To do it you put the wire in the
center hole, bend it toward the desired side (whichever V is for the
length of grab iron you want. Then place the tool with the wire inserted
and bent (the first 90 degree bend) on a flat surface and bend the wire
up into the appropriate V. Cut the wire where desired to give two legs
of the desired length. It also could have a slot as long as the longest
grab and deep enough for the drop grab bends so that the ends could be
bent down to form a drop grab. I would guess that the Vs should be
positioned and notched for 14", 16", 18", 20", 22" and 24". If there is
not enough room on the spiral for all those, then a pair of tools might
be needed. And the length of grabs should be researched to include all
the common length. I wouldn't bother with lengths for diesels, although
passenger car grabs might make sense. I am thinking that t he tools
should probably be metal, rather than plastic, as constant use will wear
out plastic.


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