[TheForge] Scroll maker

[Andy Vida]

Shannell Sugrue wrote:
> 
> I do a lot of scrolls in 10mm (3/8) round. Im thinking of making a machine
> to do the scroll part. The ends are flattened under the power hammer then I
> heat the length up , about 18 inches and bend it around a jig, its got about
> 630 degrees in it, a full 360 then 270 more. Has anyone seen plans on the
> net, or built their own? I have some ideas but its always easier to copy
> something that you know works. Id probably do this hot still. I have a 1 HP
> motor spare but no reduction gearboxes on hand, or was thinking maybe I
> could use a pneumatic ram. Any suggestions?

	At the shop in Mesa we had "Mongo", what I think is one of
	the world's largest benders.  Mongo has a 4" square drive
	socket attached to a large-ish hydraulic motor which in
	turn attaches to a separate power unit w/pump and 15hp
	motor.  15 hp doesn't sound like much until you consider
	that the 3400 rpm is geared down to 9.  Mongo will twist
	solid 3" square steel *cold* without so much as slowing
	down.

	All you need is a motor mounted to a table that is fitted
	with a coupling for accepting and driving a die, and a
	stop mechanism, which in Mongo's case was the typical
	roller, lockable anywhere along a length of rail, also
	mounted to the table's surface.  This aids in bending the
	stock to the die, especially where the lengths are to short
	to provide insufficient leverage to the hand.  Setting the
	roller/stop this way or that along its rail opens or closes
	the gap between it and the surface of the die.  There are
	several ways in which this mechanism can be emplyoed to
	do what you need.  Anyone with a lot of experience using
	hossfelds will immediately know how to use a machine such 
	as Mongo.  The only real difference lies in the presence
	of power, though a Hossfeld is also perhaps a bit more
	versatile, and lacking in ultimate capacity.  Tradeoffs.

	The most $$ aspect of running a Mongo bender is the cost
	of dies, especially for large work.  Our largest dies were
	water jetted from 5" thick tool steel for scrolling 2" thick
	stock cold.  We made many of the dies ourselves from odds
	and ends and using 4" square thick walled tubing as the 
	drive member, welded to the die body.  These were good for
	large forms made from comparatively small stock, say, 1"
	thick and less with comparatively large radii.

	With such a machine, you don't need to bend your work hot.
	But great caution is required when doing heavy stock bends
	cold.  Mongo never let loose on anything, but I can very
	distinctly recall the "wanting to be on another planet"
	feeling I had when twisting heavy stock.  Had that let go,
	I suspect things could have gotten unpleasant as there
	was a lot or stored up energy in the steel.  It was always
	entertaining to watch the mill scale pop off the surface in
	an oddly attractive little dance.