I need some outside-the-box ideas for platen wheels

Those are presses for installing bearings. They won't help remove a bearing. And more so, if there is a spacer between the bearings, you won't be able to pop them out with an expanding punch like you linked. (Also, bicycle bottom bracket bearings are going to be 22, 24, 29, or 30mm ID, so tools designed for them won't be much use on a 12.7mm ID bearing.)
 
Wyo Coyote said:
Outside of the box thought. Bicycles have press fit bearing in their bottom brackets, headsets and wheels. There are bicycle tools for removing and replacing them.
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I appreciate it, but the goal is a 5-minute change-out. I'm grinding knives at 10am that need to be at the post office at 4:15. When a wheel starts dragging I want to be able to change out the bearing and carry on with minimal interruption.
 
DevinT said:
What is your platen made out of, just curious because you grind more knives than anyone I know. Hoss
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Just a bar of D2 with a low temper. I have a jet of water spraying the inside of the belt at the top of the platen, the idea being that it blasts away some of the grit that would otherwise wear the platen. Plus the water runs down the backside of the platen and cools it. The downside of water on the inside of the belt is finicky tracking.

The quantity of knives I grind might be really high, but it's not a fair comparison because (a) my grind angles are super steep, (b) I stop at 120 grit, and (c) abrasion resistance of my steels is relatively low due to sub-60 hardness and mundane composition. A more meaningful metric would be the pounds of steel that I'm turning into dust per year, but even that doesn't reflect the advantages I enjoy from points (b) and (c). By that metric my operation is not extraordinary.
 
P.Brewster said:
Just a bar of D2 with a low temper. I have a jet of water spraying the inside of the belt at the top of the platen, the idea being that it blasts away some of the grit that would otherwise wear the platen. Plus the water runs down the backside of the platen and cools it. The downside of water on the inside of the belt is finicky tracking.

The quantity of knives I grind might be really high, but it's not a fair comparison because (a) my grind angles are super steep, (b) I stop at 120 grit, and (c) abrasion resistance of my steels is relatively low due to sub-60 hardness and mundane composition. A more meaningful metric would be the pounds of steel that I'm turning into dust per year, but even that doesn't reflect the advantages I enjoy from points (b) and (c). By that metric my operation is not extraordinary.
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Thanks, still impressive.

Hoss
 
P.Brewster said:
I appreciate it, but the goal is a 5-minute change-out. I'm grinding knives at 10am that need to be at the post office at 4:15. When a wheel starts dragging I want to be able to change out the bearing and carry on with minimal interruption.
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I can change motorcycle wheel bearings in about 15 min. You need a punch or flathead screwdriver, a vice or steel plate with an opening slightly bigger than the OD of the bearing. Push the internal collar to the side, catch the punch on the bearing and hammer it out. One or two taps is all it takes, flip it over, one tap, and the other one is out. Use a socket the same diameter as the OD of the new bearing, make sure you tap it flat, and it just pops in with a few taps. Flip the wheel over, put the collar back in, and tap the next bearing in. Done.

To make it easier for the next change, a skin of grease on the bearing pocket prevents falling, and corrosion that can seize the bearing in place.

When I raced motorcycle or bicycles, I had a second set of wheels ready to go, then changed the spare wheel bearings before the next ride. That is probably your best solution.

Just note, that this method will ruin a good bearing if you remove it this way, but since the bearings are bad anyway, no big deal.

if you need to do this frequently, make a jig to hold the wheel, and have a hole lined up to press the bearing out through.
 
Willie71 said:
I can change motorcycle wheel bearings in about 15 min.
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I do appreciate the help but when I say 5 minutes, I mean 5 minutes. I'm in a booth with a water spray, I'm wearing a rainsuit with a rubber apron and rubber boots, water is running down my arms, and I've got a forced air helmet on. Once I'm suited up, I want to be able to keep on trucking. So my first choice is a bearing change-out method that I can perform while geared up and requires one wrench that I keep near the grinder.

Like you mentioned, another way to handle it is to have a set of wheels that I maintain on off-days and keep ready. In that case I might have the patience to do what you describe. I have a box of burned-out wheels that I'm playing with now, and I definitely cannot tap out the bearing - probably because my water spray is totally seizing the steel-on-aluminum construction of these wheels.
 
P.Brewster said:
I do appreciate the help but when I say 5 minutes, I mean 5 minutes. I'm in a booth with a water spray, I'm wearing a rainsuit with a rubber apron and rubber boots, water is running down my arms, and I've got a forced air helmet on. Once I'm suited up, I want to be able to keep on trucking. So my first choice is a bearing change-out method that I can perform while geared up and requires one wrench that I keep near the grinder.

Like you mentioned, another way to handle it is to have a set of wheels that I maintain on off-days and keep ready. In that case I might have the patience to do what you describe. I have a box of burned-out wheels that I'm playing with now, and I definitely cannot tap out the bearing - probably because my water spray is totally seizing the steel-on-aluminum construction of these wheels.
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i have found grease good enough for what I do, but I know there is loctite made specifically for this in extreme environments. I find if you wait too long, it’s the heat that causes more problems than corrosion. As soon as you feel drag, change them out.

if you want to pay shipping, send them to me and I’ll see if I can salvage your old wheels. I’ve saved quite a few $500 motorcycle hubs over the years.
 
