Bearing Issues

[Brent]

I decided it was time to take apart the Huky and give it a good cleaning. The front bearing came out quite easily. (Mr Li supplies a syringe with bearing grease. I found that the cap on that syringe is the exact right size to pull through the hole in the inner part of the bearing, but the top lip of the syringe cap catches on the bearing and will pull it out. No drill bit, or dowel needed. )
The rear bearing would NOT come out though. I thought that grease had built up and with subsequent heat, had perhaps "glued" it in there because no matter how hard I pulled with the syringe cap, or pushed with a drill bit, it would not come loose! I tried steam. In fact I steamed it for 10 mins. No luck. I tried WD-40 and waited for it to soak in. No luck.   I finally had to use a hammer and small screwdriver to crack the plastic and I had to take it out in little bits.
So of course I ordered new bearings.  While trying to put the new bearings in, I found out what I think the issue may be. The front bearing is going in fine. A little snug, but with a push, it goes in. The rear bearing is so tight it will only go in about 1/3 of the way if I just push with my fingers.  It feels like I'd have to use a rubber mallet to get it in without breaking it. The fit is VERY tight!  Should I be greasing the outside ring of plastic too? I just don't think it should be so tight. Shouldn't it fit in the ring with a firm push?
Has anyone else run into this issue?  I'm thinking I should email Mr Li to get his advice, but I thought I'd check here first

[Chert]

Nice set of guitars for an avatar pic, by the way, Brent.

When I dismantled mine I removed the drum but I did not remove the rear bearing.  I appreciated having good access to grease it though.  I thought nothing of it, so I am sure I had no trouble getting the drum back into the bearing seating.  Your difficulty is returning the bearing into its housing, right?  I will bear your experience in mind and not try to change that bearing unless really needed.  I think to contact Mr Li is a good idea.  Maybe he uses a type of press to fit the bearing into place?

[edtbjon]

Hmm, that is indeed an issue. On my machine I had no problems to remove either bearing.
I guess that you do have two options, after checking with Mr Li. The first option being him sending you a new backplate, which he have checked to be within tolerances. The second is to take it to a machine shop and have the bearing holder enlarged a little bit. You may even be good with just grinding the holder a little bit with the large cylindrical grinder stone for the Dremel.

[beananimal]

I am in line with edtbjon. No problems with my Huky (A dremel should be a good choice anyway)
Make sure that you don't tilt at all the bearing.
Maybe the easiest way of diameter adaption is to apply sandpaper on the outside of the bearing.  Depending on your equipment.
But make sure everything is really clean at the end.

[Brent]

Yes Chert, it's getting the bearing into the housing that I am having an issue with. (see attached photo) I'm wondering how the first bearing was even put in!?

Thanks for your replies and suggestions.   

Anyway, I received a reply from Kuanho Li, but I'm afraid he misunderstood the issue. It seems that he thinks I was referring to the front bearing, so told me to use the washer and screw to force it in.  Even if it was the front bearing, the fit is SO tight, I am doubtful as to whether that would work.  I'm wondering if the heating cooling cycle perhaps tightened the metal holder. Maybe heating it before, then pushing it in would work. (no getting it out again though) Then again, steam wouldn't get it out. 
So I emailed Kuanho again, with some photos and explained again.  I also asked about Edtbjon's suggestion to use a dremel and sanding attachment. My only concern with that is, I'd have to use the exact right size attachment so as not to misshape the hole. I don't know if that would be an issue? I'm considering just taking it to a machine shop, but I will wait for Mr Li's reply.
 I'll update you guys if you would like

[Brent]

A friend suggested heating the back plate in the oven (or the bearing holder with a torch) and seeing if that expands the holder enough to press the bearing in.

[edtbjon]

Without having the roaster in front of me, I think the bearing holders are the same for the back and the front. I.e simply a piece of machined steel spot welded in place. If you cannot get the bearing in place with steam, you can try an oven at full blast for 30 min. But you do have to do that whenever you want to take out the bearing again too. An household oven at full blast is about the same as the Huky at drop temp, so that is OK.
Now, did you send Mr Li that last picture? It explains a lot, even through the language barrier.

[Brent]

Yes, I did send Mr Li that photo.   

As this might help other Huky users in the future, I'm going to assume Mr Li won't mind me referring to our conversation and how he told me to fix the bearing issue. I smiled when I saw the simple fix he had for this problem.  I suppose when one crafts roasters by hand as he does, you have to have some ingenuity when it comes to finding ways to deal with certain issues.

This fix did indeed work. I think having even pressure on the bearing is what helped a lot. I was able to turn the bolt by hand. Also, after lubing the outside of the bearing a bit, I'm glad to report with a little pressure (and the syringe cap that is on the supplied bearing grease syringe which seems to work just as well as a drill bit for pulling the bearing out, rather than pushing from behind as with the bit) the bearing slipped out again fairly easily too. Why it was so stuck before and impossible to get out without breaking it,  is beyond me. Overheated bearing grease that became extremely sticky perhaps?

Rather than explaining it in my often very verbose fashion,  a pic is worth a thousand words. If you don't have 6mm bolts and corresponding washers , I think 1/4" are close.

[Mayowarlord]

This is a classic Bike mechanic trick too!

[Chert]

Nice type of press.  I will try to remember that trick.

Is there a related and equally elegant solution to remove a bearing and housing?

[Brent]

Not that I know of Chert.  I mentioned the cap for the syringe that comes with the bearing grease. It's fits just right to go through the hole and pull on the bearing.

 I don't know that the issue I had is very common. As far as removing the bearings for cleaning and repacking, I don't think that has to be done very often either, as long as they're lubed regularly. I'm not sure of the actual time line though. Once a year? Anyone have suggestions on that? I lube mine about every 20 roasts. Perhaps it's good to have an extra set of bearings if one does decide to pull the old ones....just in case.

 Since they are ceramic, I'm sure they last a good long time. Many years I'd guess as long as they are maintained 

[edtbjon]

Well 1/4" is about 1/64" larger than 6mm, i.e the thickness of a hair or two...
Even though I wrote a document on how to tear the Huky apart and back I don't do it very often, maybe every 100 or so roasts (or even less). Giving the bearings an outside wipe for that black grime and regreasing them now and then should be enough.
I will rip the front off in a week or two though, once I recieve my new BT thermocouple(s ... one to spare ) which are 17mm (3/4") long instead of the 70mm (2 3/4") which is standard. A great little tip from user "beananimal" who provided these great videos with the transparent front plate, for us to see how the beans actually behave behind the front plate.