MAG77LT Worm Drive SKILSAW - Canadian Woodworking Magazine

The lightest worm drive saw on market with a bevy of great features.



There are two styles of circular saws – sidewinders (what most people refer to when they use the word 'circular saw'), and worm drive saws. The difference between the two is in the location of the motor. On a sidewinder the motor is in-line with the blade – the motor shaft transfers powers directly to the blade. On a worm drive the motor is at the rear of the saw – a pair of gears oriented 90° to each other transfer power to the blade. A slightly different version of the worm drive is a 'hypoid' saw which uses a finer tooth gear system that is permanently sealed (on a worm drive the gear oil has to be changed regularly).

Two basic types of 'circular' saws

In general most cabinet and furniture makers, renovators, and DIYers will find that a Sidewinder, like the Skil HD5687M, is all the saw they need, while carpenters, deck builders, framers, and general contractors are more likely to consider a worm drive.

Sidewinders are typically lighter in weight, making them easier to use one handed and to use at shoulder height or overhead, with the the right mounted blade makes the cut line more difficult to see and follow. The saw rests on the solid part of the stock, so the waste side can simply drop away. A decent quality sidewinder can be had for around $100.

Because of the geared system, worm drives generate more torque, delivering greater cutting power. But they're heavier, making them more tiring to use, particularly over extended periods of time. The left mounted blade makes it very easy to follow the cut line, but the body of the saw rests on the waste side, rather than the solid side of stock, which means the saw is unsupported when the cut is completed. The longer shoe and lower center of gravity makes ripping and plunge cuts easier. 

Skil invented the worm drive saw in the mid-1920s, and the model MAG77 has been available in one form or another since the late 1930s. It's pretty well the standard by which all worm drive saws are compared.

The latest incarnation of the Skil worm drive saw is the MAG77 LT. A lot of the attention that this new saw is getting has to do with it's dramatic weight loss. Most worm drives are in the 15 to 17 pound range. The MAG77 LT comes in at a svelte 11.5 pounds, or about a 30% weight loss, which is not insignificant when using a saw like this day in and out. That weight loss comes about primarily from the use of lighter magnesium components (shoe, upper and lower blade guards). However, along with being the lightest worm drive saw currently available, the MAG77 LT does have other features that make it a standout.

Cutaway: geared system on the Skil MAG77 LT

Like most worm drive saws, the MAG77 LT sports a 15 amp motor that provides ample power to easily rip through dimensional lumber and engineered wood. In general, the design of the gear system on these saws has the effect of reducing rotational speed, but increasing torque. However, Skil has managed to increased the no-load speed to 5,300 RPM (up from around 4,600 RPM on similar models like the Skil SHD77), almost as fast as the typical speed on a sidewinder. And faster speed means that you get the job done quicker.

The drive gears on these saws are oil lubricated, and they typically have a long service life. However, under heavy load they can heat up, which means that you need to replace the oil on a regular basis. It's not a difficult or time consuming job – you just have to make time to do it.

In use, I found that the MAG77 LT didn't slow down at all when cutting dimensional lumber or LVL at maximum capacity –  2-3/8" at 90° and 1-15/16" at 45°.

The MAG77 LT runs smoothly, more so than I would have expected for a gear drive saw. When you start the saw it does twist sideways slightly. This seems to be common to all worm drive saws, due to the side mounted gear train.

The soft rubberized grip handles are comfortable, though I find the top handle a tad on the small size. It only has a
3-1/2" wide grip surface, which makes for a snug fit when wearing thick work gloves. 

The saw feels well-balanced and, because of the lighter weight, I find it much more comfortable to use – four pounds really does make a noticeable difference. The saw handles very well when ripping long stock, thanks in part to the large foot plate.

Quick and easy cutting depth adjustment

On any circular saw you want to be able to quickly set the depth of cut. Most saws have the depth of cut bracket stamped with an actual measurement scale. On the MAG77 LT Skil uses a 'Cut-Ready' scale. Basically the depth of cut bracket is scaled for standard lumber sizes – which means the scale refers to the thickness of the stock you're cutting rather than actual blade depth. The depth bracket has markings for standard plywood of 1/4”, 1/2”, and 3/4”, and 1X and 2X lumber thicknesses. The actual cut depth is about 1/4" deeper than indicated on depth scale.