Water lubricated bearings and have a stream plumbed into the hub? Maybe too many rpms, can’t remember how small they go, we used to use large ones n material feed pumps in the dark ages
 
Have you considered a Synthetic Soluable Grinder Fluid in place of just plain water? It would require a catch tank with filter and pump but this could be an alternative. We use it in all the CNC machines as well as flood cooling on Mills & Lathes.
 
P.Brewster said:
I appreciate it, but the goal is a 5-minute change-out. I'm grinding knives at 10am that need to be at the post office at 4:15. When a wheel starts dragging I want to be able to change out the bearing and carry on with minimal interruption.
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3 minute ....................

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And you can tight bolt as much you want ...............
P.Brewster said:
Right, I've considered that, which is the primary reason why I want to go to a post mount (e.g. shoulder bolt or something similar). On the other hand, I'm aware of this issue and I've been very careful to only go finger tight + 1/10 wrench turn - the bare minimum to keep them locked in place. Moreover, the KMG wheels have the interior spacer which is supposed to remedy this problem. The wheels are definitely free-spinning when I install them. I do appreciate the help.
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Willie71 said:
if you want to pay shipping, send them to me and I’ll see if I can salvage your old wheels. I’ve saved quite a few $500 motorcycle hubs over the years.
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I appreciate it but the wheels that I've removed from service are worn on the OD and won't track the belt properly (this was explained in my original post). So restoring them would require truing up the OD and replacing the bearings. Thanks.

john april said:
were the bearings you have been using sealed/waterproof? maybe they rusted inside and greatly shortened their life.
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Asked and answered previously - they are just stock bearings in stock wheels that are seen on popular grinders. They are shielded. Yes, rusting inside the bearing is what's happening. Thanks.

Busto said:
Have you considered a Synthetic Soluable Grinder Fluid in place of just plain water? It would require a catch tank with filter and pump but this could be an alternative. We use it in all the CNC machines as well as flood cooling on Mills & Lathes.
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Yes, considered and dismissed due to health concerns because this liquid is all over my arms and hands for many hours every week. I'm using a borax/water solution, which is adding a tremendous amount of corrosion resistance, but not as good as a grinding/cutting solution. Thanks.

Natlek said:
3 minute ..........
And you can tight bolt as much you want ...............
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Yeah that's what I'm doing now. The goal is to change the BEARINGS in 5 minutes, not the entire wheel.
 
P.Brewster said:
I appreciate it but the wheels that I've removed from service are worn on the OD and won't track the belt properly (this was explained in my original post). So restoring them would require truing up the OD and replacing the bearings. Thanks.



Asked and answered previously - they are just stock bearings in stock wheels that are seen on popular grinders. They are shielded. Yes, rusting inside the bearing is what's happening. Thanks.



Yes, considered and dismissed due to health concerns because this liquid is all over my arms and hands for many hours every week. I'm using a borax/water solution, which is adding a tremendous amount of corrosion resistance, but not as good as a grinding/cutting solution. Thanks.



Yeah that's what I'm doing now. The goal is to change the BEARINGS in 5 minutes, not the entire wheel.
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I have a lathe, so I could true them too. If you aren’t planning on using them, would you consider selling them to me? You can email me at wjkrywko at gmail dot com.
 
P.Brewster said:
Yeah that's what I'm doing now. The goal is to change the BEARINGS in 5 minutes, not the entire wheel.
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Well , 3 minutes to change the bearing is exactly what i mean . It take me under three minute to disassemble and assemble one wheel . It is new one never used ........Some time ago I finished grinder for wet grinding .But this coronavirus thing stopped me to order belt .I will use CBN belt which cost a lot of money so I do not like the idea to get it through the mail from Germany to Macedonia in this moment . Since i expect the same problem as you have , all three wheels /two idler and tracking one/ are made that way that i can press bearing inside with my thumbs , same for inner tube . For now I have SKF bearings with rubber seal ,lubricated with water resistant grease /yamaha lube , blue one/which I use for lubricating bearings on boat trailer ... And if they don t last as I except , wheels are made with tolerance for easy change bearings...I try one wheel /dry, no water / on other grinder and i can t see any problem ...
 
The most time efficient solution is to have two tool arms set up, ready to go. Just swap out as needed. That doesn’t solve the tracking wheel, but a quick change setup there would be possible too.
 
Natlek said:
I can press bearing inside with my thumbs
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Yes, this is what I describe in the second bullet point of my original post - a wheel with a bearing pocket that is sized for a slip-fit rather than a press-fit. Such a wheel is not available as a stock product in the US (except maybe OBM); I'm having some custom made now.
 
P.Brewster said:
Yes, this is what I describe in the second bullet point of my original post - a wheel with a bearing pocket that is sized for a slip-fit rather than a press-fit. Such a wheel is not available as a stock product in the US (except maybe OBM); I'm having some custom made now.
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slip-fit ...i read it but it is not clear to me exactly what you meant, now I know :)
Is there any difference in damage between outer bearing and inner bearing on one wheel ? If outer bearing take much more damage.............you can make cover from that side which will cover bearing and bolt ....?
 
A slip fitted bearing will just destroy the wheel when the bearing locks up.
You need to change something else with your setup. Why aren't your motor bearings constantly blowing out? Why is the tracking wheel holding up but the platen wheels lock up in a month?
If you're running high sfpm(above 6000) you should consider building a custom d-plate and/or platen to accept 4" wheels.
 
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