Does anybody know if reagular 40 taper tooling can be altered to quick change tooling. I recently got a machine with a quick change 40 taper spindle. I have a full set of regular 40 taper stuff but it will not work in the the QC Spindle. It looks to me that the flange thickness is the only difference between the regular and QC holders. Can anybody confirm that? Anybody ever tried to turn regular 40 taper holders into QC holders?
Thanks for any help.
I found this on the web at:
NMTB (Quick Change) Shank
ANSI B5.18, National Machine Tool Builders' Association, 1927. DIN 2080 / IS 2340, ISO R 290-2583
Also called Quick Change, NMTB, MM, National Standard, American Standard Machine Taper, etc.
Units built to the ISO standards are commonly considered interchangeable with ANSI units. However,
there are a few differences. (See Tables below). Most (but not all) NMTB shanks are compatible with
the corresponding size Erickson Quick-Change Spindles. (See discussion below the tables).
NMTB shank compatibility with Erickson Quick-Change Spindles:
The NMTB shank was developed for use in the NMTB spindle which uses a draw bar to pull the shank up into the spindle. As a result, small variations in the tool holder flange thickness and the distance from the gage line of the taper to the outward face of the flange were not an issue when selecting one manufacturer of tool holder versus another.
The Erickson Tool Company developed the Erickson Quick-Change spindle to use the NMTB 30, 40, 45 and 50 tool holders already in existence. The Erickson QC system does not use a draw bar, it uses a quarter turn "locknut" to push and hold the tool holder taper up into the spindle. Two "lips" in the nut push against the outer face of the tool holder flange. The key dimension that causes some NMTB holders to not work in an Erickson Quick-Change spindle is the distance between the taper gage line and the outer face of the flange (dimension L4 + L5 in above tables). L4+L5 on some NMTB holders is too large which does not allow the "lips" in the QC nut to engage the outside face of the flange.
All NMTB holders made by Erickson work fine and I've read that Collis and Valenite holders work fine (at least the ones made in the last 15 years or so). I've also heard that Kennametal NMTB 30 holders work well. The compatibility of other holders is in question. However, all is not lost, the flange face of the holders that do not fit can be turned or ground down a small amount and then they work just fine. Erickson even put out a procedure to do this very thing (does anyone have a copy of the Erickson procedure ?).
The "tail" of the NMTB shank is not required when mounting in an Erickson Quick-Change Spindle. So 30-Taper and 40-Taper tooling, without tail, work fine as long as the taper and flange dimensions are correct. DO40 and DT50 tooling can also be used in Erickson Quick-Change spindles, but you may need to cut off or grind down the ribbed tail for clearance in the QC spindle.