When things are tough, you cut extravagant spending out of your operation. However, common sense is always needed to maintain a safe working environment. Everyone talks safety, but the reality is we all get complacent as we get more familiar with a task. In selling cutting tools, we rarely get asked about the safety aspects of the tool, or how to use it in the safest manner. The cost of the tool, its ability to out-produce any existing tool or method, the quality of the cut and the profile are all issues at the forefront when a new tool is under consideration. But is there a possibility of it hurting someone? That question is rarely asked.
It comes down to familiarity. Anyone buying a professional cutting tool has been around for a while and has plenty of experience. Safety is likely taken for granted, and it shouldn’t be. The machines, particularly modern CNC equipment, have many safety features built into them. Automatic shut-offs protect operators who get too close to moving parts or open guarding. But the tool itself has no such features. If insert knives and/or the gibs are not mounted properly and double-checked, there are any number of dangerous possibilities when the tool is run up to full RPM or cutting pressure is applied. The solution is to examine the tool design carefully before purchase, so you are familiar with its mounting system and comfortable with its level of complexity. This will reduce the chance of mistakes or oversights. Always mount a tool on the machine for which it was designed. We had a recent situation where a user had a large CNC router bit and asked us to reduce the shank diameter. When we asked why, he said he wanted to put it on a hand router. We didn’t do it, but had he taken it to a general machine shop he might be nursing some damaged body parts today. Another one that seems to come up regularly is mounting a heavy profiling tool on a small-shaft table saw. That is way beyond the safety limits of any component of the machine and requires complete removal of the bottom plate. Overload or go outside a machine’s limits, and eventually there will be consequences.
Removing guards is probably the most common violation of safety common sense we see in any woodworking shop. More often than not, the guards are broken or functioning poorly so they are cast aside or completely removed. Although the guard is a part of the machine and not the tool, it is often removed to accommodate the tool — one that often should not be on the machine in the first place. Often, the guards are limiting the tool or what it is trying to accomplish (such as cutting deeper, or wider, or shaping in a difficult manner), so they are pulled off or disabled. Ultimately, it is the tool that does the injury, but rarely does it cause the injury. Any attempt to take shortcuts with a tool or modify a machine to accommodate a tool without consulting the tooling supplier and the machine distributor could have disastrous results.
Doug Reid is president of BC Saw and Tool in Toronto, Ont.
A diamond tool was sent in last week for repair and sharpening. It was a tool manufactured by a reputable company, and frankly it was well designed and manufactured correctly. The problem was that it never should have been made. The profile consisted of some very thin and long sections of diamond that were at best weak, and at worst fragile.
We all know that to cut deep, narrow grooves, with a profiling tool the tool needs to be used with care, because the tenuous structure of the cutting edge will not withstand abuse. Abuse can range from sloppy handling of the tool, to running it past the point where it cuts properly and you are forcing it, to using it in material it is not strong enough to handle.
The proper match
Tools need to be matched to the material they are cutting, the machines they are running on, and the end result expected. And when you have multiple variables there are generally multiple choices, some better than others, but usually more than one. In this application there was one choice that should have been eliminated immediately, and that was diamond. Having known where it originated from, I would bet the price of it that no representative from the diamond tool company ever visited the plant, saw the application, and discussed it with the user. This is not an excuse, it never should have been made, but if the two had really analyzed what this tool was going to do, they would have come to another conclusion.
Diamond tools have one advantage over other types of tooling, and at the risk of repetition, that advantage is edge life. It is not a smoother cut, or a stronger cutting edge, or cheaper, initially, to buy. They just last longer between resharpening. In some applications, they last hundreds of times longer, and thus are more economical over the long term, whereas in other applications the longevity can be considerably less. But the one certainty about diamond is it exerts more cutting pressure than, for example, a carbide insert knife. Coupled with the fact it is more brittle than an insert knife with a profiled backer, it is obviously more prone to breakage. In this application the tool was on a double-end tenoner, profiling a deep and thin mitre lock joint in the end grain of solid, knotty material.
Look at systems
Notwithstanding that the machine was old, and in my opinion sloppy (I wouldn’t have put any diamond profiling tool on it), cutting that material with that profile was simply a bad decision. It was bound to break, and it did. Even if we had determined it could be repaired, another disaster would have followed shortly after. The diamond cutting edge is fragile, so it needs strong support behind it. If the steel support is long and thin there is no support, to speak of. Plus for clearance purposes, so it will cut properly, the steel support actually has to be thinner than the diamond edge. The only application where this might have worked would be in homogeneous composite material, or possibly, down-grain in knot-free solid wood. This tool was a total waste of the customer’s money.
There are reasons that there are multiple choices in cutting tool designs and materials. Before a decision is made about the type suited for an application, it should be reviewed with your preferred tooling supplier, so at the very least, you have assurance of performance.
Doug Reid is president of BC Saw and Tool in Toronto, Ont.