PTO Shaft size for a Ferguson to30

I’m going to order an overrunning clutch and not sure what size to order...

Well it is either 1-1/8 or 1-3/8 so easy way is the measure it unless you have good eyes and can tell the difference. I can just look at one and know but I also have 30 or so tractor to go by. Most of the tractors I have, have the 1-3/8 but I do have a few with the 1=1/8 like my 8N Ford

(quoted from post at 12:38:59 08/15/18) I’m going to order an overrunning clutch and not sure what size to order...

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All I'll add to old's comment is this: a TO30 would have originally had the smaller size. But in the 65+ years since these tractor's were made sometimes owners have replaced the PTO shaft with the larger size, so if you cannot tell by looking it's best to measure unless you know the full history of your tractor and that yours is original.

Thanks guys I’ll measure I should’ve done that to begin with…

If you have a farm and home store in your area the yare likely to have an ORC. Not to long ago I picked up an ORC at my local one and got the wrong one. I got the 1-1/8 to 1-3/8 type when I needed the 1-3/8 to 1-3/8. Took it back and go the correct one no question asked

You can but pto shaft adapter sleeves for a few dollars , buy one for the original shaft size , 1,1/8th'' and see if it fits . At least in this way you are absolutely sure that the ORC you order will be the correct one .

I measured the shaft today.. measuring the circumference of the shaft... it’s 1-1/8... that’s measuring the diameter only... not edge of tooth to edge of tooth... did I measure right?

To tell the truth I would have to go out and measure both a 1-1/8 and a 1/3-8 to tell you for sure. I have never measured one but I can just by looking see the difference but I'm a person that has always had a good eye for the size of things and noticing it something is smaller or bigger, just like looking at a nut or bolt and know what wrench I needed

Outside of the lug to the opposite outside lug. In other words, a 1-1/8 wrench will fit over it and a 1-3/8 wrench will be sloppy.
Do you have a wrench that sized?

The original PTO splined shaft diameter size was 1-1/8". The SAE later introduced the standard size of 1-3/8" which is still used today for all PTO driven implements. Both are defined as the MAJOR diameter of the spline. ORC's (Over Running Clutch) are made in both styles. You can get a female 1-1/8" to 1-3/8" male end ORC or a 1-3/8" female to 1-3/8" male end on an ORC. ORC is advised to use on an N when using a mower or brushhog. Many confuse the ORC with having/adding a LIVE PTO and that is NOT true. How did you determine the size was 1-1/8" by measuring the circumference? Then you say, "... it’s 1-1/8... that’s measuring the diameter only... not edge of tooth to edge of tooth..." Circumference is distance around, diameter is the distance across -two different formulas. You measure diameter with a 1"-2" micrometer or a set of dial calipers. Diameter is the distance measured across. It is the MAJOR diameter of the spline, one point to the other, 180? apart. If you don't have mic's or calipers, like Bruce(OR) said, take a wrench of same size and use as a gauge. Not all parts are created equal today. You get what you pay for. Check the manufacturer for country of origin, parts availability, warranty, and technical support service before you buy.

Tim *PloughNman* Daley(MI)

I measured today with calipers.. Exactly 1-1/8 .. Oddly enough I used a 1-1/8 wrench to see if it would slip over as was suggested and it didn't.