Centauro 400 SSP Bandsaw (does anyone have a manual!)

[sams93]

sams93 "How would I ensure that the bearing is mounted centrally with that though?"

If you are really worried that the bearing will not centre then cut three narrow strips off the shim. Put them 120º apart and slip the bearing in place. Wipe off any excess Locktite and then pull the shim tabs out carefully. The bearing should stay centred if sitting flat. I think the bearing would self centre with the Locktite only especially as the chamfer/radius on the outside race edge is going to centre on the edge of the ledge between the two bushings so the shims wouldn't be needed.

Pete

I've just re-read this - what is the reason to remove the shims?

 

[Ttrees]

Just giving a wee update, seems the shim needed a bit more kneading to become more cylindrical which was achieved by a little bit of pressing, at best probably about half the depth of the journal/bore where the bearing is seated.
Going to give it another lick, without altering depth of cut, i.e still the same, what's around two sheits beyond original bore ID, as the bearing seating told me it's tapered for sure,
I was a bit skeptical of that corkscrewing shim on it's own, to use that even for a rough idea.

So I'll be taking it easy, and cutting abrasive strips whats no more than half the bearing width from now on.

What is the thinking behind going for a slim bearing @Ttrees?. I have just purchased like for like replacements for mine (6004RS). I went for KOYO as that was the original and I understand they are a good brand.

Sam

I'm thinking it would be a more sureworthy road to travel, as an outer race from a bearing,
on the off chance you could find one so narrow, perhaps some could answer that,
I haven't the foggiest, but I imagine someone with that knowledge could point you towards finding apt spacers for that OD bearing.
Remembering there maybe slop in the spacer for the inner race, and there maybe slop in the circlips and the slots.
Regarding how tight...I'm all ears, not noticed issue with making them snug previously myself,
with the thinking better off having one too long what you could do something with, than too short.

The thinking behind the slimmer bearing... if you can match with your spacer that is,
that you wouldn't have to open the outside of the bore, enabling better chance should a machinist get involved,
and/or insurance, should you be thinking of wrapping the shim around the bearing,
as it would stop it from migrating into the bore.

So you'd have two spacers, and possibly some head scratching, but sortable.
Have a look at Jack's work on his Poitras machine, and note it has individual spacers for both inside and outside race.
Worth watching those bore repair videos, he's certainly a skilled fellow.



It'll likely be another day or two until I can catch up to you concerning a nice shoulder which I said looks to be 0.4 at the least to my eyes, the shoulder I've created so far looks lesser to me,
but maybe not to you, and TBH I didn't look your bearings up to note the OD, should that be throwing things off for me.

Just sayin, you may already have some middle isle special which is in a scrappy pile awaiting the dump, and not need to buy anything.
I'll get you a picture of that shoulder when I'm finished, no guarentees on any sort of timeline for someone reasonable though, so you could be finished before me.

All the best
Tom

 

[Inspector]

I've just re-read this - what is the reason to remove the shims?

Mostly because I wouldn't want little razor sharp bits sticking up that would invariably cut me. If removing them won't disturb the bearing they can come out while the Locktite is wet. If they are too snug then cutting after would be the way. Up to you. You are there.

Pete

 

[Fergie 307]

I came across something I've never heard of before on another forum that might be useful to those of you with worn bearing or seal seats/bores/surfaces. They are called Speedi Sleeves speedi sleeves, Redi-sleeves or repair sleeves. You might still have to machine or grind the surface to make it ready for the sleeve but it simplifies repairs on stuff that is not available or too expensive to replace.

Pete

You can use them on the outside as well, they are essentially just a thin tube.
My concern with this job is that given the size, weight and speed of these wheels a bodge like this is not a good idea IMHO. Can I ask why you don't just go to a local engineering firm and get them bushed, it really ought not to be that expensive, and it looks like you have plenty of material to work with. If they are out by even a couple of hundredths you will have all sorts of wobble and balance issues I would have thought.

 

[Ttrees]

Can I ask why you don't just go to a local engineering firm and get them bushed, it really ought not to be that expensive, and it looks like you have plenty of material to work with. If they are out by even a couple of hundredths you will have all sorts of wobble and balance issues I would have thought.

