CNC vise failure/repair options

Mill
1

I had a part come out “wrong”. I started to check over all sorts of things until I finally made it to suspecting the thing I would have never suspected. I was checking that the Talongrip jaws were secured and parallel. I loosened them and when I started to tighten, they would not snug, so I took everything apart and found this…

IMG_5167
IMG_51671920×1440 430 KB

I have not over-torqued (using a standard length 3/8” ratchet) or can think of anything else that would have caused a failure like this.

Anyone else have this issue?

I would imagine that this individual part is not for sale, so it looks like options are:

  1. Buy a new vise (ouch)
  2. Attempt a thread insert operation
  3. Machine a new fixed jaw from the provided CAD - but out of what type/grade of steel?
2

Helicoil both of them. Should have clearance in the hard jaws for a maybe not so perfect locating job. Sink the helicoil 1/4 to 1/3 turn below the top. Use Red Loctite. Stone surface for high spots.
All better!
Oh, use 1 1/2 diam length helicoil.

3

I had looked at this and was initially discouraged of it being a viable option. Thanks for the vote of confidence and notes. I have the inserts on order and I’ll report back with results.

4

Step the drill size up to req’d diam if you’re doing it by hand. I’ve been told by engineers that the heli coil is actually stronger set in base material. Plus threading bolts in and out takes a toll on metals. And, clean excess red loctite out with a Q tip. Let it set for an hour or two. Otherwise the bolt will unthread it. Both locked together. No fun.

5

Make a new one out of 4140 PHT

Dave

6

Most of the fixed jaws are tapped through. May be possible to reverse it. Depends on the keyway.

Dave

7

@David_Trader @Bruce_Kuller So, for either of your solutions, I would be depending upon the 3D model which does not appear to reflect reality.

Any thoughts? Thanks in advance…

8

Why do you need a 3d model? It’s a simple block.

Dave

9

I haven’t triple verified this but I would expect the 4" vise to follow the standard since you can buy jaws all willy-nilly from monster.com

10

…because I’m going about this like a computer programmer that is my educational background and not as a trained machinist… :rofl:

I’ve adjusted my expectations and tolerances appropriately and should be able to handle “winging it”.

11

Yeah, I understand that it is a common 4” CNC vise design and the bolt spacing is standard at 2.5”. I just figured the model would match exactly and it doesn’t. The width of that part is 106mm in the model where it is 102mm IRL, so good thing I didn’t try set my WCS off the corner as I originally intended…