Replaced my Windshield Wipers - Time to Make Engine Hooks!

[brockrwood]

I am told I can make engine hooks out of the long, metal strips in worn out windshield wipers. We will now find out!

(There needs to be a “budget rocketry” or “rocketry on the cheap” forum.)

 

[hobie1dog]

tear those things apart and take another picture so that we can see what you end up with, and if you can get the right dimensions you need.

 

[BEC]

I have found some wiper spines don't like to be bent 90 degrees to make motor hooks....but I don't know which spines came from which brand of wipers, all I can say is "watch out for cracking".

 

[T-Rex]

If you have a vice ( or extra hands available) they should bend better if you heat them (red hot) with a propane torch.
I've made a couple without heating in the past, just a 90 at both ends (like old school). Didn't trust them enough to use them.

 

[SolarYellow]

If you have a vice ( or extra hands available) they should bend better if you heat them (red hot) with a propane torch.
I've made a couple without heating in the past, just a 90 at both ends (like old school). Didn't trust them enough to use them.

That will anneal them, unless you make sure to cool them at the correct rates to maintain the springiness. I'd have to read up to remember how to do all that and not make them overly brittle.

Also, vise. Unless you also hang out on garage/shop forums and have a habit of collecting too many of them, then vises can become a vice.

 

[hobie1dog]

Also, vise. Unless you also hang out on garage/shop forums and have a habit of collecting too many of them, then vises can become a vice.

Wilton vises-You're Nobody unless you own a Wilton over on The Garage Journal (which I quit 5 years ago)

 

[cwbullet]

It could be a good tip or how-to post.

 

[SolarYellow]

Wilton vises-You're Nobody unless you own a Wilton over on The Garage Journal (which I quit 5 years ago)

8-incher. 100+ lbs. of garage bad-assitude. Don't know what I'd do without it.

Also have a Panavise that has Long Beach, CA cast into it. And a German Ridgid XF50 Quick Acting swivel-base vise. And the 2.5-inch Wilton that's a total Chinesium POS. And a Wilton woodworking vise.

Yeah, I might have the vice.

 

[K'Tesh]

Why wait until your wiper blades are worn out? If I did, I'd never get any old blades*... Try the trashcan outside of a Napa Auto Parts (or any other auto parts) store.

*bicycles don't have windshield wipers.

 

[rharshberger]

Who uses engine hooks anymore....I quit using them long ago and now just leave the motor mount a 1/2" long and use aluminum tape to retain motors of all sizes from13mm to 75mm (I haven't flown a 98mm yet).

 

[K'Tesh]

Who uses engine hooks anymore....I quit using them long ago and now just leave the motor mount a 1/2" long and use aluminum tape to retain motors of all sizes from13mm to 75mm (I haven't flown a 98mm yet).

I do... Then again, I'm into the history of the hobby, and the history of kits.

 

[Ladykate]

I use my own screw on retainers unless it is a motor that doesn't use an ejection charge. If you want to make the springy things, take a hint from the lock pick crowd, walk a few neighborhood streets and pick up street sweeper brushes that have broken off. You will find lots of them. It is springy, tough, and just about the right width.

 

[lakeroadster]

I have found some wiper spines don't like to be bent 90 degrees to make motor hooks....but I don't know which spines came from which brand of wipers, all I can say is "watch out for cracking".

And that's sage advice. The technique of how the hook is bent is the key to success.

What I've learned when making homemade motor hooks is to ensure there is a radius at the 90 degree bends. I typically use (2) pliers to bend the wiper spine, and not a vise and a hammer.

You only get one chance. If you bend the spine in the wrong location, you can't flatten it out and re-bend it. The forming process work hardens the material... it will indeed crack if over worked.

A nice fluid motion when bending the metal is the result when using pliers... as opposed to multiple blows with a hammer with the steel clamped in a vice.

​

 

[Rob Campbell]

Recycling at its absolute best.

 

[hobie1dog]

I thought the top 90 degree bend went into a slot in the tube?

 

[lakeroadster]

I thought the top 90 degree bend went into a slot in the tube?

