Flexible coupling ID please

[osprey877]

Does anybody know Who the manufacturer is of this coupling? I am trying to check the shaft alignment with the engine, but cannot find any information. The coupling itself is in two parts that are quite loose until fully tightened, and accordingly there does not appear to be any way to measure a gap between the forward face of the coupling and The back end of my gear box. Thanks.

[model 10]

Measuring the gap is the easy way. A dial indicator is the best way for your set-up. Lacking that, you could make a pointer and measure the gap with a feeler gauge.

[osprey877]

Originally Posted by Ecos

Measuring the gap is the easy way. A dial indicator is the best way for your set-up. Lacking that, you could make a pointer and measure the gap with a feeler gauge.

How and where do I measure “the gap”. If I loosen the bolts that secure the coupling to the gearbox, the coupling is loose on the prop shaft and the gap cannot be accurately measured because the coupling is loose and free to move in or out on the rubber bushings. If I tighten the coupling to gearbox bolts up, the gap disappears.
I don’t think a dial gauge helps either as so long as the shaft is straight and is secured at two points ie the gearbox and the cutless bearing, it will run true on a dial gauge regardless of whether it is properly aligned or not. However, if misaligned, there will be excessive side pressure on the gearbox shaft and seal and cutless bearing, and/or could eventually bend the shaft, all of which is what I’m trying to avoid. Anybody have any suggestions??

[stormalong]

The part that attaches to the shaft looks like my Vetus type 6 but the aluminum parts look very different. I would start with vetus.

[model 10]

You don't measure any gap. You measure the run out of the prop shaft relative to the trans housing. You assume the trans output flange is straight.

[osprey877]

Originally Posted by stormalong

The part that attaches to the shaft looks like my Vetus type 6 but the aluminum parts look very different. I would start with vetus.

I think you’re right. Thanks. It looks like an older version of the Vetus 6 flexible coupling. Unfortunately, the only installation instructions are an exploded view of the coupling. No indication as to how much misalignment is permitted, nor how to measure it.

[osprey877]

Originally Posted by Ecos

You don't measure any gap. You measure the run out of the prop shaft relative to the trans housing. You assume the trans output flange is straight.

I think that with a flexible coupling there won’t be any runout between the transmission case and the coupling. However, I see what your thinking is and I think that if there is any misalignment, there will be some runout between the propeller shaft and the back side of the coupling and I should measure that with a dial gauge. Thanks. Now all I have to do is find a dial gauge😊😊

[Boatyarddog]

Originally Posted by osprey877

Does anybody know Who the manufacturer is of this coupling? I am trying to check the shaft alignment with the engine, but cannot find any information. The coupling itself is in two parts that are quite loose until fully tightened, and accordingly there does not appear to be any way to measure a gap between the forward face of the coupling and The back end of my gear box. Thanks.

It's a Vetus, flexible coupling.
No coupler face alignment required, how ever the max. Lateral misalignment spec is 2 degrees.
Not likely you'll use a dial indicator for this, perfect alignment would be a bit of a challenge, thus "flexible" coupling.
https://www.vetus.com/media/magentom...24161314_0.pdf
SV Cloud Duster

[osprey877]

Originally Posted by Boatyarddog

It's a Vetus, flexible coupling.
No coupler face alignment required, how ever the max. Lateral misalignment spec is 2 degrees.
Not likely you'll use a dial indicator for this, perfect alignment would be a bit of a challenge, thus "flexible" coupling.
https://www.vetus.com/media/magentom...24161314_0.pdf
SV Cloud Duster

Great, thanks. That’s just the info I was looking for 👍👍

[Boatyarddog]

Originally Posted by osprey877

Great, thanks. That’s just the info I was looking for 👍👍

As noted in the specs, 2 degrees mis alignment, they recommend just 1500 rpm.
At 4500 rpm 0 degrees, mis alignment.
In my thinking, most SV will encounter 1500 to 3000 RPM.
So, pretty darn close to spot on.
The spec for face to face hard coupler alignment is .003, not on the flexible couplers.
No V Drives though??
Hummm!
SV cloud Duster

[osprey877]

Originally Posted by Boatyarddog

As noted in the specs, 2 degrees mis alignment, they recommend just 1500 rpm.
At 4500 rpm 0 degrees, mis alignment.
In my thinking, most SV will encounter 1500 to 3000 RPM.
So, pretty darn close to spot on.
The spec for face to face hard coupler alignment is .003, not on the flexible couplers.
No V Drives though??
Hummm!
SV cloud Duster

My gearbox has an approximate 2:1 reduction so I think I should be able to use almost all of the 2 degrees.😊😊

[Dsanduril]

Originally Posted by Boatyarddog

No V Drives though??
Hummm!....

I live with two V drives. The shaft passes through the drive and the shaft coupling is on the front. With the flexible couplings that means the prop pushing forward would put the unit in tension, and early failure. Same thing happens in reverse on most boats, I guess a short time under that condition is acceptable, but not long term.

[stormalong]

Originally Posted by Dsanduril

I live with two V drives. The shaft passes through the drive and the shaft coupling is on the front. With the flexible couplings that means the prop pushing forward would put the unit in tension, and early failure. Same thing happens in reverse on most boats, I guess a short time under that condition is acceptable, but not long term.

I have had a Vetus type 6 coupling on a V drive transmission for about 15 years and at least 3500 hours. I have no idea what you are talking about.

The coupling is held to the transmission with four grade 8 bolts and the shaft floats on four rubber spacers held within the coupling. I bought four replacement rubber spacers when I bought the coupling and have never had to use them.

If you look at the design of the type 6 you will see that the direction of the thrust is irrelevant. That is why the type 6 is ideal for V drive transmissions.

[Dsanduril]

Was referencing the unit (with link to manual) and question, both posted by BoatYardDog. That Vetus unit/manual clearly show no use on V drives (in several languages). Many flexible couplings say the same thing for the reason posted. There may be some that are suitable, but the Vetus Combiflex is not one of them.

[osprey877]

Originally Posted by stormalong

If you look at the design of the type 6 you will see that the direction of the thrust is irrelevant. That is why the type 6 is ideal for V drive transmissions.

Vetus says otherwise. “Not Allowed” according to their product manual.