Big+ CAT40 vs BT40 on a new machine (in the USA)
Close
Login to Your Account
Page 1 of 2 12 LastLast
Results 1 to 20 of 35
  1. #1
    Join Date
    Jan 2019
    Country
    ALAND ISLANDS
    Posts
    159
    Post Thanks / Like
    Likes (Given)
    28
    Likes (Received)
    98

    Default Big+ CAT40 vs BT40 on a new machine (in the USA)

    "Hypothetical" scenario for you all. You're speccing out a new machine and have a choice of either CAT40 or BT40. Both would be dual contact. You live in the US. You care about quality tooling. You use a mix of imperial and metric tooling. You have no other machines with either interface in the shop, so "get what you already use" does not apply.

    What do you choose and why? (And is it even a debate worth having?)

  2. #2
    Join Date
    Nov 2005
    Country
    UNITED STATES
    State/Province
    Illinois
    Posts
    2,195
    Post Thanks / Like
    Likes (Given)
    236
    Likes (Received)
    2083

    Default

    Most tool holder manufacturers based in the USA will have much more stock of dual contact CAT40 tool holders than BT40 dual contact tool holders. Why keep stock of a product that does not move? I probably sell 30:1 of CAT40 dual contact tool holders vs BT40 dual contact. Sure some of that may be the limited offerings I have in BT40 dual contact vs CAT40 dual contact. But the truth is I barely get any requests for a custom BT40 dual contact compared to CAT40 dual contact.

    Anyway that is my 2cents.

  3. Likes mhajicek, Oldwrench, PegroProX440 liked this post
  4. #3
    Join Date
    Dec 2019
    Country
    UNITED STATES
    State/Province
    Utah
    Posts
    41
    Post Thanks / Like
    Likes (Given)
    9
    Likes (Received)
    17

    Default

    My gut reaction, and I have no experience with this, would be don't get the one that will fit in your other machines. That way you are not tempted to mix your regular tooling and you dual contact tooling. I don't know if that will matter, good luck.

  5. #4
    Join Date
    Jan 2014
    Country
    UNITED STATES
    State/Province
    Oregon
    Posts
    709
    Post Thanks / Like
    Likes (Given)
    174
    Likes (Received)
    504

    Default

    As someone who buys a lot of Japanese and European holders, I would absolutely opt for BT40. AFAIK CAT40 is a USA only affair. Also the asymmetrical design of CAT40 seems really stupid, since balancing is now so critical.

  6. Likes Jashley73 liked this post
  7. #5
    Join Date
    Jan 2019
    Country
    ALAND ISLANDS
    Posts
    159
    Post Thanks / Like
    Likes (Given)
    28
    Likes (Received)
    98

    Default

    Quote Originally Posted by boosted View Post
    As someone who buys a lot of Japanese and European holders, I would absolutely opt for BT40. AFAIK CAT40 is a USA only affair. Also the asymmetrical design of CAT40 seems really stupid, since balancing is now so critical.
    I'm glad I'm not the only one who had this thought, tbh. On the one hand: relatively inexpensive, quality collet holders in CAT (ER and SK) from MariTool. On the other hand, extremely high quality shrink, hydraulic, etc holders from Japanese and European manufacturers in BT.

  8. Likes 2outof3 liked this post
  9. #6
    Join Date
    Jan 2007
    Location
    Flushing/Flint, Michigan
    Posts
    10,157
    Post Thanks / Like
    Likes (Given)
    572
    Likes (Received)
    8311

    Default

    Quote Originally Posted by fmari --MariTool- View Post
    .... I probably sell 30:1 of CAT40 dual contact tool holders vs BT40 dual contact. ,,,.
    In non dual contact, IE: normal holders is this ratio still true?
    Bob

  10. Likes vegard liked this post
  11. #7
    Join Date
    Nov 2005
    Country
    UNITED STATES
    State/Province
    Illinois
    Posts
    2,195
    Post Thanks / Like
    Likes (Given)
    236
    Likes (Received)
    2083

    Default

    Quote Originally Posted by CarbideBob View Post
    In non dual contact, IE: normal holders is this ratio still true?
    Bob
    Not as bad. Standard CAT40 to standard BT40 around 20:1.

  12. #8
    Join Date
    Oct 2013
    Location
    Hartford, CT
    Posts
    334
    Post Thanks / Like
    Likes (Given)
    215
    Likes (Received)
    135

    Default

    I'd go with option C, HSK63A

  13. Likes mkd, dstryr liked this post
  14. #9
    Join Date
    Jan 2014
    Country
    UNITED STATES
    State/Province
    Oregon
    Posts
    709
    Post Thanks / Like
    Likes (Given)
    174
    Likes (Received)
    504

    Default

    Quote Originally Posted by CNC Hacker View Post
    I'd go with option C, HSK63A
    ^^^By far my favorite medium sized interface.

    But FWIW HSK63 is definitely less rigid than dual contact 40 taper at lower RPMS. A dual contact 40 is pretty good for middle of the road. The rotating mass is small enough that you can get some really fast spindles, but it's stout enough that the spindle interface is more robust than the machine for most 40x20 applications.

  15. #10
    Join Date
    Nov 2015
    Country
    UNITED STATES
    State/Province
    Colorado
    Posts
    207
    Post Thanks / Like
    Likes (Given)
    32
    Likes (Received)
    80

    Default

    Yea CAT seems to be very american for example MST tools barely have any CAT interfaced tools, most are HSK or BT.

    Personally I would 100% go with HSK if I could

  16. #11
    Join Date
    Jun 2011
    Country
    UNITED STATES
    State/Province
    New Jersey
    Posts
    1,444
    Post Thanks / Like
    Likes (Given)
    764
    Likes (Received)
    616

    Default

    I prefer CAT spindles for the tooling availability and cost. Also, Full Contact (Big-Plus) is a must. After seeing it in action and demo-ing machines with it, I'm sold.

