Qctp Holder Review Part 2

[Bob Korves]

Based on this tread, I decided to purchase some CDCO QCTP Holders, to use with my Phase II QCTP. I purchased 4 ea of the 250-102 and 1 ea 250-101.

Here are some of my observations:

1) CDCO Holders though covered in oil, arrived with surface rust on the Set Screws, requiring cleaning to have them screw in and out smoothly.
2) The finish of the Phase II holders is cleaner/nicer. The CDCO holders have dings and marks on all the surfaces, while the Phase II holders are ding and mark free.
3) The Dimensions, Holder to Holder, are more consistent with the Phase II holders. All the dimensions are with in 0.001" of each other, Holder to Holder. On the CDCO holders the same measurements holder to holder varied by as much as 0.010".
Though, the difference shouldn't effect the performance of the holders, I think is speaks to Manufacturing Controls.
4) Of more importance.... I found on 2 of the 5 holders the bottom surface, where the tool rests (Opposite the set screws) was not square with the bottom of the Holder. I don't have access to a surface plate, so I can measure squareness that way, but I put a square along the back and bottom of the holder, and found it to be square. Measure from the bottom of the holder to the bottom tool surface, I found about 0.0015" difference front to back. Again this shouldn't effect things, but if it were greater, it could start to alter the angles of one's cutters.
5) The Dove Tail and back surface of the Phase II holder were ground after the black oxide coating was applied. On the CDCO the dove tail was ground before the Black Oxide was applied. (snip)

Again, the Chinese manufacturers do not seem to care a lot about long term quality control and quality assurance. A company might be making beautiful stuff, and as soon as you brag on them, the next ones are poor. And vice versa. That is why I ignore sellers touting high quality Chinese tools. I never know what I am going to get, so I choose the cheapest, and that approach does not seem to get me worse tools than buying the so called "premium" Chinese tools. It would be nice if the quality actually delivered on those tools long term was a whole lot more predictable, even if it cost more.

 

[pstemari]

Fwiw, black oxide doesn't require enough heat (280°F) to temper or distort the metal. It also doesn't affect the dimensions of the part, so doing it before or after grinding doesn't matter much.

 

[Downunder Bob]

Jbolt, A very well done and informative set of tests. Have you considered also comparing the different style of QCTP made by Algra, Dickson and I think Bison, and maybe others, also do one. This style are quite a different design, using a twin "V" groove for location, and are not interchangable with the group you have just done.

When I bought my lathe in mid 2016, it came with an Algra (Italian) QCTP and 5 holders. They are very nicely made and work well. The sizing they use is rather different as mine is called AR-AP but is approximately the same as BXA.

The Algra is rather more expensive than the dovetail styles, but I suspect is much more rigid as it uses a twin "V" groove for location, and a somewhat different but very positive mechanism for height adjustment.

However because of the cost of extra toolholders in this system I'm considering changing to Aloris BXA as I can get a completely new Aloris BXA with 5 toolholders, same as what I have, for the price of 4 spare Algra toolholders. Thereafter extra toolholders will be much cheaper.

Cheers,

Bob.

 

[ezduzit]

Photo of poor machining (distorted tool slot) on Phase II holder.

 

[middle.road]

Picked up (4) AXA holders from Shars this month. (2) #2's 250-102, and (2) 250-101XL.
I'll have to say that I was pleasantly surprised by the quality, except for the Vee grooves in the 102's.
Packaging was excellent, wrapped in plastic and individually boxed properly.
The outer machined surfaces are good all around, no jagged-ness anywhere except in the slots.
The hardware is also decent. Had to wire brush off the oxide on the large set screw and all screws operate smoothly.
I stoned the slots and didn't like the looks of the bottom of the slot so I ran them through the Mill to clean them up.
All (4) fit properly on my Dorian post.