Is this worth trying to weld ?

[Rocky J]

I can not tell by the picture if it is a belt pulley or if it has a key way in it or not. If it is I would just buy a pulley with the same diameter and belt width. Surplus Center has a big assortment with good pictures.Surplus Center I would take a 4 inch grinder with a cut off wheel and cut the pulley length ways with the shaft till it pops open and slide it off or if you half to drive a chisel into the cut and force it open to come off. If you are not a seasoned welder cast iron is not the place to start,if to cool it will not puddle and if to hot it will send little cracks all along the weld, you stand a better chance with brazing it if it has to be that pulley. Braze vs. Weld - YouTube

 

[roadhunter]

Might consider Brazing as an option.

I've had better luck brazing than welding cast iron.

 

[Shield Arc]

I need to find some cast iron and try this Silicon Bronze Tig rod on it. I bought some a while back, played with it just a little.
3/32" Silicon Bronze Tig 36" Rod - 1 Lb - AWS A5.7 ERCuSi-A | eBay

 

[GLyford]

If the pinion gear on the backside is part of the pulley, cutting it up to get it off may not be the best option.

Looks like there has already been a fair amount of pounding on the shaft, and that dent tells me a puller is likely what broke the pulley. I'm thinking you need to get that hot to get the hub to expand and break the rust free, probably grind the mashed over rod some too. This also tells me you need to get the hub off to track down whatever that other issue is, don't try to weld it in place if it only means you will will break it again trying to get at the same thing.

I would inspect the pinion gear with a mirror and figure out why they were trying to pull it. Broken gear tooth? Pulling the pulley to get at the bearings? Bent shaft? Getting the pulley off so they can get the big gear off and change those bearings? Are all the bearings in this even ball bearings, or bronze bushings or poured babbit?

So anyway, do not rush to fix the obvious, find the real break first.

 

[adventure bob]

Is the pulley keyed? Other than being old what makes this one special? Id think you could find a form fit function replacement for it. May not be OEM, but industrial pulleys are made in a billion sizes.

 

[Sodo]

ABob it looks like theres a gear on the hub part. Glyford as always your advice is expert!

Electrode welding in a circle like that, (not having any experience electric welding cast) I'd ---- be leery of it "pulling" & cracking.

I'd braze it. If you can press it back together and it stays, with brazing you can knock it around and get it true. Although it prob doesn't require trueness at the end of that belt. I doubt theres high forces on that, you can see clearly that its limited to the friction of the belt. Brazing is very strong if you can get the pieces to fit tightly together and the brass to flow into the joint.

And don't pull on it until you find a puller that grips the hub thru the access holes. :thumbsup:

Lots of other ways to fix it too. If you can machine the gear-hub flat in a lathe it can be bolted to a circular steel plate (like a large washer) then bolted to the pulley. Several smaller bolts into the gear hub at center and a bigger one on that "arm". Then slide on the shaft a little for belt alignment if the gear teeth have any extra engagement. Or two washers to shift belt alignment back to original.

....EDIT.... yeah what bcp said on pg1!!!!

 

[scons]

First of all, thanks for all your comments, I (always) find them very useful !

I decided to give it a go and went to the local welding supplier and took several Lincoln RepTec Cast 31 2.5mm rods home. They were so friendly to sell them by the piece.

I also called several people and one gave me a link to a website who sells parts. So that was another + for today. When I got home I went on the web and found the needed pulley on their website, so I will call them tomorrow for a price on the pulley.



I was planning to prep the crack tomorrow and give it a go, but reading through your answers set me a step back and got me thinking. There is one answer in particular that gave me a whole other look at the vendor's "story" on how this pulley was damaged this way.

Looks like there has already been a fair amount of pounding on the shaft, and that dent tells me a puller is likely what broke the pulley. I'm thinking you need to get that hot to get the hub to expand and break the rust free, probably grind the mashed over rod some too. This also tells me you need to get the hub off to track down whatever that other issue is

GLyford: I think you hit it right on the spot !!

If you look at the picture the marked area should be backwards, but it is not possible to get it that way back on, so the pully has broken of to the front with a snap.



On this website there is also a scheme of how it is assembled. In a normal situation the pulley should slide off once the linchpins are removed, but there are no more linchpins present and it stil is stuck like ****.



So my first task will be grinding the shaft until I can slide the base of the pulley off, maybe put some heat on it. That way it will be a lot easier to weld too. In the meantime I can inspect the rest of the shaft. I noticed there is tolerance on the big gear wheel so maybe they wanted to change the bushing of it ... anyway we will never know. I can turn the pto shaft by hand and everything seems to spin so I think the base will be okay, and maybe I just need to replace some bearings. The main shaft are ball bearings, same for the breaker shaft, the big gear wheel has a bushing.



The rod specs say: Residual stresses are decreased by peening after each layer
http://www.lincolnelectric.com/asse...odes-RepTec-RepTecCast31/REPTECCAST31-eng.pdf

I suppose hitting it with a hammer will do fine but opinions seem to differ. What are you thoughts on this peening matter ? I have no tools for it so I will have to do it manually.

Thanks

 

[Rocky J]

The iron molecules are attracted to the heat, they line up with each other. The amount of iron will determine how hard it is.The peening or tapping with a small hammer will chase the iron back away from the heat affect zone making the weld much more the same hardness as the rest of the pulley, if you could have a buddy hold a torch on this to slow down the affects of heating up and cooling down you stand a better chance of no crystallizing the weld. It growing and shrinking is what is going to crack it. The torch will help you not have part of the pulley at 150 degrees and parts at 1500 and the heat residing like the tide on the beach when you stop welding. It can be done .Just not everybody can do it.

 

[GLyford]

tap it with a chipping hammer, hard enough to leave tiny dents in the weld metal, but not hard enough to re-break the casting.

Or hit it with a needle scaler. HF has one.

I wonder if they tried to pull it before they found the pins?

 

[Soundguy]

I'd try it. I've welded a few cast parts for old tractors with great results. Certanium was one rod I used, another was?? Name? From a tool store ( not hf ), but specifies cast iron.

Clean, preheat, slow cool, peening to relieve stress.

Good luck.