  17. #12
    Join Date
    Jan 2013
    Location
    Louisville, KY
    Posts
    3,263
    Post Thanks / Like
    Likes (Given)
    7916
    Likes (Received)
    2795

    Default

    That's a tough one. CAT is certainly prevalent in the USA. But BT is better, being symetrical.

    If you said that you used "all metric" tooling, then BT hands down.

    Metric & Imperial - It's a toss up.



    Maybe get quotes on some comparable CAT & BT tools from reputable BT40 Dual-Contact makers and ask the most important question - LEAD TIMES...?

  18. Likes 2outof3 liked this post
  19. #13
    Join Date
    Nov 2005
    Country
    UNITED STATES
    State/Province
    Illinois
    Posts
    2,195
    Post Thanks / Like
    Likes (Given)
    236
    Likes (Received)
    2083

    Default

    Makes absolutely no difference if the holders are symmetrical. Material is not perfectly homogeneous. BT40 or CAT40 need the same amount of attention when balancing. If someone makes a BT40 tool holder and all holes are perfectly in center and all features symmetrical it will be hit or miss if it passes G2.5 @ 20,000 rpm spec.

  20. #14
    Join Date
    Sep 2017
    Country
    UNITED STATES
    State/Province
    Wisconsin
    Posts
    1,249
    Post Thanks / Like
    Likes (Given)
    326
    Likes (Received)
    782

    Default

    Saunders (I know, I know) just did an interview with a guy from Big Kaiser who actually talks a lot about why CAT/BT is better than HSK in a lot of applications.

  21. Likes Orange Vise liked this post
  22. #15
    Join Date
    Feb 2012
    Location
    California
    Posts
    1,543
    Post Thanks / Like
    Likes (Given)
    951
    Likes (Received)
    1719

    Default

    All else equal, a CAT40 spindle will also command higher resale value in the States.

    Resale might be an afterthought for most, but it's a safety net for the short term. For the long term, it makes it easier to trade up for new equipment before your existing equipment goes obsolete, and before your machine gets plagued with nagging issues like clogged lubrication lines, bad encoders and sensors, etc that will nickel and dime you to death.

  23. #16
    Join Date
    Jun 2009
    Location
    Clearwater, FL
    Posts
    41
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    2

    Default

    No personal knowledge on which is actually better, but when we bought our Yasda PX30, we were told by multiple manufacturers, (Big Kaiser, Zoller, Yasda) that BT was definitely superior to CAT. We buy only Big Kaiser, Big+ holders for that machine, and haven't had any issues getting tooling.

  24. #17
    Join Date
    Nov 2005
    Country
    UNITED STATES
    State/Province
    Illinois
    Posts
    2,195
    Post Thanks / Like
    Likes (Given)
    236
    Likes (Received)
    2083

    Default

    No,

    CAT40 the taper is slightly longer than BT40. So the stem length for a CAT40 retention knob is @ .115" shorter than a corresponding BT40 retention knob. Shorter stem is stronger that a longer stem if a crash should happen. Symmetry is a mute point, so CAT40 wins. Be cautious when listening to some salesman, they only know what the've been told. I make em.

  25. Likes Oldwrench, Bobw, Orange Vise, mkd, Rick Finsta and 1 others liked this post
  26. #18
    Join Date
    May 2009
    Country
    UNITED STATES
    State/Province
    Wyoming
    Posts
    3,653
    Post Thanks / Like
    Likes (Given)
    9170
    Likes (Received)
    5948

    Default

    Quote Originally Posted by fmari --MariTool- View Post
    No,

    CAT40 the taper is slightly longer than BT40. So the stem length for a CAT40 retention knob is @ .115" shorter than a corresponding BT40 retention knob. Shorter stem is stronger that a longer stem if a crash should happen. Symmetry is a mute point, so CAT40 wins. Be cautious when listening to some salesman, they only know what the've been told. I make em.
    Wish I could like this a hundred times, as well as your post about the influence of material homogeneity on balancing. What Frank says you can take to the bank.

  27. Likes mhajicek liked this post
  28. #19
    Join Date
    May 2002
    Location
    South Central PA
    Posts
    14,563
    Post Thanks / Like
    Likes (Given)
    2801
    Likes (Received)
    4293

    Default

    Something I encountered - The BT spec ends at the flange, while the CAT spec includes a reduced diameter protrusion from the flange toward the tool. This allows more freedom in designing the BT tools, and BT toolchangers. You see BT tools that are full flange diameter leading
    outward but never a CAT. Can also make converting from one toolchanger to the other complex.

    Machine Tool Shanks (Tapers)

    tapers_cat_1.jpg

    tapers_bt_1.jpg

  29. Likes mkd, Jashley73 liked this post
  30. #20
    Join Date
    Nov 2005
    Country
    UNITED STATES
    State/Province
    Illinois
    Posts
    2,195
    Post Thanks / Like
    Likes (Given)
    236
    Likes (Received)
    2083

    Default

    Yes,
    CAT40 "requires" a 1-3/4 diameter at least to 1-3/8 gage length. 99.99 % of machining centers less than 30 years old do not care for this provision. Too much trouble converting a BT40 machine to CAT40 if they need to grab on this diameter as well. So you have the same freedom for both. I make plenty of CAT40 tool holders that do not adhere to this specification. Not 1 problem.

    For a while now converting a machine from BT40 to CAT40 or the other way around is just a matter of changing the tool changer arm grippers and a Z offset if the different gripper changes the tool holder position.

  31. Likes Mud, Bobw, Oldwrench liked this post

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •