The concept is simple. Let's say the gear to cut is 100 teeth. If it were to be a spur gear (helix angle = 0) then the index gear ratio would be Index Constant divided by teeth. For an index constant = 30, the gear ratio should be 30/100 as shown in the prior topic. Using 30/100 would synchronize the hob to the workpiece so that when the workpiece completes each revolution, the hob would be meshed precisely in the same tooth.

All gear hobbing machines have an Index Constant. This constant, along with the number of teeth to cut and the number of starts in the hob cutter determine the index gear ratio and the index change gears. Some typical Index Constants are: 36, 30, 24, 15, 12, 10, etc. Let's take an example using a single start hob cutter.

There are sources listed in FAQ "Manuals for my Gear Cutting Machinery" that may have the operator's manual you need. Also, the Gear Forum is a good place to ask for this kind of help. If you can't find a source for the differential formula then you can determine the formula for yourself using the following procedure, but you must have a way to measure a gear's lead.

A hobbing machine in its simplest form has no differential, yet it is versatile and productive. A basic non-differential gear hob can serve well for break-down and production work over a wide variety of toothed members. The type of work generated is determined by the hob cutter tooling. Hob cutters are readily available to cut nearly any external tooth member: spur or helical gearing, splines, timing belt pulleys, roller chain or silent chain sprockets, and throated worm gears.

If the gear faces are parallel, the Helix Angle is the same for both gears. This means the machine is Type A. Just for information, the gear lead in this case is different for both gears but the helix angles are the same.)

Feed formulas are found in the machine's manual or on the machine itself. Table Feed as discussed here is the cutter table feed in a direction parallel to the workpiece centerline. It should not be confused with infeed or tangential feed. While some hobbing machines may be equipped with infeed or tangential feed, all hobbing machines are equipped with Table Feed. Some hobbing machines mark the machine with a whole number indicating feed (let's call it K).

Some differential hobbing machines do not use feed change gears. These machines use a hydraulic control to advance the cutter through the workpiece. A "dial" is used by the operator to control the amount of feed per revolution of the workpiece.

All hobbing machines use an Index Constant that synchronizes rotation of the workpiece with the cutter. For example, a 30:1 index constant means that the index change gear ratio is equal to 30/Teeth for a single start cutter cutting a spur gear. With the correct index change gears, a single start cutter will rotate a number of revolutions equal to the teeth on the workpiece while the workpiece makes one complete revolution.

If manual or automatic "step" shifting is used, the normal setup is unaffected. Shifting of the hob in this case occurs during the non-cutting part of the work cycle. If continuous tangential hob shift is used, then an adjustment must be made in the lead change gear ratio. In other words, a spur gear could not be cut without a differential action equal and opposite to the continuous hob shift.

Gleason's Versacut method was developed to cut spiral bevel gears on a No. 26 machine. Also known as Single Side (SS) method, there may be three separate cutting setups per member: Roughing, OB, and IB. After roughing, Each tooth flank is generated in separate setups. A stock dividing gage is used to position the blank for the second (IB) cutting.

This is a sequence of diagnostic tests for setups on new or unfamiliar hobbing machines. The main purpose is to isolate individual error sources in a setup and to diagnose a problem. The procedure is designed for any experience level. When setting up a machine for the first time, use an inexpensive blank. These tests will cause some damage to the blank's OD.

When the US defence department developed the GPS satellite system, it was meant for military applications - to help pinpoint the exact position of a soldier in the field, for example. That system is extremely accurate, within something like 50 feet. The DoD didn't want to give that capability to the enemy, so they scrambled that signal. The signal that's available to the public has been deliberately tweaked to provide a position within about 200 feet.

This a term used to describe the latest generation of CT scanners. It offers an exciting new technology enabling unparalleled imaging of complex data sets and anatomic information.

This is a complex question, however a paper (re-written in PDF - Portable Document Format) that technically explains how the Torsen T-1 (Type A) differential works can be downloaded by clicking the Traction Control Article hyperlink. This paper was published in 1988 by the Institution of Mechanical Engineers (IMechE) and describes in detail how the Torsen functions. Download it and check it out... This, by far, is the most commonly asked question.

I can find preprinted fusible interfacing with 1, 1 1/2, or 2 inch squares but not 1 1/4. Is there such a thing. I have decided to work my photo quilt with 1 1/4 inch blocks. I am not sure how critical this part is. I hope you can guide me. The book "Simply Amazing Quilted Photography" has a whole chapter on this subject. I don't use the preprinted fusible interfacing, I use plain fusible tricot. This chapter also tells you why I think 1 1/4" squares are best.

Yes and no. AlNiCo magnets are very easy to machine in any way you wish. NdFeB magnets are by nature very hard and brittle. Although they can be cut, drilled and machined, it should ONLY be done by folks who are experienced with ceramics. If the magnets get over about 300 deg F, they will lose their magnetism permanently. They are flammable, and it is not difficult while grinding or machining to get them (or the chips and dusts from cutting) so hot hot they ignite.

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The CNC control system on your milling machine determines whether it can do 3D work and most of the new control systems can run in 3D mode. If your machine is only a couple of years old it probably can be used with ArtCAM MillWizard.

Graphics cards are stated within the item description. If they're not stated, then presume them to be integrated.