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View Full Version : Options on fixing a little chipped cast iron ?



LHC
09-22-2011, 11:25 AM
Hi Folks -

My first post on this forum!

I am refinishing a little milling machine vice and have chipped out the cast iron on the entrance where the screw enters the movable jaw. The groove on the end of the screw where a retaining pin keeps it in place, had been mushroomed over time and it was impossible to get the screw out of the jaw without some creative work – i.e. I pulled the jaws together with some cap screws. I didn’t notice but had lifted the movable jaw up at the rear when it reached a bevel on the bottom of the fixed jaw (have the faces of the jaws removed) and this caused the screw to torque down in the hole and near the end, chipped it out.

Attached pic. It’s not much, and certainly does not affect the operation of the vice, but I’m going to re-paint the vice anyway and am wondering what the best way to address this is before I paint.

My options as I see them (other than doing nothing) are –
1) Fill the chip with something like bondo or a magic epoxy material and then grind it smooth again. Paint will hide the mismatch – but I am wondering if it might just chip out again.
2) Bevel the entire entrance with a little ball stone grinder and make it look like it was supposed to be that way from the beginning:)

Comments are welcome.
Thanks !

http://i307.photobucket.com/albums/nn286/LHC_02/Benchmaster%20Milling%20Machine/test.jpg

spongerich
09-22-2011, 01:08 PM
I think you'd be better off with some JB weld rather than bondo. It'll stick to the cast iron far better and it's amazingly tough.

I've got a few motorcycle engines that have JB repairs to the crankcase covers and they've been solid and leak free for years.

LHC
09-22-2011, 01:44 PM
I think you'd be better off with some JB weld rather than bondo. It'll stick to the cast iron far better and it's amazingly tough.

I've got a few motorcycle engines that have JB repairs to the crankcase covers and they've been solid and leak free for years.

Not having used this stuff before, I am wondering - can you shape it after it's cured - i.e. grind, sand etc?

Thanks for the tip,
Lewis

spongerich
09-22-2011, 02:06 PM
Not having used this stuff before, I am wondering - can you shape it after it's cured - i.e. grind, sand etc?

Thanks for the tip,
Lewis

Absolutely. Grinds and sands very nicely. Clogs up sandpaper something fierce, but you can easily get a good finish on it.

strokersix
09-22-2011, 02:15 PM
I would pick option 2.

garagemark
09-22-2011, 02:32 PM
I would look at option 2 as well since it's really only for looks.

jack3140
09-22-2011, 03:54 PM
i would counterbore the hole and press in a steel ring .imho jack

aboard_epsilon
09-22-2011, 03:59 PM
i would counterbore the hole and press in a steel ring .imho jack

yep put it a bit deeper ..put a thread in the steel ring ..and then you have a backlash adjuster .

all the best.markj