Vice Repair - cast iron welding

Hey guys - I picked up this vice in a frozen and abused state. I unfroze it, straightened a rather bent acme screw (for the most part straight), and also really securely seated the forged steel acme nut into the main body (by grinding down its tapered surfaces so they more fully engage the corresponding wedged surfaces inside the cast iron main body.
Attachment 8237

Now, the vice has good strong clamping power it seems, but its jaws are pretty sloppy, and there is a crack in the back of the main housing (I believe caused when the vice was opened too far, and then jammed closed.) There seems like excessive slop in pretty much all the sliding points, including the opening below the crack.
Attachment 8239

With some .055" shim and an .065" shims inserted on either side, it eliminated about 1/4 turn of handle rotation to get the vice jaws to clamp. So I think it's be nice to eliminate this play.
Attachment 8240

Is there some reason to purposely leave some clearance in the sliding parts? (Any reason why not to take it down as close to zero without binding as I can?)

I am considering using TIG to apply either some nickel-55 rod or some aluminum bronze A2 rod, and then use a big aggressive flat file I've got to manually machine down to desired clearances. The friction "pads" on themain vice body that would need to be built up arenot large - maybe 3/8" x 3/8" square each.

The bronze might "machine" easier than the nickel-55. But, would the nickel-55 be possibly hold up better to sliding friction? I know bronze can be decent for enduring sliding friction, so maybe that would be fine for this, and the way to go. The nickel would be a better color match, but for this vice, I don't really care. Any thoughts or recommendations?

If I went to the effort of welding, I'd probably also vee out the crack and attempt to weld it back up as well. And there are some friction pads at the front of the main body I would consider building up (to better align the moving jaw with stationary jaw) as well.

Since this is just a second vice, (and not any recognizable brand), it wouldn't be a big loss if I made a mistake. (Cracking the cast iron vice body is really the only potential concern I have on this.)

I would use a bronze option. I would also heat the whole vice up prior to doing any welding, then heat it again post welding, and slow cool it.

At work, cast parts are slow cooled in a big drum filled with vermiculite. Damn parts will still be quite warm the next morning in that stuff as it is quite the insulator.

Would it be better / easier to take the vise apart and drill and tap a few oles across the back (near where the feeler gauges are) and bolt a plate on? This looks like it woudl take care of the "pads" and also add a bit of support for the crack.

Don't weld it. Last time I checked if you weld cast iron the heating is so intense it will cause the welded area to crystalize and become super hard. So hard to the point of very easy fracture. On a vice I can see this leading to disaster. If you are going to fix it braze it with a torch and employ the proper pre and post heating.

You should take a look at Keith Fenner's page on YouTube. He has some great projects involving cast iron repair. Some of the projects you'll hear him go off on a customer who had previously tried welding cast iron. It works but messes things up. In his videos with cast iron he shows good detail on pre and post heating.

My two cents.

Quote:

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Originally Posted by bswinn

Don't weld it. Last time I checked if you weld cast iron the heating is so intense it will cause the welded area to crystalize and become super hard. So hard to the point of very easy fracture. On a vice I can see this leading to disaster. If you are going to fix it braze it with a torch and employ the proper pre and post heating.

You should take a look at Keith Fenner's page on YouTube. He has some great projects involving cast iron repair. Some of the projects you'll hear him go off on a customer who had previously tried welding cast iron. It works but messes things up. In his videos with cast iron he shows good detail on pre and post heating.

My two cents.

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Many moons ago, I found a vice that had been braze repaired. Used it for years with no further issues.

FWIW,
rivets

Thanks for the feedback, guys. I ended up using nickel-55 for welding the crack, and aluminum bronze A2 for building up four of the sliding bearing pads:
Attachment 8280

Here's how it went...

The crack was propagating along the casting seam:
Attachment 8282

I started by vee'ing out the crack (and also cleaning some of the other nearby surfaces where I was going to be depositing bronze):
Attachment 8276

Then I deposited nickel-55 in the crack; no pre-heat but rather, AC TIG to minimize heat input and keep penetration shallow (got a little bit of porosity here maybe from not prepping the top surfaces adequately):
Attachment 8277

Next, I deposited some bronze on four load bearing surfaces / "pads":
Attachment 8278

I just let the vice cool in still air, no post-heat (being a fairly substantial part, it did retain some heat for a while).

Next, a big, course flat file was very useful for setting the pad dimensions:
Attachment 8279

For big filing jobs, it's helpful to hold your work rigidly. Almost there with the flat file:
Attachment 8275

Pad dimensions are tuned to perfection:
Attachment 8272

Attachment 8281

Next, there is still play in the "yaw" direction of the moving jaw, (which I'm thinking I could eliminate by depositing some bronze on one side pad of the main body and filing ...should be easy), and also the jaws could use a little attention.

That looks like one size XL vise. What tool did you use to vee the crack in post #5, photo #3? It's got a corrugated look to it.

Hey Dave - I used a carbide burr (a 1/2" diameter cylinder shape with sharp lower corners), held at about a 45 degree angle.

It was pretty amazing how effortlessly it chewed through this cast iron. Almost as easy and fast as aluminum. I think this is a special kind of cast iron called "ductile iron"

I'd say this is a medium sized vice. My other one's a little bit bigger.