[Diane-MooreGear]

Would you prefer a helical rack for your R&P CNC machine?

More and more people have asked me for helical pricing but as a one off they are just too expensive for your average hobbyist to justify. If there is some consensus as to pitch, size and helix angle and I can work towards having Helical rack and pinion as a stock item.

Just drop a note in here and I'll try to keep up!

Thank you!
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[harryn]

Hello Dianne,

Thank you for asking. My suggestion is to consider something in the module 1.5 - 2.0 size range. This type of rack is quite expensive to normally obtain, so if you can make it at a reasonable price, it might sell quite well, even internationally.

It tends to be a bit narrow for the forces involved though, so I don't know if it is possible to make a standard and wider verion.

The aspect that needs some care by the end user with helical rack is that the side forces equal the linear forces, which is something most home builders don't really think about.

If you can combine this with an offering with split pinions or similar that can mount directly onto shafts in the 3/8ths to 1/2 in range (and I guess the metric similar) that could be very interesting.

An alternative gear instead of helical would be the double helical / chevron style. This has the advantages of the helical, but eliminates the side load. I have no idea how popular this would be though. Personally, I would love a rack like this.

[Diane-MooreGear]

Thank you for the response Harry!

My suggestion is to consider something in the module 1.5 - 2.0 size range. .

I can make metric, but would likely keep this in imperial since most of my customers are in the US.

It tends to be a bit narrow for the forces involved though, so I don't know if it is possible to make a standard and wider verion.

Since I would be making this custom anyway, this is exactly what I needed to know. Perhaps .75" square or similar?

The aspect that needs some care by the end user with helical rack is that the side forces equal the linear forces, which is something most home builders don't really think about.

If you can combine this with an offering with split pinions or similar that can mount directly onto shafts in the 3/8ths to 1/2 in range (and I guess the metric similar) that could be very interesting.

Whatever pitch, size, helix angle we go with, I would offer the pinion to match. The only problem with that is finding out the most popular/common shaft size.

An alternative gear instead of helical would be the double helical / chevron style. This has the advantages of the helical, but eliminates the side load. I have no idea how popular this would be though. Personally, I would love a rack like this

The herringbone is out of our range of manufacture, so not really an option I could offer.

[danhamm]

I also like the idea of having helical rack available to home and small business builders, as to side load and side load wear, I dont see this as any more of a problem than normal rack/pinion wear. the benefits are quietness and strength and added accuracy. 1/2 or 5/8 would be my interest.

[dodger889]

I would like this myself if affordable as far as cost. 1/2 to 3/4 widths by the same in thickness. This would keep the backlash down. Has someone mention that the side loading would not be as a big problem due to that most rack and pinion systems are belt driven.