A Novel Velvet Drive 5" Flange Adaptation

[PeteW]

Adapting the Walter 4" flange drive shaft spool adapter to a Velvet drive 5" flange has typically been done by incorporating yet another adapter to the adapter already supplied by Walter Machine. In examining this approach I located a 4" to 5" adapter manufactured by R&D Marine. The problem with cascading 2 adapters together to make the transition is that  it weakens the HP handling capability of the drive train to a mere 20 HP. (per the engineers at R&D Marine)

I needed to find a more robust and proper solution. After searching the Dana Spicer catalog I located the following Flange Yoke P/N 2-2-1379.

flange1.png

This flange yoke features a 4.25" Bolt Circle Diameter of 4 bolts same as the Velvet Drive 5" flange. It uses a standard 1310 Universal joint, also shown. (There are cross series u-joints if your Walter welded on flange yoke on the drive shaft tube is for some reason not 1310)

There are 2 problem with this flange yoke but they can be easily addressed. First, the bolt hole diameters are .484" (12 mm).   They need to be .4375" (7/16"). Using a 15/32" adjustable hand reamer the holes can be opened up a wee bit and 7/16" ID bushings pressed in. You now have a correct bolt hole pattern for the velvet drive flange.

flange2.png

The remaining issue is the incompatible pilot holes between the flange yoke and the Velvet drive flange. A simple pilot hole adapter can be machined to convert the 2.00" female pilot hole in the Spicer yoke to the required 2.5" male pilot that plugs into the Velvet Drive.

Here is a 3D model of the part that was designed online using the free software from eMachineShop.com.

flange4.png

The pilot adapter is machined from steel and the cost of QTY 1 is around $60. If I up the quantity to 10 the price comes down if anyone else out there is interested in converting to a Velvet Drive gearbox

My cost of converting over to the 4.25" diameter hole pattern yoke including the cost of a new greasable U-joint and the custom pilot adapter  is under $100.

If you feel you have to have a spool coupler between the gearbox and the 5" flange yoke you can now buy a 5" velvet Drive M/F bobbin from R&D Marine PN 808005. But personally I don't see the need for one.

flange5.jpg

Pete   Still restoring old hull #6.

[PeteW]

Walter Machine Company quoted me $2200 for a telescopic drive shaft assembly. This price did not include the 5" velvet drive spool adapter which we have learned is machined from unobtainium. Here's my finished 5" Velvet Drive to RV-10 V-drive shaft assembly that I built from scratch. No spool adapter needed. It mates up directly to the velvet drive 5" flange.

driveshaft.jpg

I found a 42" 10 tooth 1" Dia. shaft that came out of an old skiff that had an RV-10. That cost $35. I spend $200 at a machine shop to cut the shaft and re-key it and turn the 2" female to 2.5" male pilot adapter ring. Total cost was around $300.

I had them make a spare pilot adapter in case anyone needs it for a paragon to velvet drive retro fit down the road.

Pete    S/V Tartanic       Note: People question me as to the meaning of Tartanic. Google it and you will realize that, it's a tribute to really loud bagpipe music. 

[Dale Tanski]

Pete,

I am following this project of yours closely.  Nice piece of artwork my friend...

Dale