Whenever your machine’s precision movement drive exceeds what can certainly and economically be achieved via ball screws, rack and pinion may be the logical choice. On top of that, our gear rack includes indexing holes and mounting holes pre-bored. Simply bolt it to your framework.
If your travel duration is more than can be acquired from a single Helical Gear Rack amount of rack, no issue. Precision machined ends allow you to butt additional pieces and keep on 
going.
The teeth of a helical gear are set at an angle (relative to axis of the gear) and take the shape of a helix. This enables the teeth to mesh steadily, starting as point get in touch with and developing into range contact as engagement progresses. Probably the most noticeable benefits of helical gears over spur gears is less noise, especially at medium- to high-speeds. Also, with helical gears, multiple teeth are often in mesh, this means much less load on each individual tooth. This results in a smoother changeover of forces in one tooth to another, so that vibrations, shock loads, and wear are reduced.
But the inclined angle of one’s teeth also causes sliding contact between the teeth, which creates axial forces and heat, decreasing performance. These axial forces play a significant function in bearing selection for helical gears. Because the bearings have to endure both radial and axial forces, helical gears require thrust or roller bearings, which are typically larger (and more costly) compared to the simple bearings used in combination with spur gears. The axial forces vary compared to the magnitude of the tangent of the helix angle. Although bigger helix angles offer higher speed and smoother movement, the helix position is typically limited to 45 degrees due to the production of axial forces.
The axial loads made by helical gears could be countered by using dual helical or herringbone gears. These arrangements have the appearance of two helical gears with reverse hands mounted back-to-back again, although in reality they are machined from the same gear. (The difference between your two styles is that double helical gears have a groove in the middle, between the the teeth, whereas herringbone gears usually do not.) This set up cancels out the axial forces on each group of teeth, so bigger helix angles may be used. It also eliminates the necessity for thrust bearings.
Besides smoother movement, higher speed capability, and less sound, another benefit that helical gears provide more than spur gears may be the ability to be utilized with either parallel or nonparallel (crossed) shafts. Helical gears with parallel shafts require the same helix position, but opposite hands (i.e. right-handed teeth versus. left-handed teeth).
When crossed helical gears are used, they could be of either the same or opposing hands. If the gears have got the same hands, the sum of the helix angles should equivalent the angle between the shafts. The most typical exemplory case of this are crossed helical gears with perpendicular (i.e. 90 level) shafts. Both gears possess the same hand, and the sum of their helix angles equals 90 degrees. For configurations with opposite hands, the difference between helix angles should the same the angle between the shafts. Crossed helical gears provide flexibility in design, but the contact between tooth is nearer to point contact than line contact, therefore they have lower power features than parallel shaft designs.