peatoluser
Well-Known Member
- Joined
- Apr 19, 2010
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When I wanted to machine the intermediate cylinder of my engine, the limitations of a small chuck quickly became apparent. the bar was too big to be held conventionally, and with the jaws reversed, it was too small to be held on the outer steps.
the chuck is about 3 1/4" OD and the bar is 2"OD
I could hold it on the inner steps, and with a cranked tool cleanup enough of the OD, but was unable to part it of.
here's the problem
I decided to make a set of jaws specifically for larger diameters.
I had apiece of gauge plate roughly 2" by 2 1/2", cut this into 4 and roughly hacksawed to shape.
it was then a case of packing them up on the cross slide to mill the 1/8" grooves
and again to mill the clearance for the screw
the small groove was a simple filing job
here is one of the jaws next to an original
as you can see ,I hacksawed too much away and didn't leave enough of a step to clean up when fitted in the chuck, so made a thin spider to help seat work.
to 'square' the jaws, I used engineers blue and a needle file, clamping on some bar, checking the fit and filing were appropriate.
they've worked out quite well ,even in their soft state, although i do intend to harden them.
you can see the difference in clamping from the first photo - no protruding screws and a longer clamping face.
the chuck is about 3 1/4" OD and the bar is 2"OD
I could hold it on the inner steps, and with a cranked tool cleanup enough of the OD, but was unable to part it of.
here's the problem
I decided to make a set of jaws specifically for larger diameters.
I had apiece of gauge plate roughly 2" by 2 1/2", cut this into 4 and roughly hacksawed to shape.
it was then a case of packing them up on the cross slide to mill the 1/8" grooves
and again to mill the clearance for the screw
the small groove was a simple filing job
here is one of the jaws next to an original
as you can see ,I hacksawed too much away and didn't leave enough of a step to clean up when fitted in the chuck, so made a thin spider to help seat work.
to 'square' the jaws, I used engineers blue and a needle file, clamping on some bar, checking the fit and filing were appropriate.
they've worked out quite well ,even in their soft state, although i do intend to harden them.
you can see the difference in clamping from the first photo - no protruding screws and a longer clamping face.