How do you reckon an engineer would approach the bearing retention?, guessing by cutting a shoulder, no probs there, but cutting a new slot for the cir-clip might compromise the integrity of the sleeve
So perhaps a little more to it, than just the bush...
When you look at the Poitras non shouldered bore setup, I'm guessing things are starting to get expensive.

Any other solutions which wouldn't need much work that I've not grasped?

Tom

 

[Inspector]

After boring out the hole a good machinist would cut a new groove for a bigger circlip.

Pete

 

[Ttrees]

What advantage would that be over the original, the sleeve outside the cir-clips would still be
separate?

Tom

 

[sams93]

I suppose they would insert a thick enough bush to account for the need to cut the circlip groove.

I do completely accept that this would be the optimum solution, and I will be willing to concede defeat and find someone to do it if my attempt is unsuccessful.

 

[Ttrees]

I would like to see opinions of folks who've had a deep bush cut into their wheel,
and got a slot cut for the cir-clip also.
Seems there wouldn't be much meat left of the hub after that.
I haven't come across that, but if it's anywhere, it'll be on OWWM.

It seems another option might be to cut a shoulder instead on the inside,
much the same as the S45 what takes an inner cir-clip instead,
and should your bearing spacer be worn, it would be a fix for that at the same time.

You could perhaps make/buy heftier wheel retaining washers, and longer nice hex head bolts
as those could get damaged, if things are looking right, i.e the washer not bottoming out on the shaft, but clenching the bearing race what's proud by a small amount.

All the best
Tom

 

[sams93]

So I'm all prepared:
- Loctite 638 arrives at the weekend.
- Cut 3 spacers from a length of 0.15mm feeler gauge, can just about fit them in with huge effort. By using 3 I can be sure it is central.
- Made a simple jig to press the bearing out of a bolt and some bits of wood.

In between the bearings there is a spacer, which i think is 9 or 10mm thick (although havent measured). I had some ideas as to a potential change of my plan:

Option 1 - The bore of the hub is machined to 42mm the whole way through. I could actually replace the spacer with a third bearing between the two original positions (maybe this), which would help hold the position.

OR

Option 2 - I could slim down the spacer to say 5mm, and then make use of the extra space inside the hub by inserting a 16mm race width bearing, which would sit 4mm deeper into the hub and therefore in part on the 'good' area of the hub, and the part that sits in the worn channel would be supported by the loctite and the 0.15mm shims.

I think option 2 might actually be preferable, as it means I can be confident that the positioning is central.

I'd be really interested in peoples thoughts on this idea!

 

[sams93]

I think i'm going to go down the option 2 approach - have ordered one of these 20ID, 42OD, 16mm race width bearings for it.

KOYO BEARING 63004 2RS 20x42x16 Bearing 5059281004110 | eBay

 

[sams93]

So, hopefully it is obvious from the drawings, but....

The original situation is that the 20mm spoke sits on the two bearings, both of which are 12mm race width. Between these two bearings is a spacer which is 6mm wide, made from steel tube which has a 21mm ID and 25mm OD.

My proposal, is to switch one of the bearings to a 16mm race width. This will allow me to seat it partially within the good area of the wheel hub, which I hope should help ensure that alignment is correct, and provide support alongside the 'loose' bit of the wheel hub, within which I will shim and loctite 638.

This however means I need to trim down the spacer by 4mm to allow for the wider bearing. The result is that I need a 2mm wide spacer EDIT - which I have now found on eBay for cheap!

All being well the stuff will be here by Tuesday of next week, and then I’ll give it a go!

 

[Ttrees]

Hello again
I think I've mentioned this is worth finding out before you source anything.
There may well be somewhat more available smarter solutions.

Sorry can't advise on the best route to take, I'm just chancing my arm myself, and haven't came across anyone doing this bodge anywhere.

I made a new spacer previously, as the original plastic one had worn.
The spacer is important as it allows the wheel retaining bolt & washer to do it's job,
by actually pressing on the inner race, and not bottoming out on shaft,
whilst noting the raised inner race might well provide slight adjustment by way of orientation,
so depending on what might fit best, another possible thing to consider,
but I'd like to know more without actually suggesting that,
should things be too snug, the bearing cages could get damaged by compressing it too much.

Just for interests sake, is it both bearings which have worn journals?


https://owwm.org/viewtopic.php?f=1&t=180094&start=15

As I'm going to dismantle the old bearings for the inner and outer races,
they'll be 0.4 of slop regarding that,
so I'm going to try using the same toaster material to make shims from.

