How to choose the right toolholder

I have been presented with countless varieties of toolholders over the years. All have been touted as cost-reducing or quality-improving products for reasons such as extended tool life, runout minimization and powerful gripping forces, among others. In some cases, the claims were accurate; in others, they were a bit exaggerated. I suspect that most shop owners, engineers and machinists can recount similar tales and claims.

Two things are certain: Opinions about toolholders and best practices are varied, and toolholders can consume a significant portion of a shop’s budget.

All images courtesy of Christopher Tate

So how does one sort through the selections and find the best solution in terms of costs? No formula or process will derive the best choice, but there are considerations that will help make sound decisions when selecting the best toolholders.

The Common Touch

First, strive to eliminate variation in styles and technology. Common holding methods will help reduce unnecessary inventory and make the shop far more flexible, especially when reacting to short-cycle jobs and emergent situations.

Moving jobs around the shop to address capacity or maintenance issues can be difficult when machines have dissimilar toolholding requirements. Work to create a shop that has common machine interfaces so tools can be moved from machine to machine with little effort. Consider, for example, a CAT 50 toolholder and a BT50 toolholder. They are interchangeable in the machine spindle, but they are not interchangeable in the automatic toolchanger.

Having a common machine tool interface also means toolholders are not made obsolete when a machine leaves the shop. I saw hundreds of toolholders leave in scrap bins as old machines became obsolete at an aerospace manufacturer. Most of the toolholders had almost no signs of wear and actually appeared new. They were discarded because they did not fit any of the other machines in the shop.

New and Proprietary Technologies

Avoid unproven technology. It is common for a sales representative to present a new toolholding system that has not been proven effective outside the manufacturer’s controlled environment. Always review new technologies carefully and consider how the change would impact commonality. Also, project the cost and availability of spare parts and wear items, like collets.