I find this Cut-Ready scale to be 
very practical – it's faster and easier to set the correct depth for cutting dimensional lumber and sheet goods. And when I need to cut to an exact depth I measure blade projection – which is what I do with my sidewinder anyway.

(L) Bevel quadrant; (R) Cutting guide

The degree scale on the bevel quadrant is great. The numbers and the hash marks are white on a black background, making them easy to read, while the pointer doesn't block the numbers. Likewise, the cutting line guides on the front of the foot are easy to see.

Excellent line of sight

The line of sight on worm drive saws is much better than on circular saws, and the MAG77 LT is no exception, whether you're making straight or beveled cuts.

Anyone who cuts a lot of bevels will want a smooth operating bevel adjustment. On this saw I found that it takes a lot of effort to tilt the shoe – I can only trust that over time it will loosen up a tad.
Framers will appreciate the 53° bevel capacity. You get the standard two bevel stops, at 0° and 45°. However, another one at 22.5° would have been a welcome feature.

Long, ribbed magnesium foot plate

The large (5" by 12") thick, ribbed magnesium foot plate on this saw feels very rigid and sturdy, which is important, as it's the most frequently damaged part of the saw. An extra bonus is that the edge of the plate is square rather than rolled over, so you can run the saw up against a straight edge or speed square to make a perfect cut. The foot plate should have a long life, as magnesium has high impact resistance, a very high strength to weight ration, and is dimensionally stable. And, it's also considerably lighter than steel (and aluminum for that matter).
Both upper and lower blade guards are also made of  magnesium. The lower guard performs flawlessly. It retracts smoothly, and it's anti-snag design should significantly reduce the chance of snagging when you make narrow cut-offs. The thumb lever is compact, so it never gets in the way.

Blade change is straightforward

The spindle lock is located on the starboard side of the saw, directly over the oil fill bolt. I found it quite easy to depress the lock button while backing off the blade stud. Blade changeover takes about a minute.

The saw comes with a good quality 24-tooth, thin kerf, framing blade that works well for both ripping and crosscutting. The blade features premium diamond-ground titanium carbide teeth, three expansion slots, and an anti-friction coating.

The MAG77 LT also features Skil's 'Vari-Torque Clutch'. It consists of an outer washer on the shaft that enables the shaft to continue turning freely if the blade becomes pinched when cutting. This should significantly reduce the likelihood of kickback. For this feature to work properly you have to follow the blade installation instructions carefully, and not over-tighten the blade stud.

Multi-functional blade wrench

The blade wrench, held in place by a detent spring on the back end of the saw, is used for a variety of chores, including: prying out the diamond knockout on a new blade, removing the blade stud, removing the brush caps and the oil plug nut, and correcting the blade angle if it gets out of square. The wrench stays securely in place, but is easy to access
Adjustable saw hook

Most worm drive saws have a saw hook so you can hang the saw safely on a joist, rafter, ladder, or whatever. The hook on this saw can be flipped down for use, and then flipped back up out of the way when not required. It also doubles as a handy power cord wrap.

A standout worm drive saw

Anyone looking for a professional quality saw that will stand up to a lot of abuse, and give years of reliable service, should put the Skil MAG77LT be at the top of their short list. It's light weight, ample power, and a great feature set make this a standout worm drive saw.


  • Blade Size: 7-1/4"
  • Amperage: 15
  • Speed: 5,300 RPM
  • Depth of Cut at 90°2-3/8"
  • Depth of Cut at 45°1-15/16"
  • Depth of Cut at 53°1-5/8"
  • Bevel Capacity: 53°
  • Bevel Stops: 0°, 45°
  • Arbor Type: Diamond
  • Rubberized Soft-Grip Handle
  • Dual Position Saw Hook
  • On-board Wrench Storage
  • Magnesium Foot, Upper and Lower Blade Guards
  • Cord Length: 8'
  • Weight: 11.5 lbs
  • Warranty: 1 yr.
  • Includes: Multi-function wrench, carbide blade
SOURCE:Where to Buy
July 2014

Carl Duguay
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