A Norman Patent toolholder for the mini-lathe
Mert Baker, a member of the 7x12minilathe group, has been suggesting since long that machinists can do a QCTP having only a lathe with a 4 jaws chuck. I took many time until decided to make this first toolholder. With Ralph Patterson plans, showing the vertical adjustment screw and a unique post permanently mounted on compound, figured out the advantages of such design. It takes no room on the lathe and, keeping the tool over the compound and not aside, has no lever effect neither on compound, cross slide or saddle. The only disadvantage is that each time a toolholder is mounted on the lathe it has to be aligned perpendicular to the workpiece on the lathe, but that's ok for me on a manually operated hobby lathe. With it, the lathe deals very well with cutting forces and this QCTP can be as versatile as imagination can make it.
I got curious about the source of this design when found several similar toolposts over the web, as the one by George Carlson. A scan of the July 1957 issue of Model Engineer magazine have made it clear. Very similar to the ones Mert made for a Unimat and sent me pictures of, the Model Engineer magazine shows a picture of a toolholder without vertical adjustment screw and referred as the Norman toolholder for Myford - Drummond lathes. As I found it on several pages of lathes.co.uk, asked Tony Griffiths for more info about it. Tony Griffiths gently explained that the correct name of it is "Norman Patent" toolholder and that it is widely known for its use as the standard toolholder for Myford - Drummond lathes from 1925 to 1953.
Photo: Lathes.co.uk - Showing the Norman Patent toolholder as used on Myford - Drummond lathes
A so long production of the toolholder may explain some style variations shown on lathes.co.uk pages. Though I was thinking that the height adjustment screw could have been a neat addition by a machinist when making a replica of the Norman Patent toolholder, this picture Tony Griffiths sent me to publish here clearly show that the height adjustment feature was already on it since too long.
Thanks to Tony Griffiths / lathes.co.uk