Did I Goof or Junk V-Block Part

[Bob Korves]

The newer vee block clamps are investment cast castings of low grade steel. Probably Chinese grade C10 which is equivalent to our grade 1010 if you could get it. Investment casting in general has no grain structure to it and added to the failure along with the thin section around the screw. The older vee block clamps were drop forged of a good alloy steel, which could be bent into a pretzel and not break!

Has anyone had a vee block split into at the bottom of the vee? I have.

Nearly anything is possible if you have a 100 ton press... Sharp corners can cause hardened parts to break at the corners due to the creation of stress risers.

 

[4GSR]

Yep, that will do it. The one's I saw split were made of cast iron and came from either Japan or Taiwan. Don't remember. You can still buy them, I have a set in the bottom of my tool box that I've never used but have them if I ever need them. Ken

 

[Highsider]

Last week was the first time I had a chance to use my new V-Block Set, a gift from my wife. I w as attempting to hold a length of 1-inch alum. round stock prior to milling a flat. The V-Blocks in this set, include a U-Shaped "yolk" that is used to hold the stock in place. After placing the alum. in the "V" I threaded the holder finger tight in the block. Then I positioned the block on the table u sing the X-Y adjusters and indicated the center line of my stock. I used a short piece of drill rod (there is a hole in the knurled thumb nut portion of the screw) to snug up the threaded holding screw on the yolk and the yolk promptly broke in half. I want to emphasize that the snugging was just a bit more than finger tight - any less and my material would surely have moved as soon as the end mill touched it. See photos below. If you look closely, the material is surely die cast mystery metal with a narrow cross section. It broke exactly at the weakest point . Did I do something wrong or is this a poor design? I called Fowler and they are "looking into it". I'm asking because I'm an amateur at shop techniques but my engineering background tells me that there should have been a more generous cross section at the drilled hole or stronger material.

Your comments are welcome.
Best regards, Frank
View attachment 224728 View attachment 224729 View attachment 224730

Another case of low quality Chinese heat treating. It was hardened but never drawn. Brittle as glass. Always check the country of origin befor you buy ANYTHING for your shop.
It's not cast anything. It's also not equivalent to American 1010 as that would have held a lot more pressure and then just deformed.
Look at the grain structure of the broken piece. It's finer than cast iron. The piece was hardened to be as brittle as glass and just left that way. Buy just about anything but Chinese.

 

[Ken from ontario]

There are two types of V blocks. I believe the ones you would need are the ones with socket head screws that hold a flat support across the top with inverted v on them. I cant seem to get a photo of them to post

This set is not top quality of course but the design of the clamps seem to be more suitable to hold down on a round stock, notice the inverted V on the clamps,the size of these v blocks is exactly what I'm looking for,1.3/8" x 1.3/8".

 

[Bob Korves]

This set is not top quality of course but the design of the clamps seem to be more suitable to hold down on a round stock, notice the inverted V on the clamps,the size of these v blocks is exactly what I'm looking for,1.3/8" x 1.3/8".View attachment 225472

They will probably work well for you, Ken. Even with that design, go easy on tightening down on the work...

 

[kd4gij]

I have used that type on a surface grinder but never on a mill.