Some time ago I posted a self-centering mod for narrow shank Sergents in the Accumate box (sergentcouplermod.blogspot.com). This works but requires an irreversible modification to the shank and some fiddling. The reason for self-centering, for me at least, is that it is far too easy to knock the coupler out of alignment when opening the knuckle with the wand. Getting it back into alignment is frustrating to put it mildly. The spring in the shank is supposed to supply friction but in the Accumates at least, it does not provide nearly enough.

So I thought if lack of friction is the problem why not add more? After some twiddling I devised this method. I take some 3M blue painter's tape (accept no substitutes) and cut some narrow strips whose width is about the same as the height of the pivot post in the box., Then I cut segments from this strip, maybe 3/8 inch in length. I wrap these segments around the post and put the shank in place. The spring is not needed. This technique provides a significant increase in friction. Only the clumsiest operator would now knock the coupler out of alignment. But the friction is not so much that it interferes with normal operation of the coupler assembly. This is a completely reversible modification, unlike the self-centering. Will it last? Time will tell but my experience is that the 3M tape is extremely durable and does not deteriorate. But again, if it did, the mod is reversible.

As for the springs, they can be tossed. Or get a piece of monofilament, string the springs on it and give it to your wife as a necklace.

George
Edgewood, WA

I discovered how to put springy material in the Accumate narrow coupler box to provide self centering. I found that I could use shrink tubing cut into short lengths to create donuts. These are then placed one on either side of the rear end of the shank between it and the box wall. When the coupler moves side to side it squeezes the donut which provides the springiness. The tubing I'm using looks like it is about 1.5 mm in outer diameter. I tried a bigger size but it was too stiff. I also tried using insulation stripped from 24 awg silicone wire and that worked but was also quite stiff. It seems that the tubing used must have a relatively thin wall.

This solution is quick, easy, inexpensive and reversible. It works perfectly for self centering. It will be what I use going forward.

George

I discovered how to put springy material in the Accumate narrow coupler box to provide self centering. I found that I could use shrink tubing cut into short lengths to create donuts. These are then placed one on either side of the rear end of the shank between it and the box wall. When the coupler moves side to side it squeezes the donut which provides the springiness. The tubing I'm using looks like it is about 1.5 mm in outer diameter. I tried a bigger size but it was too stiff. I also tried using insulation stripped from 24 awg silicone wire and that worked but was also quite stiff. It seems that the tubing used must have a relatively thin wall.

This solution is quick, easy, inexpensive and reversible. It works perfectly for self centering. It will be what I use going forward.

George

Thanks for all the comments.

Here's the picture for Bill et. al. I believe the shrink tubing that I am using is 1/16" that I probably got from Litchfield Station, although it should be available anywhere. The length of segment (thickness of donut) is about 1/16". It must be slightly less than the height of the coupler box cavity. As Jon described, the donuts are placed so that the donut axis is vertical. In the picture you can see that they are pretty squished even when the coupler is in the centered position. They have to be placed far enough to the left to leave space for the part of the cover that extends down around the pins. Sorry that the picture is a little fuzzy around the edges. Depth of field is thin at this mag.



Regarding Andy's comment, Frank certainly made an absolutely magnificent product. But I and I think many others found them to be so cantankerous to work with that we were ready to give up.  The possibility for them to be set off center does not add to my enjoyment. Self centering helps in most circumstances and for me it's the difference between go and no go. I'll deal with the coupling on a curve issue should I encounter it.

So use this idea if you want to. It does no harm. My next quest will be to find a similar technique for the standard shank version. Others have shown various techniques for SC there but I'm hoping that this simple donut method can be adapted.

George