Bending a casting- MU2 winch

[Doc Dave]

The person that had my MU-2 before I got it must have really had a load on it once. The front base angle was bent in two planes a bit, and also the cable drum bracket (what holds the drum on the passenger side) is also bent at its ends. This bracket is not cracked and has not been welded on. The combination of these bends in these two components result in the cable guides being out of parallel with each other and prevents the spacer from fitting just under the drum properly.
I solved the base angle problem by buying a new piece of 3/8", 2X2 angle iron. I will drill the holes at the appropriate places. For the bracket, it will fit on my 20 ton press. I played around with trying to bend it back but was a little leery about really "getting on it". I know it is a casting.
Any suggestions for bending it? What about heating the casting first?

[Desoto61]

I'm honestly not sure, I'd think heat would definitely reduce the possibility of cracking the bracket, but I'm not sure how hot you'd have to get it to really help. Plus the difficulty of trying to work with it at those temps.

How much are you off? It might be worth considering getting the ends machined so that they are correct again and then making a spacer (or spacers) to make up for the material removed.

Then again it may just be cheaper to give it a try and find a new end if it goes wrong.

[Doc Dave]

Thanks for the response.
I may try a combination approach, bending on the press and machining the ends to line up better with the base angles.
If this does not work I have a source for a straight used one.

[maineSS]

Doc-

I tried responding to your PM a couple times without connecting, so I'll try here. I'm not sure if the "Leg" bracket is cast iron or steel. Cast steel is a LOT easier to work with- there are many different cast iron types, most of which are brittle and don't bend well.

I'm thinking that the bracket is steel if it bent without cracking, as ductile iron is about the only "flexible" cast iron I know of. You could touch the leg lightly to a grinder and observe spark color and pattern for a rough guess- I don't have my chart in front of me, but the info should be on the Net somewhere.

I expect you'll have to heat the bend area red hot to keep it from springing back, so you'll need to have some welder's gloves on. The problem with straightening bends is that you're also stretching the metal, which may present alignment problems with the leg being slightly long. You'll know if the shaft keeps binding in the bushings when you turn the worm by hand after you assemble the winch- you'll want to test for this off the truck, so that possible frame distortion isn't a factor.

You should be able to turn the worm one-handed with the same effort over a complete revolution of the drum shaft with all the winch frame bolts drawn up to torque. If you're in a hurry to get the winch in service, and can get a good leg bracket, that would be the way to go, as straightening things takes a LOT more time than bending them.

[Doc Dave]

Thank you for your reply.
Metalurgy is an interesting subject to me. Your point about the possibility of it stretching is well taken, and I can see where there might be alignment problems even if I was successful at bending it back.
Also with the size of the piece heating the whole thing red hot would be a challenge without a blast oven.
I recently was able to find "through the power wagon family" someone with a used straight bracket. I will try that first. If all else fails I will attempt to straighten the one I have with the advice given here.

[Gordon Maney]

Thank you for your reply.
Metalurgy is an interesting subject to me. Your point about the possibility of it stretching is well taken, and I can see where there might be alignment problems even if I was successful at bending it back.
Also with the size of the piece heating the whole thing red hot would be a challenge without a blast oven.
I recently was able to find "through the power wagon family" someone with a used straight bracket. I will try that first. If all else fails I will attempt to straighten the one I have with the advice given here.

Remember to take pictures if you do. It would make an interesting article for the magazine. Your experience, your thought processes. :-)

[maineSS]

You shouldn't need to heat the entire piece, just the bend area. An oxyacetylene torch should do nicely. It will make a huge difference in press effort, so you'll have to be careful not to overdo. The fun part is finding somewhere safe to set the torch while you're working the press- it's one of those things that needs three hands...

[Desoto61]

Remember to take pictures if you do. It would make an interesting article for the magazine. Your experience, your thought processes. :-)

The fun part is finding somewhere safe to set the torch while you're working the press- it's one of those things that needs three hands...

Four if you include a hand to take pictures while you do it.

[Gordon Maney]

Clearly, it is a job that takes two monkeys.

[gusbratz]

this is interesting, I used to work for the gas company on stationary compressor/engine units as a mechanic, very large cast iron frame with a v 4-6-8 or 12 conviguration engine cast into the top of the frame. 14-16 inch bore on the pistons to give you an idea of the size. these engines ran 24/7 under full load. (pushing overload). some have been in place since the 1930's running consistantly with only shut downs for overhauls. After may hours of stress these cast iron frames would distort enought to cause main bearing alignment issues and the solution was a tear down and re-line bore the main bearing saddles. I had a freind buy a logsplitter with a cast iron base, after about 2 weeks of splitting some nasty stuff the base was bending out. you would think cast would just crack but if the stess is slowly repeated 100's of times it will squirm and twist and do strange things, my point is the bend in your winch probobly did not happen in one magnificent winching. probobly took years and years of use to bend it. Putting it back is going to be the same. maybe you could try peening it back into place. that is how they fix big cast crank shafts when the get bent, I think it is kind of a lost art.

[Cheyenne Dave]

"Straightening" the casting is the least of your worries. You will find that the main bore that the drum spindle turns in, has been ovaled and is no longer round. Also, the ends if the casting, which are used to bolt the casting into the winch frame-work will no longer be parallel to each, even if you are able to straighten the main body of the casting. These two issues will makes proper assembly and use of the winch unlikey.

I was not able to find enough asbestose-gloved monkeys to surmount these issues and was forces to buy a reproduction piece. Maybe you will have better luck...

It would be helpful to recognize and avoid the main causes for this type of damage in the future. A front end collision can be one cause, but one you may not have any contol over.

Extreme side-pulls, those winching operations where the cable is not being spooled in from straight ahead, is something to be avoided.

More importantly, long, uninterupted pulls can be espcially damaging; where an unmonitored drum might stack the cable unevenly, allowing the cable to jump outside the drum. Being unaware of the situation, the cable will get bound up between the drum flange and the bracket. As the drum continues to turn, the cable bunches up and acts as a wedge, bending the bracket outwards. The drum flange will eventually cut the cable, or the shear pin will break, but the damage will already be done.

If you are alone, it is best to stop regularly and check that the cable is spooling on evenly; reset snatch blocks as nessesary to ensure a straight pull. A passenger should be out spotting, from a safe distance away and to the side of the cable. These things take time, but are better than the alternaive.

C.D.

[Doc Dave]

Good information Dave.
I will remember these tips when I do use the winch.
Whoever abused it before did not care about the problems they caused, whereas I have invested sweat equity in it and do not want to have to work on it again.

[Gordon Maney]

Regarding the earlier remarks about cracking, malleable cast will bend. I am not saying I think these parts are malleable cast, just offering comment on castings changing shape.