Stuffing box wrench size question

Jul 7, 2024
24
Catalina 27 Lake Keowee
I am trying to find wrenches to replace the GTU packing in my stuffing box.

This is for a 1985 Catalina 27 with a 1" diameter shaft.
I measure about 2 inches width on the flats of the packing/stuffing box, and 1.7 inches on the lock nut, which appears to be a 1-11/16 wrench from this table.
I see one other thread with the same question but not much of an answer.

If you are familiar with the sizes, please let me know.
Any low cost supply options are appreciated as well.


C27_stuffing_box.png
 
Jul 7, 2024
24
Catalina 27 Lake Keowee
I also meant to ask if anyone knows the size of the GTU packing that is needed for this particular stuffing box.
Let me know your recommendations.

Thanks!
 
Mar 6, 2008
1,239
Catalina 1999 C36 MKII #1787 Coyote Point Marina, CA.
Yes, I use two of what Richard suggested. The packing size is 1/4", 3 rings.
 
  • Helpful
Likes: ggrizzard
Dec 25, 2000
5,863
Hunter Passage 42 Shelter Bay, WA
Skimping on wrenches has not worked well for me over the years. Our stuffing box, that has a 1.25" prop shaft, takes 3/16" packing material. I've tried all kinds of tools including those mentioned in this thread and only service wrenches have worked for our application. A bit pricey, but they work and worth the money. I also have a ten inch piece of SS tubing that I slide over each wrench handle for greater leverage. An example of one is here: service wrench

Our box, which looks just like yours in the picture, takes two different sizes; one for the locking nut and the other for the box itself. As I recall, one is two inch and the other is 1-15/16". Measure before you purchase.
 
Jan 7, 2011
5,249
Oday 322 East Chicago, IN
I used standard pipe wrenches (short, small ones). The only issue I had was getting them side by side on the 2 nuts (hence the need for small wrenches). Maybe buy one of the spanners and use a pipe wrench for the other.

I finally switched to a Volvo Penta dripless shaft seal…..a game changer and no wrenches required :beer:



Greg
 
Feb 10, 2004
4,069
Hunter 40.5 Warwick, RI
I keep a set of the crow-foot wrenches onboard for in-season adjustments. But if the nuts have not moved in a year or more, I bought two of these adjustable wrenches from Harbor Freight.
At $50 for the pair, it might seem expensive, but the 18" handles give you the leverage you need to easily break the nut corrosion. And unlike the crows-foot wrenches, these wrenches fit snugly on the flats without slipping. I would keep them onboard except that they are hard to store due to their size.
I agree with @Terry Cox that the packing material is likely to be 3/16". It's easy to confirm: Just measure the diameter of the exposed threads, subtract the shaft diameter, and then divide the remainder by 2. Use a vernier caliper for the measurements- eyeballing is very imprecise.
 
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Likes: LloydB
Oct 10, 2009
1,015
Catalina 27 3657 Lake Monroe
I've used this with some success as well as crow foot wrenches. The good thing about the crow foot is it is a little easier to work with in tight spaces and they're relatively cheap.
View attachment 228197
I have used this plus a large set of channel lock pliers to adjust the nuts on my Catalina 27.
 
Sep 24, 2018
3,066
Catalina 30 MKIII Chicago
If your shaft is out, then I would look at FWD axle sockets which can be rented for free from Autozone. Otherwise, here's another suggestion. The jaws stay more parallel to one another than with a C wrench, thus less slip
1730564238991.jpeg
 
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Likes: Timm R Oday25
Jul 7, 2024
24
Catalina 27 Lake Keowee
A friend loaned me two of these. After fiddling forever to get them the right size, I was able to get the stuffing box apart. They needed to be sized tight so they would stay on as you used your only one available hand to get the other on then grip them together.
1730724630867.png



I measured the threads at 1.49, which is probably 1.5. That would imply a 1/4" packing.

I am putting on GTU packing. Let me know if there is something else.

I got a recommendation to leave the stuffing box loose and let water run through (much more than drips) for a while (undefined) to let the packing expand. Then tighten slowly. Otherwise the packing will be too tight and may burnish and not seal as well.

I also got a recommendation to use a packing grease, but have not found that. I will ask my friend. If anyone knows, drop a link.

stuffing_loose2.jpg
 
Last edited:
Jul 7, 2024
24
Catalina 27 Lake Keowee
@dLj That is a great web page. :clap: Thanks for posting it.

It does present a decision regarding GTU packing being galvanically incompatible with the shaft (and other hardware).

Teflon would be a good alternative, but as the article states, its not available. Teflon flax is available. Does that wear out too quickly?

Should I be worried about the graphite eating away my shaft?
 

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
22,214
CAL 35 Cruiser #21 moored EVERETT WA
Should I be worried about the graphite eating away my shaft?
NO. (my opinion)
Looking closely at the shaft image you posted, you can see the wear on the shaft (under the stuffing box flax) from years of service. The shaft will have several more years of service. Due to the grooves, you may not get a perfect seal (no drips). That is ok.

It is hard to beat the inexpensive cost of plain flax. It is easily serviced and has provided trusted performance for many years, so it encourages you to inspect and service your stuffing box more often. This is a positive.
 

dLj

.
Mar 23, 2017
3,835
Belliure 41 Back in the Chesapeake
@dLj That is a great web page. :clap: Thanks for posting it.
Most welcome

It does present a decision regarding GTU packing being galvanically incompatible with the shaft (and other hardware).
One of the reasons I posted the link....

Teflon would be a good alternative, but as the article states, its not available. Teflon flax is available. Does that wear out too quickly?
It's my understanding that Teflon flax does not wear out any more quickly than regular flax, perhaps is longer lasting...

Should I be worried about the graphite eating away my shaft?
I can't really answer that, but I ask – Do you want to be a Guinea Pig to find out?

dj
 
Jul 7, 2024
24
Catalina 27 Lake Keowee
I am thinking of replacing the hose from the log to the stuffing box with a longer piece, to position the packing seal on a undamaged piece of the shaft.

Is there any maximum length? I believe I will need to extend 1 inch.

any specific information on the size and a brand of hose to buy? I know it needs to be a thick hose for this specific purpose.
 

dLj

.
Mar 23, 2017
3,835
Belliure 41 Back in the Chesapeake
Is there any maximum length? I believe I will need to extend 1 inch.
How long is it now?

any specific information on the size and a brand of hose to buy? I know it needs to be a thick hose for this specific purpose.
straight from the website I posted before

Correct Hose vs. Incorrect Hose
If you happen have your shaft out, this makes for an opportune time to replace your stuffing box hose as well.

The thicker hose on top is specifically made for stuffing boxes. It’s a robust 6 ply hose, and meant to take the abuses of a drive train installation. The stuffing box hose on top is made by Buck Algonquin. Buck Algonquin a US manufacturer of quality bronze packing boxes and other drive-line components.

This Buck Algonquin hose, sized for a 1 3/4″ shaft log, can be purchased from Hamilton Marine for about $9.00 or less.
 
Oct 6, 2007
1,099
Hunter H30 1982 Chicago IL
I've used this with some success as well as crow foot wrenches. The good thing about the crow foot is it is a little easier to work with in tight spaces and they're relatively cheap.
View attachment 228197
Never knew what it’s called. I use one in combination with a channel lock wrench. Just have to face the wing nut lock side away from the other wrench.
It‘s also useful for tight access ports with finger indentations. Put the two ends in the recesses and twist with both hands on the sides rather than the handle.