Record RPBS12 lower wheel bearing replacement

[user 18352]

Hi folks

I have a RPBS12 the old square style, I inherited it from my father, and has allways been grand for my needs.

The blade stopped turning but motor seems fine, top wheel is spinning freely but the lower wheel bearing seems to be binding up, i'm trying to get at it to check it but cant get the wheel off, have removed the circlip, but the wheel won't budge, not sure how much pressure to use and thought i'd ask here first before I do any damage to the shaft.

Been floating about the forum for a while, but the knowledge is deep and the search feature works so well havent had to pipe up yet, hope someone can help, my xmas present production line has halted .

Cheers

 

[user 18352]

Ok, maybee I need to rephrase the question,

The lower wheel just doesnt want to come off, I have released it to a point where the wheel is flush to the end of the shaft, but cant get it any further, don't want to heat it or crush the bearings / damage the shaft anyone got any bright ideas before I have to take the big persuader to it ?

I removed the top wheel to see what it was like and it glided out no problem, im guessing ive got compacted sawdust somewhere nasty on the lower wheel.

 

[dickm]

I removed the top wheel to see what it was like and it glided out no problem, im guessing ive got compacted sawdust somewhere nasty on the lower wheel.

Might not be you - if a previous owner has tried "tapping" the end of the shaft (probably with a dirty great hammer!) to free the lower wheel, it may have belled out the shaft by an almost invisible amount, but still enough to stop the wheel coming off. If you can get the wheel back to its original position, might be worth gently sanding the end to remove any belling?

 

[Steve Maskery]

Never had to do this but here goes..

Hitting it with a hammer is very tempting, but the belling effect of that may do more damage than it is worth. You need a proper bearing puller and it should be a perfectly reasonable job to do.
Try PMing MyfordMan, he is a good engineer about these sorts of issues.
S

 

[Myfordman]

Did someone call???

I don't know the Record machine in question but it is usual for bearings to be pressed onto shafts and indeed is the start of problems when they are allowed to slip on a shaft.
I think DickM made a very valid point. The end of the shaft may well be a tight (correct) fit and the section behind be of reduced diameter due to fretting of the surface causes by the bearing slipping on the shaft.

The correct way to remove the wheel would be to use a bearing puller which may have to be modified to attached to the bandwheel.
My Startright has removable bandwheels which leave a central hub and a standard puller can be used. If the RP machine has a spoked wheel then the puller could attach metal bars fitted behind adjacent spokes.

When fitting new bearings onto what I suspect will be a worn shaft, some bearing retaining adhesive (loctite, bondloc etc) specifically designed for the job, should be used.

Good Luck

MM

 

[user 18352]

Thanks for that, the shaft end has a few marks on it, will inspect it closely and maybee throw some calipers on it and rub the end back if needed, but in the meantime its got a bit stranger if anything, I'm nearly sure i've had the lower wheel off before as its necessary to change the belt, its moving horizontally 5-10mm on the shaft and then stopping, I have worked it back and forward over this distance and it seems to have freed up a little, but still not coming off the shaft.

when I knocked the wheel back into place on the shaft last night with a rubber mallet, the bearing is now running smoothly and its now working which is great in the short term if the bearing lasts, up until the belt needs replaced again.

Thanks again, will drop an email to Record see if they have any ideas as well, I can take the shaft out, but its a nightmare to reset afterwards if I remember correctly

You never realise how much you use a specific machine until its down