Why you don't take a small trim cut on your cold saw

Every piece of equipment in your factory comes with a list of best practices and procedures to make sure you get the most out of your investment. A high production cold saw is no different. Whether you've purchased a Nishijimax from Pat Mooney Saws or another high production cold saw - taking a trim cut is part of your recipe for success. In this piece we will review why a trim cut is important, whether you need to take one at all, and why programming the correct length is critical to your saw blade life.

Why a trim cut is important for cold sawing

If you have a high production cold saw like the Nishijimax, Tsune, or Marvel saw you need to produce hundreds to thousands of steel billets consistently for your next process. Normally, this involves forging or machining the cut steel into a finished or nearly finished product. Before purchasing a cold saw, many facilities will use a production bandsaw or a shear. While a production bandsaw can give you a good surface finish, it can't produce as many parts per hour as a high production cold saw. Compared to a bandsaw, a shear may seem like a great option for high production rates. In fact a shear can out-produce some cold saws, but they have a tendency to break down or require significant downtime when changing between diameters. What shear can't give you is a clean surface finish. This is why a trim cut is important for cold sawing. Because many manufacturers choose a cold saw for it's high production rate and clean surface finish, you want to take a trim cut to remove the mill end of your steel bar or tube.

Do I need to take a trim cut?

In almost all cases, you should absolutely need to take a trim cut. It will help reduce cycle times on your downstream processes and gives you the clean surface expected from a cold saw. In some cases - normally forging operations - some manufacturers don’t require this finish in both ends. For these applications the Nishijimax cold saw sold and supported by Pat Mooney Saws has a “zero trim” program available that removes the trim cut from automatic operation increasing the yield from each bar processed through the saw.

Why do I have to take at least a 1” trim cut?

I recommend taking at least a 1 inch trim cut at the minimum.1 The reason why is both chemical and procedural. In a production environment you want a standard operating procedure to ensure operators are trained properly and you have a consistent output. Sometimes when turnover is high and information doesn’t get passed on the reason why this recommendation gets made and operators will attempt to take the smallest trim cut possible thinking this will save money.[1] [1 or as a game to make the shift go faster] There are serious problems for saw blade stability and tool life when this is done. In the first place, a small trim cut will not have enough weight to fall down the exit chute when the outfeed clamps of your cold saw disengage to release the part. This means the trim cut can fall back into the saw blade and break your teeth - even on a new blade. In the second place - when a steel bar is processed in the mill the ends of the bar will have a higher hardness rating than what is quoted on the spec. If the saw blade cuts through this harder material it runs a higher chance of chipping prematurely and lowering your overall tool life. This means more downtime because the operator has to change blades.

The best part of using a high production cold saw is the high production output and reliable surface finish you get with a saw cut. Machines like the Nishijimax (NHC) are easy to program and perform reliably - provided the proper procedure is followed. Making sure you or your operators start by take the right trim cut off a bar is just as important as choosing the right blade and settings.

What questions do you have about cold sawing? Let me know in the comments and you’ll see your question answered in future posts!