Arneson 17-20 CV Joint and Yoke Setup
01-01-2019, 09:31 PM
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Arneson 17-20 CV Joint and Yoke Setup
New to me boat, recently rigged before i bought it, I'm going though everything to double check...
BW velvet drives with flange yokes on the transmissions, double u-joint (1350) CV shaft/joint, and then a spline yoke on the Anreson 17-20 drive input shafts.
The crankshaft and drive input shafts are non parallel by 2 or 2.5 degrees, not a major deal and the CV should take care of that. I need to get some better dial indicators set up and get better numbers, but that's not my current issue.
My issue/concern is the yoke and drive input shaft is set up for a nut, but one was not installed so it's functioning as a "slip yoke" currently. Spline engagement was 0.375" short of full engagement (yoke chamfer hitting shaft chamfer just pas the spline ends) as I found it.
The yoke would bang/flop around on the spline by hand and when in gear. The drive input shafts are almost brand new and have the machine tooling marks on them so I know they are not worn, and the yokes show no signs of wear and have 0.003" to 0.005" clearance to the splines when i use a cheap dial caliper (ID of yoke to OD of splines). If i push the yoke on 98% of full engagement the slop is greatly reduced but still there, 100% on with the yoke chamfer against the shaft chamfer the slop is gone (I'm sure its there but I'm not strong enough to move it).
My current plan of action:
Put a dial indicator on the drive input shaft and move/trim the drive to see how/if it moves - I have the Arneson drawings and it doesn't look like it will move, there appears to be slip joint in the prop shaft outboard of the ball joint and second double Cardan CV joint but I want to make sure.
Option A - If the drive input shaft moves, I plan to machine a spacer to go between the transmission output shaft flange and flange yoke, ~0.350" thick, so i'm 0.025" away from full engagement at the closest possible position on the drive input shaft and run without a yoke nut, so there is still some slip yoke action occurring.
Option B - If the drive input shaft does not move, I plan to machine a spacer to go between the transmission output shaft flange and flange yoke, ~0.375" thick, and install a yoke nut, so the yoke has full engagement on the drive input shaft and spacer makes the double Cardan CV fit the length perfectly. My concern with this is there wont be any slip yoke action occurring, so hull flex, thermal expansion, etc could present an issue.
I do rotating equipment alignment frequently so I can configure this however I need to - but I'm not sure how these drives are typically done and dont want to cause myself more headaches than i need to. I think Option A is more correct, but it sure seems like the yoke should be bolted on... (the Arneson manuals I have say "install a yoke nut if your application requires one" so...
Any insight is appreciated!
- Alex
BW velvet drives with flange yokes on the transmissions, double u-joint (1350) CV shaft/joint, and then a spline yoke on the Anreson 17-20 drive input shafts.
The crankshaft and drive input shafts are non parallel by 2 or 2.5 degrees, not a major deal and the CV should take care of that. I need to get some better dial indicators set up and get better numbers, but that's not my current issue.
My issue/concern is the yoke and drive input shaft is set up for a nut, but one was not installed so it's functioning as a "slip yoke" currently. Spline engagement was 0.375" short of full engagement (yoke chamfer hitting shaft chamfer just pas the spline ends) as I found it.
The yoke would bang/flop around on the spline by hand and when in gear. The drive input shafts are almost brand new and have the machine tooling marks on them so I know they are not worn, and the yokes show no signs of wear and have 0.003" to 0.005" clearance to the splines when i use a cheap dial caliper (ID of yoke to OD of splines). If i push the yoke on 98% of full engagement the slop is greatly reduced but still there, 100% on with the yoke chamfer against the shaft chamfer the slop is gone (I'm sure its there but I'm not strong enough to move it).
My current plan of action:
Put a dial indicator on the drive input shaft and move/trim the drive to see how/if it moves - I have the Arneson drawings and it doesn't look like it will move, there appears to be slip joint in the prop shaft outboard of the ball joint and second double Cardan CV joint but I want to make sure.
Option A - If the drive input shaft moves, I plan to machine a spacer to go between the transmission output shaft flange and flange yoke, ~0.350" thick, so i'm 0.025" away from full engagement at the closest possible position on the drive input shaft and run without a yoke nut, so there is still some slip yoke action occurring.
Option B - If the drive input shaft does not move, I plan to machine a spacer to go between the transmission output shaft flange and flange yoke, ~0.375" thick, and install a yoke nut, so the yoke has full engagement on the drive input shaft and spacer makes the double Cardan CV fit the length perfectly. My concern with this is there wont be any slip yoke action occurring, so hull flex, thermal expansion, etc could present an issue.
I do rotating equipment alignment frequently so I can configure this however I need to - but I'm not sure how these drives are typically done and dont want to cause myself more headaches than i need to. I think Option A is more correct, but it sure seems like the yoke should be bolted on... (the Arneson manuals I have say "install a yoke nut if your application requires one" so...
Any insight is appreciated!
- Alex
