Sheet rolls re-build

[Kent]

Picked up the sheet metal rollers of Tinbasherdan yesterday. I knew there was some work in them to get them back to full spec. but they would have rolled stuff from the off I simply cant be doing with stuff breaking down mid- job as its usually a rush job it happens on. So no complaints we did the deal off what I saw but here is the re-build thread.

first obvious issue was the massive amount of slop in the handle greated by a very enlarged square hole in the handle and a not inconsiderable amount of wear on the shaft

 

[Kent]

the rolls themselves full and left and right. Still not 100% about resurfacing at this stage

 

[Kent]

 

[Kent]

 

[Kent]

Now to fix that slop in the handle. Shaft built up with MIG and touched with angle grinder then hand filed to 21mm square

 

[Kent]

handle built up internally with MMA (mallable I think) again filed but this time all the way as I have no power tool for this then fitted - yeah slop gone!.

 

[Kent]

cleaning time on the bronze bushes. Few realise the damage ginding dust and grease can do to moving parts when combined and the primary reason that everything was coming in bits on this job

 

[Kent]

Now this gear looks a little suspect to how its fitted! No key evident in the keyway and a dirty great big bit of shim rammed in between the ID of the gear and the shaft (grub screw not in). Off it comes few plate packers and two improvised steel wedges

 

[Kent]

Now what did I find?

 

[Maker]

They seem to be coming up nicely, keep it up. What's the surface of the rollers like?

 

[Kent]

More

Yep its actually far worse than it looks in the picture (due to flash photography in the dim workshop) basically think Pit Bull and bone minus 4 hrs! yep tomorrow's task is a big shaft build up job then off to a machinist to skim up on lathe and cut a fresh keyway in the mill.

That's not all I did (on a Sunday as well) more to follow

 

[Kent]

They seem to be coming up nicely, keep it up. What's the surface of the rollers like?

Well I was thinking a light dressing skim up job by a turner. useable but not for real fine finish stuff. Running 180 degree opposite beads filling three 3" diameter rollers then paying a machinist might stretch things a wee bit - still not decided will speak to the guy who gets to do the shaft and make a decision. I don't do a lot of fine finish material, mostly its just hot rolled and over 3mm

 

[Kent]

Well today I got to work on the chewed ends of the shaft. Some more pictures on how bad things were

 

[Kent]

Now to build it up again for machining. For those who haven't ever done this here is a few tips.

1. work lengthwise never around the shaft
2. overlap each weld about 50% of the last or you risk gaps needing more weld during machining
3. to prevent distortion weld in this sequence
first weld 12 o'clock
second weld 180 degree opposite at 6 o'clock
third at 9 0'clock
forth at 3 o'clock
then weld the overlaps starting at 12, then 6, 9 and lastly 3. Now start at the coldest weld 12 etc.

here is the picture, note I don't have pipe rolls so I set up between two sections of SHS clamped to the bench and rotated like that instead

 

[Maker]

Why do you weld lengthways? Does it reduce distortion? I might try this later, just for practice.

 

[Kent]

Now my neighbour works on repairing and selling tractor mowers , so I bobbed across to see if he could do the machining. "too busy but you can use the big lathe if you want" great over two and a half decades from when I last did any machine shop work but the roll was a tiny little midges off getting through the headstock hole! If we could have taken a finishing skim off it would have gone in but he had no steady and the end was too messy to get a good centre.
So he made a few phone calls and I was off into town to meet a mate of his with a bigger lathe and luckily I am already known to them and have an account set up. "End of the week ok?" "blooming heck yeah that will be great!"
Back home I am painting the castings up. Was going to do them black as I have it in stock but I am using red for Bowland fabrications company colours so I picked up a tin while in town with the shaft.

 

[Kent]

Why do you weld lengthways? Does it reduce distortion? I might try this later, just for practice.

yes and it also tends to leave less gaps when the cut comes off in the lathe. The idea is welding opposites lengthwise through the procedure the pull is turned negative. The shaft obviously gets very hot, this one took a good 40 mins before you could handle it with std work gloves!

 

[Pete.]

John Stevenson repairs and modifies pump and motor shafts by the truck load and the photos he puts up always show welding around the shaft.

http://bbs.homeshopmachinist.net/threads/62713

 

[dan.taylor.1]

I suppose however you do it if you add enough to machine back its irrelevant!

 

[Pete.]

Trouble is most shafts are turned between centres, and if you bend it with weld then use the centre to turn it the turned part will run true but the rest will run out.