Fixed a Chinesium Vice

[Shotgun]

We've talked about these cheap chinese vices that you get off eBay for $100, ad infinitum. Yeah, they suck. . .

except when they don't!!!

I took mine apart today. I had measured the moveable jaw lift before at 1.5thou. I measure it by putting an approximately 2" round bar in the vice and then clamping down on it with an indicator on the moveable jaw. What I did was to remove the large "ball bearing cut in half" from the moveable jaw and polished it with a 2000 grit sponge pad under running water. I'm telling you, I made the thing shine. Then I took a grinding ball that came with the dremel tool pack, and cleaned up the pocket that the "ball bearing cut in half" lives in. You can't get in there very well, so I just sort of ran it around until the casting roughness was gone. Cleaned it all up, put a gob of molybdenum grease in the socket, and stuck the half ball back in.

Then I turned my attention to the ram, Clean up the edges with a small file. They were kind of sharp. Then filed the angled surface that engages the half ball until it was smooth. It had a sort of ridge in the middle. I kept going at it, pressure through the file into the center of the angle, until it felt really smooth. Spread some of the grease that had squeezed from under the half ball onto the face, then put it all back together.

Clamped that heavy sucker back onto the mill and put the 2" round back in. This time the moveable jaw DROPPED about 4 thou as I cranked down on it. I figured I had screwed something up and got a bad reading, so I backed it off, and went at it again. It dropped the SAME 4 THOU!!!

It ain't a Kurt. It will never be a Kurt. But, it's mine and it's working!

Word to the wise: Chinesium is never a finished product. It is a kit at best. For the Kurt look-alike vices being sold right now, take it apart and file the ram perfectly smooth, polish the half-ball, and clean out the pocket it lives in. Then I think you'll be happy with the money spent.

 

[MrWhoopee]

My vise came with the mill and I know nothing about its history. I just recently gave it a cursory check. Nothing intense, just a few .0005 indicator passes over the jaws and bed after stoning off any irregularities. Every thing was surprisingly good, but what really caught my attention was that the moving jaw pulled down .0005 under pressure.

 

[graham-xrf]

I don't know, but I am guessing that 0.004" drop, and for @MrWhoopee 's case 0.0005" drop is an intentional and desirable design feature that will drag down on the surface it contacts, to have the work snug up better to any parallel (or whatever) under it?

I have not yet taken a machinist vise apart, so I am unsure what the "ball bearing cut in half" part looks like.

 

[WobblyHand]

It's literally a ball bearing sliced nearly through it's diameter. To make mine used a pipe with 0.485 ID, pushed in a 0.500 ball bearing and pushed the assembly into a belt grinder. Made the flat.

 

[Shotgun]

I don't know, but I am guessing that 0.004" drop, and for @MrWhoopee 's case 0.0005" drop is an intentional and desirable design feature that will drag down on the surface it contacts, to have the work snug up better to any parallel (or whatever) under it?

I have not yet taken a machinist vise apart, so I am unsure what the "ball bearing cut in half" part looks like.

Yes, @graham-xrf , you got it in one. Mine was raising when I clamped down. So you go to the trouble of setting an item up on parallels, give it a good tap to seat it, and then the vice pushes it out of place. Now, the device will pull it down to where you were trying to get it to be.

 

[jeffmaxwell_amarillo]

Thanks--I will give that method a try on my "precision" chinese vice.

 

[WobblyHand]

Thanks--I will give that method a try on my "precision" chinese vice.

Good luck with it. I tried with mine - it did get better, but wasn't great. Reduced the lift some. Maybe I need more patience to work on the nut some more. Found it awkward.

 

[graham-xrf]

It's literally a ball bearing sliced nearly through it's diameter. To make mine used a pipe with 0.485 ID, pushed in a 0.500 ball bearing and pushed the assembly into a belt grinder. Made the flat.

Ahh - got it now. I got scrambled on the word order "ball bearing" vs "bearing ball".
Oops!

I have a vise still to be unpacked that is similar in style to the one in the picture.



With the screw lock at 45° like that, it looks as if it will always "drag down".

 

[WobblyHand]

@graham-xrf, that style vise is a very good value. They are relatively inexpensive and work very well. Very low jaw lift. One thing you may need to watch out for is the bottom edge of the hole in the moveable jaw. On mine, that edge was very sharp (totally unfinished) and the burr would catch on the screw threads on occasion. I lost 3 screws in 6 months of use.

The fix is to ease or radius the edge of the hole by lightly grinding the edge with a dremel stone. Just went through this recently.

 

[mattthemuppet2]

I did a similar work through on my Shars 4" vise ($110 I think). Fixing the half ball and wedge made a bit difference. I also made the fixed jaw key fit better and tapped the base for longer bolts for the fixed jaw. Funnily enough I get a little bit of lift from the fixed jaw flexing backwards, but a tap with a dead blow hammer usually fixes that. Other than that it's dimensionally dead on as far as I am able to measure. Pretty good value, even with the extra work.