Nice having some old bearings to help making them, I'm guessing they would be very good for holding the stuff.

Got back out to the shed yesterday, and might or might not be finished today, taking fine passes with the tool, and getting feedback now, should it be of interest, I'll be taking a photo of the ridge on the bore.
Might or might not have to cut another shim as I've mistakenly made mine the same width as the bearing, but it might prove useful either.

Tom

 

[sams93]

Hello again
I think I've mentioned this is worth finding out before you source anything.
There may well be somewhat more available smarter solutions.

Sorry can't advise on the best route to take, I'm just chancing my arm myself, and haven't came across anyone doing this bodge anywhere.

I made a new spacer previously, as the original plastic one had worn.
The spacer is important as it allows the wheel retaining bolt & washer to do it's job,
by actually pressing on the inner race, and not bottoming out on shaft,
whilst noting the raised inner race might well provide slight adjustment by way of orientation,
so depending on what might fit best, another possible thing to consider,
but I'd like to know more without actually suggesting that,
should things be too snug, the bearing cages could get damaged by compressing it too much.

Just for interests sake, is it both bearings which have worn journals?


https://owwm.org/viewtopic.php?f=1&t=180094&start=15
View attachment 159462
View attachment 159463

As I'm going to dismantle the old bearings for the inner and outer races,
they'll be 0.4 of slop regarding that,
so I'm going to try using the same toaster material to make shims from.

Nice having some old bearings to help making them, I'm guessing they would be very good for holding the stuff.
View attachment 159464
Got back out to the shed yesterday, and might or might not be finished today, taking fine passes with the tool, and getting feedback now, should it be of interest, I'll be taking a photo of the ridge on the bore.
Might or might not have to cut another shim as I've mistakenly made mine the same width as the bearing, but it might prove useful either.

Tom

I originally posted about trying to make the spacer, but it was always going to be difficult to make one at 2.0mm so I was pleased to find the shim washers. I don't think the wheel retaining bolt and washer was doing much on my saw - it certainly wasn't pressing the bearing in or anything. The original spacer certainly had some slack to it, maybe 0.75mm.

I have also ordered a couple of 0.25mm shim washers so that I can make some finer adjustments of that distance to keep the bearings tight, I don't want the space to be so big that it affects the ability to insert the circlips though.


My plan is:

1. Insert the bearings into the wheel, I might try and lightly heat the wheel beforehand and put the bearings in the freezer for a while before fitting.
2. Insert the spindle into the bearings.

I thought about whether I could do it the other way round, and whether that would help with alignment, however I think there are legitamate concerns about the spacing of the bearings on the shaft and whether they could move during insertion, which could turn into a nightmare. When I do put the shaft in I intend to freeze it beforehand again to help with the fitment.

 

[Ttrees]

Makes for interesting reading of the sourcing of these components, and bearing locking formulas,
as I've not ventured seeing what's available.
As said I'm just winging it myself, can't advise anything beyond what's said already.

Keep us posted.
All the best
Tom

 

[Fergie 307]

How do you reckon an engineer would approach the bearing retention?, guessing by cutting a shoulder, no probs there, but cutting a new slot for the cir-clip might compromise the integrity of the sleeve
So perhaps a little more to it, than just the bush...
When you look at the Poitras non shouldered bore setup, I'm guessing things are starting to get expensive.

Any other solutions which wouldn't need much work that I've not grasped?

Tom

The easiest way of there is not a lot of metal to play with is to ditch the eared flat circlip in favour of a wire one, needs a much shallower groove. Alternatively you might find a slightly larger bearing which the bore could be machined to match, and taking less out than a sleeve. You might find for example an imperial bearing that is a tad bigger. Or you could use a variety of metal deposition methods, metal spraying, hard chrome etc etc to build it back up and then machine it back to the original size. The possibilities are enormous, depending on the exact application. The important thing is that it needs to be concentric and aligned correctly so the wheel runs true, we are talking very small tolerances here, in the hundredth of a mm area, or a few ten thousandth of an inch of you prefer. If your bearing has been rotating in the bore I very much doubt it has worn a truly round hole, and unfortunately the method you are using will simply give you a larger version of what is already there, any ovality, bell mouthing or eccentricity included. Machining the part properly on a lathe will remove any error caused by the worn bearing, and ensure it is spot on. Worst case scenario is that you find your bodge doesn't work, but in the process you have compromised the chances of a proper repair, making it more difficult and expensive. Sorry if I seem a party pooper, but this is a job for a machine shop. And incidentally be very careful buying bearings on line, they are amongst the most widely counterfieted things on the planet. Stick with the likes of simply bearings, or better still find a local bearing supplier, where you can take stuff and talk face to face with someone who knows these things inside out. They are often cheaper too.

