The Northridge Tool Difference
When we set out to make the Northridge Tool 2x72 Belt Grinder line of knife grinders, we wanted to make the best belt grinder on the market, at a price that made it a true value, all while keeping the entire manufacturing in the USA. We believe we’ve done just that, and here’s how!
Our knife making belt grinder features 1/4 thick side and bottom plates made from A-36 USA made steel sheet cut on the Cincinnati CL-707 laser with an 8x20 foot bed and a guaranteed tolerance of 0.001 one thousandths of an inch, which is almost unheard of for laser cutting! The belt grinder side and bottom plates are then acid washed and powder coated with a special silver vein powder coating, the toughest powder coating available.
The Tracking arm
The belt grinders tracking arm is first cut out of USA made 1/2 thick plate, CNC machined for perfect alignment of the gas shock, then drilled and tapped for the tracking knob 3/8-24 fine thread adjustment screw. The tracking adjustment nob has a custom made tension spring with flat ground ends, to keep pressure on the threads and reduce the chance of the tracking nob accidentally turning while in use, which helps prevent belt wandering. We profile the tracking arm, chamfer it, and countersink it for socket head screws. No mating surface is left raw or unfinished, and we drill our holes with Titex drill bits which never drill oversized holes.
Check out the video section to see it being made!
After machining it’s black coated for a corrosion resistant finish and it’s ready for assembly. The tracking arm is secured between the side plates with 2 spacers which we precision machine for a perfect fit, no stacked washers here! For the tracking arm pivot, we ended up custom making our own bolt out of 4140 heat treated steel with a solid shoulder all the way through the tracking arm, spacers and both side plates so that the entire bearing surface is on the solid shaft, preventing the threads from wearing and guaranteeing perfect alignment for the life of the grinder.
We also make our own knurled tracking knob and tracking arm handle, because we think they’re much better made of solid aluminum rather than plastic!
Tracking wheel pivot assembly
The belt grinders tracking pivot assembly is secured to the tracking arm with 2 1/4-20 alloy socket head cap screws and the pivot is secured with a precision heat treated ground dowel pin. The holes for the pivot assembly are drilled and reamed for a press fit no slop! This guarantees that there is no wobble in the tracking assembly, which all translates into a better running and smoother tracking belt.
The Northridge 2x72 belt grinder is assembled with care and attention to detail. The center spacer bars are 6061 aircraft grade aluminum. We start with oversized material and mill them to our tooling arm specification to ensure the proper tooling arm clearance for a perfect fit, no short cuts! We also drill and tap both sides, no through holes to create weak points. We roll form tap them to make the strongest thread in aluminum possible, they are then bolted together with high quality heat treated socket head cap screw fasteners, not cheap galvanized depot nuts and bolts. We then apply medium strength Loctite and torque them to the proper specifications for maximum strength and durability.
Our wheels are made on our state of the art late model turning centers. The drive wheel is machined so the outside diameter, the bore and the keyway are made in a single setup so they are as concentric as the machine spindle, you can’t get better than that! We then dish out the faces to lighten them and crown the drive wheel and tracking wheel with a low crown. When your belt grinder is lined up properly you do not need the high crowns used by our competitors that stretch the center of your belts and decrease belt life. We also put shallow 0.012 deep grooves in the faces of all of our wheels to aid in cooling and act as a visual guide for tracking alignment. All wheels have bearing bore shoulders for the bearing depth press fit and a precision bearing spacer to eliminate the chance of over tightening and destroying the bearings. We machine the wheel mounting spacers with a taper fit to the bearing on one side and machine the other side so everything lines up perfectly with no shims or guess work. We also supply a drive wheel assembly gauge block to aid in the install of the drive wheel. This guarantees the correct offset to get your machine perfectly lined up fast and easy, no straight edge or guess work.
Tooling arm and locking handle
The locking handle for the tooling arm is a 3/8-16 thread and the end is machined flat to minimize scoring on the tooling arms. The tooling arm itself has relief cuts in the sides so if it does get scored it will not affect the fit. The locking handle thread plates are 1/2” x 1” steel bolt on, so if your threads are ever damaged it’s an easy replacement.
Belt grinder gas spring/shock
For our tensioning arm, we opted for a gas strut because unlike the traditional coil spring, which exerts more force the farther it’s compressed, a gas strut has the same force throughout it’s entire motion. This leads to better belt tensioning by taking the guesswork out of how far to compress your coil spring.
It also gives a streamlined tensioning system without the exposed crannies of a traditional spring, making it easier to clean.
We use a top of the line gas spring manufactured in Canada with double pressure seals, rather than the single seals used on most gas springs, for years of maintenance free service. We also machine a custom lower mount for the gas spring to ensure perfect alignment.
Most belt grinders look the same at first glance, but the devil is in the details. You can have a beautiful grinder that tracks terrible or vibrates at speed. Some say make it out of thicker steel to absorb vibration, we say if you make your components as precise as possible there won't be any vibration! No one else is making a 2x72 belt grinder with the precision and attention to detail equal to ours, and we feel our grinders are the best value for the price.
We have tried to leave no detail unchecked in the manufacturing of this 2x72 knife making belt grinder and we believe it to be the most thought out and precisely made belt grinder on the market.
And that is why the Northridge Tool 2x72 belt grinder is the new standard for quality, performance & value!