Honing a cylinder

[jmnjrpa]

Just for general consumption. I had a Master Cylinder with a nicked bore. In machining we often use a flapper rod and die grinder to "buzz" it out. Saw a slot centered in a straight metal rod (bigger bores need bigger rods). Clamp the part in a vise or fixed somehow so it won't spin on you. Work with smooth strokes and you can "hone" a cylinder IF it is not too bad. Stop the grinder before exiting the bore! Use one hand to steady the rod and practice on a POS before moving to the job. By using progressive grits (180,240,320,etc.) of cloth backed sand paper you can save a bore without the expense of various hones. A good variable speed die grinder is essential. I have buzzed out up to 12 inch bores. Note the rod in the pic is 1/4" and I buzzed out a 11/16 bore. It is critical to wrap the sandpaper around the rod tightly with minimal clearance between it and the bore size. Insert fully with a twist motion prior engaging the die grinder. You can also use scotchbrite for cleanup operations.

[crazy steve]

Good tip, but I'll point out that the bodies on our Masters are aluminum, so I'd recommend starting with 600 grit paper and go finer. I did this on mine, but I used a drillmotor and a 6" piece of 3/8" wood dowling. No chance of damaging the soft aluminum bore with wood....

'78E original owner

[jmnjrpa]

Yeah, if all you are doing is polishing

It would burn up your compressor before you took anything off with 600 grit. I regularly put a 16 finish (you feel nothing with a fingernail) on with 320.
Trying to save someone money and work. The high RPM of the die grinder promotes a true bore without excess work.

BTW - I have tried to remove a couple (.002) thou out of steel and wore myself out. The aluminum will cut faster but not so fast as to be an issue. I have used a wooden dowel with minimal results. Been doing it 40 years and works like a charm.