mikegolding
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Have you got a fixed steady for your lathe ?
- Thread starter Screwdriver
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Screwdriver
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I've got one of everything.
Kram
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If it wasnt needing to come apart for frequent bearing cleaning/replacement, doesnt look like he would anyway...
1610 taper lock bushes go upto 42mm. So, I'd turn the pulley seat down to 22mm or as much needed to get round. Make up a 42mm OD, 21.93mm ID sleeve from a decent grade steel. Cut a crude keyway in it with carefull use of grinder. Assemble machine and shrink fit it on. No way it can slip.
Itll come off easy enough with heat and a puller if needed. The bigger diameter will give the bush and easier job.
Or if the pulley is small Id make up a pulley instead, shrink fit straight on.
1610 taper lock bushes go upto 42mm. So, I'd turn the pulley seat down to 22mm or as much needed to get round. Make up a 42mm OD, 21.93mm ID sleeve from a decent grade steel. Cut a crude keyway in it with carefull use of grinder. Assemble machine and shrink fit it on. No way it can slip.
Itll come off easy enough with heat and a puller if needed. The bigger diameter will give the bush and easier job.
Or if the pulley is small Id make up a pulley instead, shrink fit straight on.
mikegolding
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Pull the shaft out from the chuck so you can clock behind the disk where the bearing runs. Set where the other bearing runs true and support it with the steady. It will be running then as it does in the machine and any run out on the worn area can be measured , and the same setup used to re-machine after welding.You may find it helps to centre drill the end after welding and support with a running centre.
Mike.
Screwdriver
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Good idea. Hopefully I can get away with just turning it down to suit the next size off the shelf taper lock fitting. But if I get stuck, that does sound like a plan.
8ob
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I agree, clocking the shaft next to where its welded into the rotor is less than ideal, truing up between centres would be a better job
Bob
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Appreciate that would give me a better measurement but it is what it is and if I have to do anything to realign the shaft with the "rotor", it's game over.
I would not be surprised to find the rotor running eccentric to the bearings because the shaft might be one long banana. All the force is concentrated at the rotor so a big bang would tend to deform it at the centre. I can't/won't fix that, though it can be fixed as shown above.
With my consulting hat on I would say my next step is "management of expectation". I need to discuss with the client exactly what he expects to get back and weigh that up against what needs to happen to this item to achieve that and whether or not I am happy to do it.
My gut feeling is he wants a cheap and quick repair that keeps it going. Yes it could be "perfect" for circa £200 but it might also be "good enough" for the £20-£40 range I am looking at. Whatever happens, it needs to be his decision and he's not answering the phone currently.
Screwdriver
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I sort of disagree. I think the rotor needs to be aligned with the part of the shaft that holds the bearings. Just in case the whole shaft is banana'd. In which case, aligning the rotor with the two bearing faces would be as good as it gets.
I can't do that because I don't have the entire machine. I don't want to overthink this. Ten more pages and I'm out!
Screwdriver
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In fact, I suggest the ideal solution would be to hold the rotor in the four jaw, set that up to run true and then machine the shaft. If the non machined end of the shaft runs out after that, it's just too bad!
I have a dim and distant (slightly blurry) recollection of a couple of pillow block bearings (bushings??) that may have been ~ a couple of inches from the rotor either side of it, the pulley ran outboard of the other pillow block. if I recall correctly.
It was early morning and I didn't have my contacts in or glasses with me!
I have a dim and distant (slightly blurry) recollection of a couple of pillow block bearings (bushings??) that may have been ~ a couple of inches from the rotor either side of it, the pulley ran outboard of the other pillow block. if I recall correctly.
It was early morning and I didn't have my contacts in or glasses with me!
8ob
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Thats how they run, the last thing you want is the pulley bobbing up and down on the end of a bent shaft. If changing the shaft is out of the question then it needs truing up between centres, you could spin up a socket with a blanked off end with a small hole in it that's a snug fit over the end of the knobbed shaft, use the small hole to drill reference/start for a revolving centre and go from there.
Bob
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Perhaps true. There's no way to be sure since I didn't set the shaft/rotor up properly, it was more of a looksee.
Like I said in the video, I'm not entirely sure what I achieved there. I should do it again and ideally set it up so that the rotor is true.
I'm in two minds about that now. How important is it for a stump grinder to have a "perfectly" running rotor? Compared to say the pulley??
I really would like to at least have both bearing surfaces running true and see what happens with the rotor. It would take a LOT to do any damage to that item but it has taken a substantial amount of damage. There's a chip taken out of one end for example.
Really need to chat with the owner now before I decide what to do next. Thanks to all of this amazing info, I'm in a much better position to advise him and I am still receptive to the idea of someone who does know what they're doing, giving him a quote for this work.
I've seen this chap around Ealing on and off for the past 20 years and am a big fan of supporting local business, especially in these difficult times. This is not a business opportunity as such, it's more of a learning curve and an excuse to use some of the tools/skills I have assembled over the years. Having said that, obviously I am hoping for some repeat business and a long term reputation as the local go-to guy for fixing stuff. The more random it is, the better.
My primary focus is building up a presence on YouTube (or similar). Most of my work will be restoring stuff, making stuff and then reselling possibly off the back of YouTube. So really, I am happy to do virtually anything I can film...
Screwdriver
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Too late now but tomorrow, I'll try to do a better job of getting this thing set up properly in the lathe and running as true as possible.
James1979
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very. Even on a small one such as yours there are a lot of forces acting on it. They very quickly find any out of balance or out of true parts and then it self perpetuates.
If you think about it, you are powering up a flywheel then trying to stop it with a stump. Several times a second. It will find weaknesses and it will be bad. Even if you snap a tooth off they sound like they are about to explode.
Screwdriver
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I am tempted to try out an idea I saw on a channel I recommended here recently: https://www.youtube.com/c/CuttingEdgeEngineeringAustralia/featured
Curtis has made up a rotating tailstock chuck. Looks dead handy and would be just about perfect for this setup. I even have a spare mini fourjaw and possibly even a slightly broken live centre I could cannibalise...
Curtis has made up a rotating tailstock chuck. Looks dead handy and would be just about perfect for this setup. I even have a spare mini fourjaw and possibly even a slightly broken live centre I could cannibalise...
Screwdriver
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We haven't even discussed money. He can pay me what he thinks the repair is worth. I haven't actually done anything yet!
James1979
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That’s my thoughts, sort of. It’s a high wear machine which as far as arb kit goes is probably the most abused and unloved thing in general use. No one looks after them really, although that one is just out and out abuse.
He (owner not OP) needs to put his hand in his pocket for the new bit and just get on with it. The length of time it’s been in secrewdrivers possession so far it could have been back running and earning its keep.
some people really will spend a hundred quid to save a tenner!
that’s not a dig at OP, he’s had it to make a decision on what to do about it and advise his friend accordingly. I think if it was mine the decision would have been to order the bit, present screwdriver with bit and stump grinder to fit bit, pay screwdriver, grind stumps.
