T0-20 Dwell angle?

Does anyone know, I'll bet yes, the dwell angle for a T0-20? Also my Shop manual says point gap is .022 and my Operation and Maintenance manual says .020. Small difference, but which is correct?

Dwell refers to the amount of time the points stay closed in the ignition cycle of the dist. It's not an angle. That being said I don't remember ever seeing a tune-up chart on a tractor listing dwell specs.
Dwell seemed to come around in the late 50's thru the 80's if my memory serves me right. I wouldn't worry to much about .002 difference, most people can't use a feeler gauge that close anyway.

Dwell angle or points gap? One is determined with a dwell meter and the other with a thickness gauge.
Which one are you using?
Dwell meter going on the positive side of the coil to an engine ground, if memory serves.
Thickness gauge used to set the widest opening of the ignition points on the high side of the distributor lobe.
So, which one are you using?
The dwell meter can be useful if your distributor has a window in the front of it with ignition points utilizing an allen headed fastener for dynamic adjustment.
Is your set up as such?
I would like to see photo's of it if it is.
As for points gap with a thickness gauge, I have seen both specs of .020 and .022.
If you are doing a dynamic adjustment you are aware that points gap/Dwell angle will effect ignition timing. Consequently you should index your distributor housing to the engine and toss that now near useless timing light in the bottom drawer.
If however, you do not have that window in the front of the dist cap, you will still need that timing light to set the timing after the adjust the points.
As for a points gap width, I might be tempted to either go wide at .022 or split the difference at .021, the wider setting being good for the ignition points rubbing block wearing down over time. However as the points narrow, your ignition timing will also change.

So, are you doing a static or dynamic adjustment?

If checking with a dwell meter, they will set around 50*.

A dwell meter is really handy when setting used points, when the surfaces
are no longer flat and a feeler gauge will not give an accurate reading.

Good thing about using a dwell meter is you can get a real life view of
what is happening in the distributor.

If the reading fluctuates, the shaft is bent or the cam is running off
center for some reason.

If the reading changes with varying RPM, the distributor shaft bushings
are worn.

Thanks Bruce and Steve. Yes I know the difference and have set many points with a feeler gauge through my many years.
The reason I was asking is because my TO-20 is getting harder and harder to start and kind of runs rough. There is a hydraulic hose for my F.E.L. that is routed right over the top of the distributor cap. So rather then going to the trouble of moving that hose to look into the distributor I hooked up my dwell meter to see what I have, which was so low it was off scale. So I know what needs to be done, but was curious what a good reading would be.
When I get him all tuned up I'll measure the dwell and report back.