What causes idler pulley wear?

S

skillgannon

Joined
Apr 27, 2009
Messages
991
I just noticed that my idler pulley was all dished out. It's the second time it happened. I have a mild steel platen and while its wearing it isn't fast and doesn't affect my grinder as much as the pulley. Seams like a wierd place to wear
 
The only thing I can think of is drag from bad bearings.

~Chip
 
A photo from the front and side as well as a close-up of the wer would help a lot.
 
Stacy E. Apelt - Bladesmith said:
A photo from the front and side as well as a close-up of the wer would help a lot.
Click to expand...
OGpnUtf.jpg

This is a pic of the last one. I can get a pic of this one later. It looks the same other than maybe reversed.
 
Thats alot !
Is that aluminum pulley ? Is it running true & square to the belt..?
 
Either the bearring is shot on one side, or the belt is so crazy tight and is cupping. Too much tension can also greatly shorten berring life.
 
Look at your bearings and be sure they have not shifted.

I had a contact wheel from BM and they mill the bearing pocket to deep on one side. This cause the wheel to slide to one side and wore it out.

Check your bearings.
 
Lieblad said:
Thats alot !
Is that aluminum pulley ? Is it running true & square to the belt..?
Click to expand...

I don t think so . .. I think that belt don t sit/lying on wheel properly ,does not press parallel on wheel with the whole width .Probably belt run something like this ........
ntwjmDv.png
 
Last edited:
AVigil said:
Look at your bearings and be sure they have not shifted.

I had a contact wheel from BM and they mill the bearing pocket to deep on one side. This cause the wheel to slide to one side and wore it out.

Check your bearings.
Click to expand...
I do not understand how this can happen ? On one side always bearing pocket MUST be deeper then bearing width ??

RZwZAvK.png
 
Last edited:
cjVNoKD.jpg

Here is the one that's on there now. It's not as bad but it definitely has damage. It used to have a pretty good crown. You can see a difference in how its wearing too. I replaced it in April and I haven't made that many knives this summer
 
Natlek said:
I do not understand how this can happen ? On one side always bearing pocket MUST be deeper then bearing width ??

RZwZAvK.png
Click to expand...
In your picture the entire wheel can drift to the right
 
Lieblad said:
Thats alot !
Is that aluminum pulley ? Is it running true & square to the belt..?
Click to expand...
It is a aluminum pulley. I think he said 6061.its a esteem grinder and I don't really know how I could do anything to square it.
The bearing seem to be fine and were last year as well.
 
Are those wheels free running at all temperatures ?

Perhaps the belt runs/rubs on the wheel and the backing is abrasive.
 
AVigil said:
In your picture the entire wheel can drift to the right
Click to expand...
Yes ...... :) My wheel are all made that way ...and they still are stay on place , they run 13 000 rpm. Look , we are talking about 0.5 - 1 mm longer spacer .If tolerance is right , both bearing are pressed with force and that is more then enough to hold them in place . Other way would be very , very difficult to make all dimension precise to 1/100 of mm . Inner ring of both bearing pressed tight to spacer and then outer ring must gently touching house .......because tension between inner and outer ring on bearing is disaster .... difficult task . Other way is to use snap ring ;)
What I was trying to say with drawing is this ... maybe belt have more pressure on wheel where is arrow on picture ....
FlaK8jR.jpg

because of this ................blue is right way , of course
UBc8NM7.jpg


Or simple two crowned wheel are fighting between themselves .One want to track that way , other wheel says , no that way ...go this way :D
I should avoid thread like this because is difficult to me to find right words to explain what I mean :oops:
 
Last edited:
skillgannon said:
I just noticed that my idler pulley was all dished out. It's the second time it happened. I have a mild steel platen and while its wearing it isn't fast and doesn't affect my grinder as much as the pulley. Seams like a wierd place to wear
Click to expand...
I wonder where all that dust/sandpaper from that soft mild steel plate go ? Try ceramic glass . .. . or tile
 
N Natlek in my case my wheel did drift to one side and wore out the contact wheel down into a cone. That is why I replaced it and the one I have now is from Ameribrade it is is far higher quality then BM metals
 
How easily are your idlers turning without a belt in place? They should turn freely. Do you know if the wheels have a spacer/bushing between the bearings? Are you using machine bushings between your bolt/axle and the outside of the bearing races? Looks like you're binding your bearings and getting too much drag.

I buy my idlers from vwjackstraw on ebay and use machine bushings on the outsides. His wheels come with internal spacers that bear against the inner race of the bearing, and with the machine bushings, any nut or bolt tension will bear against the inner race as well. This means I can essentially tighten my wheels to my platen until the bolt strips out, and my wheel bearings will still turn freely.
 
I know exactly what causes the dishing. The tracking wheel being crowned puts extra pressure in the center of the platen's top wheel. The dishing also shows up on contact wheels, and rather quickly.
Are your wheels 60 series aluminium? In Europe many grinders come with steel wheels.
An anodized wheel set will slow down the wear, but it will still happen.
This is one reason to only have SLIGHT crowning on your tracking wheel. Also a non-crowned drive wheel is better if your grinder design allows for it.
 
Yes they 60 series aluminum. It's a esteem with stock parts. I talked to Brett and he doesn't know what's up either. He said he has only had one other cliant have wear issues and ge is a full time maker with a lot more hours in the grinder. Its just a stock spring I don't think tension is to high. I assume its something that I am doing. I have heard grinding dust could be a issue but I think I would see more wear on the plantennif dust or wet grinding was doing it.
knife to a gunfight said:
How easily are your idlers turning without a belt in place? They should turn freely. Do you know if the wheels have a spacer/bushing between the bearings? Are you using machine bushings between your bolt/axle and the outside of the bearing races? Looks like you're binding your bearings and getting too much drag.

I buy my idlers from vwjackstraw on ebay and use machine bushings on the outsides. His wheels come with internal spacers that bear against the inner race of the bearing, and with the machine bushings, any nut or bolt tension will bear against the inner race as well. This means I can essentially tighten my wheels to my platen until the bolt strips out, and my wheel bearings will still turn freely.
Click to expand...
How would I check and why would my grinder be the only one with this problem?
 
Take off the belt and spin the idler by hand. If it spins like a skateboard wheel, then the bearings are OK. If it doesn't ... then one or both bearings are bad. Check the tracking wheel bearings and the lower idler, too.

If the bearings are OK, put the belt back on and check that the tracking wheel isn't over domed. It doesn't take much dome to track the belt, but if over domed, the center will try to cup after the belt leaved the tyracking wheel. You should look at the belt as it goes between the tracking and idler wheels. Is it dead flat or cupped slightly?

No matter what the issue is, once you find it you need a new wheel and probably bearings.
 
You must log in or register to reply here.
Back
Top