re-gearing a Hardinge mill gearbox

I recently bought a gearbox without gears for my Hardinge mill. Since the gears are so hard to come by, and I need a full set, I'd like to consider adapting to readily available gears.

Has anyone else taken this idea any further than the speculation above? If so, I'd like to hear your thoughts about what is involved.

Dave

rimcanyon
We have been discussing this specific subject for a month or so on two other topics which you might want to check out. All the pics might not be working, but I'll fix it when I find some time.
(on the second one, disregard my rudeness toward the seller. I was having a bad day and just needed a little rant.)

http://www.practicalmachinist.com/ubb/Forum12/HTML/000190.html

http://www.practicalmachinist.com/ubb/Forum12/HTML/000213.html

We haven't nailed down exactly what Hardinge is doing on their gears yet, but there might be some useful information for you.
One option that came up was to pick up a set of standard gears that come close and engineer some kind of eccentric arrangement to replace the fixed shafts in the gearbox with some that enable you to adjust the centerline distances enough to mesh the standard gears properly.
We might be at the mercy of an insider at Hardinge to know what to call it, but carefully measuring a few gears might give us enough to grind a gear cutter (even if it's a single-tooth fly cutter for the finish pass) to make gears that mesh with Hardinge OEM's.
Any ideas and information are welcome.

The gearbox arrived, no gears, but all the shafts and collars were included. Even though my mill is a 1942 and the gearbox is a much newer serial number, the dowels were a press fit into the table end - pretty amazing precision.

The good news is that the gear geometry can be solved without resorting to expensive Hardinge gears. The five gears that require an exact fit (the two 45's, the two 50's and the idler gear) do not require any specific number of teeth: all that matters is that the
drive gear and the pivot shaft gear have the same number of teeth (for rh spirals, the gears have to mesh with each other, for lh spirals, they mesh with the idler shaft gear). The rest of the gears in the gear train all have adjustable mesh, so any dp will work, as long as the gears fit in the gearbox!

I went through my collection of junk and found what I needed: two 24 tooth 16dp gears, and one 22 tooth 16dp gear solve the lh spiral drive. I forgot to find the size for the direct mesh, I will check next weekend. I think these gears are from a K&T rotary table drive, something I bought at auction years ago and saved for a future project.

I will take some pictures once I finish machining the adaptor bushings for the gears (which have 7/8 dia. bores and three keyways).