Frequently Asked Questions (FAQ)
- Is the chain really that easy to snap apart and snap together?
- I have a gear, but how do I determine its pitch?
- I need a compound gear, what are my options?
- Can 'super glue' or epoxy be used to bond gears or sprockets to a shaft?
- I don't like the 'press fit' attachment means, wouldn't a setscrew work better?
- Can you make a gear or sprocket to match a shaft that has a flat or other special shapes?
- Are special bore sizes readily available, how about metric?
- I need a large number of special gears, how much would the mold cost?
- Can I attach something to the chain to move a load?
- Why Delrin®, are there not better plastic materials available today?
- What if the gear or sprocket needs to turn freely, is Delrin® a good bearing material?
- Should I apply any sort of lubricant to the gears/sprockets?
- What about moisture problems? I understand plastic gears 'swell' when exposed to water.
Is the chain really that easy to snap apart and snap together?
Yes, it really is that easy. Our snap-link chain design is not only unique but also quite simple. There are no special splicing tools required, just a little manual dexterity and practice. It takes but a few seconds to fabricate the chain to any loop length desired.
I have a gear, but how do I determine its pitch?
Measure the outside diameter of the gear in inches using a set of calipers. Count the number of teeth and add "2" to that number. Divide the (number teeth + 2) by the outside diameter. The results should indicate the Pitch of that gear.
Pitch = (number of teeth + 2) / outside diameter
Common Pitch numbers include 24, 32, 48, 64, 80 and 120.
I need a compound gear, what are my options?
Obviously, any two gears secured to a common shaft will effectively produce a compound gear. Compound gears can also be fabricated by attaching two gears via a common bushing. For example: we have a gear having a hub diameter of 0.194" and we wish to compound this gear with a larger gear having a ¼" bore. A simple bushing, OD=0.250" and ID=0.193", may be used to secure these gears as a common assembly. It's also possible to reduce the hub diameter of one gear while increasing the bore of the second such that the two may be pressed together, again to create a compound gear assembly. It is the responsibility of the designer to assure that maximum system torque requirements do not exceed the breakaway torque of such assemblies.
Can 'super glue' or epoxy be used to bond gears or sprockets to a shaft?
The excellent chemical resistance of Delrin® also makes it quite immune to even the most advanced adhesive systems. Nothing really adheres to Delrin® well enough to be considered a bonding agent.
I don't like the 'press fit' attachment means, wouldn't a setscrew work better?
Screw threads do not hold up well in plastic and are not recommended. Our 'press fit' method of assembly works quite well in most applications. When very high torque or high shock loads are anticipated, other methods of attachment should be considered.
Can you make a gear or sprocket to match a shaft that has a flat or other special shapes?
We routinely produce gears and sprockets that conform to shafts having a flat on one side. We commonly refer to these as a "D" bore. This configuration provides very high torque breakaway properties and generally do not require expensive tooling charges. We have produced many different bore configurations including square, hex and other shapes.
Are special bore sizes readily available, how about metric?
All of our products may be produced with custom bore sizes including metric. These are not considered stock items and are generally subject to tooling charges and minimum order quantities. In addition, the maximum bore size may not exceed that of our standard product.
I need a large number of special gears, how much would the mold cost?
We do not offer any custom mold tooling services. Maintaining our existing molds and providing the custom bores keep our tooling department operating on a full schedule.
Can I attach something to the chain to move a load?
Occasionally customers need to provide a linear reciprocating motion by attaching a clamping device to the chain. This practice works well so long as the user understands some of the basic limitations. All chain and belt drives will exhibit a certain amount of elasticity, making precise positioning subject to errors unless some type of position feedback is employed. The mass of the clamp device that attaches to the chain as well as the load should be minimal.
Why Delrin®, are there not better plastic materials available today?
Delrin®, generically known as acetal resin, was first introduced by E. I. du Pont de Nemours & Company® in 1959. Since that time there have been hundreds of new plastic resins and resin compounds introduced. Surprisingly, none of these resins have proven to be better suited for injection molded gears and sprockets.
What if the gear or sprocket needs to turn freely, is Delrin® a good bearing material?
Yes. Delrin® exhibits outstanding wear characteristics and has a very low coefficient of friction, two very important properties when producing gears or sprockets.
Should I apply any sort of lubricant to the gears/sprockets?
The low friction properties of Delrin® eliminate the need for lubrication in most applications. Gears operating at very high torque will benefit slightly by the application of light gear grease directly to the teeth. Our testing of the chain did not show significant improvement when several commercial lubricants were applied.
What about moisture problems? I understand plastic gears 'swell' when exposed to water.
You are probably referring to Nylon gears. Nylon and Delrin® both offer good strength, toughness and outstanding wear characteristics. Nylon exhibits a relatively high moisture absorption characteristic compared to Delrin®.