Dual Linear Ball Bearings

Warning: Buzzwords debuzzed in this post.

If you've looked at miter saws at all, you've probably seen some mention of linear ball bearings. If you've looked at the Makita miters at all, you've probably seen dual linear ball bearings mentioned. But that brings the question, what the heck is that?

Picture: Dual Linear Ball Bearings

As you can see in the above diagram included on a Makita marketing piece, the linear ball bearings are exactly like they sound - ball bearings in a line. When you're using a sliding miter (the only place you'll see these), the linear bearings are used around the rails of the slide mechanism. The alternative is to use a sleeve.

Using a sleeve means two bad things happen.
1) More friction.
2) Less accuracy.

The basis of a sleeve is that you have a rail and a sleeve. The sleeve needs to be just loose enough to slide over the rail. However, since a sleeve has no rolling parts, there is more friction. This leads to a less smooth motion of the slide, creating the possibility of irregular cuts. It also isn't held together as tight - there has to be some play to allow the rails to slide - so there will be some loss of accuracy. Add in age and the cuts become less accurate. Sliding miters aren't for your average homeowner ($500 saws are a bit pricier than what most people want for the home), so accuracy should be a huge consideration when buying a sliding miter.

But why dual? Well, that's quite simple. Dual means you have one linear ball bearing on each rail. This makes for the most accurate cuts, smoothest motion and best performance. So then, why not dual? Well, Makita loves this part. If you save $20 per miter saw by leaving off a linear ball bearing and sell 1 million saws, you have saved enough money to sponsor a racecar.

I didn't really know what I was doing when I bought my miter saw. I purchased a Makita LS0711Z some time back, just as they were being discontinued. I consider myself fortunate. I got a decent saw, and the cordless is incredibly handy. I certainly hope they make another cordless at some point. Until then, my father will be incredibly envious.

If you're in the market for a very good sliding compound miter saw with dual linear ball baearings, I highly recommend the LS1013 (10") or LS1014 (12"). They are available with or without the laser, and are very well built. They also have a few other features that I'll be discussing in later posts.