Qcgb Bearings (bronze And Roller)

[Hozzie]

I did a search, but didn't see an answer to my question. I needed to replace the felts on my newly acquired Heavy 10 so while I had it apart, I am refinishing and taking the time to perform any needed maintenance.

I have the QCGB apart and stripped. In the rebuild guide it says replace any bearings that need it. This is where I am not sure if this is simply known by experience or if there is a quantitative way for me to determine this. While I am pretty mechanically apt, but this is my first lathe and I don't know how much wear is too much.

Can I simply check the bronze bearings inside diameter and then check the steel shaft outside diameter to determine wear? Or is it more of a feel thing?

Also on the roller bearings, should I just replace them? They were a bit tight after cleaning in degreaser, but I put some oil in them and they loosened up, but I have no idea if they are ok or not. I lean towards just replacing everything now and doing it once, but if it isn't needed, I hate to waste the money.

Anyway, what is my best option for knowing if these items need replacing? If they do, what is the best source for bearings?

This is my QCGB as it sits right now.

 

[Bob Korves]

You will need to make the call. Be aware that new bushings will need to be finished to size and in line internally after pressing them in. If the bearings, roller or ball (looks like balls), roll freely and pass a close visual inspection of the races and balls or rollers looking for any pitting and/or corrosion, then they are probably OK after a really good cleaning. A few thousandths clearance between bushings and shafts is no big deal, but more will cause bad gear meshing and excessive wear on them leading to eventual failure.

 

[Ulma Doctor]

i'm of the opinion that if you have the unit torn down, replace everyting you can - so you don't have to do it again.
in doing that, you may need to do some reaming on the bushings.
bearings and bushings are relatively cheap.
if you replace them all, there will be no question of the integrity of the completed work.

 

[Hozzie]

Thanks for the responses. I am kinda with you Ulma Doctor. Question now is where to get the bearings? I guess it is just a matter of measuring and finding the same kind in the right size, but being new to lathes I want to make sure I get the right kind. Anyone have any examples of what they have bought in the past. I usually just get these things from McMaster Carr. Is that my best bet?

Edit: Found the roller bearings on Ebay for a good price. I will get the bronze and do what I need to make the others.

Thanks again.

 

[Ulma Doctor]

measure the bearings -inside diameter, outside diameter and thickness
measure the bushing- ID, OD, and Flange thickness (for flanged bushings)
here is a link to bearing sizes
https://www.bearingworks.com/bearing-sizes/

you bearings may be metric , but your bushings should be imperial.
if your bearing measures to be a weird metric size, (i.e. 10.3mm) it may be that it's an imperial bearing
metric bearings are usually full millimeter nominal diameters
ABEC3 bearings will suffice for this operation

if you have the numbers, i buy off ebay
VBX bearings
good quality, great prices- no connection just a happy industrial customer

 

[Hozzie]

Thanks. The roller bearings were metric. I checked the bronze bushings and they all seemed to be very close to spec so I am just going to leave them.