rongfu 6x4 bandsaw fix

[tanii51]

my rongfu bandsaw' s (rf115) worm spindle bearing is gettting very worn has anyone tried to remove it
john

[Grahame Collins]

Pictures will help you get a better answer.
Grahame

[tanii51]

problem sort of solved its more the shaft has worn but pics coming hopefully sunday i got it out just remove the seal and gentle tapping with a persuader
john

[Oldneweng]

problem sort of solved its more the shaft has worn but pics coming hopefully sunday i got it out just remove the seal and gentle tapping with a persuader
john

I have had my 6x4 apart. Would need pics tho. It was a while ago.

Dean

[tanii51]

well the assembly is out its not too hard dig out the seal from the pulley end and then tap on the worm end and it all slides out.
Now the fix part
what would you suggest ?
it appears that the shaft has been spinning inside the seized bearing and worn it down so its now very loose especially the pulley end
probably because very little lubrication and bearings with only one side sealed
6202z bearings so 15mm shaft
pulley end shaft where the bearing runs is only13.6mm

john

[pipeclay]

Depending how hard the shaft is,you could turn the shaft down to say12mm and shrink a sleeve on then finish turn to suit the bearing and pulley.

I wouldn't try for less than 1.5mm wall thickness.

Other choice may be,once again if its not to hard where the worm is,is to cut the shaft off near the bearing,drill and ream the worm and turn a replacement shaft and press into the reamed hole and pin it,then finish machine.

Last choice buy a new one.

[tanii51]

thanks peter the sleeving option seems to be in my capabilities... is say 12x15 mm sleeving available or make itmyself
john

[pipeclay]

John it could be but i really have no idea.

I would just get a piece of 20mm bar and drill and ream to suit your shaft , and then finish turn.

If you haven't got a reamer long enough just put a couple of pieces on the shaft.

If you haven't got a 12 mm reamer you could probably get away with .500".

When you turn the od give your self about .0005" interference,you would probably have to heat the sleeve or sleeves and drop them on.

you could probably use loctite if you had to ,my choice would be a shrink fit.

[Toggy]

Could also build up the shaft with weld and remachine it between centres.

Does this damage make if the Rong One":rolleyes:

Ken

[tanii51]

ken its crossed my mind but see what happens

[Ueee]

The rong fu is not strong with this one....:D That name just calls for bad puns!

Just to add to what PC said, a .001" per 1" interference fit is a good guide for a shrink fit. So .002" for a 2" shaft, .0005" for a 1/2" shaft etc.

Ew

[Oldneweng]

I would have thought that this shaft is a bit small for a welding fix. It is going to cause a lot of distortion.

Dean

[simonl]

I have built up a shaft with weld. It was 24mm though. Eventhough I built it up slowly with small tacks and kept the shaft cool with a wet rag, it still distorted. Welding up the shaft would be the last resort. I have never tried to built something up with metal butty and then machine to size. I would be interested to see if that would work. At least you have not damaged anything if it does not work!

Also, the worm looks like its been heat treated so not sure if welding would damage it's tempering or not if that part got too hot?

PC suggestion seems to be the best.

Simon

[simonl]

Also, depending on just how worn the shaft is, loctite have some great products that allow for sloppy fitting bearings and will fill large voids. Worth a try also.

Simon

[tanii51]

problem solvered new ones are still available $65+ GST AND POSTRAGE

[Oldneweng]

problem solvered new ones are still available $65+ GST AND POSTRAGE

New worm shaft? $65 + GST and postage? What is the postage? aybe I need to revisit mine just to check. I had a problem that I resolved but I cannot remember what it was sigh. Old age. I do know I replaced the bearings tho.

Dean

[tanii51]

around about $15 dollars so i guess thats not too much to lick the bag and seal it and put it in the post box
take me a lot longer to cut through a piece of 4 inch round with a hand operated hack saw
if theres room ill probably fit 2 bearings to the pulley end make it a bit stronger
and use sealed bearings with seals both sides
6202z bearings