Brass setup bars are incredibly useful for all kinds of tool setup and measurement tasks in the shop. These Mag Shims, from Fastcap, are quite different, but look to be almost as versatile. Mag Shims are larger than typical brass setup bars, and they come in only two easily identifiable thicknesses: the thicker red shim and the thinner steel spacer.
The biggest thing that sets these highly visible red plastic shims apart from brass setup bars is the embedded magnets. The shims can stack and stick to each other, or to the steel spacers, or to any ferrous surface.
Since they are made out of plastic, FastCap Mag Shims shouldn’t damage or dull your cutting edges, as long as you keep the steel spacer in the center of the shims and the magnets away from the cutting edge.
Besides being able to stack to create any thickness from 1/8″ to 1-1/8″, FastCap Mag Shims also have rounded corners that can be used as templates for 1/8″, 1/4″, 1/2″, and 3/4″ radiuses, and even the inner notch can be used as a 1/4″ inside radius reference.
Mag Shims come in two different sets: imperial and metric. The imperial set comes with (8) 1/8″ red plastic shims and (2) 1/16″ steel spacers, and the metric set comes with (6) 2 mm red plastic shims and (2) 1 mm steel spacers. Unfortunately, imperial and metric sets are not color coded. If you buy both sets, try not to mix them up.
The imperial version of the Mag Shims are on sales right now at Rockler for $20, thru February 27th, 2015. They are normally priced at $25 at Rockler, Woodcraft, and other FastCap distributors.
You can find the Metric set of Mag Shims over at Tool Nut, where they are regularly priced at $20.
I use brass setup bars all the time in my shop, but I think these Mag Shims could have a place too. The fact that the shims stay together means they’re going to be better at certain tasks.
Say I want to set the bit on my router table to 3/4″ high. I would need to stack a 1/4″ bar on top of a 1/2″ bar and then use another bar to bridge across the top of the bit and the stack to check that the bit is exactly 3/4″ high.
With the Mag Shims I would stack 7 of the 1/8″ thick red shims next to the bit and then slide the 7th shim over the bit to see if it’s the correct height.
Mag Shims may be easier to use in certain situations, but because they are plastic I wonder how accurate they are. A related question is how close in thickness are the shims to each other? If you take one stack of four, how close in measurement is the other stack of four?
Lastly, are measuring tools made of plastic going to hold up in the shop? One could argue in some ways they might be better than brass. I’ve dropped one of my brass setup bars on the cement floor of my shop and dinged the edge making it less useful. I don’t think the Mag Shims would have the same problem.
What do you think? If you regularly use brass setup bars, or other brands’ tooling setup shims, is this something you would use also or instead?
Here’s an in-depth overview promo video that shows the many ways how the Mag Shims are intended to be used: