I have a small hand operated hydraulic press for removing drive shafts from hubs, it's rated at 10 tonnes, there is a 'HD' version rated at 25.... The amount of (controlled) force required to put the two components together will likely exceed several blows with any size hammer, concentrated, irresistible force with a press is likely to be the original assembly method (possibly with the application of liquid nitrogen to the steel component), can the manufacturer give any guidance on replacement? after all, they - I assume - sold you the replacement part...Is there any chance that there's a ridge (manufacturing defect or caused by you interference fitting) inside the cast part? It wouldn't need to be much to stop a tight interference fit.
From how you described having to get the old part off I'd guess it's more interference than fit as it were. May well have been hydraulic pressed on in the first place.
Measure the shaft diameter and the bush diameter,Ladies and gentlemen of Her Majesty’s Royal Electrical and Mechanical Engineers (or anyone else reading the thread with ideas!), I seek some advice please.
I have a part for a kitchen mixer that I need to replace. This is the planetary gear assembly. There is a shaft coming down from the gearbox, that goes through the main mixer housing, and then into a receptacle in the planetary assy.
View attachment 589480
The problem is that it appears to be an interference fit. As shown in the pic above, the shaft will go no further into the receptacle without doing something to either force it, or ease the fit. It has to go about 3/4” further in, so that I can insert the locking pin through the holes.
The receptacle is just cast into the mounting plate:
View attachment 589479
A few things have occurred to me:
1. Heat the receptacle hole with a heat gun. Tried that briefly last night, didn’t give me much of an improvement, maybe 1/8” further down. Also need to pack the gears with grease, and heat would be an issue there.
2. Press them together. I have a hydraulic press, but unless I get the holes aligned before pressing, I’m in trouble. No idea how to ensure the holes are exactly aligned.
3. Ream out the receptacle. My guess is it would require a very specific drill bit that I don’t necessarily have.
4. Reduce shaft diameter. I’m reluctant to do that, because the shaft is obviously machined, so is probably accurate. The hole is more likely the problem, at least to my eyes.
I could just get to it with a file or Dremel, but I don’t want to end up with a slack fit and it wallowing out.
I’m guessing you chaps spent many hours in SEME and then in the field doing exactly stuff like this, probably in the pissing rain under an MK in 3 inches of mud. So I’ve got it easy, that is recognised.
Virtual Yeller Handbag on offer to the DS solution here.
Thanks in advance!
0.25mm is quite a bit to force in (ask the Mrs.) My concern with opening it out with anything but a reamer is that it won't necassarily be equal or straight. Think how the planetary gear will move around if the shaft is not perfectly aligned in relation to it. Possibly liquid nitrogen will shrink the shaft enough, with fitting lubrication. If it were me, I'd be reaming it out to size (but I already have the kit to do it).
There's no reason not to use abrasives, if you want it to last, I'd recommend machining.
You begrudge spending $40?
Which part of Scotland are you originally from?
If your repair isn't perfect, you do realise when you turn it on you'll break some other part, thus adding to the cost of replacement parts you'll need to buy.
Also, spending $729 in the first place on a food mixer is only something a woman or someone good with colours would do.
Enjoy your beer and tomorrow run a file around it, no more than 3mm down from the chamfer, I did see some scoring on your original photo but it wasn't clear if that was pre or post 'insertion'Well I think I may have found my culprit. Seeing the scoring in the housing made me think there’s some small burring on the shaft, because the measurements say it should fit. Looks like there is, right on the end.
View attachment 589608
So I think I’ll clean up the shaft with some 400 grit paper, and perhaps run my my Dremel round the housing a couple times with the sanding sleeve, but not actually turn the motor on, just a “round sanding”.
But that‘ll be tomorrow. Quite fancy a beer or three now, not farting about with a mixer