Surface grinder wheel adapter taper angle?

[MidniteMachinist]

I've got a TML surface grinder, probably from somewhere in the 1940's-50's. I'd like a few extra wheel adapters, so I'm not constantly having to swap/redress wheels. Internet searches lead me to the Williams Sopko catalog, where it mentions a TML/older Harig adapter (P/N 00169), but I'm not sure it's the correct one for my machine. The catalog lists the taper angle as 4.256" TPF, which I'm assuming is the included angle.

I've measured my existing adapter, and came up with 4.614" TPF, included.

This is where I'm lost. Closest I can find are adapters with 4.5" TPF. Just figured I'd ask here, if anyone has any ideas/guidance.

 

[Dabbler]

Sopko are genuine experts on surface grinder arbors. If they say it is 4.256 and you measure somethings else, this doesn't make sense.

Call them; their technical staff are top notch.