Odd Size Drive Plate

[angelo49]

I have this 5'' drive plate with a 7/8'' x 9 tpi thread.
the ID is .766'' which makes the 7/8'' OD correct. (adding one pitch, .111'' to the ID)
I might have posted about this a few years ago but I'm not sure.
I can't find any machine with this thread.
Any ideas ??

[spro]

I guess somebody needs to ask if this is metric. 9 TPI is weird.

[angelo49]

I guess somebody needs to ask if this is metric. 9 TPI is weird.

That's what I thought, but it's not that uncommon.
It's definately not metric.
http://www.victornet.com/reference/Tap_Drill.html

[spro]

I measured a collar of 1 3/8 X 8. There were only three internal threads but the gages know the difference between 8 and 9. You know what you are doing. Some one here knows that spindle.

[Mr Ron]

Could it possibly be for a wood lathe?

[spro]

Respectfully, why would that be?

[angelo49]

Could it possibly be for a wood lathe?

I googled every which way possible and the only place I found that thread
was for taps or dies.
No machine spindle.

[John Hasler]

Shop made for some special purpose?