When your machine’s precision movement drive exceeds what can certainly and economically be achieved via ball screws, rack and pinion is the logical choice. On top of that, our gear rack comes with indexing holes and installation holes pre-bored. Just bolt it to your Helical Gear Rack framework.
If your travel size is more than can be obtained from a single amount of rack, no problem. Precision machined ends enable you to butt additional pieces and continue going.
One’s teeth of a helical gear are set at an angle (in accordance with axis of the apparatus) and take the shape of a helix. This allows the teeth to mesh gradually, starting as point get in touch with and developing into range contact as engagement progresses. Probably the most noticeable advantages of helical gears over spur gears is less noise, especially at moderate- to high-speeds. Also, with helical gears, multiple the teeth are often in mesh, which means much less load on each individual tooth. This results in a smoother changeover of forces from one tooth to another, to ensure that vibrations, shock loads, and wear are reduced.
But the inclined angle of the teeth also causes sliding contact between your teeth, which generates axial forces and heat, decreasing efficiency. These axial forces perform a significant part in bearing selection for helical gears. As the bearings have to withstand both radial and axial forces, helical gears need thrust or roller bearings, which are typically larger (and more expensive) compared to the simple bearings used in combination with spur gears. The axial forces vary in proportion to the magnitude of the tangent of the helix angle. Although bigger helix angles offer higher rate and smoother movement, the helix position is typically limited by 45 degrees because of the production of axial forces.
The axial loads produced by helical gears could be countered by using double helical or herringbone gears. These arrangements have the looks of two helical gears with opposite hands mounted back-to-back, although in reality they are machined from the same gear. (The difference between your two styles is that dual helical gears have a groove in the centre, between the the teeth, whereas herringbone gears do not.) This set up cancels out the axial forces on each set of teeth, so larger helix angles can be used. It also eliminates the need 
for thrust bearings.
Besides smoother motion, higher speed ability, and less noise, another advantage that helical gears provide over spur gears is the ability to be used with either parallel or nonparallel (crossed) shafts. Helical gears with parallel shafts require the same helix position, but opposing hands (i.e. right-handed teeth vs. left-handed teeth).
When crossed helical gears are used, they can be of possibly the same or opposing hands. If the gears have got the same hands, the sum of the helix angles should equivalent the angle between your shafts. The most typical example of this are crossed helical gears with perpendicular (i.e. 90 level) shafts. Both gears have the same hand, and the sum of their helix angles equals 90 degrees. For configurations with reverse hands, the difference between helix angles should equivalent the angle between your shafts. Crossed helical gears offer flexibility in design, however the contact between teeth is closer to point contact than line contact, so they have lower power features than parallel shaft designs.