HST is Big Plus certifiedHST Is Big Plus Certified. At High Speed Technologies, Inc. we repair Big Plus tapers to OEM standards. With our in house grinding and climate controlled environment we can guarantee all of our Big Plus repairs. If you have a spindle with a damaged Big Plus taper call us at 1-603-483-0333

Big Plus was developed to provide a simultaneous contact system that could also utilize a customer’s existing inventory of BT, and CAT taper tooling. This system allows a shop that may have tens of thousands of dollars in tooling to step up to simultaneous face contact tooling for special jobs and still use all of their older tooling and tool holders.

Being Big Plus Certified means that HST can provide extraordinarily accurate tool interface grinding. This capability also carries into our other simultaneous face contact repairs such as HSK and KM interfaces.

What Are Some Advantages of Big Plus Tooling?

Machines with Big Plus spindles can use all of your standard CAT or BT tooling. Additionally, Big Plus tooling can work in a standard tool magazine. So you can have the benefits of simultaneous contact with some tools and not have to replace your whole inventory.

Increased rigidity is achieved by simultaneous contact of taper and face. Manufacturers claim productivity improvements with heavy or high speed cutting, deep or large diameter boring and especially when using a cutting tool with longer projection length. Another important improvement is the tool life of end milling operations due to the vibration free cutting.

All Big Plus Tooling is manufactured to very precise tolerances which means tools can be used in all Big Plus machines.

Why Do Big Plus Taper Repairs Cost More than a Standard CAT Tapers?

The primary reason for the cost difference is that the Big Plus Tapers take much more time to finish than a standard taper of even an HSK.

All measurements must be made with the shaft at a very specific temperature to minimize the effects of thermal expansion. The grinder induces a significant amount of heat into the spindle shaft as it removes material. This causes the shaft to expand into the abrasive surface with the very real potential for removing too much material.

As the finished dimension is approached the work must be stopped regularly, cooled and checked. So the operation slowly creeps into the finished dimension to avoid removing too much material.

Gaging must be calibrated before each check. The taper can only be check at a certain temperature. The measurements are in 1 micron increments. Big_plus

Gaging must be calibrated before each check. The taper can only be check at a certain temperature. The measurements are in 1 micron increments.

Job I-1168

This Mori Seiki NH 5000 failed due to conatmination in the bearing. But our inspection also found run-out in the taper and poor surface contact. Because the spindle is a Big Plus the repair required GPG.  When the Big Plus repair was completed the results were excellent. We only measured about 1 micron out at 300 mm on our test bar.

Job I-0891 

Mori Seiki NH 5000 Before and After Big Plus Taper Repair

Mori Seiki NH 5000 Before and After Big Plus Taper Repair

This job was also a Mori Seiki NH 5000. Because high speed spindles do not have positive seals they often fail due to contamination getting past the labyrinth seals.  Like Job I-1168 above this spindle also failed due to contamination.

Labyrinth Seal Mori NH 5000

Contamination can get past a labyrinth seal.

The taper ID had some dings. But because it was a Big Plus we couldn’t just Kiss Grind the surface for the repair. Even slight material removal on a simultaneous contact taper will result in poor performance. So we GPGed the taper.

The taper came out perfect with 1µm run-out on the test bar. Mori Seiki spindles are real good and we do our best to provide a repair that matches the quality of the spindle.

At HST we repair Big Plus tapers to OEM specifications. High Speed Technologies is certified and licensed to repair Big Plus. We will only use top name brand ABEC 7 super precision spindle bearing in your repair. If you have a problem or damaged spindle and need emergency repair call us at 1-603-483-0333 or email us at info@highspeedtechnologies.com

Anytime during business hours we’ll answer the phone.