 

[Fergie 307]

I originally posted about trying to make the spacer, but it was always going to be difficult to make one at 2.0mm so I was pleased to find the shim washers. I don't think the wheel retaining bolt and washer was doing much on my saw - it certainly wasn't pressing the bearing in or anything. The original spacer certainly had some slack to it, maybe 0.75mm.

I have also ordered a couple of 0.25mm shim washers so that I can make some finer adjustments of that distance to keep the bearings tight, I don't want the space to be so big that it affects the ability to insert the circlips though.


My plan is:

1. Insert the bearings into the wheel, I might try and lightly heat the wheel beforehand and put the bearings in the freezer for a while before fitting.
2. Insert the spindle into the bearings.

I thought about whether I could do it the other way round, and whether that would help with alignment, however I think there are legitamate concerns about the spacing of the bearings on the shaft and whether they could move during insertion, which could turn into a nightmare. When I do put the shaft in I intend to freeze it beforehand again to help with the fitment.

Ok if you have a spacer between the bearing inner races it is very doubtful it's just a bit of tube. It will be a precision ground spacer to space the inner races EXACTLY the same distance apart as outer races, determined by the circlips. The spindle will then clamp the inner races and spacer. The whole idea is that with the whole lot installed there is no sideways force at All between the inner and outer bearing races, if there is they will quickly fail. If a previous owner hasn't understood this, and has just used any old bit of tube as a spacer, that may well be how the problem came about in the first place.

 

[Ttrees]

Agreed the chances are optimistic, and hoping the three bearings in the bore will be concentric,
but with allocated time for patience, things are going very steady indeed.
Nice job to do whilst it's raining, after a good lot of other jobs are done for the next while.
I was thinking I'd get another picture of the progress, but I'm still a ways yet from that.
Happy now things are getting slower and consistent.

Not so sure of the chances without opening the bore to fit and relying on the bore being concentric, but as you said possibly less destructive than what I'm trying.

Tom

 

[Ttrees]

Hello again, spent the day getting that bearing progressively seated.
Just about finished with the tool, might be perhaps a bit snug, but it's home.
Used three strips of masking tape in the end, three licks at that last depth of cut
and made sure it went in alright, not by the bolt and washer though, as I found it was
better to have a few more licks to transition to the next layer for the deeper cut,
so just used my fists for tapping it down evenly.

Still more needed from the bottom, this was after knocking that extra wide bearing out,
so it's nicely formed, and a clear picture of whats going on.
Finished cuts were made with a tad lesser width strips than the OEM bearing.
That shim stock turned out to be a really good tool for finding a taper.

Still perhaps a little lick at the very bottom might help, but might see how things go without,
It'll become apparent when this gets knocked out again.

Gonna dismantle a bearing soon to use the races for spacers, so that bearing will be 1mm lower
and may likely need a spacer aswell.
I'll be photoing the shoulder in the bore again before assembly,
and hopefully publishing a video, if I can get all the clips merged.

Getting closer to seeing how it fairs drawing the line, how it sounds,
and setting the other wheel and motor to.

All the best.
Tom

 

[Ttrees]

Took a little more work than expected to get that shim stock below the cir clip.
Took a few more narrow cuts, and couldn't seem to get it much lower, so a little more off select areas of the shim to get fit, as felt it was a good fit.

Piccy of the shoulder cut

Dismantled one of the old bearings as had one done already.

Seems a good fit, no slop in-between cir-clips.

Little screwdriver for making sure the circlip is seated, and not possible to lift out.

Worth noting even with the shaft cleaned every time, plus bearings, it's not as tight in the bearings as it was,
though I noted that happened before, but sorted itself out.
Noticed the other bearing not so tight either, but hoping I can see what the results are like before.
Keen to get testing this wheel now, lots of work might need to be done yet.

If it's good, I will post a separate thread about it, as I've been documenting this in detail.