General Industrial Mortiser Review

by Randy Gillard

Some time ago I posted a tool gloat about purchasing the General International Hollow Chisel Mortiser, Model 75-050. I have had a chance to cut a few square holes with this machine and thought that some would find a review useful.

First of all, there was very little assembly required. The machine goes together quickly and easily. There was no large amount of cosmoline to clean off, just a little light oil. The fence and hold down system on this machine are excellent. The fence is guided by a steel bar in a slot, much like a mitre gauge in table saw. The action is smooth with virtually no play in the slot. The cast iron fence is tightened in position by two ratcheting levers. The fence seems perfectly square to the slot.

The hold down is very easy to adjust up and down. You simply loosen a knob the release the clamping jaws from the dovetail way on the column, position the hold down, and re-tighten the knob. The massive dovetail way that makes up the vertical column is one feature that separates this machine from the smaller ones with a tubular column. The plunging action is very smooth, and the long arm gives plenty of leverage.

There is a clamping jaw at the front of the machine that is adjusted with a hand-wheel. It pushes the work tightly against the fence. It is very substantial and is excellent for positioning the work and providing additional hold down force when extracting the chisel in deep cuts.

The depth stop is simply a round piece of metal with a threaded hole that clamps to a threaded rod using a locking bolt with a knob. It seems to work OK.

After the initial assembly, this machine can be completely set up for a mortising job with no tools other than the chuck key. Everything is knobs and levers. No additional screw drivers, Allen wrenches, etc. required. Nice touch.

The chisels that came with the machine (1/4'', 5/16'', 3/8'' & 1/2") seem to work well enough. I honed them using the scary sharp method prior to use, and it cut 1/2" x 2" x 1 1/4" deep mortises in spruce with ease. No burning. In oak, a little more care needs to be taken not to burn, but I had very little.

Overall, an excellent benchtop machine. I highly recommend it.

Some additional observations and a few tips from Garrett Lambert

I, too, own one of these machines. My experience parallels Randy's, i.e. the machine is really solid, and the surprisingly good chisels cut square holes accurately and cleanly. My machine also came with an adaptor for chisels with a ¾" shank which lets me use the set of 5 I already owned.

However, as with any machine there are a few small nags:

The adjustable work-piece stop that screws into the cast iron base on the right side works very well. However, for a job when I needed the stop on the left side, I discovered that although the casting has a boss on the left side as it does on the right, the left one has no hole. The thread is a standard 5/16" x 18, and it took all of 3 or 4 minutes to drill and tap the boss. Small thing, but should have been done in the factory.
The column height and depth stops are cleverly-designed slip-thread rings for fast adjustment that are kept in place with a simple screw. However, the clamp can loosen due to vibration unless you crank it REALLY tight. Something to check on regularly as you work.
The work-piece clamp is heavier than necessary and a too-tight fit inside the jaws of the extruded aluminum hold-down. It appears the specs didn't allow for the enamel coating. Again an easy fix that ought to have been done in the factory. And,
The 2 spring-loaded clamps that adjust the fence are a nice idea but extremely inconvenient because the handles - especially the one on the left side - have a travel arc of only about 90° and quickly become a real PITA. Again, there's a very easy solution: unscrew the handles and put them, the screws, and the springs in a safe place where you'll never, ever find them again. A ½" or 13 mm wrench now fits the heads perfectly, and once loosened the bolts can be turned off or on easily with just fingers."