What Does it do?
Dunham Tool manufactures a range of manual expanding mandrels (miser mandrel) with diameter capacities of 5/16" to 6". This expanding mandrel can be used with standard collets, vises, jaw chucks and many other special fixtures. These expanding mandrels are machinable by the customer. Multiple expanding mandrels are also used in other special fixtures for holding multiple workpieces "side by side".
The Dunham mandrel provides an expanding lathe mandrel to locate and chuck work from the bore for light secondary operations using your present machine tools.
How is it used?
Chuck the shank of the expanding mandrel in a collet, jaw chuck, or fixture.
With an Allen Key tighten the hex draw bolt until it expands .005.
Then machine the slotted member .001 larger than bore of part.
Loosen hex draw bolt, position part, tighten draw screw. The part is now chucked and ready for machining.
Features and Benefits
Requires no special adapters
Can be used with any standard Jaw Chuck
Can be used with vises or special fixtures
Actuated manually via hex head draw bolt
Available from 5/16” to 6” diameter
Available from 1” to 2” expandable length
Machinable by customer to desired diameter
No draw back gives positive location