Andymark/Vex Dog Gears Interchangeable?

[Richard.Varone]

I'm not sure if this has been discussed or not, but are AndyMark and Vex Dog/Dog Gear's interchangeable? I want to use a standard AndyMark dog shifter assembly but instead of an AndyMark 48t I want to switch it with a Vex 50t. Looking at the drawings they seem like they'd work, or would take little modification to make work, but I just want to be sure.

[stufflikethat]

I have switched these out with success. Though I swapped a 45 tooth for a 45 tooth gear.

There is no reason I could think of that it wouldn't work.

[Jared]

Originally Posted by Richard.Varone

I'm not sure if this has been discussed or not, but are AndyMark and Vex Dog/Dog Gear's interchangeable? I want to use a standard AndyMark dog shifter assembly but instead of an AndyMark 48t I want to switch it with a Vex 50t. Looking at the drawings they seem like they'd work, or would take little modification to make work, but I just want to be sure.

It depends on the gears. The Vex Pro dog has a bigger OD than the andymark one, so on a small gear, like the 28 tooth AM gear, the Vex Pro dog might be too big.

Also, some andymark gears have a 0.875" bearing bore as opposed to 1.125". The vex pro bearing bores also cause the bearing to stick out the back of the gear more than the andymark ones do, so you may need to increase the depth of the bearing pocket.

[JamesCH95]

To make sure that spur gears mesh you nominally need to match the diametral pitch (DP) and pressure angle are the same. To replace gears 1-for-1 the tooth count must also match. I assume this is what you're really interested in. Most of the common AM & VexPro gears are 20DP and 14.5deg pressure angle, so the teeth should mesh just fine.

Dog gears are something else entirely, they are the mechanism that 'shifts' in your normal AM shifter transmission. A VexPro shifter transmission uses a 'ball shifter' mechanism that functions in a slightly different manor from a dog gear.

Dog gear.

Spur gear with dog gear on the side.

Spur gear.

[Richard.Varone]

Sorry I should of clarified my terminology, my team typically calls the spur gears with the dog cut outs dog gears and the part that attaches to the shaft and engages the gears the dog.

So to restate my post, to achieve the spread I'm looking for, I want to use a VexPro spur gear(50t with the dog cut outs) with the AndyMark Dog. So has anyone had issues or needed to make modifications to use an AndyMark Dog with a VexPro spur gear?

[AdamHeard]

Originally Posted by Richard.Varone

Sorry I should of clarified my terminology, my team typically calls the spur gears with the dog cut outs dog gears and the part that attaches to the shaft and engages the gears the dog.

So to restate my post, to achieve the spread I'm looking for, I want to use a VexPro spur gear(50t with the dog cut outs) with the AndyMark Dog. So has anyone had issues or needed to make modifications to use an AndyMark Dog with a VexPro spur gear?

Open them both up in CAD, and see if they physically will fit together based on the angular width of the teeth.

I've never verified personally, but I would assume they will fit. Please do the above and verify for yourself though.

[Richard.Varone]

Originally Posted by AdamHeard

Open them both up in CAD, and see if they physically will fit together based on the angular width of the teeth.

I've never verified personally, but I would assume they will fit. Please do the above and verify for yourself though.

Wow, I feel like an idiot. I have no idea why I didn't think of this, woops. Sorry guys for the useless post, it seems like it should work just fine.

[AdamHeard]

Originally Posted by Richard.Varone

Wow, I feel like an idiot. I have no idea why I didn't think of this, woops. Sorry guys for the useless post, it seems like it should work just fine.

No worries.We all start somewhere.

You asking answered the question for others afraid to ask.