Double Taper Shaft

Just finished machining my single taper prop shaft into a double taper shaft. I ordered a new coupling and machined my old shaft to accept the new coupling. Worked great. below are some of the pics along the way.
This pic shows indicating the taper on the prop end so as to set up the lathe to the proper angle so I can duplicate it to the straight end of the shaft. Came out close to 2 degree included angle.



Started turning the end for the thread and taper. Insert cutter did not like the interrupted cut of the old key way.


Now I am "single point" threading the shaft to accept the nut. Opted for a 3/4-16 fine thread for this end. Ordered new brass nut to fit it. You can see the dull finish on the taper where I had started lapping it to fit the coupling.


Moved over to the mill to cut the 1/4" key way in. New brass key to be used.


Very little lapping was involved and was able to power lap it in the lathe and was a very quick operation. Looks like a good way to save $$ over the price of a new double taper shaft. The coupling blued in nicely. Showed about .001 total run out on the face when assembled, which a quick finish cut took care of. Hate that blue goop, it gets every where.

Duane,
Nice work!    Now all I need to add to my shop is some equipment to cut metal instead of wood! I wonder what my local machine shop would charge. How long total did you put into making the double taper?

BTW, I don't feel the Prussian blue is as bad as Never Seize!   

Duane in Indy wrote: I don't see how that the single taper coupling could be pressed off of the shaft while still in the boat. Mine took 15 tons of power in my hydraulic press to push it off. With out heat I think it would be a lot of effort.

Duane,
Yes, I know you were surprised by the tonnage but the deep socket and threaded rod trick has worked for may years. It would be interesting to find out just how much force can be created with the 4 threaded rods. I always use 3/8 fine thread grade 8 rod and plenty of Never Seize. Yup, another mess!!

KENO wrote: Looks great Duane Did the new coupling come with the removal tool for removing it from the tapered shaft or did you have to make one of those too?

All I got was the coupling. I will probably make a plate with 4 holes and a stud in the middle to extract the tapered coupling from the shaft. Don't need it yet.

I don't know what brand of coupling you have but the ARE couplings have an internal thread and they sell a plug that threads in to push the shaft off the coupling.

They charged me an extra 20 bucks for it and amazingly I haven't lost or misplaced it yet

It works good, probably no better than the plate setup, but fits in tight clearance spots better and I know you have the capability of duplicating that setup too

Just thought I'd mention it They call it a separator in the link below

Elbert's link

KENO wrote: I don't know what brand of coupling you have but the ARE couplings have an internal thread and they sell a plug that threads in to push the shaft off thecoupling.They charged me an extra 20 bucks for it and amazingly I haven't lost or misplaced it yet It works good, probably no better than the plate setup, but fits in tight clearance spots better and I know you have the capability of duplicating that setup too Just thought I'd mention it They call it a separator in the link below Elbert's link

Mine is not an A.R.E.   It does not have the internal thread nor the set screw to retain the nut. But I will drill and tap for the set screw. Will have to go thru receipts to see where I ordered it from.
And again, thanks for the compliments from you.

Duane in Indy wrote: Mine is not an A.R.E.   It does not have the internal thread nor the set screw to retain the nut.

Duane,
After you mentioned this, I took a closer look at the taper you cut. It's certainly longer than ARE's which may create a problem on some boats. Some like the Cuda I did last do not have much shaft length between the gland and trans and the reason the ARE coupling is so short.

8122pbrainard wrote: Duane in Indy wrote: Mine is not an A.R.E.   It does not have the internal thread nor the set screw to retain the nut.    Duane, After you mentioned this, I took a closer look at the taper you cut. It's certainly longer than ARE's which may create a problem on some boats. Some like the Cuda I did last do not have much shaft length between the gland and trans and the reason the ARE coupling is so short.

The coupling that I ordered was the same taper as the prop taper. That is why I indicated that taper in as close as I could. Seems strange that they would offer a shaft with two different tapers. If that is so, then the company that I got mine from would also have to manufacture and sell you their own shaft. Do some research and let me know. That is interesting.

8122pbrainard wrote: After you mentioned this, I took a closer look at the taper you cut. It's certainly longer than ARE's which may create a problem on some boats. Some like the Cuda I did last do not have much shaft length between the gland and trans and the reason the ARE coupling is so short.

I may have misunderstood you Pete. Could be the same taper, just shorter. I cut mine so as to maintain the same length between couplers as stock setup. That makes more sense.

Duane, you're hired! This is perfect timing.

I also have what is likely a General Propeller taper coupler and an ARE in the garage. I'd be happy to let you play with them.

The GP is currently on a 54" shaft
The ARE is on a [dinged up] 41" shaft

Also have factory couplers on another 54" and 41" shafts. Let's see what can be salvaged?

Zach might be coming up here in a week I'll bundle all the shafts for him to take back to Indy.

Hi Duane

Found my Supra coupling and the stub end of the shaft I saved.

The coupling itself is 2 1/2 inches long.

The shaft which I have included a picture of has a tapered area 1.4 inches long and the taper goes from 1 inch down to 0.945 inch at the end of the taper. It was a little tough to measure at the small end at least for me.


This is bringing back memories of a certain distributor or 2 that you made work for people

Is brass strong enough for a key? Maybe it would be a good shear fuse in case of a prop hit.    Or could it would let go early?

SNobsessed wrote: Is brass strong enough for a key? Maybe it would be a good shear fuse in case of a prop hit.    Or could it would let go early?

It is about a 1 1/2" long 1/4" square key, not a half moon woodruff style. As tight as the taper fit is and the lock nut on it, I would almost guess it would run with out any key Not going to try, just saying the key is probably not doing much. A.R.E. uses a woodruff key but I elected to go with the square style. Same type that is on the prop end. The press on couplers use a square key also. If it is an issue then I can use steel.

edit Tim, you beat me too it. I type slower.

Nice Machine work on your shaft. Great tools make some really cool stuff.

8122pbrainard wrote: SNobsessed wrote: Is brass strong enough for a key? Maybe it would be a good shear fuse in case of a prop hit.    Or could it would let go early? Chris, You are forgetting that the taper transmits the majority of the torque. You need to read the "proper prop" thread again!

Chris,
For us old guys who have a hard time remembering, here's some content out of the "proper prop" thread:

8122pbrainard wrote: Keep in mind that our props are held on by a close fitting taper. According to one of the prop manufacturers, 70% of the torque is said to be transmitted through this fit and the rest is the key/keyway. I personally feel it's 100% because the taper fit shouldn't slip at all. I've seen some pretty sloppy keys with 0 evidence that any force has been applied to them.

eric lavine wrote: too add on such a great topic on how important tapers are, on larger transmissions the "BullGear" which usually are the output gears and weigh about 400 lbs do not use a key, it is simply a keyless taper and you advance the gear on the shaft and the fit relies on the close tolerances of the 2 tapers, the transmission will use an 8" shaft, so you can imagine the torque going through the taper's and they dont spin on the shaft, as Pete states the tapers need to be free of blemishes and the more contact the better of the surfaces

8122pbrainard wrote: Keep in mind that a taper is the only thing that holds a drill chuck in a drill press spindle!! Also, take note of Eric's comment that many trans components are held together with tapers only. No nuts!!! Think about why a puller is needed to get a prop off!!