Not Quite Farm Engineering or a Quick Bodge.

[Nearly]

Always take it off before you call in at the shop on the way home.

 

[JohnBoy]

I figure this belongs more in here than the tool addiction thread.

I recently upgraded from a 170a mig and 175a inverter to a thermal arc 252i which didnt fit on the trolley I'd made for the other machines. I picked up an old small filing cabinet off ebay and built a trolley around it, threw a bit of paint on a calling it done.

 

[sjt01]

I figure this belongs more in here than the tool addiction thread.

I recently upgraded from a 170a mig and 175a inverter to a thermal arc 252i which didnt fit on the trolley I'd made for the other machines. I picked up an old small filing cabinet off ebay and built a trolley around it, threw a bit of paint on a calling it done.

Just looked up the welder on the web, looks really nice. Presently using a Fronius TIG on a 13A plug, and a 3 phase MIG

 

[milkloss]

Evening my fellow bodgineers! Need to get you twittering like bodgerigars over this one.

Ok enough of that rubbish. my shear grab has gone flopsy, I’m going to bodge it tomorrow once I’ve found a new pin. It’s the twisted pin brackets that are the problem. The original pin broke in half allowing everything to twist so I drove the draw pin in with a rather large hammer but it bent that like a ‘nana too.

What grade steel do they make the ram pins out of, would another fresh draw pin do or not tough enough?

Suggestions as to the method on unflopsying it welcome.

 

[Shovelhands]

The key to the pin not bending is making the gap between the brackets as tight as possible and still receive then rod end. Whatever you do, however you do it, whatever grade of pin you use, you must get those pin bosses back to gether against the rod end.

Going to be some heat and/or cutting and welding taking place I should think, to get it all back to position.
The drawbar pin may we’ll be strong enough if the bosses are in the correct position and strong enough.
A new pin of en8 or en16 would be my choice I think.

When it’s done, a piece of plate across here will add strength and prevent it happening again

It looks like there is enough room for it, unless I’m missing something, there is no reason why this piece cannot be added. It will not only tie the two brackets together, but will also help anchor them to the piece of box section that goes across the top of the grab.
You will have to redrill another grease nipple, or fit a 90 degree nipple.

I would also recommend adding the same strengthening plate to the other side, as it is more than likely the bracket that flexed first and the pin broke second.

 

[Dave W]

What @Shovelhands said ^^^^^

The actual grade of steel for the pin isn’t overly critical if it’s all set up properly ie correct diameter and properly braced.

 

[mikep]

Evening my fellow bodgineers! Need to get you twittering like bodgerigars over this one.

Ok enough of that rubbish. my shear grab has gone flopsy, I’m going to bodge it tomorrow once I’ve found a new pin. It’s the twisted pin brackets that are the problem. The original pin broke in half allowing everything to twist so I drove the draw pin in with a rather large hammer but it bent that like a ‘nana too.

What grade steel do they make the ram pins out of, would another fresh draw pin do or not tough enough?

Suggestions as to the method on unflopsying it welcome.

View attachment 662772 View attachment 662774

With damage like that I would use a cutting disc and cut halfway through the bent endplate just about where the good welds are. This makes getting the plate straight much easier and the slot can be welded up after. Make sure the plate is securely welded all around and a drawbar pin of the right diameter will be fine as long a your weldings good. I always keep old hydraulic piston rods as they are great for pins.

 

[milkloss]

Thank you all, esp @Shovelhands ; I like the front plate idea because all I was going to do was a strap across the bracket near the ram.

The pin surely broke first as I find out this morning someone noticed the original pin was slightly bent and so turned it round! What is also strange and I hadn’t noticed before is that the bosses don’t actually go against the rod end, there’s probably half inch either side to play which is surprising.

 

[Pan mixer]

The key to the pin not bending is making the gap between the brackets as tight as possible and still receive then rod end. Whatever you do, however you do it, whatever grade of pin you use, you must get those pin bosses back to gether against the rod end.

Going to be some heat and/or cutting and welding taking place I should think, to get it all back to position.
The drawbar pin may we’ll be strong enough if the bosses are in the correct position and strong enough.
A new pin of en8 or en16 would be my choice I think.

When it’s done, a piece of plate across here will add strength and prevent it happening again
View attachment 662790It looks like there is enough room for it, unless I’m missing something, there is no reason why this piece cannot be added. It will not only tie the two brackets together, but will also help anchor them to the piece of box section that goes across the top of the grab.
You will have to redrill another grease nipple, or fit a 90 degree nipple.

I would also recommend adding the same strengthening plate to the other side, as it is more than likely the bracket that flexed first and the pin broke second. View attachment 662792

Good plan, don't you sleep at all?

 

[Shovelhands]

Thank you all, esp @Shovelhands ; I like the front plate idea because all I was going to do was a strap across the bracket near the ram.

The pin surely broke first as I find out this morning someone noticed the original pin was slightly bent and so turned it round! What is also strange and I hadn’t noticed before is that the bosses don’t actually go against the rod end, there’s probably half inch either side to play which is surprising.

The ‘play’ is surprising?...if that is the case, then it’s even more important to make the bosses as strong as possible, but I cannot see any reason why they are made with such tolerance in the first place?
Weather the pin broke first or not, we shall never know, but if the bracket is ‘flexing’ then this will, in time, cause the pin to break, IMO.
I noticed that the outer plate appears to have had a crack around the weld for some time? Are there cracks appearing on the other side? Cracks only appear if there is movement/flexing, this leads to cracking and fatigue, game over.....

Personally, if it were mine, I’d be having a bit of a modification of those bosses to bring them up to a reasonable tolerance, but that’s just me maybe?

Good luck with the repair, and don’t forget pictures

 

[startinghandle]

does the blade need sharpening??
has it been used for something it was not designed for?

 

[dannewhouse]

if it buggers you about in future cut bosses out and get new u bosses which fit a new pin tight and weld them in in situ??

 

[milkloss]

does the blade need sharpening??
has it been used for something it was not designed for?

Blade sharp and, no, it’s only cut silage albiet very dry at the minute.

if it buggers you about in future cut bosses out and get new u bosses which fit a new pin tight and weld them in in situ??

Yes, that’s what it might get on the near future as the other side has started to bend the pin. Any ideas where I might get some weld in bosses?


We repaired it, it is a bodge and I haven’t any pics as I keep walking past it and forgetting what we did was to put a large bolt in the bosses and tighten it up as we bashed the crud out of it. When we got halfway we then put a portapower ram across the back between the brackets to help reduce the twist on the inside one. Welded it up and put a new swinging drawbar pin in it which cut off to leave a spare pin......not bad for £15 I thought. Need to get new bushes for the rod end of the ram too.

 

[Ukjay]

The key to the pin not bending is making the gap between the brackets as tight as possible and still receive then rod end. Whatever you do, however you do it, whatever grade of pin you use, you must get those pin bosses back to gether against the rod end.

Going to be some heat and/or cutting and welding taking place I should think, to get it all back to position.
The drawbar pin may we’ll be strong enough if the bosses are in the correct position and strong enough.
A new pin of en8 or en16 would be my choice I think.

When it’s done, a piece of plate across here will add strength and prevent it happening again
View attachment 662790It looks like there is enough room for it, unless I’m missing something, there is no reason why this piece cannot be added. It will not only tie the two brackets together, but will also help anchor them to the piece of box section that goes across the top of the grab.
You will have to redrill another grease nipple, or fit a 90 degree nipple.

I would also recommend adding the same strengthening plate to the other side, as it is more than likely the bracket that flexed first and the pin broke second. View attachment 662792

Additionally, I would also get a shorter pin, or at least use spacers to take the slack up. That pin is allowing flex, which when it flexes - it draws more of the pin inside to the pivot point as the ram pushes out, thus you end up with the splayed plates as it has put too much stress on the welds and they cracked.

 

[Bob c]

i agree with @Shovelhands
the bosses need to be longer so there is only a 5mm gap between rod end bosse and the bosses in red
also you could have two small plates to try the bosses down in blue
dont no what the length pin is but it needs to be the right diameter for the bosses

 

[milkloss]

Additionally, I would also get a shorter pin, or at least use spacers to take the slack up. That pin is allowing flex, which when it flexes - it draws more of the pin inside to the pivot point as the ram pushes out, thus you end up with the splayed plates as it has put too much stress on the welds and they cracked.

That’s not the original pin. I think the proper pin broke in the middle (half of it still rolling about in the truck footwell) which allowed the outside boss to flex and break the weld. Or the weld broke first which allowed the pin to bend, got turned round, bent the other way and broke. I drove, with a sledge, a draw pin that was a good fit in hurry over the weekend but as it got bent due to the now wonky bosses it didn’t last long as you can see.

i agree with @Shovelhands
the bosses need to be longer so there is only a 5mm gap between rod end bosse and the bosses in red
also you could have two small plates to try the bosses down in blue
dont no what the length pin is but it needs to be the right diameter for the bosses

View attachment 663412

I was thinking about the bosses today and I have a feeling, might be wrong, they are what looks too short to prevent them flexing and fatiguing the welds/structure in that area. Having short bosses and space around the rod end would enable the pin (a wearing part in this instance) to take the flex rather than the ‘rigid’ construction. So it might not be a design fault but actually a feature.

 

[Bob c]

That’s not the original pin. I think the proper pin broke in the middle (half of it still rolling about in the truck footwell) which allowed the outside boss to flex and break the weld. Or the weld broke first which allowed the pin to bend, got turned round, bent the other way and broke. I drove, with a sledge, a draw pin that was a good fit in hurry over the weekend but as it was bent it didn’t last long as you can see.



I was thinking about the bosses today and I have a feeling, might be wrong, they are what looks too short to prevent them flexing and fatiguing the welds/structure in that area. Having short bosses and space around the rod end would enable the pin (a wearing part in this instance) to take the flex rather than the ‘rigid’ construction. So it might not be a design fault but actually a feature.

design is lacking there ,.....i no gap looks bigger now due to failure but a few well placed gussets would of stopped that
the amount of push tonnage that cylinder has

 

[Shovelhands]

That’s not the original pin. I think the proper pin broke in the middle (half of it still rolling about in the truck footwell) which allowed the outside boss to flex and break the weld. Or the weld broke first which allowed the pin to bend, got turned round, bent the other way and broke. I drove, with a sledge, a draw pin that was a good fit in hurry over the weekend but as it got bent due to the now wonky bosses it didn’t last long as you can see.



I was thinking about the bosses today and I have a feeling, might be wrong, they are what looks too short to prevent them flexing and fatiguing the welds/structure in that area. Having short bosses and space around the rod end would enable the pin (a wearing part in this instance) to take the flex rather than the ‘rigid’ construction. So it might not be a design fault but actually a feature.

I’d be very surprised if the gap is a design feature!
Bigger bosses are what’s needed, as you’ve already established.

Totally understand why you’ve bodged it to get yourself going, it’s going to take a bit of time to get it right, and now you’ve realised the other side pin is bent, then it’s only a matter of time before the other side gives up!
Are there visible cracks in the other side?

I’ve been thinking about this, and I wonder if the manufacurer changed cylinder suppliers, specifying the open centres and pin diameter, but failing to get the rod end width correct? Easy mistake to make? Who knows?
There’s a reason for it, I’m sure, but it maybe an oversight rather than intentional.

 

[joe soapy]

The cold lap welding did not help.
Sloppy manufacturing all round, the pin should only subjected to "shear" stress, no way should there be enough room for flex of the pin

 

[davieh3350]

The tongs I made years ago were too short to get the piece of railway line out of the furnace, so knocked these up.