stuffing box cord sizing

[larryeddington]

After messing with my stuffing boxes I am gonna shoot for repacking them. I have seen here or somewhere a sizing chart but cannot locate it.

I have one inch shafts I think 1/4 is what to use but need some advice.

[The Dog House]

I'll be repacking my stuffing box next week. I have a 1 inch shaft and was told to use 1/4" packing. I'm using 1/4" Gore GFO packing. I can tell you next week if it fits or not. I sure hope it does!

[prowlersfish]

This should help

1" uses 1/4" packing
1 1/8" shaft uses 3/16" packing
1 1/4" shaft uses 1/4" packing
1 3/8" shaft uses 5/16" packing
1 1/2" shaft uses 1/4" packing
1 3/4" shaft uses 1/2" packing
2" shaft uses 3/8" packing
2 1/4" shaft uses 7/16" packing
2 1/2" shaft uses 5/16" packing
3" shaft uses 9/16" packing

[larryeddington]

Thanks paul, was looking for that chart, interesting some larger shaft sizes use smaller packing then some smaller shafts.

[prowlersfish]

Thanks paul, was looking for that chart, interesting some larger shaft sizes use smaller packing then some smaller shafts.

Thats because the same casting ( bored different ) its used for more than 1 shaft size (2?) .So you would need a larger packing with a smaller shaft as there is a larger gap between the packing nut and the shaft to fill .

[larryeddington]

I measured the shaft and bore just for curiosity and the shaft is exactly 1" and bore of box is 1.0165 inch. Gonna pack them while in the water. Estimating 2 food deep there will not be much water incursion, in fact water was pouring in with packing in place. have two 1000 gph bilge pumps so do not see any problem. I do not think more than 10gph will come in per shaft, of course both will not be open at same time. We first estimated the hole at 1.125 inch and calculated 18 gph at 2 feet. So in reality will be much less.

[prowlersfish]

I aways do them in the water , and don't be surprize ir the water flow is more . BTW have you just tried ajusting them ?

[larryeddington]

Yes tried and one stopped the other still flowing too much and both seem to be bottomed out on adjustment. I feel more comfortable if I replace packing then I know where my starting point is. Would rather not as V drives are definitely no fun. In my case just to get enough room (barely) to work I have to take out propulsion engine batteries and genny battery then unscrew their battery cases, only then can one get down to do the work.

[The Dog House]

I'll be repacking my stuffing box next week. I have a 1 inch shaft and was told to use 1/4" packing. I'm using 1/4" Gore GFO packing. I can tell you next week if it fits or not. I sure hope it does!

I repacked my stuffing box yesterday with 1/4" Gore GFO packing (1 inch shaft). It fit, but was very tight in the packing nut. The packing nut was clean and the packing was cut correctly. The packing nut is on as loose as I can have it and still have a decent amount of thread contact. It will definitely provide a good seal. I'm hoping it will loosen up a little bit once I run the boat but we'll see.

[prowlersfish]

The Gore GFO packing seems to be a tighter fit the regular packing maybe a hair larger or just stiffer . Maybe some of both

[larryeddington]

If three is almost too much should one consider using two layers in the nut.

[The Dog House]

If three is almost too much should one consider using two layers in the nut.

I used three. It was difficult to get the packing nut started. I really had to make sure the packing was properly seated before the nut would catch any threads. Even so, I still think having the three layers is worth the extra peace of mind.

[bigralph]

Dumb guy intruding - I had a steady leak on the stbd side, someone first suggested I repack in the water, then someone else in the harbor recommended I try tightening. Not really knowing wth I'm doing, I grabbed a big pipe wrench and I think I tightened the wrong thing - I tightened the end closest to the engine. There is no more leak, but guessing I need to restart. Is there a packing stuffing box for dummies link somewhere?

[larryeddington]

Well on the bright side that end does need to be tightened though me thinks a wrench is too much other than for holding while tightening the jam nut.

[The Dog House]

A good tutorial on how to repack a stuffing box is at http://www.pbase.com/mainecruising/stuffing_box. It will tell you pretty much everything you need to know.