Is this the end of the road for our power hammer?

[Kevin Sutton]

This small cast part broke away from the part of the frame that guides the hammer as it rises and falls. We re-welded it on the outside and will attempt to also weld on the inside of the track, taking care not to interfere with the travel of the hammer. Any suggestions?

 

[Frosty]

Welcome aboard Kevin, glad to have you. If you put your general location in the header you'll have a much better chance of meeting up with people living within visiting distance. You know, like someone who can help?

I'm not going to offer welding advice, it's too far outside my range of expertise, even when I ran a lot of rod. The one suggestion I do have is, after welding it maybe weld a couple reinforcing straps across the weld. Heat and form it to match the guide where it's welded, 3/8" x 1" and long enough to pass at least 1 1/2" past the weld on each side. Just stitch the weld on alternate sides to minimize pull as it cools. Take it slow and easy, you don't want the reinforcing bar to get hot or it WILL pull as it cools.

Frosty The Lucky.

 

[Will Brouwers]

Would running pins through it and the rest of the hammer help?

[Frosty]

I don't know, I can't see what the break looks like well enough and there is no picture of the other side so I know what it's supposed to look like. If it's supposed to be solid to the bearing surface then welding full depth should do it. If it is as wide as the shiny black between the weld bead and the bearing surface, the weld they made is barely a tack weld for what it should be.

I hadn't imagined they'd put 1/4" weld to repair a 2" break. It would've been a better join if they'd totally degreased it and silver brazed it. Done properly it would be at least as strong as the original cast iron unless it was malleable / gray cast iron and nobody spent the time and money heat treating cast for that kind of part. Cast iron ASOs are gray / malleable iron and it requires a long cooling process IIRC. It's been a while since I read how malleable is made. What it is is more expensive and impact resistant, something that part of a power hammer doesn't need at all.

I'm just hoping Kevin takes a few better pictures so I can maybe make a useful suggestion.

Frosty The Lucky.

[Nobody Special]

I'm certainly not a good enough welder to suggest much, but most of the power hammers and cast iron power machinery that I've seen repaired were put back together by brazing, which is supposed to hold well and be a lot easier to do.

[Bud in PA]

If I remember correctly you have to heat the object to at least 300 deg. and insulate it so that it cools slowly when using NI ROD. I don't know how you would insulate that vertical piece to cool it slowly.

[JHCC]

Wrap it in several layers of kaowool. 

[BillyBones]

On 4/6/2024 at 11:06 PM, Will Brouwers said:

Would running pins through it and the rest of the hammer help?

We just repaired a casting on a machine at work. Mill or grind a couple flats on the broken off part. Drill, i would use 3 from the looks of the size of the piece, holes through the piece. Drill and tap 3 holes in the place it broke from. A bit of JB weld will hold it in place while drilling and can be easily dislodged after. Clean both surfaces really well then bolt it on and have a competent welder run a bead around the seems. 

The machine we repaired is basically and automatic lathe, Davenport 5 spindle, that is pushing a tool into a 7/8" round bar of steel. The repair point is the fulcrum for the tool and i will guarantee it has way more pressure on it that what you have. The repair has been holding up nicely. 

[jason0012]

I would tack with nickel rod in a few places. Drill and pin in a few places, then grind deep and wide channels around the break. The pins holding alignment. Preheat as much as possible and peen your weld at each pass. Weld all the way around. Wrap in refractory wool and wire it up tight when done welding- to let it cool slow ( nickel rod isn’t terribly sensitive but it doesn’t hurt)then the hard part, grind, file and scrape the sliding surfaces level. I am sure someone here will sugest something better than nickel rod, but it is what I have the most experience with on castings.

[BeaverNZ]

Part of what I do in my business is cast iron welding, In my experiance the best way to repair a casting is metal spraying for the most reliable repair but it is expensive as most of the nickle rich processes are like stick welding and metal spray. I would set up the broken pieces as best I can with the smaller part being slightly proud into the bearing surface and set it up so it can be held in position probably by bolting, Then I would take it apart and do a weld prep that allows plenty of acess to the weld area. Then i would use a nickel bronze rod and using a cast iron tinning flux tin or coat the smaller part first to see if it will take a coat of the bronze and do the entire face of the repair. Then reassemble the pices and heat the whole casting up using LPG or a diesel burner after wrapping the whole thing with Koawool or simmilar and heat it up to 4-500 deg cent and tin the second area. Once this has been done then its just fill up the weld prep. When doing the tinning coat if the bronze does not freely flow then the area is not clean enough, not hot enough or not enough flux and any repair where this does not happen you are wasting your time and money proceding. with one of my repairs in the past the cast iron just would not take a tinning coat so I tried a coat using the metal spraying torch then continued with the bronze on that and it was succesful. Their is always more than one way to do a repair and I enjoy the challange of doing repairs no one else will try. after the reair has cooled overnight then the protruding smaller part of the repair could be machined or filed or some by other means back to where it needs to be.

[Frosty]

Thanks Beaver CR, tinning and brazing in place sounds good to me. Tinning and clamping parts to be brazed is pretty standard when there isn't space or there is too much distance to rely on the hard solder to flow reliably. Do you use a past bronze? There are products available that are fluxed bronze or almost any alloy hard solder you can spread in the joint, clamp and heat. 

I've never used one but if I were in the business. . . 

Frosty The Lucky.