The one I am showing is for a scratch build that used a AT composite motor (as shown). Composite motors have a much higher ejection force and can zipper the motor hook right out of a cardboard motor tube.

I've proved that theory....

 

[Paul Howard]

I save my used windshild wiper blade spines all the time and make all sorts of things with them since they tend to be pretty good stainless steel. I've made engine retainer hooks too, and generally they work great!

 

[rharshberger]

And that's sage advice. The technique of how the hook is bent is the key to success.

What I've learned when making homemade motor hooks is to ensure there is a radius at the 90 degree bends. I typically use (2) pliers to bend the wiper spine, and not a vise and a hammer.

You only get one chance. If you bend the spine in the wrong location, you can't flatten it out and re-bend it. The forming process work hardens the material... it will indeed crack if over worked.

A nice fluid motion when bending the metal is the result when using pliers... as opposed to multiple blows with a hammer with the steel clamped in a vice.

View attachment 561245 View attachment 561244​

You can also clamp an aluminum block as a heat sink and spot anneal the bends leaving the long section springy(?), I used to use an old Radio Shack mini torch (two CO2 cylinder looking tanks) for that purpose and silver soldering gun sights.

 

[GlenP]

I thought the top 90 degree bend went into a slot in the tube?

When I make my own, I make them long enough to go over the thrust ring, so the slot is on top of that reinforced part of the motor tube. Estes kits have the hook in a slot just under the thrust ring.

 

[brockrwood]

Now to turn them into engine hooks. Child number 2 hot them out with the PVC pipe cutter.

 

[lakeroadster]

When I make my own, I make them long enough to go over the thrust ring, so the slot is on top of that reinforced part of the motor tube. Estes kits have the hook in a slot just under the thrust ring.

Proceed with caution and....
<<<------

That's sage advice GlenP is offering up! Relying on just the body tube to withstand the motor's ejection charge isn't sufficient for any motor bigger than, let's say.. an 18mm Estes BP C6... IMO.

And the narrower the clip the more likely it is to rip through the body tube.

 

[brockrwood]

The one I am showing is for a scratch build that used a AT composite motor (as shown). Composite motors have a much higher ejection force and can zipper the motor hook right out of a cardboard motor tube.

I've proved that theory....

My homemade engine hooks will be used with Estes BP motors. Nothing more powerful than E black powder motor. Is the zipper issue still applicable? Definite don’t want zippered motor tubes!

 

[lakeroadster]

My homemade engine hooks will be used with Estes BP motors. Nothing more powerful than E black powder motor. Is the zipper issue still applicable? Definite don’t want zippered motor tubes!

Sure, they'll work but the top end of the hook needs needs a centering ring or a motor thrust ring to bear against.

​

 

[kuririn]

When I make my own, I make them long enough to go over the thrust ring, so the slot is on top of that reinforced part of the motor tube. Estes kits have the hook in a slot just under the thrust ring.

Odd'l Rockets used to sell an extended engine hook like that.
Two benefits:
The forward motor thrust is distributed by the thrust ring rather than by the narrow area in front of the engine hook.
At ejection the rearward motion of the engine hook is stopped by the thrust ring.
I think the hook was 1/4" longer than standard.

 

[dakota196]

You know I have found while walking my dog, street sweepers brush parts. They are just the right size and bend nicely if you make a single pass with the bend. I find multiples in the gutters. That’s where I hangout.

 

[Bruiser]

I work in a garage and will be digging in the trashcans for a blade that has the metal spine. Not all do anymore. The cheaper ones are all plastic. I need to bend up one for a 13mm mini I'm getting reading to start.

I never saw that about the opposite bend for centering rings (post 23). Learned something new today.

Oh, but I also learned a bunch about BT-20 based rockets with 13mm motors

-Bob

 

[PDawg]

Who uses engine hooks anymore....I quit using them long ago and now just leave the motor mount a 1/2" long and use aluminum tape to retain motors of all sizes from13mm to 75mm (I haven't flown a 98mm yet).

Does removing the aluminum tape damage the tube or do you reinforce the tube? Is aluminum tape the stuff they use on heating ducts?