Made my own prop puller for my 1 3/8" shafts from an old velvet drive coupler

Simply, going to use 5/8" 10" long grade 8 bolts and grade 8 nuts, three bolts to pull the prop off.
Idea is use the heavy steel plate to bear on the aft of shaft where nuts go.
Spent the morning drilling six 5/8" holes.

I heard it can take 20 tons of force to separate prop from shaft, I don't know.
Idea is crank greased bolts to 200 ft pounds.
Then whack the old coupler with a sledge hammer and hope that jars it enough to come loose.
May even heat prop hub with propane torch.

Coupler is reversed on shaft, and I made the old coupler a sliding fit to shaft.

I have to go get the bolts, price is $5-6 per bolt locally here at York Bolt.

I slipped shaft off together with props. I have never had these props off the shaft.
It will be easier to put shaft back in without prop on. And maybe easier to align.

pics of concept




Head of bolt to bear here, and not really on the flange. more of the thick collar.
Edge of hole sits at the collar.

Think it will work?

 

I am sharing a chatgpt I had about this puller

ChatGPT - Strength comparison bolts 1/2" 7/16" https://chatgpt.com/share/68aa4447-85fc-8010-a74f-a7c00d059b5a

 

Not very versatile as prop pullers go.
It Will work for your application, but not at all once the shaft is installed in the boat.

 

I would suggest you find another thick backing ring to go behind the hub and flange, with the bolts going through it as well. If you tension it as shown, the flange may warp or bend at the bolt holes, becoming useless. It may be an SS hub, which may bend and stay bent, but looks to possibly be cast iron, which may crack. Do it on trestles or a bench, so you can get a straight hit on it, not on the ground.
Get some penetrating lube down the keyway and between shaft and prop, front and back - every little bit helps.
Put a nut on the shaft thread pushed up to the rusty plate, to help spread the shock load, anti seize the bolt threads, tighten evenly, ice the shaft, heat the prop boss not too much, hit the plate square and centre with a big hammer. If the shaft warms up, let it cool properly right through, and start again. Don't be in a hurry, it may need several heating cooling cycles to weaken the binding corrosion.
Good luck, I've done similar things with old rusted car axle tapers and wheel stud flanges; one took half a day, but was salvaged intact.

 

Well I think it will work, the bolt heads are partially bearing on that thick collar, but yeah could replace with another thick plate.
It would pull any 1 3/8 or smaller prop.
I slid the shaft out without pulling the prop and did that on a prior haul. It will come out but it does add weight to carrying it around.
The shaft is 9 feet long.
I imagine heavy as it is, anything bigger might be too hard to lug around.
It might take a 1 3/8" slot cut out of the velvet drive coupler so could slip around a shaft

Those couplers are not cast iron, they are ductile iron. They are not going to crack.

 

I agree, but it is cheap, I had all the parts except for the bolts.
My cost will be $20.

A slot could be put into the velvet drive 5" diameter coupler.
Or another steel plate could be made with a slot to use in place of it.

If I created a plate, I could up the bolt size to 3/4" grade 8.
That could pull over 2" shaft mounted props.
But I don't need such a thing.

I think my example could allow others to make their own prop pullers, give them ideas. The large pullers are very expensive.

 

Here is all the tools I needed for this.

I drilled the 6 holes in stages upping the drill sizes till the 5/8 one.
And used oil to cool the drill bit.
Some of the drills are carbide tipped, which I found last a long time. I have yet to break one, they stay very reliably sharp. The non carbide tipped bits drilled faster. So when they are good quality and sharp they work well.
The 3/16 blue drill on far left, I could have skipped using, but it was a test to see how easy that steel tie plate would drill. That bright one in the middle I think is masonry carbide tipped for a hammer drill, and it also drilled the steel just fine.

The largest drill bit I bought at a thrift store for $2 years ago. It worked very well, a PO gave it lots of use.
Surprised it drilled so well.
That bit needed the gear reduction Bosch drill, which has a ton of torque. The other drill could not do it.

The large pipe wrench I used to break off the nuts, after warming them with propane torch.
The hammer I hit the pipe wrench handle with to shock them loose. I could not hold the prop and push hard enough to break the nuts free.

 

Chatgpt says those 5/8" grade 8 can pull 28 tons of force at 180 foot pounds.
I find Chatgpt to be capable of some good advice, it has to be prompted to redirect sometimes as it can start thinking one way and it is not seeing the picture you have.

But I also found you can drag a picture into the chat and show it what you have. Then it can see what you have. Just like people like pictures, it can understand that too.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
got it — here are solid, per-bolt torque targets and the total pull you’ll get with three 5/8-11 Grade 8 bolts, assuming lubed threads + hardened washers (K≈0.18):

Formula: Fper bolt=T⋅12K⋅dF_\text{per bolt}=\dfrac{T\cdot12}{K\cdot d}Fper bolt=K⋅dT⋅12 with d=0.625 ind=0.625\text{ in}d=0.625 in.
Total pull = 3 × F_per_bolt. (1 ton = 2000 lbf)

Torque per bolt (ft·lb) Per-bolt preload (lbf) Total pull (lbf) Total (tons)
150 16,000 48,000 24.0 t
160 17,067 51,200 25.6 t
170 18,133 54,400 27.2 t
180 19,200 57,600 28.8 t
Recommendations

• Aim for 160–170 ft·lb per bolt first (≈ 25.6–27.2 tons total).
  
  
• If it’s stubborn, creep to 180 ft·lb (≈ 28.8 tons) — still ~70% of Grade 8 proof per bolt.
  
  
• If your threads are dry (K≈0.20), expect ~10–15% less pull for the same torque.
  
  
• Keep using: hardened washers, anti-seize/oil, tighten in a star pattern, then add light heat on the bronze hub and give the coupler a sharp rap under load.
  
  
• Leave the prop nut on a few turns as a catch.

 

Forget propane. Get and oxy-acetylene rig and a decent sized rosebud tip. You need 50 X the btu output of that propane torch to make a difference. And use it. It will probably take more than ten minutes at full song to do any good. Keep the puller out of the way, or you will end up softening the puller and it will just fold up as soon as you torque the bolts. In my neck of the woods, I can borrow a 7 ton puller from any auto parts store. I often fashion custom bits for them out of scrap metal and chain and whatnot. Oh, and use an infrared temp gun to keep track of what's hot and how hot. It's very helpful to know the temp when it lets go for future reference.

Also, it is surprisingly easy to mushroom the end of the shaft. It doesn't take a sledge hammer or even a four-pound hand sledge. A bunch of whacks with a 24oz decker will completely mess up the end of the shaft, even when plated over and piloted. You absolutely must protect the shaft with the prop nuts. Lock them up with a 1/16" of nut proud of the shaft.

Hydraulic wheel motors on equipment are set up exactly the same way. I'm always having to rig pullers - with the added fun of trying not to destroy a $5k motor's seals in the process. I've got a whole rack of holey plates like yours. But the plates should be thick - like more than half as thick as the shaft. Otherwise things can get very jumpy when something lets loose.

 

I am going to whack the velvet drive coupler, with it under tension, if it does not come apart, not the end of the shaft.
They made these things to come apart using pullers, so I expect it will come apart.

I thought about leaving the thick nut on the shaft, for the plate to bear against, but was concerned the pressure would mess up the bronze nut or the shaft's threads
It can only engage half the nuts threads. Maybe it would help.

I suppose could thread thin nut first, then thick nut, set them tight to each other, with big nut flat to shaft end.

What do most people do when using a prop puller?

 

I found a large steel nut in my bolt stash that fits the shaft.
I can run the thick bronze nut on, then put the steel nut on
Or go the other way steel first, bronze second.

Which is better?
Steel less likely to distort.
Or will it matter?

Leaves a 1/8" gap to allow prop to pop off taper.

 

Here it is assembled but not yet greased with some moly grease.

I got 2H nuts, also have grade 8 nuts.
2H nuts are bigger.
Grade 8 bolts are 10" length.
I also got 3 thicker grade washers which are smaller diameter for the velvet drive hub. They fit perfect, and will spread the load on the coupler.

I may try pulling today or in the AM.

 

That's a lot better. Now if you only had an air hammer with a mushroom head instead of the sledge. Be prepared to heat cycle it twice a day for two weeks up to 700C. It'll come off. Had one stubborn wheel hub take me a month, then it threw 700C metal all over the shop and jumped off the jackstands when it did let go (I had it under a bit of tension - like 15 tons or so - for a month - sprayed it, heated it, beat on it twice a day for a month).

 

2 weeks!
I hope not.
I got another just like it, since the boat has dual props.

Supposedly these 3 bolts can pull up to 28 tons.

How do you all feel about 2H nuts versus grade 8?
I will update this thread.

 

It is off!
No pop, snap, only silent release, it just slid off after about 80 foot pounds.
Bolts kept losing tension, I thought what?
So not a huge deal.
This prop has been on in salt water ever since I owned it and likely before me, I got boat in 1998.
All this metal was new in 1970, so at least 55 year old stuff.
Prop is 22 by 20 Michigan wheel.

I did have to hit coupler with a 2 pound hammer to slide it all way off shaft.
I moved as far as I could using puller, reset took off big nuts.
Maybe a pry bar between shaft end and the plate could work.
Maybe if was attached to boat, it would pull off by hand after breaking free.

prop key is in the pic.